• Availability of an eligible haploidentical donor
• Hematologic malignancy or solid tumor
• Patients with more than one malignancy (hematologic or solid tumor) are eligible
• Patients with hematologic malignancy must have no HLA identical sibling or suitable unrelated donor OR time needed to find an acceptable unrelated donor match would likely result in disease progression such that the patient may become ineligible for any type of potentially curative transplant
• Relapsed or primary therapy-refractory AML with bone marrow blast < 20%
• High-risk refractory or relapsed ALL in patients for whom transplantation is deemed indicated (relapse occurring < 30 months from diagnosis, patients relapsing after previous allogeneic transplant, relapse after 2nd remission, primary induction failure or hypodiploidy)
• Relapsed Hodgkin lymphoma unable to achieve 2nd remission or Very Good Partial Response (VGPR) and therefore ineligible to receive autologous hematopoietic stem cell transplant (auto-HSCT)
• Hodgkin lymphoma relapsing after auto-HSCT
• Primary refractory or relapsed non-Hodgkin lymphoma unable to achieve 2nd remission or VGPR and therefore ineligible to receive auto-HSCT
• Non-Hodgkin lymphoma relapsing after auto-HSCT
• Myelodysplastic Syndrome/Myeloproliferative Syndrome Solid Tumor
• Patients with solid tumor must have failed or have been ineligible to receive auto-HSCT or if auto-HSCT would not offer > 20% chance of cure
• Neuroblastoma
• high risk with relapsed or refractory disease
• Soft tissue sarcomas (Rhabdomyosarcoma, Ewing sarcoma, Primitive Neuroectodermal Tumor or other high-risk extracranial solid tumors)
• Relapsed or primary refractory metastatic
• 1st complete remission, but very high-risk features (i.e., < 20% survival with conventional therapy)
• Osteosarcoma
• Failure to achieve Complete Response (CR) following initial therapy
• Relapsed with pulmonary or bone metastases and did not achieve a CR with surgery and/or chemotherapy
• Karnofsky (patients > 16 years) or Lansky (patients 16 years or older) performance score of ≥ 60
• Life expectancy of ≥ 3 months
• Patient must have fully recovered from acute toxic effects of all prior chemotherapy, immunotherapy, or radiotherapy prior to entering this study
• Study enrollment no earlier than 3 months after preceding HSCT
• Glomerular Filtration Rate (GFR) ≥ 60 ml/min/1.73m2
• Total bilirubin < 3 mg/dL
• ALT (alanine aminotransferase, SCPT) ≤ 5 x Upper LImit of Normal (ULN) for age
• Ejection fraction of > 40% by Multigated Acquisition Scan (MUGA) or echocardiogram
• No evidence of dyspnea at rest
• No supplemental oxygen requirement
• If measured, carbon monoxide diffusion capacity (DLCO) >50%
• No severe peripheral neuropathy, signs of leukoencephalopathy or active Central Nervous System (CNS) infection
• Patients with seizure disorders may be enrolled if seizures are well controlled on anticonvulsant therapy
• If of reproductive potential, negative pregnancy test and willing to use effective birth control method
• Informed consent from patient or legal guardian (if patient is minor) Inclusion Criteria for Donors:
• Donor must be 18 years of age minimum, 65 years of age maximum
• Donor must be in good general health as determined by evaluating medical provider
• Must meet donor criteria for human cells, tissues, and cellular and tissue-based products per Code of Federal Regulations 21 CFR 1271, subpart C. Specifically:
• Donor screening in accordance with 1271.75 indicates that the donor:
• Is free from risk factors for, and clinical evidence of, infection due to relevant communicable disease agents and diseases; and
• Is free from communicable disease risks associated with xenotransplantation; and
• The results of donor testing for relevant communicable disease agents in accordance with 1271.80 and 1271.85 are negative or nonreactive, except as provided in 1271.80(d)(1).
• Haploidentical by HLA-typing
• Preference will be given to donors who demonstrate KIR incompatibility with recipient HLA class I ligands defined as the donor expressing a KIR gene for which the corresponding HLA class I ligand is not expressed by the recipient.
