Inclusion Criteria for HD Participants:
• Estimated at low or high probability of motor diagnosis based on the multivariate risk score (MRS)
• Willing to commit to two in-person assessment visits (baseline and 2-year follow-up) and remote assessments as needed
• No active comorbidities (i.e. receiving stable treatment)
• All medications will be allowed although the protocol will mandate documentation of medications and analyses will particularly assess potential impact of medications on outcomes (i.e., sedation of abnormal movements)
• If previously measured, CAG results must be 36 or above (previous CAG is not a requirement, but this threshold will be upheld for those participants who have their CAG scores and/or have them in their medical record). Inclusion Criteria for Healthy Controls (HC):
• Willing to commit to two in-person assessment visits (baseline and 2-year follow-up) and remote assessments as needed
• In generally good health
• IQ > 70
• Able to undergo an MRI scan Exclusion Criteria (for all Participants):
• Evidence of unstable medical or psychiatric illness (including substance abuse)
• History of severe learning disability, mental retardation, or other central nervous system (CNS) disease or event (e.g., seizures, head trauma, additional neurological diagnoses)
• Treatment with phenothiazine-derivative antiemetic medications such as prochlorperazine, metoclopramide, promethazine and Inapsine greater than 3 times per month
• History of serious alcohol or drug abuse within the past year
• Unable (determined by patient's prescribing doctor) to not take tryptophan, leucine, niacin or niacinamide-containing dietary supplements, anti-inflammatory medications, anti-coagulants (such as warfarin and heparin) or anti-platelets (such as aspirin) in the past 14 days to assure safety during lumbar puncture
• Unable to fast (no food or drink, only water) overnight before the lumbar puncture

• Feasibility phase: patients must be >= 2 years and =< 21 years of age at the time of enrollment
• Efficacy phase: patients must be >= 2 years and =< 25 years of age at the time of enrollment
• All patients > 21 years of age at the time of enrollment must have had initial diagnosis of low-grade glioma by 21 years of age
• Patients must have a body surface area (BSA) of >= 0.5 m^2 at enrollment
• Patients must have eligibility confirmed by rapid central pathology and central molecular screening reviews performed on APEC14B1
• Non-neurofibromatosis type 1 (non-NF1), non-tuberous sclerosis complex (non-TSC) low-grade glioma (LGG) without a BRAFV600E or IDH1 mutation
• Patients must have progressive or recurrent LGG. Note: Biopsy may be at either initial diagnosis or recurrence
• Patients must have measurable disease, defined as having a two-dimensional measurable tumor volume of >= 1 cm^2
• Tumor size will be measured to include both solid and cystic components of the tumor (whether or not tumor is enhancing) + fluid attenuated inversion recovery (FLAIR) signal
• Eligible histologies will include all tumors considered low-grade glioma or low-grade astrocytoma (World Health Organization [WHO] grade 1 and II) by the WHO Classification of Tumors of the Central Nervous System
•4th Edition Revised, with the exception of subependymal giant cell astrocytoma
• Patients with metastatic disease or multiple independent primary LGGs are eligible
• Patients must be progressive or recurrent after having been treated with at least one prior tumor-directed therapy before enrollment
• Patients must have fully recovered from the acute toxic effects of all prior chemotherapy, immunotherapy, or radiotherapy prior to entering this study
• Myelosuppressive chemotherapy: Must not have received within 2 weeks of entry onto this study (4 weeks if prior nitrosourea);
• Biologic (anti-neoplastic agent): At least 7 days since the completion of therapy with a biologic agent;
• Radiation therapy (RT): >= 2 weeks (wks) for local palliative RT (small port); >= 6 months must have elapsed if prior craniospinal RT or if >= 50% radiation of pelvis; >= 6 wks must have elapsed if other substantial bone marrow (BM) radiation;
• Antibodies: >= 21 days must have elapsed from infusion of last dose of antibody, and toxicity related to prior antibody therapy must be recovered to =< grade 1;
• MEK inhibitor or vinblastine: Must not have received treatment with a MEK inhibitor or vinblastine within 6 months of study enrollment
• Creatinine clearance or radioisotope glomerular filtration rate (GFR) >= 70 mL/min/1.73 m^ 2 or a serum creatinine based on age/gender as follows (within 7 days prior to enrollment):
• 2 to < 6 years: 0.8 mg/dL (male) 0.8 mg/dL (female)
• 6 to < 10 years: 1 mg/dL (male) 1 mg/dL (female)
• 10 to < 13 years: 1.2 mg/dL (male) 1.2 mg/dL (female)
• 13 to < 16 years: 1.5 mg/dL (male) 1.4 mg/dL (female)
• >= 16 years: 1.7 mg/dL (male) 1.4 mg/dL (female)
• Total bilirubin =< 1.5 x upper limit of normal (ULN) for age (within 7 days prior to enrollment) (children with a diagnosis of Gilbert's syndrome will be allowed on study regardless of their total and indirect [unconjugated] bilirubin levels as long as their direct [conjugated] bilirubin is < 3.1 mg/dL)
• Serum glutamic pyruvic transaminase (SGPT) (alanine aminotransferase [ALT]) =< 135 U/L (within 7 days prior to enrollment)
• Note: For the purpose of this study, the ULN for SGPT (ALT) has been set to the value of 45 U/L
• Albumin >= 2 g/L (within 7 days prior to enrollment)
• Left ventricular ejection fraction (LVEF) >= 53% (or institutional normal; if the LVEF result is given as a range of values, then the upper value of the range will be used) by echocardiogram (within 4 weeks prior to enrollment)
• Corrected QT interval (QTc interval) =< 450 msec by electrocardiogram (EKG) (within 4 weeks prior to enrollment)
• Absolute neutrophil count >= 1,000/uL (unsupported) (within 7 days prior to enrollment)
• Platelets >= 100,000/uL (unsupported) (within 7 days prior to enrollment)
• Hemoglobin >= 8 g/dL (may be supported) (within 7 days prior to enrollment)
• Patients with a known seizure disorder should be stable and should not have experienced a significant increase in seizure frequency within 2 weeks prior to enrollment
• Stable neurological examination for >= 1 week
• HYPERTENSION:
• Patients 2-17 years of age must have a blood pressure that is =< 95th percentile for age, height, and gender at the time of enrollment (with or without the use of anti-hypertensive medications);
• Patients >= 18 years of age must have a blood pressure =< 130/80 mmHg at the time of enrollment (with or without the use of anti-hypertensive medications)
• Note for patients of all ages: Adequate blood pressure can be achieved using medication for the treatment of hypertension
• All patients must have ophthalmology toxicity assessments performed within 4 weeks prior to enrollment
• For all patients, an MRI of the brain (with orbital cuts for optic pathway tumors) and/or spine (depending on the site[s] of primary disease) with and without contrast must be performed within 4 weeks prior to enrollment
• Note: If surgical resection or biopsy is performed at the time of progression or recurrence, a post-operative MRI is required
• Patients must have a performance status corresponding to Eastern Cooperative Oncology Group (ECOG) scores of 0, 1, or 2. Use Karnofsky for patients > 16 years of age and Lansky for patients =< 16 years of age
• Patients must have the ability to swallow whole capsules
• Prior therapy with vinblastine and/or a MEK inhibitor is permitted, with the following exceptions:
• Patients must not have had progressive disease while on therapy with vinblastine or a MEK inhibitor;
• Patients must not have discontinued vinblastine or selumetinib due to toxicity
• Patients with a concurrent malignancy or history of treatment (other than surgery) for another tumor within the last year are ineligible
• Patients with diffuse intrinsic pontine tumors as seen on MRI (> 2/3 of pons involvement on imaging) are not eligible even if biopsy reveals grade I/II histology
• Patients may not be receiving any other investigational agents
• Patients must not have known hypersensitivity to selumetinib, vinblastine, or similar compounds
• CYP3A4 agents: Patients must not have received fluconazole or drugs that are strong inducers or inhibitors of CYP3A4 within 7 days prior to study enrollment
• Patients with any serious medical or psychiatric illness/condition, including substance use disorders or ophthalmological conditions, likely in the judgment of the investigator to interfere or limit compliance with study requirements/treatment
• Patients who, in the opinion of the investigator, are not able to comply with the study procedures are not eligible
• PRE-EXISTING CONDITIONS (CARDIAC):
• Known genetic disorder that increases risk for coronary artery disease. Note: The presence of dyslipidemia in a family with a history of myocardial infarction is not in itself an exclusion unless there is a known genetic disorder documented;
• Symptomatic heart failure
• New York Heart Association (NYHA) class II-IV prior or current cardiomyopathy
• Severe valvular heart disease
• History of atrial fibrillation
• PRE-EXISTING CONDITIONS (OPHTHALMOLOGIC CONDITIONS):
• Current or past history of central serous retinopathy
• Current or past history of retinal vein occlusion or retinal detachment
• Patients with uncontrolled glaucoma
• If checking pressure is clinically indicated, patients with intraocular pressure (IOP) > 22 mmHg or upper limit of normal (ULN) adjusted by age are not eligible
• Any multivitamin containing vitamin E must be stopped prior to study enrollment even if it contains less than 100% of the daily recommended dosing for vitamin E
• Surgery within 2 weeks prior to enrollment, with the exception of a surgical biopsy, placement of a vascular access device or cerebrospinal fluid (CSF) diverting procedure such as endoscopic third ventriculostomy (ETV) and ventriculoperitoneal (VP) shunt
• Note: Patients must have healed from any prior surgery
• Patients who have an uncontrolled infection are not eligible
• Female patients who are pregnant are not eligible since fetal toxicities and teratogenic effects have been noted for several of the study drugs. A pregnancy test is required for female patients of childbearing potential
• Lactating females who plan to breastfeed their infants
• Sexually active patients of reproductive potential who have not agreed to use an effective contraceptive method for the duration of their study participation and for 12 weeks after stopping study therapy are not eligible
• Note: Women of child-bearing potential and males with sexual partners who are pregnant or who could become pregnant (i.e., women of child-bearing potential) should use effective methods of contraception for the duration of the study and for 12 weeks after stopping study therapy to avoid pregnancy and/or potential adverse effects on the developing embryo
• All patients and/or their parents or legal guardians must sign a written informed consent
• All institutional, Food and Drug Administration (FDA), and National Cancer Institute (NCI) requirements for human studies must be met

• Subjects with advanced or metastatic solid tumor in subjects whose disease has progressed despite standard therapy, or who has no further standard therapy, or who is unsuitable for available standard treatment options.
• Eastern Cooperative Oncology Group (ECOG) performance status 0 or 1 with adequate organ function
• Have known PD-L1 status with prior testing by immunohistochemistry and a corresponding combined positive score (CPS) For dose expansion study only:
• Advanced or metastatic gastric cancer, gastroesophageal junction carcinoma, and esophageal adenocarcinoma without further standard therapy or unsuitable for available standard treatment options.
• Must have CLDN18.2-positive tumor expression as determined by the CLDN18.2 IHC assay Exclusion Criteria
• Prior exposure to CLDN18.2 -targeted therapy
• Prior exposure to 4-1BB agonists
• Second malignancy within the last 3 years with the exception of cutaneous squamous cell carcinoma or cutaneous basal cell carcinoma or cervical carcinoma in situ
• Known active or chronic Hepatitis B or Hepatitis C, other hepatitides
• Unstable/active ulcer or digestive tract bleeding within 6 weeks
• Active autoimmune disease requiring systemic treatment within the past 2 years
• Active interstitial lung disease (ILD) or pneumonitis or a history of ILD or pneumonitis requiring treatment
• Known active CNS metastases and/or carcinomatous meningitis. Subjects with previously treated brain metastases may participate provided they are clinically stable and without requirement of steroid treatment for at least 14 days prior to first dose of study treatment;
• New York Heart Association (NYHA) Class 3 or 4 congestive heart failure, severe/unstable angina, myocardial infarction (MI), symptomatic congestive heart failure, cerebrovascular accident, transient ischemic attack (TIA), arterial embolism, pulmonary embolism, percutaneous transluminal coronary angioplasty (PTCA), deep vein thrombosis, or coronary artery bypass grafting (CABG) in the previous 6 months
• Diagnosis of immunodeficiency such as known active HIV
• Any active infection requiring parenteral treatment

• Patients have measurable disease per Response Evaluation Criteria in Solid Tumors version 1.1 (RECIST v1.1).
• Patients must have disease with evidence of KRAS G12C mutation in tumor tissue or circulating tumor deoxyribonucleic acid (DNA).
• Participants must have a histological or a cytologically proven diagnosis of locally advanced, unresectable, and/or metastatic cancer and meet cohort-specific criteria.
• Have an Eastern Cooperative Oncology Group (ECOG) Performance Status of 0 or 1.
• Have adequate organ function.
• Have discontinued all previous treatments for cancer with resolution of any significant ongoing adverse events (AEs), (except in certain scenarios).
• Must be able to swallow capsule/tablet.
• Agree and adhere to contraceptive use, if applicable.
• For some parts of the study, (i.e., one of the two arms with LY3537982 in combination with pembrolizumab and the arm of LY3537982 in combination with pembrolizumab, pemetrexed, and platinum therapy) histologically or cytologically confirmed Stage IIIB-IIIC or Stage IV NSCLC that is previously untreated in the advanced/metastatic setting and not suitable for curative intent radical surgery or radiation therapy. Previously untreated patients who received adjuvant and neoadjuvant therapy are eligible if the last dose of the systemic treatment was completed at least 6 months prior to enrollment. For untreated patients in the arm with LY3537982 in combination with pembrolizumab noted above, a single cycle of pembrolizumab may be initiated within 21 days prior to enrollment. For untreated patients in the arm of LY3537982 in combination with pembrolizumab, pemetrexed, and platinum therapy, a single cycle of any or all of the drugs other than LY3537982 may be initiated within 21 days prior to enrollment. Start of study treatment may be delayed to allow sufficient time for recovery from treatment-related toxicity.
• For one part of the study, participants must have received at least one prior oxaliplatin- or irinotecan-containing regimen for advanced or metastatic CRC.
• Disease suitable for local therapy administered with curative intent.
• Have an active, ongoing, or untreated infection.
• Have a serious pre-existing medical condition(s) that, in the judgment of the investigator, would preclude participation in this study.
• Have a serious cardiac condition.
• Have a second active primary malignancy or have been diagnosed and/or treated for an additional malignancy within 3 years prior to enrollment.
• Have symptomatic central nervous system (CNS) malignancy or metastasis and/or carcinomatous meningitis. Patients with treated CNS metastases are eligible for this study if their disease is asymptomatic, radiographically stable for at least 30 days, and they do not require treatment with steroids in the two-week period prior to study treatment. This only applies to some parts of the study.
• Have received prior treatment with any KRAS G12C small molecule inhibitor, except in certain scenarios where such prior therapy is allowed as per protocol.
• The following patients will be excluded from some parts of the study:
• Experienced certain serious side effects with prior immunotherapy.
• Have an active autoimmune disease that has required systemic anti-autoimmune treatment in the past 2 years.
• Have received a live vaccine within 30 days prior to the first dose of study drug.
• Pregnant, breastfeeding, or expecting to conceive or father children within the projected duration of the trial through 180 days after the last dose of study medication.
• Known allergic reaction against any of the components of the study treatments.

• Participant must be neurologically normal, defined as free of unstable neurologic and psychiatric disease as confirmed by a normal neurologic examination at screening
• Participant (GBCA-exposed or controls) agrees to undergo unenhanced magnetic resonance imaging (UE-MRI) of the brain at enrollment and at the end of the observation period (5 years)
• Participants should have at least 1 of the following indications: a) Medium to high risk for breast cancer or dense breasts undergoing breast cancer screening with MRI, b) Elevated prostate-specific antigen (PSA) and under active diagnostic surveillance for prostate cancer, c) Chronic liver disease (eg, liver cirrhosis limited to Child class A, post-hepatitis chronic hepatopathy, or primary sclerosing cholangitis) for surveillance of hepatocellular carcinoma development, d) Low-grade colorectal cancer or neuroendocrine tumor undergoing screening for liver metastases or e) Branch-duct intraductal papillary mucinous neoplasm (IPMN) of the pancreas (maximum size ≤2 cm) undergoing imaging surveillance. In addition, for participants in the GBCA Arms only:
• Each participant should be likely to undergo ≥5 GBCA-enhanced MR examinations with the same GBCA at least annually throughout the 5-year study duration
• Prospective participants with up to 3 well documented GBCA administrations prior to study screening are acceptable, provided that the imaging was performed with the same GBCA as the one to be prospectively used in the study. If the GBCA used cannot be identified, he/she cannot be enrolled. For the Control Arm:
• Participants who never had and are not likely to receive any GBCA injection during the course of the study
• Each control participant must be willing to undergo UE-MRI of the brain at baseline and at Year 5. In Years 1 to 4, the control participants will undergo their clinically indicated UE-MRIs, computed tomography (CT), ultrasound, or X-ray procedures
• As evidenced by history or determined in the neurologic exam at screening, concurrent neurological and/or psychiatric disease (or treatments) that could influence the results of the study's motor and cognitive tests (e.g. Cerebrovascular disease, Multiple sclerosis, Neurodegenerative disease, Malignant disease other than listed in indications, Carcinoid tumors, Epilepsy, Prior neurosurgery, Psychotic disorders or any prior psychotic episode not otherwise specified
•any documented prior history of chronic schizophrenia, Remittent or current medically confirmed major depressive disorder or bipolar disorder, History of long-term major depression or bipolar affective disorder with an active episode in the past 2 to 5 years, Neurodevelopmental disorders (eg, trisomy 21), Uncontrolled severe migraine, Uncontrolled or controlled anxiety or depression within 6 months before enrollment, Screening scores of ≤24 on the MMSE and/or ≥11 on the Hospital Anxiety and Depression Scale (HADS)).
• Prior, planned, or ongoing chemotherapy or brain irradiation
• Use of concomitant medication(s) affecting neuro-cognitive or motor function
• Substance or alcohol abuse as determined by the investigator
• Alcoholic cirrhosis
• Renal disease, defined as estimated glomerular filtration rate (eGFR) < 60 mL/min/1.73 m2
• History of environmental/occupational/other exposure to one or more chemicals that may affect cognitive and/or motor function, including, but not limited to, heavy metals (arsenic [As], cadmium [Cd], lead [Pb], manganese [Mn], and mercury [Hg]), pesticides, solvents, or carbon monoxide.
• Clinical indications requiring >1 contrast enhanced magnetic resonance imaging (CE-MRI) every 6 months
• Pregnant or nursing (lactating) women
• Presence of any metal-containing joint implants/prostheses In addition, for participants in either of the GBCA Arms only:
•Receipt of a GBCA or generic prior to study entry other than the specific GBCA to be administered during the course of the study. For participants in the Control Arm only:
• Participants with any previous exposure to a GBCA.
• Participants with any contraindication to UE-MRI examinations.