• Negative testing for relevant communicable diseases:
• Hepatitis B surface antigen (HBsAg)
• Hepatitis B core antibody (Anti-HBc)
• Hepatitis C antibody (Anti-HCV)
• HIV 1 & 2 antibody (Anti-HIV-1, 2 plus O)
• HTLV I/II antibody (Anti-HTLV I/II)
• RPR (Syphilis TP)
• CMV (Capture CMV)
• MPX for: HepB (HBV-PCR), HepC (HCV-PCR), HIV (HIV-PCR)
• NAT for West Nile Virus (WNV-PCR)
• T. Cruzi
•EIA (Chagas)
• Pregnant or breast-feeding
• HIV infection
• Heart failure or uncontrolled cardiac rhythm disturbance
• Uncontrolled, Serious Active Infection
• Prior organ allograft
• Significant serious intercurrent illness unrelated to cancer or its treatment not covered by other exclusion criteria expected to significantly increase the risk of HSCT
• Any mental or physical condition, in the opinion of the PI (or PI designee), which could interfere with the ability of the subject (or the only parent or legal guardian available to care for the subject) to understand or adhere to the requirements of the study
• Enrollment in any other clinical study from screening up to Day 100 (unless PI judges such enrollment would not interfere with endpoints of this study) Exclusion Criteria for Donors:
• Lactating females
• Pregnant females

All Patients
• Previously confirmed (histologically or cytologically) pediatric solid tumor (e.g., neuroblastoma, sarcoma), lymphoma (including Hodgkin's lymphoma), or malignant brain tumors that are clinically or radiographically suspected to be relapsed, refractory, or recurrent for which there are no standard treatment options with curative potential. Note: patients with diffuse intrinsic pontine glioma (DIPG) may enroll without histological or cytological confirmation.
• ≥ 2 years of age and ≤ 25 years of age at time of consent/assent
• If ≥ age 16 years, Karnofsky performance status of ≥ 60. If < age 16 years, Lansky performance status ≥ 60
• Platelets ≥ 75,000/µL (last transfusion, if any, must be at least 1 week prior to study registration, and, unless deemed medically necessary, no transfusions are allowed between registration and dosing)
• Absolute neutrophil count ≥ 750/µL
• Hemoglobin ≥ 8 g/dL (last transfusion must be at least 1 week prior to study registration, and, unless deemed medically necessary, no transfusions are allowed between registration and dosing)
• Using the bedside Schwartz formula, estimated GFR (creatinine clearance) > 60 ml/min/1.73m2
• Alanine aminotransferase < 3 × ULN
• Bilirubin < 2 × ULN
• Patients who have undergone autologous or allogeneic bone marrow transplant must be at least 3 months from transplant.
• Patients enrolling at total dose levels > 30 millicurie (mCi)/m2 must have availability or ability to collect an autologous hematopoietic stem cell back-up product prior to CLR 131 administration. At minimum, 2 x 10^6/kg cryopreserved CD34+ cells must be available.
• Patient or his or her legal representative is judged by the Investigator to have the initiative and means to be compliant with the protocol. Patients with Pediatric Solid Tumor or Lymphoma
• At least 1 measurable lesion with longest diameter of at least 10 mm. Patients with a lesion(s) that are determined to be Metaiodobenzylguanidine (MIBG) or positron emission tomography (PET) positive may be enrolled at the investigator's discretion, even if not associated with a measurable lesion of at least 10 mm. Patients with neuroblastoma who have detectable disease may enroll provided they meet the requirements of the International Neuroblastoma Response Criteria.
• Patients with known brain metastases must have completed any radiotherapy or systemic treatments for brain metastases prior to enrollment; by investigator assessment be considered stable with no new signs or symptoms for at least 1 month, and on a stable dose of steroids (unchanged for three weeks prior to registration or on a steroid tapering regimen). Patients with Recurrent or Refractory Brain Tumors
• At least 1 measurable lesion with longest diameter of at least 10 mm on any imaging sequence.