Key
• Disease:
• Part A: Individuals with histologically or cytologically confirmed advanced solid tumors who have received, been intolerant to, or been ineligible for all treatment known to confer clinical benefit.
• Part B: Individuals with histologically or cytologically confirmed select indications who have received, been intolerant to, or been ineligible for all treatment known to confer clinical benefit.
• Part C: Individuals with histologically or cytologically confirmed advanced solid tumors who have received, been intolerant to, or been ineligible for all treatments known to confer clinical benefit or whose disease is indicated for anti- programmed cell death protein 1 or programmed cell death ligand 1 (PD-[L]1) monoclonal antibody monotherapy.
• Part D: Individuals with pathologically confirmed select advanced solid tumors.
• Part E: Individuals with pathologically confirmed select advanced solid tumors. Participants must have received, have been intolerant to, or have been ineligible for all treatment known to confer clinical benefit.
• Part F: Individuals with pathologically-confirmed select advanced solid tumors. Participants must have received, have been intolerant to, or have been ineligible for all treatments known to confer clinical benefit; or, for participants who will undergo combination therapy, have disease which is indicated for anti-PD-(L)1 mAb monotherapy.
• Measurable disease per Response Evaluation Criteria in Solid Tumors (RECIST) v1.1
• Eastern Cooperative Oncology Group (ECOG) performance status 0, 1, or 2 for individuals in Parts A, B, and C, and 0 or 1 for individuals in Parts D, E, and F.
• Adequate organ function.
• Male individuals and female individuals of childbearing potential who engage in heterosexual intercourse must agree to use methods of contraception.
• Tissue requirement:
• Parts A, C, D, E and F: Must provide pre-treatment adequate tumor tissue sample prior to enrollment.
• Part B and select participants in Parts C and F: Must have fresh pre-treatment and on-treatment biopsies for biomarker analysis. Key
• Concurrent anticancer treatment.
• Any anti-cancer therapy, whether investigational or approved, within protocol specified time prior to initiation of study including: immunotherapy or biologic therapy (< 28 days), chemotherapy (< 21 days), targeted small molecule therapy (< 14 days), hormonal therapy or other adjunctive therapy (< 14 days) or radiotherapy (< 21 days).
• Any prior CCR8 directed therapy.
• Prior allogeneic tissue/solid organ transplantation, including allogeneic stem cell transplantation. Exception: prior corneal transplant without requirement for systemic immunosuppressive agents is allowed.
• Concurrent active malignancy other than nonmelanoma skin cancer, curatively resected carcinoma in situ, localized prostate cancer, or superficial bladder cancer after undergoing potentially curative therapy with no evidence of disease. Individuals with other previous malignancies are eligible if disease-free for > 2 years.
• History of intolerance, hypersensitivity, or treatment discontinuation due to severe immune-related adverse events (irAEs) on prior immunotherapy.
• History of autoimmune disease or active autoimmune disease requiring systemic treatment within 2 years.
• History of pneumonitis, interstitial lung disease, or severe radiation pneumonitis (excluding localized radiation pneumonitis).
• Active and clinically relevant bacterial, fungal, or viral infection that is not controlled or requires IV antibiotics.
• Active hepatitis B virus (HBV) and/or hepatitis C virus (HCV), and/or human immunodeficiency virus (HIV).
• Positive serum pregnancy test or breastfeeding female.
• Live vaccines within 30 days prior to first dose.
• Significant cardiovascular disease. Note: Other protocol defined Inclusion/Exclusion criteria may apply.

General (applies to all cohorts) 1. Signed written informed consent. 2. Male or female patients aged ≥ 18 years. 3. Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1 at study entry and an estimated life expectancy of at least 3 months. 4. Baseline Left Ventricular Ejection Fraction (LVEF) ≥ 55% measured by echocardiography (preferred) or multigated acquisition (MUGA) scan. 5. Adequate hematological function. 6. Adequate hepatic function. 7. Adequate renal function. 8. Effective contraception for women of child bearing potential (WOCBP) patients as defined by World Health Organization (WHO) guidelines for 1 "highly effective" method or 2 "effective" methods. NSCLC (HER2 Activated) Exploratory Efficacy Cohorts
•Monotherapy and Combination with Sacituzumab Govitecan-hziy. 1. Have progression of unresectable locally advanced or metastatic NSCLC after last systemic therapy (as confirmed by investigator) or be intolerant of last systemic therapy. 2. Have HER2 overexpression status (IHC 2+ or 3+), or ERBB2 amplification, or HER2 activating mutation 3. Have recurrent or progressive disease during or after platinum doublet-based chemotherapy. 4. Have received and progressed on or after anti-PD-(L)1 therapy. Metastatic Breast Cancer (HR+/HER2-) Exploratory Efficacy Cohort - Monotherapy and Combination with Sacituzumab Govitecan-hziy. 1. Documented evidence of HR+ metastatic breast cancer 2. Documented evidence of HER2- status. 3. Disease progression or recurrence after prior therapy. Metastatic Breast Cancer (HER2+) Exploratory Efficacy Cohorts - Combination with Sacituzumab Govitecan-hziy 1. Have histologically confirmed HER2+ breast cancer. 2. Have received prior treatment with trastuzumab, pertuzumab, ado-trastuzumab emtansine (T-DM1), or trastuzumab deruxtecan (T-DXd). 3. Have progression of unresectable locally advanced metastatic breast cancer after last systemic therapy or be intolerant of last systemic therapy. Dose Escalation 1. Evidence of objective disease, but participation does not require a measurable lesion. 2. Locally advanced or metastatic solid tumors, for which no standard therapy exists, or standard therapy has failed. 3. HER2 expression by immunohistochemistry and/or erbb2 amplification and/or erbb2 activating mutations. "3+3" Nivolumab Combination Cohort 1. Eligible to receive nivolumab per its label for a malignancy of epithelial origin; or 2. Have no standard therapy available, or standard therapy has failed, and must not have received nivolumab prior to joining the study. 3. HER2 expression by immunohistochemistry and/or ebb2 amplification and/or erbb2 activating mutations must be documented on either archival tissue or fresh tumor biopsy. "3+3" Nab paclitaxel Combination Cohort 1. Patients must be eligible for treatment with nab-paclitaxel per its label, or have no standard therapy available, or standard therapy has failed. 2. HER2 expression by immunohistochemistry and/or erbb2 amplification and/or erbb2 activating mutations must be documented on either archival tissue or fresh tumor biopsy. Safety/PK/PD Expansion Cohorts (Monotherapy and Combination Therapy). 1. Fresh tumor biopsy must be obtained during the screening window. 2. HER2 expression by immunohistochemistry (IHC). 3. Disease must be measurable with at least 1 unidimensional measurable lesion by RECIST 1.1. Urothelial Bladder Cancer Expansion Cohort(s). 1. Disease must be measurable with at least 1 unidimensional measurable lesion by RECIST 1.1. 2. Histologically or cytologically documented locally advanced or metastatic transitional cell carcinoma of the urothelium (including renal pelvis, ureters, urinary urothelial, urethra). 3. Patients must have received a platinum containing chemotherapy and an anti PD-1 or anti PD-L1 for the treatment of urothelial bladder cancer. Breast Cancer (HER2 Low) Expansion Cohort 1. Disease must be measurable with at least 1 unidimensional measurable lesion by RECIST 1.1 2. Histologically documented (metastatic or locally advanced) breast cancer. 3. Absence of erbb2 amplification by ISH and/or HER2 IHC of 0, 1+, or 2+. 4. Patient must have progressed after one line of systemic chemotherapy. Breast Cancer (HER2 High) Expansion Cohort 1. Disease must be measurable with at least 1 unidimensional measurable lesion by RECIST 1.1 2. Histologically documented (metastatic or locally advanced) breast cancer. 3. Erbb2 amplification by ISH and/or HER2 IHC of 3+, or 2+. If Herceptest score is 2+, ISH results should demonstrate erbb2 amplification. Basket erbb2 amplified Expansion Cohort 1. Disease must be measurable with at least 1 unidimensional measurable lesion by RECIST 1.1. 2. Documented history of erbb2 amplification. 3. Patients must have received at least one line of an approved or established therapy. Gastric Cancer (HER2 High) Expansion Cohort 1. Disease must be measurable with at least 1 unidimensional measurable lesion by RECIST 1.1. 2. Advanced (unresectable/recurrent/metastatic) gastric cancer or cancer of the gastro-esophageal junction. 3. Tumor must have been declared HER2 positive. Gastric Cancer (HER2 Low) Expansion Cohort 1. Disease must be measurable with at least 1 unidimensional measurable lesion by RECIST 1.1. 2. Advanced (unresectable/recurrent/metastatic) gastric cancer or cancer of the gastro-esophageal junction. 3. Tumor must have been declared HER2 low; ISH non-amplified and/or HER2 IHC of 0, 1+ or 2+. If Herceptest score is 0, HER2 must be detected by IHC on at least 1+ of the tumor cells. Esophageal Cancer (HER2 High) Expansion Cohort 1. Disease must be measurable with at least 1 unidimensional measurable lesion by RECIST 1.1. 2. Advanced (unresectable/recurrent/metastatic) esophageal cancer. 3. Tumor must have been declared HER2 positive. Esophageal Cancer (HER2 Low) Expansion Cohort 1. Disease must be measurable with at least 1 unidimensional measurable lesion by RECIST 1.1. 2. Advanced (unresectable/recurrent/metastatic) esophageal cancer. 3. Tumor must have been declared HER2 low; ISH non-amplified and/or HER2 IHC of 0, 1+ or 2+. If Herceptest score is 0, HER2 must be detected by IHC on at least 1+ of the tumor cells. Non-small Cell Lung Cancer (HER2 Low) Expansion Cohort 1. Disease must be measurable with at least 1 unidimensional measurable lesion by RECIST 1.1. 2. Histologically confirmed NSCLC meeting stage criteria for stage IIIB, stage IV, or recurrent disease that has been confirmed to have HER2 expression (at least 1+, however, patients must not carry an erbb2 amplification) via archival or fresh biopsy tissue prior to study enrollment. 3. Patients must have recurrent or progressive disease during or after platinum doublet-based chemotherapy. Non-small Cell Lung Cancer (HER2 High) Expansion Cohort 1. Disease must be measurable with at least 1 unidimensional measurable lesion by RECIST 1.1. 2. Histologically confirmed NSCLC meeting stage criteria for stage IIIB, stage IV, or recurrent disease that has been confirmed to have amplification of erbb2 via archival or fresh biopsy tissue prior to study enrollment. 3. Patients must have recurrent or progressive disease during or after platinum doublet-based chemotherapy. 1. Concurrent anticancer treatment (eg, cytoreductive therapy, radiotherapy [with the exception of palliative bone directed radiotherapy], immune therapy, or cytokine therapy except for erythropoietin), major surgery (excluding prior diagnostic biopsy), concurrent systemic therapy with steroids or other immunosuppressive agents, or use of any investigational drug within 28 days or 5 half-lives before the start of study treatment. Note: Patients receiving bisphosphonates are eligible provided treatment was initiated at least 14 days before the first dose of DF1001. 2. Previous malignant disease other than the target malignancy to be investigated in this study within the last 3 years, with the exception of basal or squamous cell carcinoma of the skin or cervical carcinoma in situ. 3. Rapidly progressive disease. 4. Active or history of central nervous system (CNS) metastases. 5. Receipt of any organ transplantation including autologous or allogeneic stem-cell transplantation. 6. Significant acute or chronic infections (including historic positive test for human immunodeficiency virus [HIV], or active or latent hepatitis B or active hepatitis C tested during the screening window). 7. Preexisting autoimmune disease (except for patients with vitiligo) needing treatment with systemic immunosuppressive agents for more than 28 days within the last 3 years or clinically relevant immunodeficiencies (eg, dys-gammaglobulinemia or congenital immunodeficiencies), or fever within 7 days of Day 1. 8. Known severe hypersensitivity reactions to mAbs (≥ Grade 3 NCI-CTCAE v5.0), any history of anaphylaxis, or uncontrolled asthma (ie, 3 or more features of partly controlled asthma). 9. Persisting toxicity related to prior therapy > Grade 1 NCI-CTCAE v5.0, however alopecia and sensory neuropathy ≤ Grade 2 is acceptable. 10. Pregnancy or lactation in females during the study. 11. Known alcohol or drug abuse. 12. Serious cardiac illness 13. NYHA III of IV heart failure or systolic dysfunction (LVEF < 55%) 14. High-risk uncontrolled arrhythmias ie, tachycardia with a heart rate > 100/min at rest 15. Significant ventricular arrhythmia (ventricular tachycardia) or higher-grade Atrioventricular block (AV-block; second-degree AV-block Type 2 [Mobitz 2] or third-degree AV-block) 16. Angina pectoris requiring anti-anginal medication 17. Clinically significant valvular heart disease 18. Evidence of transmural infarction on ECG 19. Poorly controlled hypertension (defined by: systolic > 180 mm Hg or diastolic > 100 mm Hg) 20. Clinically relevant uncontrolled cardiac risk factors, clinically relevant pulmonary disease or any clinically relevant medical condition in the opinion of the Investigator that may limit participation in this study. 21. Severe dyspnea at rest due to complications of advanced malignancy or requiring supplementary oxygen therapy. 22. All other significant diseases (e.g., inflammatory bowel disease), which, in the opinion of the Investigator, might impair the patient's ability to participate 23. Any psychiatric condition that would prohibit the understanding or rendering of informed consent. 24. Legal incapacity or limited legal capacity. 25. Incapable of giving signed informed consent, which includes compliance with the requirements and restrictions listed in the informed consent form (ICF) and in this protocol .