• Patients with previously known neurological deficits must be clinically stable at time of enrollment and able to complete all study related procedures. Patients with documented or newly diagnosed neurological deficits will be enrolled at the investigator's discretion.
• If patient receives steroids for neurological symptom control, the dose must be stable (unchanged for three weeks prior to registration) or on a steroid tapering regimen. Initiation of steroids per routine care immediately prior to CLR 131 dosing is acceptable.
• Patients receiving active treatment for central nervous system metastases or those that are likely to require active treatment during anticipated participation in this trial. Patients with stable brain metastases treated with steroids may enroll at the investigator's discretion
• For solid tumor and lymphoma patients only, central nervous system involvement unless previously treated with surgery, systemic therapy, or radiotherapy with the patient neurologically stable. Patients with metastatic brain tumors that have been previously treated are allowed, provided the patient is neurologically stable (determined at the investigator's discretion).
• Antitumor therapy or investigational therapy, within 2 weeks of dosing. For certain types of radiation (craniospinal, total abdominal, whole lung [spot irradiation to skull-based metastases is not considered craniospinal radiation for the purposes of this study]), at least 3 months must have elapsed. No washout is required for palliative focal radiation. NOTE: Patients participating in non-interventional clinical trials (i.e., non-drug) are allowed to participate in this trial
• Patients previously treated with iodine-131 (131I)-MIBG who have already received a cumulative I-131 dose > 54 mCi/kg or who would exceed 54 mCi/kg by participating in this trial, are not eligible.

• Patient must have enrolled onto APEC1621SC and must have been given a treatment assignment to Molecular Analysis for Therapy Choice (MATCH) to APEC1621F based on the presence of an actionable mutation
• Patients must be >= than 12 months and =< 21 years of age at the time of study enrollment.
• Patients must have a body surface area >= 0.5 m^2 at enrollment
• Patients must have radiographically measurable disease at the time of study enrollment. Patients with neuroblastoma who do not have measurable disease but have iobenguane (MIBG) positive (+) evaluable disease are eligible; measurable disease in patients with CNS involvement is defined as any lesion that is at minimum 10 mm in one dimension on a standard MRI or CT
• Note: The following do not qualify as measurable disease:
• Malignant fluid collections (e.g., ascites, pleural effusions)
• Bone marrow infiltration except that detected by MIBG scan for neuroblastoma
• Lesions only detected by nuclear medicine studies (e.g., bone, gallium or positron emission tomography [PET] scans) except as noted for neuroblastoma
• Elevated tumor markers in plasma or cerebrospinal fluid (CSF)
• Previously radiated lesions that have not demonstrated clear progression post radiation
• Leptomeningeal lesions that do not meet the measurement requirements for Response Evaluation Criteria in Solid Tumors (RECIST) 1.1
• Karnofsky >= 50% for patients > 16 years of age and Lansky >= 50 for patients =< 16 years of age
• Note: Neurologic deficits in patients with CNS tumors must have been relatively stable for at least 7 days prior to study enrollment; patients who are unable to walk because of paralysis, but who are up in a wheelchair, will be considered ambulatory for the purpose of assessing the performance score
• Patients must have fully recovered from the acute toxic effects of all prior anti-cancer therapy and must meet the following minimum duration from prior anti-cancer directed therapy prior to enrollment; if after the required timeframe, the numerical eligibility criteria are met, e.g. blood count criteria, the patient is considered to have recovered adequately
• Cytotoxic chemotherapy or other anti-cancer agents known to be myelosuppressive: >= 21 days after the last dose of cytotoxic or myelosuppressive chemotherapy (42 days if prior nitrosourea)
• Anti-cancer agents not known to be myelosuppressive (e.g. not associated with reduced platelet or absolute neutrophil counts [ANC] counts): >= 7 days after the last dose of agent
• 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
• Corticosteroids: if used to modify immune adverse events related to prior therapy, >= 14 days must have elapsed since last dose of corticosteroid
• Hematopoietic growth factors: >= 14 days after the last dose of a long-acting growth factor (e.g. pegfilgrastim) or 7 days for short-acting growth factor; for growth factors that have known adverse events occurring beyond 7 days after administration, this period must be extended beyond the time during which adverse events are known to occur; the duration of this interval must be discussed with the study chair and the study-assigned research coordinator
• Interleukins, interferons and cytokines (other than hematopoietic growth factors): >= 21 days after the completion of interleukins, interferon or cytokines (other than hematopoietic growth factors)
• Stem cell Infusions (with or without total body irradiation [TBI]):
• Allogeneic (non-autologous) bone marrow or stem cell transplant, or any stem cell infusion including donor lymphocyte infusion (DLI) or boost infusion: >= 84 days after infusion and no evidence of graft versus host disease (GVHD)
• Autologous stem cell infusion including boost infusion: >= 42 days
• Cellular therapy: >= 42 days after the completion of any type of cellular therapy (e.g. modified T cells, natural killer [NK] cells, dendritic cells, etc.)