• Pathologically (histologically or cytologically) proven diagnosis of small cell lung cancer within 5 years of registration. If the original histologic proof of malignancy is greater than 5 years, then pathological (i.e., more recent) confirmation is required (e.g., from a systemic or brain metastasis);
• Patients with de novo or recurrent small cell lung cancer are permitted.
• Ten or fewer brain metastases ≤ 3 cm in largest diameter and outside a 5-mm margin around either hippocampus must be visible on contrast-enhanced magnetic resonance imaging (MRI) performed ≤ 21 days prior to study entry.
• Brain metastases can be diagnosed synchronous to the initial diagnosis of small cell lung cancer or metachronous to the initial diagnosis and management of small cell lung cancer.
• The total tumor volume must be 30 cm^3 or less. Lesion volume will be approximated by measuring the lesion's three perpendicular diameters on contrast enhanced, T1-weighted MRI and the product of those diameters will be divided by 2 to estimate the lesion volume (e.g. xyz/2). Alternatively, direct volumetric measurements via slice by slice contouring on a treatment planning software package can be used to calculate the total tumor volume.
• Brain metastases must be diagnosed on MRI, which will include the following elements:
• REQUIRED MRI ELEMENTS
• Post gadolinium contrast-enhanced T1-weighted three-dimensional (3D) spoiled gradient (SPGR). Acceptable 3D SPGR sequences include magnetization prepared 3D gradient recalled echo (GRE) rapid gradient echo (MP-RAGE), turbo field echo (TFE) MRI, BRAVO (Brain Volume Imaging) or 3D Fast FE (field echo). The T1-weighted 3D scan should use the smallest possible axial slice thickness, not to exceed 1.5 mm.
• Pre-contrast T1 weighted imaging (3D imaging sequence strongly encouraged).
• A minimum of one axial T2 FLAIR (preferred) or T2 sequence is required. This can be acquired as a two dimensional (2D) or 3D image. If 2D, the images should be obtained in the axial plane.
• ADDITIONAL RECOMMENDATIONS
• Recommendation is that an axial T2 FLAIR (preferred) sequence be performed instead of a T2 sequence.
• Recommendation is that that pre-contrast 3D T1 be performed with the same parameters as the post-contrast 3D T1.
• Recommendation is that imaging be performed on a 3 Tesla (3T) MRI.
• Recommendation is that the study participants be scanned on the same MRI instrument at each time point.
• Recommendation is that if additional sequences are obtained, these should meet the criteria outlined in Kaufmann et al., 2020.
• If additional sequences are obtained, total imaging time should not exceed 60 minutes.
• History/physical examination
• Age ≥ 18
• Karnofsky performance status of ≥ 70
• Creatinine clearance ≥ 30 ml/min
• Following the diagnosis of brain metastases, patients can initiate and treat with systemic (chemotherapy and/or immunotherapy) before enrollment only if their brain metastases are asymptomatic and not located in eloquent locations (e.g., brainstem, pre-/post-central gyrus, visual cortex). However, within 21 days prior to enrollment, brain MRI must be repeated to confirm eligibility.
• Patients with symptomatic brain metastases and/or brain metastases in eloquent locations (e.g., brainstem, pre-/post central gyrus, visual cortex) are eligible for enrollment on the trial; however, the specific treatment approach of starting with systemic therapy alone and delaying brain radiation is not recommended for these patients.
• Concurrent immunotherapy with brain radiation (SRS or HA-WBRT) is permitted.
• Negative urine or serum pregnancy test (in women of childbearing potential) within 14 days prior to registration. Women of childbearing potential and men who are sexually active must use contraception while on study.
• Patients may have had prior intracranial surgical resection. Patients must have completed prior intracranial surgical resection at least 14 days prior to registration.
• Because neurocognitive testing is the primary goal of this study, patients must be proficient in English or French Canadian.
• The patient must provide study-specific informed consent prior to study entry.
• Patients with impaired decision-making capacity are not permitted on study.
• ELIGIBILITY CRITERIA PRIOR TO STEP 2 REGISTRATION
• The following baseline neurocognitive tests must be completed within 21 days prior to Step 2 registration: HVLT-R, TMT, and COWA. The neurocognitive test will be uploaded into RAVE for evaluation by Dr. Wefel. Once the upload is complete, within 3 business days a notification will be sent via email to the RA to proceed to Step 2.
• NOTE: Completed baseline neurocognitive tests can be uploaded at the time of Step 1 registration.
• Planned infusion of cytotoxic chemotherapy on the same day as SRS or HA-WBRT treatment. Patients may have had prior chemotherapy. Concurrent immunotherapy is permitted.
• Prior allergic reaction to memantine.
• Intractable seizures while on adequate anticonvulsant therapy; more than 1 seizure per month for the past 2 months.
• Patients with definitive leptomeningeal metastases.
• Known history of demyelinating disease such as multiple sclerosis.
• Contraindication to MR imaging such as implanted metal devices that are MRI-incompatible, allergy to MRI contrast that cannot be adequately addressed with pre-contrast medications, or foreign bodies that preclude MRI imaging. (Questions regarding MRI compatibility of implanted objects should be reviewed with the Radiology Department performing the MRI).
• Current use of (other N-methyl-D-aspartate [NMDA] antagonists) amantadine, ketamine, or dextromethorphan.
• Radiographic evidence of hydrocephalus or other architectural change of the ventricular system resulting in significant anatomic distortion of the hippocampus, including placement of external ventricular drain or ventriculoperitoneal shunt.
• Mild cases of hydrocephalus not resulting in significant anatomic distortion of the hippocampus are permitted.
• Prior radiotherapy to the brain, including SRS, WBRT, or prophylactic cranial irradiation (PCI).
• Severe, active co-morbidity defined as follows:
• Unstable angina and/or congestive heart failure requiring hospitalization within the last 6 months
• Transmural myocardial infarction within the last 6 months
• Acute bacterial or fungal infection requiring intravenous antibiotics at the time of registration
• Chronic obstructive pulmonary disease exacerbation or other acute respiratory illness precluding study therapy at the time of registration
• Hepatic insufficiency resulting in clinical jaundice and/or coagulation defects

1. Patients must have a malignant solid tumor with a pathogenic inactivating TSC1 or TSC2 alteration. Genetic alterations should be identified using NGS in tumor tissue or liquid biopsy). • Patients will be enrolled after the central evaluation of NGS report confirms eligibility. 2. Patients must have solid tumors that are metastatic or locally advanced where surgical resection is not an option or likely to result in severe morbidity. 3. Patients must have received all standard therapies appropriate for their tumor type and stage of disease or, in the opinion of the Investigator, the patient would be unlikely to tolerate or derive clinically meaningful benefit from appropriate standard of care therapy, or the patient has no satisfactory alternative treatments. 4. Patients must have 1 or more measurable target lesions by computed tomography (CT) scan or magnetic resonance imaging (MRI) (RECIST v1.1). 5. Age: 12 years or older. 6. Eastern Cooperative Oncology Group (ECOG) performance status 0 or 1 or Karnofsky Performance Status (KPS) ≥80 or Lansky play-performance scale for pediatric patients ≥80. 7. Adequate liver function: 1. Total bilirubin ≤1.5 × upper limit of normal (ULN) (unless due to Gilbert's syndrome, then ≤3 × ULN) 2. Aspartate aminotransferase (AST) ≤2.5 × ULN (≤5 × ULN if attributable to liver metastases) 8. Adequate renal function: creatinine clearance ≥30 mL/min, Cockcroft-Gault CCr = ((140-age) × weight[kg]) / (72 × SCr[mL/min]) × 0.85, if female 9. Adequate hematologic parameters: 1. Absolute neutrophil count (ANC) ≥1.0 × 109/L (growth factor support allowed) 2. Platelet count ≥100,000/mm3 (100 × 109/L) (transfusion and/or growth factor support allowed) 3. Hemoglobin ≥8.0 g/dL (transfusion and/or growth factor support allowed) 10. Fasting serum triglyceride must be ≤300 mg/dL; fasting serum cholesterol must be ≤350 mg/dL. 11. Minimum of 4 weeks since any major surgery, completion of radiation, or completion of prior systemic anticancer therapy, or at least 5 half-lives if the prior therapy is a single agent small-molecule therapeutic, and adequately recovered from the acute toxicities of any prior therapy, including neuropathy, to Grade ≤1. 12. Male or non-pregnant and non-breastfeeding female: 1. Females of childbearing potential must agree to use effective contraception or abstinence without interruption from 28 days prior to starting investigational product (IP) throughout 3 months after last dose of IP and have a negative serum pregnancy test (beta human chorionic gonadotropin, β-hCG) result at screening and agree to ongoing pregnancy testing during the course of the study, and after the end of study treatment. A second form of birth control is required even if she has had a tubal ligation. 2. Male patients must agree not to donate sperm and must practice abstinence or agree to use a condom during sexual contact with a pregnant female or a female of childbearing potential while participating in the study and throughout 3 months after last dose of IP. A second form of birth control is required even if he has undergone a successful vasectomy. 13. The patient or the patient's parent(s) or legal guardian(s) understand(s) and sign(s) the informed consent. 14. Willingness and ability to comply with scheduled visits, laboratory tests, and other study procedures. 1. Prior treatment with an mTOR inhibitor, including nab-sirolimus. 2. Severe (Grade ≥3) ongoing infection requiring parenteral or oral anti-infective treatment, either ongoing or completed ≤7 days prior to enrollment. 3. Patients with primary brain tumors or PEComa. 4. Patients who have any severe and/or uncontrolled medical or psychiatric conditions or other conditions that could affect their participation including: 1. Patients with meningeal carcinomatosis, leptomeningeal carcinomatosis, spinal cord compression, untreated brain metastases or symptomatic or unstable brain metastases. Note: Patients with stable brain metastases (defined as asymptomatic or no requirement for high-dose [defined as dexamethasone 10 mg daily or higher] or increasing dose of systemic corticosteroids) and without imminent need of radiation therapy are eligible. If applicable, patients must have completed brain radiation therapy and recovered adequately from any associated toxicity and/or complications prior to eligibility assessment. For patients who have received prior radiation therapy, post-treatment MRI scan should show no increase in brain lesion size/volume. 2. Unstable angina pectoris, symptomatic congestive heart failure (New York Heart Association, NYHA class III or IV), myocardial infarction ≤6 months prior to first study treatment, serious uncontrolled cardiac arrhythmia or any other clinically significant cardiac disease. 3. Pre-existing severely impaired lung function. If a patient has a pre-existing pulmonary condition, eligible patients should have a spirometry and diffusing capacity for carbon monoxide (DLCO) that is >50% of the normal predicted value and/or O2 saturation that is >88% at rest on room air (Note: spirometry and pulmonary function tests [PFTs] not required to be performed unless clinically indicated). 4. Nonmalignant medical illnesses that are uncontrolled or whose control may be jeopardized by the treatment with the study therapy. 5. A history of malignancies other than the one under treatment unless the patient is disease-free for more than 5 years from diagnosis. Note, controlled non-melanoma skin cancers, carcinoma in situ of the cervix, resected incidental prostate cancer, certain low grade hematologic malignancies (eg CLL, follicular lymphoma, etc), or other adequately treated carcinoma-in-situ may be eligible, after discussion with the medical monitor. 6. Uncontrolled hypertension (systolic blood pressure ≥160 mm-Hg and/or diastolic blood pressure ≥100 mm Hg). 7. Patients with history of interstitial lung disease and/or pneumonitis, or pulmonary hypertension. 8. Individuals with known human immunodeficiency virus (HIV) infection are excluded from this study as combination antiretroviral therapy could potentially result in significant pharmacokinetic interactions. In addition, these individuals are at increased risk of serious infections due to the immunosuppressive effects of mTOR inhibition. 9. Active Hepatitis B or Hepatitis C, with detectable viral load. 5. Regarding concomitant medications with significant CYP3A4 and P-gp interactions, discontinuation of strong inhibitors (eg, ketoconazole, itraconazole, voriconazole, erythromycin, clarithromycin, telithromycin, and others), strong inducers (eg, rifampin, rifabutin), and known CYP3A4 substrates with a narrow therapeutic window (eg, fentanyl, alfentanil, astemizole, cisapride, dihydroergotamine, pimozide, quinidine, or terfenadine) is required at least 5 half lives prior to receiving the first dose of nab-sirolimus, whichever is longer.

Key
• Has a Karnofsky performance scale (KPS) score ≥ 70 at screening
• Has a new diagnosis of GBM (WHO GRADE III or Grade IV GBM) based on the treating neurosurgeon's best clinical judgement
• Has a diagnostic contrast-enhanced magnetic resonance imaging (MRI) scan with fluid attenuated inversion-recovery (FLAIR) sequence of the brain at screening. Participants must have a confirmed measurable disease pre-operatively with at least 1 lesion measuring a total bi-perpendicular product of 4 centimeter square (cm^2) in 2 different planes (axial, sagittal, or coronal)
• The tumor must be located in the supratentorial compartment
• Has adequate bone marrow and organ function at screening Key
• Has bi-hemispheric disease, multicentric disease, or disease burden involving the brain stem or cerebellum based on MRI post-gadolinium enhancement
• Has received any previous surgical resection or any anticancer intervention for glioma
• Has any history of glioma, a concurrent malignancy, or malignancy within 3 years of randomization, unless definitive therapy is completed, with the exception of basal or squamous cell skin cancer, superficial bladder cancer, or carcinoma in situ of the cervix or breast that has completed curative therapy
• Has any severe immunocompromised condition (eg, human immunodeficiency virus (HIV) with a cluster of differentiation [CD] 4+ cell count <200*10^6/liter [L]) or any active uncontrolled autoimmune disease (eg, Crohn's disease)
• Has an active cardiac disease or a history of cardiac dysfunction
• Is receiving any other investigational agent(s) or has received an investigational agent within 30 days or 5 half-lives of investigational agent use, whichever is longer, prior to screening
• Is partaking in another interventional study. Participants who are partaking in an observational study are eligible
• Has received a live vaccine within 30 days of screening
• Has active and uncontrolled/untreated hepatitis B virus (HBV), hepatitis C virus (HCV), HIV, or any other active infections that, in the Investigator's opinion, would impair or prohibit a participant's participation in this study.
• Is receiving treatment with Tumor Treating Fields or Optune®

• >= 4 and < 18 years at time of study entry
• Patients must weigh 15 kg or greater at time of study entry
• Primary central nervous system tumors that have not received prior cranial radiotherapy
• Planned focal, cranial or craniospinal radiation treatment for a primary central nervous system tumor
• The patient must have receptive and expressive language skills in English, French or Spanish since the neurocognitive function and quality of life (QOL) assessment instruments are available in these languages only
• Creatinine clearance or radioisotope glomerular filtration rate (GFR) >= 70 mL/min/1.73 m^2 or a serum creatinine based on age/gender as follows:
• Age: 4 to < 6 years; Maximum serum creatinine (mg/dL): 0.8 male; 0.8 female
• Age: 6 to < 10 years; Maximum serum creatinine (mg/dL): 1 male; 1 female
• Age: 10 to < 13 years; Maximum serum creatinine (mg/dL): 1.2 male; 1.2 female
• Age: 13 to < 16 years; Maximum serum creatinine (mg/dL): 1.5 male; 1.4 female
• Age: >= 16 years; Maximum serum creatinine (mg/dL): 1.7 male; 1.4 female
• Total bilirubin =< 1.5 x upper limit of normal (ULN) for age
• Serum glutamate pyruvate transaminase (SGPT) (alanine aminotransferase [ALT]) =< 135 U/L
• Note: For the purpose of this study, the ULN for SGPT (ALT) has been set to the value of 45 U/L
• The patient must be able to undergo magnetic resonance imaging
• All patients and/or their parents or legal guardians must sign a written informed consent
• All institutional, Food and Drug Administration (FDA), and National Cancer Institute (NCI) requirements for human studies must be met
• Life expectancy of less than 18 months
• Pre-existing conditions:
• Any contraindication or allergy to study drug (memantine or placebo)
• Intractable seizures while on adequate anticonvulsant therapy, defined as more than one seizure per month for the past 2 months or since initiating anticonvulsant therapy
• History of neurodevelopmental disorder such as Down syndrome, Fragile X, William's Syndrome, intellectual disability (presumed intelligence quotient [IQ] < 70), etc
• Co-morbid systemic illnesses, psychiatric conditions, social situations, or other severe concurrent disease which, in the judgment of the investigator, would make the patient inappropriate for entry into this study or interfere significantly with the proper assessment of safety and toxicity of the prescribed regimens or would limit compliance with the study requirements
• Patients with a motor, visual, or auditory condition that precludes participation in computerized neurocognitive assessments
• Patients with any medical condition or taking medications that lead to alterations of urine pH towards the alkaline condition (e.g., renal tubular acidosis, carbonic anhydrase inhibitors, sodium bicarbonate)
• Personal history of prior cranial or craniospinal radiotherapy is not allowed
• Note: Prior anti-cancer therapy including surgery, chemotherapy, targeted agents are allowed as per standard of care clinical treatment guidelines
• Female patients who are pregnant are excluded since fetal toxicities and teratogenic effects have been noted for the study drug. A pregnancy test is required for female patients of childbearing potential
• Lactating females who plan to breastfeed their infants
• Sexually active patients of reproductive potential who do not agree to use an effective contraceptive method for the duration of their study participation