• Radiation therapy (XRT)/external beam irradiation including protons: >= 14 days after local XRT; >= 150 days after TBI, craniospinal XRT or if radiation to >= 50% of the pelvis; >= 42 days if other substantial none marrow (BM) radiation
• Note: Radiation may not be delivered to "measurable disease" tumor site(s) being used to follow response to subprotocol treatment
• Radiopharmaceutical therapy (e.g., radiolabeled antibody, 131I-MIBG): >= 42 days after systemically administered radiopharmaceutical therapy
• Patients must not have received prior exposure to ensartinib; prior treatment with other ALK inhibitors is permitted given that at least 5 half-lives or 21 days have elapsed since therapy discontinuation, whichever is greater
• For patients with solid tumors without known bone marrow involvement:
• Peripheral absolute neutrophil count (ANC) >= 1000/mm^3 (within 7 days prior to enrollment)
• Platelet count >= 100,000/mm^3 (transfusion independent, defined as not receiving platelet transfusions for at least 7 days prior to enrollment) (within 7 days prior to enrollment)
• Patients with known bone marrow metastatic disease will be eligible for study provided they meet the blood counts (may receive transfusions provided they are not known to be refractory to red cell or platelet transfusions); these patients will not be evaluable for hematologic toxicity
• Creatinine clearance or radioisotope glomerular filtration rate (GFR) >= 70 ml/min/1.73 m^2 (within 7 days prior to enrollment) or a serum creatinine based on age/gender as follows (within 7 days prior to enrollment):
• Age 1 to < 2 years: maximum serum creatinine 0.6 mg/dL for male and 0.6 mg/dL for female
• Age 2 to < 6 years: maximum serum creatinine 0.8 mg/dL for male and 0.8 mg/dL for female
• Age 6 to < 10 years: maximum serum creatinine 1 mg/dL for male and 1 mg/dL for female
• Age 10 to < 13 years: maximum serum creatinine 1.2 mg/dL for male and 1.2 mg/dL for female
• Age 13 to < 16 years: maximum serum creatinine 1.5 mg/dL for male and 1.4 mg/dL for female
• Age >= 16 years: maximum serum creatinine 1.7 mg/dL for male and 1.4 mg/dL for female
• Bilirubin (sum of conjugated + unconjugated) =< 1.5 x upper limit of normal (ULN) for age (within 7 days prior to enrollment)
• Serum glutamic pyruvic transaminase (SGPT) (alanine aminotransferase [ALT]) =< 135 U/L (within 7 days prior to enrollment) (for the purpose of this study, the ULN for SGPT is 45 U/L)
• Serum albumin >= 2 g/dL (within 7 days prior to enrollment)
• Patients must be able to swallow intact capsules
• All patients and/or their parents or legally authorized representatives must sign a written informed consent; assent, when appropriate, will be obtained according to institutional guidelines
• Pregnant or breast-feeding women will not be entered on this study because there is currently no available information regarding human fetal or teratogenic toxicities; pregnancy tests must be obtained in girls who are post-menarchal; males or females of reproductive potential may not participate unless they have agreed to use an effective contraceptive method for the duration of study treatment and for one week after the last dose of ensartinib
• Concomitant medications
• Corticosteroids: patients receiving corticosteroids who have not been on a stable or decreasing dose of corticosteroid for at least 7 days prior to enrollment are not eligible; if used to modify immune adverse events related to prior therapy, >= 14 days must have elapsed since last dose of corticosteroid
• Investigational drugs: patients who are currently receiving another investigational drug are not eligible
• Anti-cancer agents: patients who are currently receiving other anti-cancer agents are not eligible
• Anti-GVHD agents post-transplant: patients who are receiving cyclosporine, tacrolimus or other agents to prevent graft-versus-host disease post bone marrow transplant are not eligible for this trial
• CYP3A4 agents: patients who are currently receiving drugs that are strong inducers or strong inhibitors of CYP3A4 are not eligible; strong inducers or inhibitors of CYP3A4 should be avoided from 14 days prior to enrollment to the end of the study
• Note: CYP3A4 inducing anti-epileptic drugs and dexamethasone for CNS tumors or metastases, on a stable dose, are allowed
• Patients who have an uncontrolled infection are not eligible
• Patients who have received a prior solid organ transplantation are not eligible
• Patients who in the opinion of the investigator may not be able to comply with the safety monitoring requirements of the study are not eligible

• ELIGIBILITY CRITERIA FOR ENROLLMENT ONTO APEC1621SC: Patients must be >= 12 months and =< 21 years of age at the time of study enrollment
• ELIGIBILITY CRITERIA FOR ENROLLMENT ONTO APEC1621SC: Patients with recurrent or refractory solid tumors, including non-Hodgkin lymphomas, histiocytoses (e.g. langerhans cell histiocytosis [LCH], juvenile xanthogranuloma [JXG], histiocytic sarcoma), and central nervous system (CNS) tumors are eligible; patients must have had histologic verification of malignancy at original diagnosis or relapse except in patients with intrinsic brain stem tumors, optic pathway gliomas, or patients with pineal tumors and elevations of cerebrospinal fluid (CSF) or serum tumor markers including alpha-fetoprotein or beta-human chorionic gonadotropin (HCG); in cases where patient enrolls prior to histologic confirmation of recurrent disease, patient is ineligible and should be withdrawn from study if histology fails to confirm recurrence; please note: Patients with Hodgkin lymphoma and plexiform neurofibroma are not eligible
• ELIGIBILITY CRITERIA FOR ENROLLMENT ONTO APEC1621SC: Tumor Testing Requirement: Tumor sample availability requirement for stage 1 of Pediatric MATCH (patients enrolled from start of study in July 2017 through 12/31/21); Patients must have an formalin-fixed paraffin-embedded (FFPE) tumor sample available for MATCH study testing from a biopsy or surgery that was performed at any point after initial tumor recurrence/progression, or be planned to have a procedure to obtain such a sample that is considered to be of potential benefit by the treating clinicians; a tumor sample from a clinically performed diagnostic (pre-treatment) biopsy will be acceptable for enrollment onto Pediatric MATCH only for children with high-grade gliomas of the brainstem (diffuse intrinsic pontine gliomas) or thalamus
• Please note: Samples that have been decalcified using standardly utilized acid-based decalcification methods are not generally suitable for MATCH study testing; the nucleic acids will have been degraded in the decalcification process
• ELIGIBILITY CRITERIA FOR ENROLLMENT ONTO APEC1621SC: Tumor molecular profiling report availability requirement for Stage 2 of Pediatric MATCH (patients enrolled starting 2022): In stage 2 of the study, no tumor samples will be submitted for centralized clinical tumor profiling; instead, a tumor molecular profiling report from a College of American Pathologists (CAP)/ Clinical Laboratory Improvements Amendments (CLIA)-approved testing laboratory must be submitted for review by the Molecular Review Committee (MRC)
• This molecular profiling must have been performed on a tumor sample that was obtained at any point after initial tumor recurrence/progression and must be accompanied by a pathology report for the same tumor specimen; a molecular profiling report for a diagnostic (pre-treatment) tumor sample will be acceptable for enrollment onto Pediatric MATCH only for children with high-grade gliomas of the brainstem (diffuse intrinsic pontine gliomas) or thalamus. In the event that molecular profiling reports are available from multiple timepoints, the most recent report should be prioritized for study submission