Key Inclusion Criteria Patient has ECOG performance status of 0-1 One or more documented primary oncogenic PIK3CA mutation(s) in blood and/or tumor per local assessment
•Other potentially oncogenic PIK3CA mutations may be considered but must be approved by the Sponsor prior to enrollment. Part 1
•Ability to provide archived tumor tissue or be willing to undergo pretreatment tumor biopsy to assess PIK3CA status retrospectively Part 2
•Submit tumor tissue prior to study drug initiation for determination of PIK3CA mutation retrospectively. Key Inclusion for RLY-2608 Single Agent Arm
• [For Part 1]: Evaluable disease per RECIST v1.1
• [For Part 2]: Measurable disease per RECIST v1.1
• Disease that is refractory to standard therapy, intolerant to standard therapy, or has declined standard therapy.
• Part 1- histologically or cytologically confirmed diagnosis of unresectable or metastatic solid tumor
• Part 2
•Unresectable or metastatic solid tumor with PIK3CA mutation(s) and one of the following tumor types: Group 1: clear cell ovarian cancer Group 2: head and neck squamous cell carcinoma Group 3: cervical cancer Group 4: other solid tumors, excluding colorectal, clear cell ovarian, head and neck squamous cell, and cervical cancers Group 5: unresectable or metastatic solid tumors with PIK3CA double mutations Key Inclusion for Combination Arms
• [For Part 1 and Part 2]: Evaluable disease per RECIST v1.1
• Male or female with histologically or cytologically confirmed diagnosis of HR+, HER2- unresectable or metastatic breast cancer that is not amenable to curative therapy. Females may be postmenopausal, premenopausal, or perimenopausal. Premenopausal or perimenopausal females must have a histologically or cytologically confirmed diagnosis of HR+ HER2- advanced or metastatic breast cancer that is not amenable to curative therapy and must have been previously treated with GnRH agonist at least 4 weeks prior to start of study drug
• [For Part 1 and Part 2]: Had previous treatment for advanced or metastatic breast cancer with: 1. ≤1 line of chemotherapy, 2. ≥1 cyclin-dependent kinases (CDK) 4/6 inhibitor, and 3. ≥1 antiestrogen therapy including, but not limited to, selective estrogen-receptor degraders (eg, fulvestrant), selective estrogen receptor modulators (eg, tamoxifen), and aromatase inhibitors (AI) (letrozole, anastrozole, exemestane), and 4. ≥1 PARP inhibitor, if appropriate, if documented germline BRCA1/2 mutation Note: Systemic local, loco-regional, or adjuvant treatment is not to be included in enumeration or previous treatment [For RLY-2608 + fulvestrant arm; Part 2, Group 2]: Received prior treatment with a PI3Kα inhibitor and discontinued the inhibitor due to intolerance and not disease progression, where intolerance is defined as treatment discontinuation due to treatment related AE (eg. hyperglycemia, rash, diarrhea, stomatitis) other than severe hypersensitivity reaction and/or life-threatening reactions, such as anaphylaxis and Stevens-Johnson syndrome. Key Exclusion Criteria Prior treatment with PI3Kα, AKT, or mTOR inhibitors (except for RLY-2608 + fulvestrant arm, Part 2, Group 2). Type 1 or Type 2 diabetes requiring antihyperglycemic medication, or fasting plasma glucose ≥140 mg/dL and glycosylated hemoglobin (HbA1c) ≥7.0%. History of hypersensitivity to PI3K inhibitors. For combination arms only: hypersensitivity to fulvestrant, palbociclib, and/or ribociclib, as appropriate for the combination. For triple combination arms only: history of pneumonitis or interstitial lung disease. For the single agent and combination arms other than with ribociclib: mean QT interval corrected using Fridericia's formula (QTcF) >480 msec. For the combination arms with ribociclib: mean QTcF ≥450 msec. Patient has a history of prolonged QT syndrome or torsades de pointes. Patient has a familial history of prolonged QT syndrome. Clinically significant, uncontrolled cardiovascular disease CNS metastases or primary CNS tumor that is associated with progressive neurologic symptoms

• Participants must have histologically and pathologically confirmed melanoma that has metastasized to the brain
• Any primary (cutaneous, acral/mucosal, etc) or unknown origin are permitted, except that participants with uveal primary are not eligible
• Participants must have BRAF-V600 mutant melanoma documented by a Clinical Laboratory Improvement Act (CLIA)-certified laboratory
• All participants must have an magnetic resonance imaging (MRI) of the brain within 28 days prior to registration and must have central nervous system metastases with at least one measurable brain metastasis >= 0.5 cm in size (per modified RECIST 1.1) that has not been irradiated, or progressed (in the opinion of the treating physician) after prior radiation therapy. Participating sites MUST use MRI slice thickness of =< 1.5 mm and are recommended to adhere to the 'minimum' Brain Tumor Imaging Protocol for Clinical Trials in Brain Metastases (BTIP-BM) compliant MRI acquisition protocol. Computed tomography (CT) of the head cannot substitute for brain MRI. (NOTE: All central nervous system [CNS] disease must be documented on BOTH the Brain Metastases Baseline Tumor Assessment Form, using modified RECIST, and the Baseline Tumor Assessment Form [RECIST 1.1] using RECIST 1.1.)
• Participants may have measurable or non-measurable extracranial disease. All measurable disease must be assessed within 28 days prior to randomization; all non-measurable disease must be assessed within 42 days prior to randomization. Please note, while any extracranial disease will also be assessed and followed, participants are NOT required to have extracranial disease for randomization. NOTE: All disease must be assessed and documented on the Baseline Tumor Assessment Form (RECIST 1.1). CNS disease must be documented on BOTH the Brain Metastases Baseline Tumor Assessment Form, using modified RECIST, and the Baseline Tumor Assessment Form (RECIST 1.1) using RECIST 1.1
• Participants may have leptomeningeal disease
• Participants may be receiving corticosteroids for brain metastases at a dose of up to 8 mg of dexamethasone per day. The dose must not have exceeded 8 mg per day for at least 7 days prior to randomization
• Participants must have Zubrod performance status =< 2
• Participants must have complete history and physical examination within 28 days prior to randomization
• Participants must be able to swallow and retain pills
• Hemoglobin >= 8.0 g/dL (within 28 days prior to randomization)
• Absolute neutrophil count >= 1,500/mcL (within 28 days prior to randomization)
• Platelets >= 75,000/mcL (within 28 days prior to randomization)
• Total bilirubin =< 1.5 institutional upper limit of normal (ULN) (within 28 days prior to randomization)
• Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) =< 2.5 x institutional ULN (in participants with liver metastases =< 5 x ULN) (within 28 days prior to randomization)
• Creatinine =< 2.0 institutional ULN (within 28 days prior to randomization)
• Participants with known history or current symptoms of cardiac disease, or history of treatment with cardiotoxic agents, must have a clinical risk assessment of cardiac function using the New York Heart Association Functional Classification. To be eligible for this trial, participants must be class 2B or better
• Participants with a prior or concurrent malignancy whose natural history or treatment (in the opinion of the treating physician) does not have the potential to interfere with the safety or efficacy assessment of the investigational regimen are eligible for this trial
• Participants with known human immunodeficiency virus (HIV)-infection are eligible providing they are on effective anti-retroviral therapy and have undetectable viral load at their most recent viral load test and within 90 days prior to randomization
• Participants with a known history of hepatitis C virus (HCV) infection must have been treated and cured. Participants with HCV infection who are currently on treatment must have an undetectable HCV viral load prior to randomization
• Participants must agree to participate in image banking. Images must be submitted via the Triad System
• Participants must be offered the opportunity to participate in specimen and blood collections
• Participants must be informed of the investigational nature of this study and must sign and give informed consent in accordance with institutional and federal guidelines
• As a part of the OPEN registration process the treating institution's identity is provided in order to ensure that the current (within 365 days) date of institutional review board approval for this study has been entered in the system
• Participants must not have received prior systemic therapy for metastatic disease. Prior systemic therapy received only in the neoadjuvant and/or adjuvant setting (e.g., BRAF/MEK inhibitor therapy, anti-PD-1 therapy or anti-CTLA4 therapy, alfa-interferon, etc.) is permitted. If patients received prior neoadjuvant/adjuvant therapy, they must have had eventual disease relapse prior to randomization
• Participants must not have had prior radiation therapy within 7 days prior to randomization
• Participants must not be planning to require any additional form of systemic anti-tumor therapy for melanoma while on protocol treatment
• Participants must not be planning to use hormonal contraceptives
• Participants must not have a serious active infection requiring systemic therapy at time of randomization in the opinion of the treating physician
• Participants must not have active autoimmune disease that has required treatment in the past 6 months with use of biologic disease modifying agents (.e.g. infliximab, adalimumab). Patients on non-biologic disease modifying agents (e.g. methotrexate) or patients on corticosteroids =< 10 mg prednisone daily or equivalent (to treat auto-immune disease), or on replacement therapy (e.g., thyroxine, insulin) are eligible if deemed in the best interest of the patient by treating physician
• Participants must not have had grade 3 or 4 immune-related adverse events on ipilimumab or nivolumab that required more than 12 weeks of immune suppression with corticosteroids
• Participants must not have had adverse events related to encorafenib and/or binimetinib specifically, that required discontinuation of one or both drugs. (Please note this does not apply to other BRAF/MEK inhibitor drugs.)
• Participants must not be pregnant or nursing. Women/men of reproductive potential must have agreed to use an effective method of contraception. (NOTE: Patients must agree to not use hormonal contraceptives, as encorafenib can result in decreased concentration and loss of efficacy.) A woman is considered to be of "reproductive potential" if she has had menses at any time in the preceding 12 consecutive months. In addition to routine contraceptive methods, "effective contraception" also includes heterosexual celibacy and surgery intended to prevent pregnancy (or with a side-effect of pregnancy prevention) defined as a hysterectomy, bilateral oophorectomy or bilateral tubal ligation. However, if at any point a previously celibate participant chooses to become heterosexually active during the time period for use of contraceptive measures outlined in the protocol, he/she is responsible for beginning contraceptive measures

• Diagnosis of MG with generalized muscle weakness meeting the clinical criteria defined by Myasthenia Gravis Foundation of America (MGFA) Class II, III or IV
• Positive serological test for autoantibodies against AChR
• History of thymectomy, or any other thymic surgery within 12 months prior to Screening
• Untreated thymic malignancy, carcinoma, or thymoma
• History of Neisseria meningitidis infection
• Pregnancy, breastfeeding, or intention to conceive during the course of the study

• Patients must be >= 3 years and < 30 years at the time of study enrollment
• Patients must be newly diagnosed with localized primary CNS NGGCT of the suprasellar and/or pineal region by pathology and/or serum or cerebrospinal fluid (CSF) elevation of AFP above institutional normal or > 10 ng/mL or human chorionic gonadotropin (hCG) beta > 100 mIU/mL as confirmed by Rapid Central Marker Screening Review on APEC14B1-CNS. Suprasellar, pineal and bifocal tumors are included. (CSF tumor markers and cytology must be within 31 days prior to enrollment and start of protocol therapy [repeat if necessary]. Serum tumor markers, AFP and hCGbeta must be within 7 days prior to enrollment and start of protocol therapy [repeat if necessary]). Basal ganglia or other primary sites are excluded
• Patients with any of the following pathological elements are eligible: endodermal sinus (yolk sac), embryonal carcinoma, choriocarcinoma, malignant/immature teratoma and mixed germ cell tumor (GCT) (i.e., may include some pure germinoma) if malignant elements listed above are present. Patients with only mature teratoma are excluded. Patients with pure germinoma admixed with mature teratoma are excluded (would be eligible for pure germinoma protocols)
• Patients must have a cranial MRI with and without gadolinium at diagnosis/prior to enrollment. If surgical resection is performed, patients must have pre-operative and post operative brain MRI with and without gadolinium. The post operative brain MRI should be obtained within 72 hours of surgery. If patient has a biopsy only, post-operative brain MRI is recommended but not required (within 31 days prior to study enrollment and start of protocol therapy )
• Patients must have a spine MRI with gadolinium obtained at diagnosis/prior to enrollment. Spine MRI with and without gadolinium is recommended (within 31 days prior to study enrollment and start of protocol therapy)
• Lumbar CSF must be obtained prior to study enrollment unless medically contraindicated. If a patient undergoes surgery and lumbar CSF cytology cannot be obtained at the time of surgery, then it should be performed at least 10 days following surgery and prior to study enrollment. False positive cytology can occur within 10 days of surgery
• Patients must have RAPID CENTRAL TUMOR MARKER REVIEW CSF tumor markers obtained prior to enrollment unless medically contraindicated. Ventricular CSF obtained at the time of CSF diversion procedure (if performed) is acceptable for tumor markers but lumbar CSF is preferred. In case CSF diversion and biopsy/surgery are combined, CSF tumor markers should be collected first
• Peripheral absolute neutrophil count (ANC) >= 1000/uL (within 7 days prior to enrollment)
• Platelet count >= 100,000/uL (transfusion independent) (within 7 days prior to enrollment)
• Hemoglobin >= 8.0 g/dL (may receive red blood cell [RBC] transfusions) (within 7 days prior to enrollment)
• Creatinine clearance or radioisotope glomerular filtration rate (GFR) >= 70 mL/min/1.73 m^2 or a serum creatinine based on age/gender as follows (within 7 days prior to enrollment):
• Age: Maximum serum creatinine (mg/dL)
• 3 to < 6 years: 0.8 (male), 0.8 (female)
• 6 to < 10 years: 1 (male), 1 (female)
• 10 to < 13 years: 1.2 (male), 1.2 (female)
• 13 to < 16 years: 1.5 (male), 1.4 (female)
• >= 16 years: male (1.7), 1.4 (female)
• Total bilirubin =< 1.5 x upper limit of normal (ULN) for age (within 7 days prior to enrollment)
• Serum glutamate pyruvate transaminase (SGPT) (alanine aminotransferase [ALT]) =< 135 U/L (within 7 days prior to enrollment)
• Note: For the purpose of this study, the ULN for SGPT (ALT) has been set to the value of 45 U/L
• Central nervous system function defined as:
• Patients with seizure disorder may be enrolled if on anticonvulsants and well controlled
• Patients must not be in status epilepticus, coma or assisted ventilation prior to study enrollment
• Protocol therapy must begin within 31 calendar days of definitive surgery or clinical diagnosis, whichever is later. If a biopsy only was performed, the biopsy date will be considered the date of definitive surgery. For patients who have a biopsy or incomplete resection at diagnosis followed by additional surgery, the date of the last resection will be considered the date of definitive surgery.
• All patients and/or their parents or legal guardians must sign a written informed consent
• All institutional, Food and Drug Administration (FDA), and National Cancer Institute (NCI) requirements for human studies must be met
• NEUROCOGNITIVE FUNCTION AND QUALITY OF LIFE ASSESSMENT:
• English-, Spanish-, or French- speaking
• Note: Patients who speak a language other than English, Spanish, or French will be allowed to participate in ACNS2021 but will not complete the neurocognitive and quality of life assessments
• No known history of neurodevelopmental disorder prior to diagnosis of NGGCT (e.g., Down syndrome, fragile X, William syndrome, intellectual disability). Patients with NF1 will be allowed to participate
• Additional eligibility criteria for the COG Standardized Neuropsychological Battery only: must be at a site that has a psychologist to administer the battery
• Note: If not eligible for the COG Standardized Battery, patients should still complete the Behavior Rating Inventory of Executive Function, Second Edition (BRIEF-2), Pediatric Quality of Life Inventory (PedsQL), Adaptive Behavior Assessment System Third Edition (ABAS-3), and Behavior Assessment System for Children, Third Edition (BASC-3) questionnaires
• Patients with tumors located outside the ventricles (i.e., basal ganglia, thalamus)
• Patients with only mature teratoma and non-elevated markers upon tumor sampling at diagnosis
• Patients who have received any prior tumor-directed therapy for their diagnosis of NGGCT other than surgical intervention and corticosteroids
• Patients with metastatic disease (i.e., MRI evaluation, lumbar CSF cytology or intraoperative evidence of dissemination)
• Female patients who are pregnant, since fetal toxicities and teratogenic effects have been noted for several of the study drugs
• Note: Serum and urine pregnancy tests may be falsely positive due to HCGbeta-secreting germ cell tumors. Ensure the patient is not pregnant by institutional standards
• Lactating females who plan to breastfeed their infants
• Sexually active patients of reproductive potential who have not agreed to use an effective contraceptive method for the duration of their study participation

1. Participant, participant's parent, guardian, or legal authorized representative (LAR) must provide signed of informed consent/assent, and once capable (per institution guidelines), there must be documentation of consent/assent by the participant demonstrating they are willing and aware of the investigational nature of the study and related procedures. Where allowed by law, where the participant lacks the capacity to make informed decisions regarding his/her medical treatment options, the treating clinician may follow their deferred consenting practices. The clinician will make the final decision based on the best interests of the particiapant. 2. Male or females 12 years of age and older at the time of the first dose of IP 3. SE meeting the following criteria: a. A diagnosis of SE with or without prominent motor features based on clinical and EEG findings: i. Diagnosis is established by:
• For SE with prominent motor features: Clinical and EEG seizure activity indicative of convulsive, myoclonic or focal motor SE.
• For SE without prominent motor features (nonconvulsive SE): Appropriate clinical features and an EEG indicative of non-convulsive status epilepticus (NCSE) ii. For any type of SE:
• At least 6 minutes of cumulative seizure activity over a 30-minute period within the hour before IP initiation, AND
• Seizure activity during the 30 minutes immediately prior to IP initiation b. The treating clinician(s) anticipate that IV anesthesia is likely to be the next treatment for SE that persists following initiation of IP 4. Participants must have received any two or more of the following agents for treatment of the current episode of SE administered at an adequate dose and for a sufficient duration, in the judgment of the investigator, to demonstrate efficacy
• Benzodiazepines,
• IV Fosphenytoin/phenytoin,
• IV Valproic acid,
• IV Levetiracetam,
• IV Lacosamide,
• IV Brivaracetam, or
• IV Phenobarbital 5. Body mass index (BMI) < 40 or, if BMI is not able to be calculated at screening, participant is assessed by investigator as not morbidly obese 1. Life expectancy of less than 24 hours 2. Anoxic brain injury or an uncorrected rapidly reversable metabolic condition as the primary cause of SE (e.g., hypoglycemia < 50 milligram per deciliter [mg/dL] or hyperglycemia > 400 mg/dL) 3. Participants who have received high-dose IV anesthetics (e.g., midazolam, propofol, thiopental, or pentobarbital) during the current episode of SE for more than 18 hours, or who continue to have clinical or electrographic evidence of persistent seizures while receiving high-dose IV anesthetics. 4. Clinical condition or advance directive that would NOT permit use of IV anesthesia 5. Participants known or suspected to be pregnant 6. Participants with known allergy or sensitivity to progesterone or allopregnanolone medications/supplements 7. Receiving a concomitant IV product containing Captisol® 8. Known or suspected hepatic insufficiency or hepatic failure leading to impaired synthetic liver function. 9. Known or suspected stage 3B (moderate to severe; estimated glomerular filtration rate [eGFR] 44-30 milliliter/minutes/1.73-meter square [mL/min/1.73m^2]), stage 4 (severe; eGFR 29-15 mL/min/1.73m^2), or stage 5 (kidney failure; eGFR < 15 mL/min/1.73m^2 or dialysis) kidney disease 10. Use of an investigational product for which less than 30 days or 5 half-lives have elapsed from the final product administration. Participation in a non-interventional clinical study does not exclude eligibility.

• Acute focal symptoms or signs of any duration associated with imaging, pathological, or other objective evidence of arterial infarction OR clinical evidence of cerebral, spinal cord, or retinal focal arterial ischemic injury based on symptoms persisting greater than or equal to 24 hours that occurred within 30 days prior to randomization
• Index stroke is attributed to 70-99% stenosis (or flow gap on MRA) of a major intracranial artery (carotid artery, middle cerebral artery (M1 or M2), vertebral artery (V4), basilar artery, posterior cerebral artery (P1), or anterior cerebral artery (A1)) documented by CTA, MRA, or catheter angiography
• Modified Rankin Scale score of ≤ 4, at time of consent
• Ability to swallow pills
• At least 30 years of age, inclusive, at time of consent
• Subjects 30-49 years of age are required to meet at least ONE of the following additional criteria below to qualify for the study: 1. diabetes treated with insulin for at least 15 years 2. at least 2 of the following atherosclerotic risk factors: hypertension (BP > 140/90 or on antihypertensive therapy); dyslipidemia (LDL > 130 mg /dl or HDL < 40 mg/dl or fasting triglycerides > 150 mg/dl or on lipid lowering therapy); smoking; non-insulin dependent diabetes or insulin dependent diabetes of less than 15 years duration; any of the following vascular events occurring in a parent or sibling who was < 55 years of age for men or < 65 years of age for women at the time of the event: myocardial infarction, coronary artery bypass, coronary angioplasty or stenting, stroke, carotid endarterectomy or stenting, peripheral vascular surgery for atherosclerotic disease 3. personal history of any of the following: myocardial infarction, coronary artery bypass, coronary angioplasty or stenting, carotid endarterectomy or stenting, or peripheral vascular surgery for atherosclerotic disease 4. any stenosis of an extracranial carotid or vertebral artery, another intracranial artery, subclavian artery, coronary artery, iliac or femoral artery, other lower or upper extremity artery, mesenteric artery, or renal artery that was documented by non-invasive vascular imaging or catheter angiography and is considered atherosclerotic 5. aortic arch atheroma documented by non-invasive vascular imaging or catheter angiography 6. any aortic aneurysm documented by non-invasive vascular imaging or catheter angiography that is considered atherosclerotic
• Negative pregnancy test in a female who has had any menses in the last 18 months and has not had surgery that would make her unable to become pregnant
• Subject is willing and able to return for all follow-up evaluations required by the protocol
• Subject is available by phone
• Subject understands the purpose and requirements of the study and can make him/herself understood
• Subject has provided informed consent (use of a LAR is not permitted)
• Previous treatment of target lesion with a stent, angioplasty, or other mechanical device, including mechanical thrombectomy for the qualifying stroke, or plan to perform one of these procedures
• Plan to perform concomitant endarterectomy, angioplasty or stenting of an extracranial vessel tandem to the symptomatic intracranial stenosis
• Intracranial tumor (except meningioma) or any intracranial vascular malformation
• Thrombolytic therapy within 24 hours prior to randomization
• Progressive neurological signs within 24 hours prior to randomization
• History of any intracranial hemorrhage (parenchymal, subarachnoid, subdural, epidural)
• Intracranial arterial stenosis due to: arterial dissection; MoyaMoya disease; any known vasculitic disease; herpes zoster, varicella zoster or other viral vasculopathy; neurosyphilis; any other intracranial infection; any intracranial stenosis associated with CSF pleocytosis; radiation induced vasculopathy; fibromuscular dysplasia; sickle cell disease; neurofibromatosis; benign angiopathy of central nervous system; postpartum angiopathy; suspected vasospastic process; reversible cerebral vasoconstriction syndrome (RCVS); suspected recanalized embolus
• Presence of any of the following unequivocal cardiac sources of embolism: chronic or paroxysmal atrial fibrillation, mitral stenosis, mechanical valve, endocarditis, intracardiac clot or vegetation, myocardial infarction within three months, left atrial spontaneous echo contrast
• Known allergy or contraindication to aspirin, rivaroxaban, clopidogrel, or ticagrelor
• Uncontrolled severe hypertension (systolic pressure > 180 mm Hg or diastolic pressure > 115 mm Hg), active peptic ulcer disease, major systemic hemorrhage within 30 days prior to randomization, active bleed or bleeding diathesis, platelets < 100,000, hematocrit < 30, INR > 1.5, clotting factor abnormality that increases the risk of bleeding, current alcohol or substance abuse, severe liver impairment (AST or ALT > 3 x normal, cirrhosis), or CrCl < 15 mL/min or on dialysis
• Major surgery (including stenting of any vessel; open femoral, aortic, or carotid surgery; or cardiac surgery) within previous 30 days prior to randomization or planned in the next 90 days after randomization
• Any condition other than intracranial arterial stenosis that requires the subject to take any antithrombotic medication other than aspirin (NOTE: exceptions allowed for subcutaneous heparin for deep vein thrombosis (DVT) prophylaxis)
• Dementia or psychiatric problem that prevents the subject from following an outpatient program reliably
• Co-morbid conditions that may limit survival to less than 12 months
• Pregnancy or of childbearing potential and unwilling to use contraception for the duration of this study, or currently breastfeeding
• Current or anticipated concomitant oral or intravenous therapy with strong CYP3A4 inhibitors or CYP3A4 substrates that cannot be stopped for the course of this study
• Enrollment in another study that would conflict with the current study

• Provision of signed and dated, written informed consent form ICF in accordance with ICH-GCP and local legislation prior to any trial-specific procedures, sampling, or analyses.
• Pathologically documented, advanced solid tumors.
• Patients fulfilling one or more of the following criteria:
• Radiologically documented disease progression or relapse
• Patients who are not eligible to receive standard of care treatments, and for whom no proven treatments exist.
• Patients with MDM2 amplified sarcomas who require first line treatment (for Ph Ib/dose expansion
•Cohort 1 only).
• Patients with MDM2 amplified sarcomas may fulfil any one of the above three criteria to be considered eligible.
• Phase Ia (dose escalation) only:
• Patient has a tumor with either a known TP53 wild type status, or unknown TP53 status, and regardless of MDM2 amplification status, at the time of study entry.
• Phase Ib (expansion phase) only:
• Cohort 1: TP53 wt and MDM2-amplified sarcoma with advanced/metastatic disease at any line of therapy. If TP53 status is not available during screening, the patient may be included with unknown TP53 status if a tissue sample is submitted for central laboratory assessment. If TP53 status cannot be evaluated, the patient may be included if agreed between the Investigator and Sponsor.
• Cohort 2: TP53 wt and MDM2- amplified NSCLC, urothelial, gastric, biliary tract (including cholangiocarcinoma, intra- and extrahepatic biliary tree, gall blander and ampulla of vater) or pancreatic solidPDAC tumors who have had at least one previous line of therapy for advanced/metastatic disease. If TP53 status cannot be evaluated the patient may be included if agreed between the Investigator and Sponsor
• Phase Ia (dose escalation) only:
• Patient with either measurable or non-measurable disease.
• Non-evaluable disease allowed.
• Phase Ib (expansion phase) only:
• At least one target lesion that can be accurately measured per RECIST v.1.1.
• Phase Ia:
• Patient must be willing to undergo blood sampling for PK, pharmacodynamic, biomarker, and PGx analyses.
• Phase Ib:
• Patient must be willing to undergo tumor biopsy sampling for pharmacodynamic analyses and blood sampling for PK, pharmacodynamics, and biomarker analyses.
• Willingness to provide a fresh tumor tissue sample obtained after relapse/ progression during or after prior therapy. In case a fresh biopsy cannot be obtained (e.g. inaccessible lesions or patient safety concern), an archived specimen, collected before screening within 12 months of enrollment, may be submitted. If these requirements cannot be met, then the patient may be allowed to enter the study at Sponsor discretion, after agreement between the Investigator and Sponsor.
• Further inclusion criteria apply
• Previous administration of BI 907828 (brigimadlin) or any other MDM2-p53 or MDMX (MDM4)-p53 antagonist.
• Known TP53 mutant tumor.
• Symptomatic metastases from non-brain tumors. Note: Patients with previously treated brain metastases may participate provided they are stable, without evidence of progression by imaging (using the identical imaging modality for each assessment, either MRI or computed tomography (CT) scan), for at least four weeks prior to the first dose of trial treatment, and any neurologic symptoms have returned to baseline; have no evidence of new or enlarging brain metastases. Patients on corticosteroids must have a stable dose for at least 5 days prior to baseline MRI.
• Patients with history of bleeding diathesis.
• Major surgery (major according to the Investigator's assessment) performed within 12 weeks prior to start of study treatment, or planned within 12 months after screening (e.g. hip replacement).
• Any other documented active or suspected malignancy or history of malignancy within 3 years prior to screening, except appropriately treated basal cell carcinoma of the skin or in situ carcinoma of uterine cervix, or other local tumors considered cured by local treatment.
• Patients who must or wish to continue the intake of restricted medications or any drug considered likely to interfere with the safe conduct of the trial.
• Further exclusion criteria apply.

• Patients must have histologically confirmed malignancy that is metastatic or unresectable with participation in this clinical trial determined to be the best option for next treatment in the opinion of the investigator
• Patients must have a solid tumor with HER2-positivity as determined by any one or more of the following:
• HER2 overexpression defined by IHC 3+
• ERBB2 amplification by ISH or next-generation sequencing as determined by any CLIA certified lab
• A known HER2 activating mutation
• HER2 overexpression by IHC/ISH will follow histology specific ASCO-CAP guidelines for breast and gastric cancers. For tumor histologies without specific guidelines the following criteria will apply:
• HER2 IHC should be performed first, followed by ISH methods in cases showing 2+ (equivocal) expression by IHC. Positive (IHC 3+) or negative (IHC 0 or 1+) do not require further ISH testing. Cases with HER2:CEP17 ratio ≥2 or an average HER2 copy number ≥6.0 signals per cell are considered positive by ISH
• Known HER2 activating mutations:
• G309A/E
• S310F/Y
• S653C
• V659E
• G660D
• R678Q
• E693K
• Q709L
• L755S/P
• Del. 755-759
• D769Y/H
• G776V/C
• V777L
• V842I
• T862A
• L869R
• H878Y
• All exon 20 insertions, including:
• A771_Y772insYVMA
• A775_G776insYVMA
• Y772_A775dup
• P780_Y781insGSP
• G778_P780dup
• V697L
• T733I
• D769N
• L841V
• L866M
• R896C
• If a different mutation is identified, contact the study chair for conferral. Synonymous mutations are not eligible
• Patients must have received at least 1 prior line of therapy in the advanced/metastatic setting. No limitation on number of prior therapies; however, patients may not have received neratinib or DS-8201a previously. Prior HER2-targeted therapy other than neratinib or DS-8201a is allowed (e.g., trastuzumab, pertuzumab, TDM-1, lapatinib, etc.)
• Age >= 18 years. Because no dosing or adverse event data are currently available on the use of neratinib in combination with DS-8201a in patients < 18 years of age, children are excluded from this study
• Patients must have Eastern Cooperative Oncology Group (ECOG) performance status =< 1 (Karnofsky >= 70%)
• Hemoglobin >= 9.0 g/dL (>= 8.0 g/dL for gastric cancer [GC] only) (within 14 days of enrollment)
• No transfusions with red blood cells or platelets are allowed within 1 week prior to screening assessment
• Serum albumin >= 2.5 g/dL (within 14 days of enrollment)
• Leukocytes >= 3.0 K/cumm (within 14 days of enrollment)
• Absolute neutrophil count >= 1.5 K/cumm (within 14 days of enrollment)
• No administration of granulocyte colony-stimulating factor (G-CSF) is allowed within 1 week prior to screening assessment
• Platelets >= 100 K/cumm (within 14 days of enrollment)
• No transfusions with red blood cells or platelets are allowed within 1 week prior to screening assessment
• Total bilirubin =< 1.5 × institutional upper limit of normal (ULN), (< 3 × ULN in the presence of documented Gilbert's syndrome or liver metastases at baseline) (within 14 days of enrollment)
• Aspartate aminotransferase (AST) (serum glutamic-oxaloacetic transaminase [SGOT])/alanine aminotransferase (ALT) (serum glutamate pyruvate transaminase [SGPT]) =< 3 x ULN (if liver metastases are present =< 5 x ULN) (within 14 days of enrollment)
• International normalized ratio (INR)/prothrombin time (PT) and activated partial thromboplastin time (aPTT) =< 1.5 x institutional ULN (within 14 days of enrollment)
• This applies only to patients who are not receiving therapeutic anticoagulation that may affect INR. Those who are on therapeutic anticoagulation, should be on a stable dose for 4 weeks and should be considered within therapeutic range
• Creatinine =< 1.5 x institutional ULN OR Glomerular filtration rate (GFR) >= 30 mL/min/1.73 m^2 (using the Cockcroft-Gault equation) (within 14 days of enrollment)
• Patients who are human immunodeficiency virus (HIV)-positive may participate IF they meet the following eligibility requirements:
• They must be stable on their anti-retroviral regimen, and they must be healthy from an HIV perspective
• They must have a CD4 count of greater than 250 cells/mcL over the past 6 months on this same anti-retroviral regimen and must not have had a CD4 count < 200 cells/ul over the past 2 years, unless it was deemed related to THE CANCER AND/OR CHEMOTHERAPY-induced bone marrow suppression
• For patients who have received chemotherapy in the past 6 months, a CD4 count < 250 cells/ul during chemotherapy is permitted as long as viral loads were undetectable during this same chemotherapy
• They must have an undetectable viral load and a CD4 count >= 250 cells/uL within 7 days of enrollment
• They must not be currently receiving prophylactic therapy for an opportunistic infection and must not have had an opportunistic infection within the past 6 months HIV-infected patients should be monitored every 12 weeks for viral load and CD4 counts
• For patients with evidence of chronic hepatitis B virus (HBV) infection, the HBV viral load must be undetectable on suppressive therapy, if indicated
• Patients with a history of hepatitis C virus (HCV) infection must have been treated and cured. For patients with HCV infection who are currently on treatment, they are eligible if they have an undetectable HCV viral load
• Patients with treated brain metastases are eligible if the following criteria are met: 1) follow-up brain imaging done at least in 4 weeks after central nervous system (CNS)-directed therapy shows no evidence of progression and 2) the patient no longer requires steroids, or is on a stable steroid dose > 4 weeks
• Patients with radiographically new or progressive brain metastases (active brain metastases) or leptomeningeal disease are eligible only if has no progressive clinical symptoms and if the treating physician determines that immediate CNS specific treatment is not required and is unlikely to be required during the first cycle of therapy
• Patients should be New York Heart Association functional classification of class 2B or better
• Patients must have left ventricular ejection fraction (LVEF) >= 50% by either an echocardiogram (ECHO) or multigated acquisition (MUGA) scan within 28 days before randomization/enrollment
• Dose expansion phase (PD cohort): Patients must have disease that is evaluable or measurable by Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1
• Dose expansion phase (PD cohort): Patients must have at least one lesion suitable for biopsy without significant risk to the patient. The biopsiable lesion can be the same as the evaluable lesion for response by RECIST 1.1
• Patients who had clinically significant side effects from prior cancer therapy must have recovered to grade 1 or below
• HER2 antibody conjugated to a topoisomerase 1 inhibitor agents as well as other therapeutic agents used in this trial are known to be teratogenic; thus, women of child-bearing potential and men must agree to use adequate contraception (hormonal or barrier method of birth control; abstinence) prior to study entry, for the duration of study participation, and for at least 1 month after the last dose of neratinib, or at least 7 months after the last dose of DS-8201a, whichever is longer (women of childbearing potential [WOCBP] only). Should a woman become pregnant or suspect she is pregnant while she or her partner is participating in this study, she should inform her treating physician immediately. Men treated or enrolled on this protocol must also agree to use adequate contraception prior to the study, for the duration of study participation, and 3 months after the last dose of neratinib, or 4 months after completion of DS-8021a administration, whichever is longer
• Women of non-child-bearing potential defined as pre-menopausal females with a documented tubal ligation or hysterectomy; or postmenopausal defined as 12 months of spontaneous amenorrhea (in questionable cases, a blood sample with simultaneous follicle-stimulating hormone [FSH] > 40 mIU/mL and estradiol < 40 pg/mL [< 147 pmol/L] is confirmatory) are eligible. Females on hormone replacement therapy (HRT) and whose menopausal status is in doubt will be required to use one of the contraception methods outlined for women of child-bearing potential if they wish to continue their HRT during the study. Otherwise, they must discontinue HRT to allow confirmation of post-menopausal status prior to study enrollment. For most forms of HRT, at least 2-4 weeks will elapse between the cessation of therapy and the blood draw; this interval depends on the type and dosage of HRT. Following confirmation of their post-menopausal status, they can resume use of HRT during the study without use of a contraceptive method
• Male subjects must not freeze or donate sperm starting at screening and throughout the study period, and at least 4 months after the final study drug administration. Preservation of sperm should be considered prior to enrollment in this study
• Female subjects must not donate, or retrieve for their own use, ova from the time of screening and throughout the study treatment period, and for at least 7 months after the final study drug administration
• Ability to understand and the willingness to sign a written informed consent document. Participants with impaired decision-making capacity who have a legally-authorized representative (LAR) and/or family member available will also be eligible
• With the exception of medications that are under investigation in the study (e.g., standard of care, comparators, or combination therapies), the following medications, treatment, and procedures will be prohibited during the treatment period. The sponsor must be notified if a subject receives any of these during the study:
• Other anticancer therapy, including small-molecule targeted agents within 2 weeks or five half-lives, whichever is longer; chemotherapy otherwise not specified (including, but not limited to cytotoxic chemotherapy, antibody drug conjugates, retinoid therapy, hormonal therapy) within 3 weeks; immunotherapy or monoclonal antibody within 4 weeks; and nitrosureas or mitomycin C within 6 weeks (concurrent use of hormones for noncancer-related conditions [e.g., insulin for diabetes and hormone replacement therapy] is acceptable)
• Other investigational therapeutic agents
• Patients who have had major surgery or radiation within 4 weeks; palliative stereotactic radiation within 2 weeks (except for palliative radiation to known metastatic sites as long as it does not affect assessment of response or interrupt treatment for more than the maximum time specified in dose modification section)
• Radiotherapy to the thorax (palliative radiation to known metastatic sites in the thoracic spine is permitted in this study)
• Concomitant use of chronic systemic (IV or oral) corticosteroids or other immunosuppressive medications except for managing adverse events (inhaled steroids or intra-articular steroid injections are permitted in this study); chronic replacement dose steroids (e.g., for those with adrenal insufficiency) are permitted in this study
• Subjects with bronchopulmonary disorders who require intermittent use of bronchodilators (such as albuterol) will not be excluded from this study
• Concomitant treatment with chloroquine or hydroxychloroquine is not allowed during the study treatment due to concern for overlapping toxicities. If treatment with chloroquine and hydroxychloroquine treatment is absolutely required, study treatment must be interrupted. If chloroquine or hydroxychloroquine is administered, then a wash-out period of more than 14 days is required before restarting study treatment
• Patients with a history of (non-infectious) interstitial lung disease (ILD)/pneumonitis that required steroids, has current ILD/pneumonitis, or where suspected ILD/pneumonitis cannot be ruled out by imaging at screening
• Patients with clinically severe pulmonary compromise resulting from intercurrent pulmonary illnesses including, but not limited to, any underlying pulmonary disorder (i.e. pulmonary emboli within three months of the study enrollment, severe asthma, severe chronic obstructive pulmonary disease (COPD), restrictive lung disease, pleural effusion, etc.), and any autoimmune, connective tissue or inflammatory disorders with potential pulmonary involvement (i.e. rheumatoid arthritis, Sjogren's, sarcoidosis, etc.), or prior pneumonectomy
• Patients with history of allergic reactions attributed to compounds of similar chemical or biologic composition to DS-8201a, the inactive ingredients in the drug product, or neratinib
• Patients who have a history of severe hypersensitivity reactions to other monoclonal antibodies
• Patients receiving any medications or substances that are moderate or strong inhibitors or inducers of CYP3A4 and P-glycoprotein are ineligible. Avoid concomitant use with proton pump inhibitors and P-glycoprotein substrates. Because the lists of these agents are constantly changing, it is important to regularly consult a frequently-updated medical reference. As part of the enrollment/informed consent procedures, the patient will be counseled on the risk of interactions with other agents, and what to do if new medications need to be prescribed or if the patient is considering a new over-the-counter medicine or herbal product
• Patients with a medical history of myocardial infarction within 6 months before enrollment, or symptomatic congestive heart failure (CHF) (New York Heart Association class II to IV)
• Patients with a corrected QT interval (QTc) prolongation to > 470 ms (females) or > 450 ms (males) based on average of the screening triplicate 12-lead electrocardiogram (ECG)
• Patients with clinically significant corneal disease in the opinion of the investigator
• Patients with a pleural effusion, ascites, or pericardial effusion that requires drainage, peritoneal shunt, or cell-free and concentrated ascites reinfusion therapy (CART). (Drainage and CART are not allowed within 2 weeks prior to screening assessment) (GC indication)
• Patients with spinal cord compression
• Patients with an uncontrolled infection requiring IV antibiotics, antivirals, or antifungals
• Patients with unresolved toxicities from previous anticancer therapy, defined as toxicities (other than alopecia) not yet resolved to grade =< 1 or baseline. Subjects with chronic grade 2 toxicities may be eligible per the discretion of the investigator after consultation with the sponsor medical monitor or designee (e.g., grade 2 chemotherapy-induced neuropathy)
• Patients with substance abuse or any other medical conditions such as clinically significant cardiac or psychological conditions, that may, in the opinion of the investigator, interfere with the subject's participation in the clinical study or evaluation of the clinical study results
• Pregnant women are excluded from this study because DS-8201a is a HER2 antibody conjugated to a topoisomerase 1 inhibitor agent with the potential for teratogenic or abortifacient effects. Because there is an unknown but potential risk for adverse events in nursing infants secondary to treatment of the mother with DS-8201a, breastfeeding should be discontinued if the mother is treated with DS-8201a. These potential risks may also apply to other agents used in this study
• Prior treatment with neratinib or DS-8201a
• Clinically significant chronic gastrointestinal disorder with diarrhea as a major symptom; G2 or greater diarrhea at baseline. Please contact the study PI for any patient with more than two episodes of diarrhea per day averaged over at least a 7 day period at time of screening to determine whether the diarrhea would be considered clinically significant
• Inability to swallow tablets
• Patients with active additional malignancy or a personal history of additional malignancy that may affect outcome of disease under treatment (patients with a prior or concurrent malignancy whose natural history or treatment does not have the potential to interfere with the safety or efficacy assessment of the investigational regimen at the discretion of the treating investigator are allowed)
• Patients with prior allogeneic organ transplantation including allogeneic stem cell transplantation

• Participants with a cancer diagnosis: Documentation of disease:
• Histologic documentation: Histologically confirmed diagnosis of invasive cancer
• Stage: Stage I-IV per American Joint Committee on Cancer (AJCC) 7th edition, with the exception of patients with leukemia, lymphoma, and multiple myeloma
• For leukemia: Type (chronic lymphocytic leukemia [CLL], chronic myeloid leukemia [CML], acute lymphoblastic lymphoma [ALL], acute myeloid leukemia [AML])
• For lymphoma: Stage I-IV based on Ann Arbor staging
• For multiple myeloma: Stage I, II, III based on Revised International Staging System (RISS)
• One of the following tumor types:
• Colorectal
• Bladder
• Head and neck
• Hepatobiliary
• Lung
• Lymphoma
• Leukemia
• Ovary *** For these specific cancer types only, patients may be enrolled prior to histologic confirmation of malignancy. Sites are required to contact the study chairs to review appropriateness for enrollment
• Pancreas *** For these specific cancer types only, patients may be enrolled prior to histologic confirmation of malignancy. Sites are required to contact the study chairs to review appropriateness for enrollment
• Multiple myeloma
• Gastric, esophageal or gastroesophageal
• Breast
• Thyroid
• Kidney
• For these specific cancer types only, patients may be enrolled prior to histologic confirmation of malignancy. Sites are required to contact the study chairs to review appropriateness for enrollment
• Endometrium
• Prostate
• Melanoma *** For these specific cancer types only, patients may be enrolled prior to histologic confirmation of malignancy. Sites are required to contact the study chairs to review appropriateness for enrollment
• Sarcoma
• Participants with a cancer diagnosis: No prior definitive systemic or local anti-cancer intervention
• Participants with a cancer diagnosis: Age >= 40 and =< 75
• Participants with a cancer diagnosis: No known current pregnancy by self-report
• Participants with a cancer diagnosis: No known or prior history of in situ or invasive malignancy (excluding in situ non-melanoma skin cancers) other than the current cancer diagnosis
• Participants with a cancer diagnosis: Willingness to provide blood samples for research use
• Participants with a cancer diagnosis: Absence of medical contraindications to a research blood draw volume of 60 mL
• Participants with a cancer diagnosis: No history of organ transplantation
• Participants with a cancer diagnosis: Ability to read and comprehend English or Spanish * Eligibility is restricted to individuals who can comprehend and read English or Spanish given that participation in the study will require the ability to read and complete questionnaires that are available only in those two languages
• Participants without a cancer diagnosis and without suspicion of cancer: Age >= 40 and =< 75
• Participants without a cancer diagnosis and without suspicion of cancer: No known current pregnancy by self-report
• Participants without a cancer diagnosis and without suspicion of cancer: No known or prior history of in situ or invasive malignancy (excluding in situ non-melanoma skin cancers)
• Participants without a cancer diagnosis and without suspicion of cancer: Willingness to provide blood samples for research use
• Participants without a cancer diagnosis and without suspicion of cancer: Absence of medical contraindications to a research blood draw volume of 60 mL
• Participants without a cancer diagnosis and without suspicion of cancer: No history of organ transplantation
• Participants without a cancer diagnosis and without suspicion of cancer: Ability to read and comprehend English or Spanish * Eligibility is restricted to individuals who can comprehend and read English or Spanish given that participation in the study will require the ability to read and complete questionnaires that are available only in those two languages
• Participants with a high suspicion of cancer: High suspicion of ovarian cancer, pancreatic cancer, kidney cancer, or melanoma by clinical and/or radiological assessment, with plans for histologic or cytologic confirmation within 28 days after study blood draw * Examples of highly suspicious cases include: elevated CA125 and abnormal transvaginal ultrasound, suspicious renal or pancreatic mass on imaging, suspicious cutaneous lesion concerning for melanoma
• Participants with a high suspicion of cancer: Central review of radiology reports and/or clinical documentation conducted by study chairs
• Participants with a high suspicion of cancer: Age >= 40 and =< 75
• Participants with a high suspicion of cancer: No known current pregnancy by self-report
• Participants with a high suspicion of cancer: No known or prior history of in situ or invasive malignancy (excluding in situ non-melanoma skin cancers) other than the current cancer diagnosis
• Participants with a high suspicion of cancer: Willingness to provide blood samples for research use
• Participants with a high suspicion of cancer: Absence of medical contraindications to a research blood draw volume of 60 mL
• Participants with a high suspicion of cancer: No history or organ transplantation
• Participants with a high suspicion of cancer: Ability to read and comprehend English or Spanish * Eligibility is restricted to individuals who can comprehend and read English and Spanish given that participation in the study will require the ability to read and complete questionnaires that are available only in those two languages

• Age 2-21 years
• Body weight ≥ 10 kg
• Subject has histologically confirmed diagnosis of any one of the following cancers: (A) Synovial Sarcoma, (B) MPNST, (C) Neuroblastoma, or (D) Osteosarcoma
• Must have previously received a systemic chemotherapy
• Measurable disease according to RECIST v1.1 (or INCR, 2017 Neuroblastoma only).
• HLA-A*02 positive
• Tumor shows MAGE-A4 expression confirmed by central laboratory.
• Performance Status: ECOG 0-1 or Lansky Score ≥ 80
• HLA-A*02:05 in either allele; or any A*02 having same protein sequence as HLA-A*02:05
• History of allergic reactions attributed to compounds of similar chemical or biologic composition to fludarabine, cyclophosphamide.
• History of autoimmune or immune mediated disease
• Known central nervous system (CNS) metastases.
• Other prior malignancy that is not considered by the Investigator to be in complete remission
• Clinically significant cardiovascular disease
• Active infection with human immunodeficiency virus, hepatitis B virus, hepatitis C virus, or human T cell leukemia virus
• Pregnant or breastfeeding

• Radiographic confirmation of 1-4 brain metastases, one of which requires resection, as defined by magnetic resonance imaging (MRI) with contrast obtained within 14 days prior to registration
• The maximum diameter of the lesion to be resected on the post-contrast MRI, as measured on any orthogonal plane (axial, sagittal, coronal), must measure > 2.0 cm and < 5.0 cm.
• The maximum diameter of the lesions not to be resected must measure < 4.0 cm
• Known active or history of invasive non-central nervous system (CNS) primary cancer based on documented pathologic diagnosis within the past 3 years
• All brain metastases must be located > 5 mm from the optic chiasm and outside the brainstem
• Patient is able to medically tolerate surgery and SRS
• The lesion chosen for surgical therapy must be deemed an appropriate target for safe, gross total resection by the treating surgeon
• History/physical examination within 14 days prior to registration
• Age >= 18
• Karnofsky performance status (KPS) >= 60 within 14 days prior to registration
• A negative urine or serum pregnancy test (in persons of childbearing potential) within =< 14 days prior to registration. Childbearing potential is defined as any person who has experienced menarche and who has not undergone surgical sterilization (hysterectomy or bilateral oophorectomy) or who is not postmenopausal for at least 12 consecutive months
• Participants who are sexually active must agree to use medically acceptable forms of contraception during treatment on this study to prevent pregnancy
• The patient or a legally authorized representative must provide study-specific informed consent prior to study entry and, for patients treated in the United States (U.S.), authorization permitting release of personal health information
• Prior cranial radiotherapy, including whole brain radiotherapy, or SRS to the resection site
• Note: The index lesion to be resected cannot have been previously treated with SRS (i.e. repeat radiosurgery to the same location/lesion is not allowed on this protocol). Previous SRS to other lesions is allowed
• Evidence of leptomeningeal disease (LMD)
• Note: For the purposes of exclusion, LMD is a clinical diagnosis, defined as positive cerebrospinal fluid (CSF) cytology and/or unequivocal radiologic or clinical evidence of leptomeningeal involvement. Patients with leptomeningeal symptoms in the setting of leptomeningeal enhancement by imaging (MRI) would be considered to have LMD even in the absence of positive CSF cytology. In contrast, an asymptomatic or minimally symptomatic patient with mild or nonspecific leptomeningeal enhancement (MRI) would not be considered to have LMD. In that patient, CSF sampling is not required to formally exclude LMD, but can be performed at the investigator's discretion based on level of clinical suspicion
• Any medical conditions which would make this protocol unreasonably hazardous, including, but not limited to: contraindications to general endotracheal anesthesia; intracranial surgery; and stereotactic radiosurgery
• Primary histology of germ cell tumor, small cell carcinoma or lymphoma
• More than one brain metastasis planned for resection
• Inability to undergo MRI with contrast
• Planned administration of cytotoxic chemotherapy or tyrosine/multi-kinase inhibitors within the 3 days prior to, the day of, or within 3 days after the completion of SRS
• Note: chemotherapy and immunotherapy outside of this window are allowed

• Patient must have measurable disease
• Patient must have an Eastern Cooperative Oncology Group (ECOG) performance status between 0-2 OR patient must have Lansky performance status of >= 50% or Karnofsky performance status of >= 50%
• Patient must be deemed potentially eligible for a ComboMATCH Treatment Trial as assessed by the enrolling provider
• All patients must have sequencing results available from a National Cancer Institute (NCI) credentialed Designated Laboratory (DL)
• Patients must have locally advanced or advanced histologically documented solid tumors requiring therapy and meet one of the following criteria:
• Patients must have progressed on at least one line of standard systemic therapy OR
• Patients whose disease has no standard treatment that has been shown to prolong overall survival
• Patient must meet one of the following requirements:
• Patients 18 years and older who have tumor amenable to minimal risk image-guided or direct vision biopsy and must be willing and able to undergo a tumor biopsy to obtain samples for research if the patient is to enroll in a ComboMATCH treatment trial OR
• Patients 18 years and older who do not have disease that is biopsiable at minimal risk to the patient must confirm availability of an archival tumor tissue specimen for submission for research if the patient enrolls to a ComboMATCH Treatment Trial. This tumor tissue must meet the following criteria:
• Tissue must have been collected within 12 months prior to registration to the EAY191 Registration Trial
• Patient must not have had a Response Evaluation Criteria in Solid Tumors (RECIST) response (complete response [CR] or partial response [PR]) to any intervening therapy after collection of the tissue
• Formalin-fixed paraffin-embedded tumor tissue block(s) or slides must be available OR
• Patients under 18 years old must confirm availability of an archival tumor tissue specimen for submission for research if patient enrolls to a ComboMATCH Treatment Trial. This tumor tissue must meet the following criteria:
• Formalin-fixed paraffin-embedded tumor tissue block(s) or slides must be available
• NOTE: See specific ComboMATCH Treatment Trial protocol for tissue collection and management instructions. Performance of the mandatory research biopsy or submission of pre-trial formalin-fixed paraffin-embedded (FFPE) and collection and submission of the blood specimens for the integrated studies will be performed under the consent authority of the specific treatment trial protocol to which the patient is registered. No procedures to collect specimens for research only are to be performed for patients registered to the EAY191 Registration Trial only
• NOTE: Each ComboMATCH Treatment Trial contains specific eligibility criteria. If patient is found to not be eligible for the assigned ComboMATCH Treatment Trial, indication of ineligibility will trigger re-evaluation and potential assignment to another Treatment Trial

• Patient must have enrolled onto EAY191 and must have been given a treatment assignment to ComboMATCH to EAY191-S3 based on the presence of an actionable mutation as defined in EAY191
• GENERAL COMBOMATCH EAY191 REGISTRATION INCLUSION CRITERIA:
• Participants must be enrolled on the ComboMATCH Master Registration Trial EAY191
• Participants must have an activating AKT mutation (a known mutation in AKT1, AKT2, or AKT3, a single nucleotide variant, insertion, or deletion) as determined by the ComboMATCH screening assessment
• GENERAL COMBOMATCH EAY191 REGISTRATION EXCLUSION CRITERIA:
• Participants must not have an activating KRAS, NRAS, HRAS, or BRAF mutation (a single nucleotide variant, insertion, or deletion) as determined by the ComboMATCH screening assessment
• Participants must have disease that can be safely biopsied and agree to a pre-treatment biopsy or have archival tissue available from within 12 months prior to the date of registration on the ComboMATCH Registration Trial (EAY191)
• Participants must have a histologically confirmed non-breast solid malignancy
• Participants must have locally advanced, unresectable, or metastatic disease in the opinion of the treating investigator
• Participants must have measurable disease documented by CT or MRI. Measurable disease must be assessed within 28 days prior to registration. Non-measurable disease must be assessed within 42 days prior to registration. The CT from a combined positron emission tomography (PET)/CT may be used only if it is of diagnostic quality. All known sites of disease must be assessed and documented on the Baseline Tumor Assessment Form (Response Evaluation Criteria in Solid Tumors [RECIST] 1.1). Participants whose only measurable disease is within a previous radiation therapy port must demonstrate clearly progressive disease (in the opinion of the treating investigator) prior to registration
• Participants with known brain metastases must have a CT/MRI scan to evaluate for central nervous system (CNS) disease and show no evidence of progression within 42 days prior to registration
• Participants must have completed any CNS-directed therapy and/or local therapy for spinal cord compression at least 28 days prior to registration
• Participants must not have spinal cord compression or brain metastases unless: (1) metastases have been locally treated and have remained clinically controlled and asymptomatic for at least 14 days prior to registration, AND (2) participant has no residual neurological dysfunction and has been off corticosteroids for at least 24 hours prior to registration
• Participants must not have leptomeningeal disease
• Participants must have progressed within 6 months of taxane-based therapy in the neoadjuvant/adjuvant or metastatic setting
• Participants must not have received any prior AKT inhibitor (e.g., capivasertib or ipatasertib); prior PI3K/mTOR inhibitor is acceptable
• Participants must not be planning to receive any concurrent chemotherapy, immunotherapy, biologic, radiation, or hormonal therapy for cancer treatment while receiving treatment on this study
• Participants must be >= 18 years of age
• Participants must be able to swallow oral medications whole
• Participants must have a pre-study history and physical exam done within 28 days prior to registration
• Participants must have a Zubrod performance status of 0-2 within 28 days prior to registration
• Participants must have adverse events resolved =< grade 1 related to any prior therapy, except alopecia within 14 days prior to registration
• Participants with neuropathy must have resolved to < grade 2 within 14 days prior to registration
• Leukocytes >= 3 x 10^3/uL (within 28 days prior to registration)
• Absolute neutrophil count >= 1.5 x 10^3/uL (within 28 days prior to registration)
• Platelets >= 100 x 10^3/uL (within 28 days prior to registration)
• Total bilirubin =< institutional upper limit of normal (ULN) unless history of Gilbert's disease. Participants with history of Gilbert's disease must have total bilirubin =< 5 x institutional ULN (within 28 days prior to registration)
• Aspartate aminotransferase (AST) & alanine aminotransferase (ALT) =< 3 x institutional ULN (within 28 days prior to registration)
• Participants must have adequate cardiac function, class IIB (2B) or better. Participants with known history or current symptoms of cardiac disease, or history of treatment with cardiotoxic agents, must have a clinical risk assessment of cardiac function using the New York Heart Association Functional Classification
• Participants must have a measured OR calculated creatinine clearance >= 50 mL/min using the following Cockcroft-Gault formula. This specimen must have been drawn within 28 days prior to registration
• Participants with known human immunodeficiency virus (HIV)-infection must be receiving anti-retroviral therapy and have an undetectable viral load test on the most recent test results obtained within 6 months prior to registration
• Participants with evidence of chronic hepatitis B virus (HBV) infection must have undetectable HBV viral load on suppressive therapy within 28 days prior to registration
• Participants with a history of hepatitis C virus (HCV) infection must have been treated and cured. Participants with HCV infection who are currently on treatment must have an undetectable HCV viral load within 28 days prior to registration
• Participants must have an electrocardiography (ECG) performed (if clinically indicated with a corrected QTc interval of =< 470 msec) within 28 days prior to registration
• Participants must not have a history of allergic reactions attributed to compounds of similar chemical or biologic composition to ipatasertib and/or paclitaxel
• Participants must not have an active small/large bowel inflammation such as ulcerative colitis or Crohn's disease
• Participants must not have grade 2 or higher uncontrolled intercurrent illness
• NOTE: To receive an agent, participant must not have any uncontrolled intercurrent illness requiring antibiotic/antiviral/antifungal therapy or interventional procedures. Participants with infections unlikely to be resolved within 2 weeks following registration should not be considered for the trial
• Participants must not have a known grade 2 or higher uncontrolled or untreated hypercholesterolemia or hypertriglyceridemia
• Participants must not have any of the following:
• Cirrhosis at a level of Child-Pugh B (or worse),
• Cirrhosis (any degree) and a history of hepatic encephalopathy, or
• Clinically meaningful ascites resulting from cirrhosis. Clinically meaningful ascites is defined as ascites from cirrhosis requiring diuretics or paracentesis
• Participants must not be receiving any medications or substances that are inhibitors or inducers of CYP3A. Treatment with strong CYP3A inhibitors or strong CYP3A inducers within 2 weeks or 5 drug-elimination half-lives, whichever is longer, prior to initiation of study drug is prohibited.
• NOTE: Because the lists of these agents are constantly changing, it is important to regularly consult a frequently updated medical reference. As part of the enrollment/informed consent procedures, the participant will be counseled on the risk of interactions with other agents, and what to do if new medications need to be prescribed or if the participant is considering a new over-the-counter medicine or herbal product. The participant wallet card should be presented to the participant
• Participants must not have baseline fasting glucose (after 8-hour fast) > 160 mg/dL (8.9 mmol/L) within 28 days prior to registration
• Participants with known diabetes mellitus must not require insulin therapy or have a baseline fasting glucose >150 mg/dL (8.3 mmol/L) or high glycosylated hemoglobin (Hb)A1c, (>= 8.0%), suggesting poorly controlled diabetes
• Participants who are on a stable dose of oral diabetes medication >= 2 weeks prior to initiation of study drug treatment are eligible for enrollment
• Participants with a prior or concurrent malignancy whose natural history or treatment (in the opinion of the treating physician) must not have a potential to interfere with the safety or efficacy assessment of the investigational regimen
• Participants must not have lung disease requiring active systemic therapy or placing participants at increased risk of toxicity related to study-directed therapy including, but not limited to pneumonitis, interstitial lung disease, idiopathic pulmonary fibrosis, cystic fibrosis, aspergillosis, active tuberculosis, or history of opportunistic infections (pneumocystis pneumonia or cytomegalovirus pneumonia)
• Participants must not be pregnant or nursing. Individuals who are of reproductive potential must have agreed to use an effective contraceptive method with details provided as a part of the consent process. A person who has had menses at any time in the preceding 12 consecutive months or who has semen likely to contain sperm is of "reproductive potential". In addition to routine contraceptive methods, "effective contraception" also includes surgery intended to prevent pregnancy (or with a side-effect of pregnancy prevention) including hysterectomy, bilateral oophorectomy, bilateral tubal ligation/occlusion, and vasectomy with testing showing no sperm in the semen
• Participants must not have psychiatric illness/social situations that would limit compliance with study requirements

1. Able to understand the study procedures and agree to participate in the study by providing written informed consent (by participant or legally authorized representative), and assent when applicable. 2. Body weight ≥ 10 kg at time of randomization. 3. Histologically diagnosed H3 K27M-mutant diffuse glioma (new diagnosis). Detection of a missense K27M mutation in any histone H3-encoding gene detected by testing of tumor tissue (immunohistochemistry [IHC] or next-generation sequencing [NGS] in a Clinical Laboratory Improvement Amendments [CLIA]-certified or equivalent laboratory). [Site to provide (as available): ≥ 10 unstained formalin-fixed paraffin-embedded (FFPE) slides from tumor tissue.] 4. At least one, high-quality, contrast-enhanced MRI of the brain obtained prior to starting radiotherapy for submission to sponsor's imaging vendor for central read. For participants who had a surgical resection, this scan must be post-resection; for participants who did not have a resection, this scan may be pre- or post-biopsy. 5. At least one, high-quality, contrast-enhanced MRI of the brain obtained 2 to 6 weeks after completion of frontline radiotherapy. If unable to obtain contrast-enhanced imaging due to lack of venous access after multiple attempts, a patient may still be eligible after collection of a nonenhanced MRI of the brain. [Site to also provide all available MRIs completed prior to initiating treatment with study intervention.] 6. Received frontline radiotherapy 1. Initiated radiotherapy within 12 weeks from the initial diagnosis of H3 K27M-mutant diffuse glioma. 2. Completed radiotherapy within 2 to 6 weeks prior to randomization 3. Completed standard fractionated radiotherapy (eg. 54 to 60 Gy in 28 to 33 fractions given over approximately 6 weeks or hypofractionated radiotherapy (eg. 40 Gy in 15 fractions given over approximately 3 weeks). 7. Karnofsky Performance Status or Lansky Performance Status ≥ 70 at time of randomization. 8. Stable or decreasing dose of corticosteroids and anti-seizure medications for 7 days prior to randomization, if applicable. Stable steroid dose is defined as ≤ 2 mg/day increase (based on dexamethasone dose or equivalent dose of an alternative steroid). 1. Primary spinal tumor. 2. Diffuse intrinsic pontine glioma (DIPG), defined as tumors with a pontine epicenter and diffuse involvement of the pons. 3. Evidence of leptomeningeal spread of disease or cerebrospinal fluid dissemination. 4. Any known concurrent malignancy. 5. New lesion(s) outside of the radiation field. 6. Received whole-brain radiotherapy. 7. Received proton therapy for glioma. 8. Use of any of the following treatments within the specified time periods prior to randomization: 1. ONC201 or ONC206 at any time. 2. Systemic bevacizumab (includes biosimilars) at any time since the initial diagnosis of H3 K27M-mutant diffuse glioma. 3. Temozolomide within past 3 weeks. 4. Tumor treating fields at any time. 5. DRD2 antagonist within past 2 weeks. 6. Any investigational therapy within past 4 weeks. 7. Strong CYP3A4 inhibitors within 3 days. 8. Strong CYP3A4 inducers (includes enzyme-inducing antiepileptic drugs) within 2 weeks. 9. Laboratory test results meeting any of the following parameters within 2 weeks prior to randomization: 1. Absolute neutrophil count < 1.0 × 109/L or platelets < 75 × 109/L. 2. Total bilirubin > 1.5 × upper limit of normal (ULN) (participants with Gilbert's syndrome may be included with total bilirubin > 1.5 × ULN if direct bilirubin is ≤ 1.5 × ULN). 3. Aspartate aminotransferase (AST) or alanine aminotransferase (ALT) > 2.5 × ULN. 4. Creatinine clearance ≤ 60 mL/min as calculated by the Cockcroft Gault equation (or estimated glomerular filtration rate < 60 mL/min/1.73 m2). 10. QTc > 480 msec (based on mean from triplicate electrocardiograms) during screening. 11. Known hypersensitivity to any excipients used in the study intervention formulation. 12. Pregnant, breastfeeding, or planning to become pregnant while receiving study intervention or within 3 months after the last dose. Participants of childbearing potential must have a negative serum pregnancy test within 72 hours prior to receiving the first dose of study intervention. 13. Uncontrolled intercurrent illness including, but not limited to, ongoing or active infection requiring systemic therapy or psychiatric illness/social situations that would limit compliance with study requirements. 14. Any other condition (eg, medical, psychiatric, or social) that, in the opinion of the investigator, may interfere with participant safety or the ability to complete the study according to the protocol.

Inclusion Criteria 1. Participants who are diagnosed with PD consistent with UK Brain Bank criteria and MDS Research Criteria; must include bradykinesia with sequence effect and motor asymmetry. 2. Receiving no anti-parkinsonian therapy 3. Modified Hoehn/Yahr Stage < 3.0 4. Montreal Cognitive Assessment ≥ 24 5. Patient expected to be able to participate in trial without need for additional anti-parkinsonian therapy Sex and Contraceptive/Barrier Requirements: 1. Male participants must agree to practice an acceptable method of highly effective birth control from the screening visit, while on study and for 30 days after receiving the last dose of study drug. Highly effective methods of birth control include sexual abstinence, vasectomy, or a condom with spermicide (men) in combination with their partner's highly effective method. 2. Female participants of childbearing potential and male participants with female partners of childbearing potential must agree to either remain abstinent or use adequate and reliable contraception throughout the study and at least 30 days after the last dose of study drug has been taken. Informed Consent: 1. Capable of giving signed ICF as described in Appendix 1 which includes compliance with the requirements and restrictions listed in the ICF and in this protocol. Other Inclusions: 1. Approved as an appropriate and suitable candidate by the EAC. Exclusion Criteria 1. Diagnosis/suspicion of secondary or atypical parkinsonism 2. Previous procedure or surgery for PD, or anticipation of these during the study 3. High likelihood of needing anti-parkinsonian treatment over the study period, in the opinion of the investigator 4. Clinically significant orthostatic hypotension 5. Clinically significant hallucinations requiring antipsychotic use in the 12 months prior to Screening 6. Clinically significant medical, surgical, psychiatric, or laboratory abnormalities in the judgement of the treating investigator or the EAC Prior/Concomitant Therapy: 1. Past treatment with levodopa, dopaminergic agonists, monoamine oxidase-B inhibitors, supplements containing levodopa (i.e. Mucana pruriens), or A2A antagonists for more than 28 days, or treatment with any of these medications or supplements within 28 days prior to screening 2. Past treatment with irreversible monoamine oxidase-B inhibitors (e.g., selegiline) for more than 28 days; must be discontinued for at least 90 days before screening 3. Currently receiving moderate or strong Cytochrome P450 (CYP) 3A4/5 inducers or CYP3A4/5 inhibitors (except for topical administration) 4. Currently receiving any antipsychotic, metoclopramide, reserpine, or amphetamine. Prior/Concurrent Clinical Study Experience: 1. Current participation in another investigational clinical trial and/or receipt of any investigational medication within 90 days prior to screening 2. Previous randomization into this or another IkT-148009 study Diagnostic Assessments: 1. Active suicidal ideation within one year prior to screening visit, as determined by the Columbia Suicide Rating Scale (answer of "yes" on question 4 or 5) 2. Current diagnosis or history of substance abuse (excluding nicotine or caffeine) by Diagnostic and Statistical Manual of Mental Disorders (DSM)-5 criteria 3. Medical or recreational use of marijuana in the 3 months prior to the screening visit 4. Any social or behavioral reason that would preclude completion of the study, in the judgement of the investigator 5. Any skin condition that would interfere with obtaining adequate samples 6. Evidence of advanced, age-related macular degeneration (neovascular or geographic atrophy) or intermediate macular degeneration as defined by Beckman classification (Large drusen > 125 um and/or any AMD pigmentary abnormalities). Evidence of retina/choroid neovascularization from any cause. Evidence of central serous retinopathy. 7. Abnormal amylase and/or lipase at screening (may be repeated during screening period) 8. Alanine aminotransferase (ALT) or aspartate aminotransferase (AST) levels greater than 2.5 times the upper limit of normal (ULN) 9. Significant renal impairment as determined by the following criteria:
• Creatinine clearance (CrCL) less than or equal to 60 mL/min for subjects < 65 years of age
• Creatine clearance (CrCL) greater than or equal to 55 mL/min and the absence of proteinuria or hematuria for subjects ≥ 65 years of age 10. Currently lactating, pregnant or planning on becoming pregnant during the study

1. History of migraine (with or without aura) for > 6 months before Screening according to the IHS Classification ICHD-319 specifications for pediatric migraine. History may be verified using both medical records and recall by the participant and/or participant's parent(s)/legal representative(s). 2. History of 1 to 8 moderate or severe attacks per month during the 2 months prior to enrollment, with attacks lasting > 3 hours without treatment, and attacks occurring at intervals > 24 hours. 3. Prophylactic migraine medication are permitted if the dose has been stable for at least 12 weeks prior to the Baseline Visit, and the dose is not expected to change during the course of the study. 1. Participants may remain on one (1) medication with possible migraine prophylactic effects, excluding CGRP antagonists [biologic or small molecule], during the treatment phases. 2. Concomitant use of a CGRP antagonist, such as erenumab or fremanezumab, is prohibited. 3. Previously discontinued prophylactic migraine medication must have done so at least 90 days prior to the Screening Visit. 4. Verbally distinguish between migraine and other types of headaches. 5. Participants must have a weight > 40 kg at the Screening Visit. 6. Adequate venous access for blood sampling. 7. Male and female participants ≥ 6 to < 18 years of age (participants must not reach their 18th birthday during the study). 1. History of cluster headache or hemiplegic migraine headache. 2. Confounding and clinically significant pain syndrome that may interfere with the participant's ability to participate in this study. 3. Current psychiatric condition that is uncontrolled and/or untreated for a minimum of 6 months prior to the Screening Visit. Participants with a lifetime history of psychosis and/or mania. 4. History of suicidal behavior or major psychiatric disorder. 5. Current diagnosis or history of substance abuse; positive drug test at Screening. 6. History of moderate or severe head trauma or other neurological disorder (including seizure disorder) or systemic medical disease that is likely to affect central nervous system functioning. 7. Recent or planned surgery, requiring general anesthesia, <8 weeks prior to the Screening Visit. 8. Participant has had gastrointestinal surgery that interferes with physiological absorption and motility (i.e., gastric bypass, duodenectomy, or gastric banding). 9. Current diagnosis of viral hepatitis or a history of liver disease. 10. Conditions considered clinically relevant in the context of the study such as uncontrolled hypertension (high blood pressure), diabetes, a life-threatening allergy

1. History of migraine (with or without aura) for ≥ 6 months before Screening 2. History of 1 to 8 moderate or severe attacks per month during the 2 months prior to enrollment. 3. 1 or more migraine days requiring treatment during the Observation Phase. 4. Prophylactic migraine medication is permitted if the dose has been stable for at least 12 weeks prior to the Baseline Visit 5. Ability to distinguish between migraine and other types of headaches. 6. Weight ≥ 40 kg at the Screening Visit. 7. Adequate venous access for blood sampling. 8. Male and female participants ≥ 6 to < 18 years of age (participants must not reach their 18th birthday before enrollment into the study) 1. History of cluster headache or hemiplegic migraine headache. 2. Confounding and clinically significant pain syndrome 3. Current uncontrolled and/or untreated psychiatric condition for a minimum of 6 months prior to the Screening Visit (lifetime history of psychosis and/or mania are excluded). 4. History of suicidal behavior or major psychiatric disorder. 5. Current diagnosis or history of substance abuse; positive drug test at Screening.

General (applies to all cohorts) 1. Signed written informed consent. 2. Male or female patients aged ≥ 18 years. 3. Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1 at study entry and an estimated life expectancy of at least 3 months. 4. Adequate hematological function. 5. Adequate hepatic function. 6. Adequate renal function. 7. Effective contraception for women of child bearing potential (WOCBP) patients as defined by World Health Organization (WHO) guidelines for 1 "highly effective" method or 2 "effective" methods. Dose Escalation (Monotherapy and Combination) 1. Histologically or cytologically proven locally advanced or metastatic solid tumors of epithelial origin with documented EGFR expression on tumor tissue by IHC and must have progressed on standard of care therapy. 2. Evidence of objective disease, but participation does not require a measurable lesion. Safety PK/PD Expansion Cohorts 1. Histologically or cytologically proven locally advanced or metastatic solid tumor from the following list, where standard therapy has failed, that has been confirmed to have EGFR expression via archival or fresh biopsy tissue prior to study enrollment. i. NSCLC ii. HNSCC iii. CRC iv. Esophageal adenocarcinoma v. Gastric cancer vi. Renal cell carcinoma vii. Pancreatic cancer 2. Disease must be measurable with at least 1 unidimensional measurable lesion by RECIST 1.1. 3. Able and willing to have a fresh tumor biopsy obtained during the screening window and an on-treatment biopsy for pharmacodynamic analysis. Head and Neck Squamous Cell Carcinoma (HNSCC) Expansion Cohorts 1. Histologically or cytologically documented relapsed or metastatic HNSCC that has been confirmed to have EGFR expression via archival or fresh biopsy tissue prior to study enrollment. Primary tumor locations include oropharynx, oral cavity, hypopharynx, or larynx. Participants may not have a primary tumor site of nasopharynx (any histology). 2. Participants must have radiographic disease progression while on or after having received both platinum-based chemotherapy and an anti-PD-(L)1 antibody, administered either concurrent or sequentially. 3. Documented EGFR expression by IHC. 4. Able and willing to have a fresh tumor biopsy obtained during the screening window and an on-treatment biopsy for pharmacodynamic analysis. Colorectal Cancer (CRC) Expansion Cohorts 1. Histologically or cytologically documented relapsed or metastatic colorectal cancer that has been confirmed to have EGFR expression via archival or fresh biopsy tissue prior to study enrollment. 2. Must have received 1 line of either FOLFOX, CAPOX, FOLFIRI, or FOLFOXIRI with or without a biological agent. Prior treatment with an anti-EGFR antibody is required for RAS wild-type participants. 3. Participants cannot be known mismatch repair (MMR)/MSI high. 4. Participants must not have received an anti-PD-(L)1. 5. Participants must have radiographic disease progression while or after receiving treatment for their advanced (recurrent/unresectable/metastatic) disease. 6. Presence of at least 1 tumor lesion accessible for biopsy. A fresh tumor biopsy must be obtained and shipped for analysis at the Sponsor-designated laboratory during the screening window and while on study treatment in accordance with the study Laboratory Manual. Non-Small Cell Lung Cancer (NSCLC) Expansion Cohorts 1. Histologically confirmed NSCLC meeting stage criteria for stage IIIB, stage IV (per the 7th IASCLC classification of NSCLC), or recurrent disease that has been confirmed to have EGFR expression via archival or fresh biopsy tissue prior to study enrollment. 2. Patients must have recurrent or progressive disease during or after first line combination therapy with checkpoint inhibitors and platinum-based chemotherapy. They must not have received any subsequent lines of therapy. 3. Patients with Stage IIIB must be ineligible for local therapies with curative intent (eg, radiotherapy or surgery). 4. Patients must have received and progressed on or after anti-PD-(L)1 therapy including those with actionable genomic alterations. 5. Status for actionable mutations (EGFR, ALK, ROS1, RET, etc.) must be known (when testing is available as per country/region standard of care practices); patients with actionable mutations must have received and progressed on, have been intolerant to, or not be a candidate for standard TKIs (as available per country/region standard of care practices). 6. Presence of at least 1 tumor lesion accessible for biopsy. A fresh tumor biopsy must be obtained and shipped for analysis at the Sponsor-designated laboratory during the screening window and while on study treatment in accordance with the study Laboratory Manual. 1. Participants must not have had chemotherapy, radiotherapy (other than palliative bone-directed radiotherapy), or major surgery, or received another investigational agent within 28 days or 5-half-lives of the drug (if known), whichever is shorter, before the start of study treatment. 2. Concurrent anticancer treatment (eg, cytoreductive therapy, radiotherapy [except for palliative bone-directed radiotherapy], immune therapy, or cytokine therapy [except for erythropoietin]), major surgery (excluding prior diagnostic biopsy), concurrent systemic therapy with steroids or other immunosuppressive agents, or use of any investigational drug within 28 days or 5-half-lives of the drug (if known), whichever is shorter, before the start of study treatment. Short-term administration of systemic steroids (eg, for allergic reactions or the management of irAEs) is allowed. Note: Participants receiving bisphosphonate or denosumab are eligible, provided treatment was initiated at least 14 days before the first dose of DF9001. 3. Previous malignant disease other than the target malignancy to be investigated in this study within the last 3 years, with the exception of basal or squamous cell carcinoma of the skin, low-grade prostate cancer (Gleason score of ≤6), or cervical carcinoma in situ. 4. Life expectancy of less than 3 months. 5. Participants with brain metastases are excluded, unless all of the following criteria are met:
• Central nervous system (CNS) lesions are asymptomatic, previously treated and no active therapy is required (i.e., no steroids for edema).
• Imaging demonstrates stability of disease 28 days from last treatment for CNS metastases. 6. Receipt of any organ transplantation, including autologous or allogeneic stem-cell transplantation. 7. Significant acute or chronic infections (including historic positive test for human immunodeficiency virus [HIV], or active or latent hepatitis B or active hepatitis C tested during the screening window). If HBsAg is negative and the anti-hepatitis B core antibody is positive, then hepatitis B viral DNA load must be undetectable. 8. Preexisting autoimmune disease (except for participants with vitiligo) needing treatment with systemic immunosuppressive agents for more than 28 days within the last 3 years, or clinically relevant immunodeficiencies (eg, dysgammaglobulinemia or congenital immunodeficiencies). Participants with a history of immune related endocrinopathies (e.g. hypothyroidism, type 1 diabetes mellitus [TIDM] and adrenal insufficiency) that are stable on hormone replacement therapy may be eligible for this study. 9. Participants with a known medical history that may place them at risk of known toxicities of EGFR-blockage.
• History of or ongoing keratitis, ulcerative keratitis, or corneal perforation,
• History of cardiopulmonary arrest unless this was caused by an acute, reversible etiology that is no longer present.
• History of or ongoing pulmonary fibrosis or interstitial lung disease. 10. Known severe hypersensitivity reactions to monoclonal antibodies (≥Grade 3 of the NCI-CTCAE v5.0), any history of anaphylaxis, or uncontrolled asthma (ie, 3 or more features of partly controlled asthma). 11. Persisting toxicity related to prior therapy >Grade 1 NCI-CTCAE v5.0; however, alopecia ≤Grade 2, endocrinopathies ≤Grade 2, and sensory neuropathy ≤Grade 2 is acceptable. 12. Participants who have received an anti-PD-(L)1 as a previous line of therapy are eligible for the study, unless they have experienced either:
• a Grade 3 or 4 drug-related toxicity during and attributed to treatment with the anti-PD-(L)1.
• a Grade 2 drug-related toxicity that impacted either the lungs or the nervous system, caused by the administration of the anti-PD-(L)1. 13. Pregnancy or lactation in females during the study. 14. Known alcohol or drug abuse. 15. Serious cardiac illness or medical conditions, including but not limited to:
• History of New York Heart Association class III or IV heart failure or systolic dysfunction (left ventricular ejection fraction [LVEF] <55%).
• High-risk uncontrolled arrhythmias (eg, tachycardia with a heart rate >100/min at rest).
• Significant ventricular arrhythmia (ventricular tachycardia) or higher-grade atrioventricular (AV) block (eg, AV-block, second degree AV block Type 2 [Mobitz 2], or third-degree AV-block).
• Angina pectoris requiring anti-anginal medication.
• Clinically significant valvular heart disease.
• Evidence of transmural infarction on ECGs.
• Poorly controlled hypertension (defined as systolic >160 mm Hg or diastolic >100 mm Hg).
• Clinically relevant uncontrolled cardiac risk factors, clinically relevant pulmonary disease, or any clinically relevant medical condition in the opinion of the Investigator that may limit participation in this study.
• Severe dyspnea at rest due to complications of advanced malignancy or requiring supplementary oxygen therapy. 16. All other significant diseases (eg, inflammatory bowel disease), which, in the opinion of the Investigator, might impair the participant's ability to participate. 17. Any psychiatric condition that would prohibit the understanding or rendering of informed consent. 18. Legal incapacity or limited legal capacity. 19. Incapable of giving signed informed consent, which includes compliance with the requirements and restrictions listed in the ICF and in this protocol.

• Patients must have developed their first or second distant brain relapse(s) at least 8 weeks after upfront SRS and within 21 days prior to randomization
• Distant brain relapse lesions to be treated must measure =< 3.0 cm in maximal extent and total volume of distant brain relapses to be treated must measure < 30 mL on the contrast-enhanced diagnostic magnetic resonance imaging (MRI) brain scan obtained within 21 days prior to randomization
• Distant brain relapse lesions must be diagnosed on MRI, which will include the following elements:
• REQUIRED MRI ELEMENTS
• Post gadolinium contrast-enhanced T1-weighted three-dimensional (3D) spoiled gradient (SPGR). Acceptable 3D SPGR sequences include magnetization-prepared 3D gradient recalled echo (GRE) rapid gradient echo (MP-RAGE), turbo field echo (TFE) MRI, BRAVO (brain volume imaging) or 3D fast FE (field echo). The T1-weighted 3D scan should use the smallest possible axial slice thickness, not to exceed 1.5 mm
• Pre-contrast T1 weighted imaging (3D imaging sequence strongly encouraged)
• A minimum of one axial T2 fluid attenuated inversion recovery (FLAIR) (preferred) or T2 sequence is required. This can be acquired as a 2D or 3D image. If 2D, the images should be obtained in the axial plane
• ADDITIONAL RECOMMENDATIONS
• Recommendation is that an axial T2 FLAIR (preferred) sequence be performed instead of a T2 sequence
• Recommendation is that that pre-contrast 3D T1 be performed with the same parameters as the post-contrast 3D T1
• Recommendation is that imaging be performed on a 3 Tesla (3T) MRI
• Recommendation is that the study participants be scanned on the same MRI instrument at each time point
• Recommendation is that if additional sequences are obtained, these should meet the criteria outlined in Kaufmann et al., 2020
• If additional sequences are obtained, total imaging time should not exceed 60 minutes
• Brain metastasis velocity (BMV) since upfront SRS must be >= 4 brain metastases/year
• The patient or a legally authorized representative must provide study-specific informed consent prior to study entry
• Pathologically (histologically or cytologically) proven diagnosis of non-small cell lung cancer, melanoma, breast cancer, renal cell carcinoma, or gastrointestinal cancer within 10 years prior to randomization. If the original histologic proof of malignancy is greater than 10 years, then pathological (i.e., more recent) confirmation is required (e.g., from a systemic metastasis or brain metastasis)
• Other histologies are not permitted
• History and physical examination within 28 days prior to randomization
• Karnofsky performance status of >= 70 within 28 days prior to randomization
• Calculated creatinine clearance (CrCl) >= 30 ml/min (within 28 days prior to randomization)
• Blood urea nitrogen (BUN) within 1.5 times the institutional upper limit of normal (ULN) (e.g., if the ULN is 20 mg/dL, then BUN up to 30 mg/dL is permitted) (within 28 days prior to randomization)
• Negative urine or serum pregnancy test (in women of childbearing potential) within 14 days prior to randomization
• Prior WBRT or prophylactic cranial irradiation
• Local relapse of metastasis previously treated with upfront SRS (i.e., relapse outside previously SRS-treated metastases is allowed)
• Brain metastases from primary germ cell tumor, small cell carcinoma, or lymphoma
• Definitive leptomeningeal metastasis
• Planned cytotoxic chemotherapy on the same day as SRS or HA-WBRT; concurrent immunotherapy is permitted
• Radiographic evidence of enlargement or other architectural distortion of the lateral ventricles, including placement of external ventricular drain or ventriculoperitoneal shunt
• Known history of demyelinating disease such as multiple sclerosis
• Inability to swallow pills
• Contraindication to MR imaging such as non-MR conditional implanted metal devices or unknown metallic foreign bodies, or contraindication to gadolinium contrast administration during MR imaging, such as anaphylactic allergy that cannot be adequately addressed with pre-contrast medications or acute kidney injury
• Contraindications to memantine, including:
• Allergy, including prior allergic reaction to memantine
• Intractable seizures on adequate anticonvulsive therapy-more than 1 seizure per month for the past 2 months
• Current use of N-methyl-D-aspartate (NMDA) agonist
• Current alcohol or drug abuse, which can exacerbate lethargy/dizziness with memantine
• Severe, active co-morbidity defined as follows:
• Unstable angina and/or congestive heart failure requiring hospitalization within the last 6 months
• Transmural myocardial infarction within the last 6 months
• Acute bacterial or fungal infection requiring intravenous antibiotics at the time of randomization
• Chronic obstructive pulmonary disease exacerbation or other acute respiratory illness precluding study therapy at the time of randomization
• Severe hepatic disease defined as a diagnosis of Child-Pugh class B or C hepatic disease
• Renal tubular acidosis or metabolic acidosis
• Human immunodeficiency virus (HIV) positive with CD4 count < 200 cells/microliter. Note that patients who are HIV positive are eligible, provided they are under treatment with highly active antiretroviral therapy (HAART) and have a CD4 count >= 200 cells/microliter within 30 days prior to randomization. Note also that HIV testing is not required for eligibility for this protocol
• Pregnant or lactating women, or women of childbearing potential and men who are sexually active and not willing/able to use medically acceptable forms of contraception; this exclusion is necessary because the medication and radiation involved in this study has unknown effects on the unborn fetus