• ELIGIBILITY CRITERIA FOR ENROLLMENT ONTO APEC1621SC: Karnofsky >= 50% for patients > 16 years of age and Lansky >= 50 for patients =< 16 years of age); note: neurologic deficits in patients with central nervous system (CNS) tumors must have been stable for at least 7 days prior to study enrollment; patients who are unable to walk because of paralysis, but who are up in a wheelchair, will be considered ambulatory for the purpose of assessing the performance score
• ELIGIBILITY CRITERIA FOR ENROLLMENT ONTO APEC1621SC: Patients must have radiographically measurable disease; measurable disease based on imaging obtained less than or equal to 56 days prior to enrollment; patients with neuroblastoma who do not have measurable disease but have metaiodobenzylguanidine (MIBG) positive (+) evaluable disease are eligible; measurable disease in patients with CNS involvement is defined as any lesion that is at minimum 10 mm in one dimension on standard magnetic resonance imaging (MRI) or computed tomography (CT)
• Note: The following do not qualify as measurable disease:
• Malignant fluid collections (e.g., ascites, pleural effusions)
• Bone marrow infiltration except that detected by MIBG scan for neuroblastoma
• Lesions only detected by nuclear medicine studies (e.g., bone, gallium or positron emission tomography [PET] scans) except as noted for neuroblastoma
• Elevated tumor markers in plasma or CSF
• Previously radiated lesions that have not demonstrated clear progression post radiation
• Leptomeningeal lesions that do not meet the measurement requirements for Response Evaluation Criteria in Solid Tumors (RECIST) 1.1
• GENERAL INCLUSION CRITERIA FOR SUBPROTOCOLS: NOTE: patient does not need to meet all subprotocol criteria at time of enrollment onto the APEC1621SC screening protocol, but will need to meet all criteria prior to enrollment on any assigned treatment subprotocol. Patients must be enrolled onto a subprotocol within 2 weeks (14 days) of treatment assignment
• GENERAL INCLUSION CRITERIA FOR SUBPROTOCOLS: Karnofsky >= 50% for patients > 16 years of age and Lansky >= 50 for patients =< 16 years of age); Note: neurologic deficits in patients with CNS tumors must have been stable for at least 7 days prior to study enrollment; patients who are unable to walk because of paralysis, but who are up in a wheelchair, will be considered ambulatory for the purpose of assessing the performance score
• GENERAL INCLUSION CRITERIA FOR SUBPROTOCOLS: At the time of treatment with subprotocol specified therapy, the patients must have radiographically measurable disease; patients with neuroblastoma who do not have measurable disease but have MIBG+ evaluable are eligible; measurable disease in patients with CNS involvement is defined as any lesion that is at minimum 10 mm in one dimension on standard MRI or CT
• Note: The following do not qualify as measurable disease:
• Malignant fluid collections (e.g., ascites, pleural effusions)
• Bone marrow infiltration except that detected by MIBG scan for neuroblastoma
• Lesions only detected by nuclear medicine studies (e.g., bone, gallium or positron emission tomography [PET] scans) except as noted for neuroblastoma
• Elevated tumor markers in plasma or CSF
• Previously radiated lesions that have not demonstrated clear progression post radiation
• Leptomeningeal lesions that do not meet the measurement requirements for RECIST 1.1
• GENERAL INCLUSION CRITERIA FOR SUBPROTOCOLS: At the time of enrollment onto a subprotocol, the following general criteria for initiation of therapy will be required:
• Patients must have fully recovered from the acute toxic effects of all prior anticancer therapy and must meet the following minimum duration from prior anticancer directed therapy prior to enrollment to the subprotocol; if after the required timeframe, the numerical eligibility criteria are met, e.g. blood count criteria, the patient is considered to have recovered adequately
• Cytotoxic chemotherapy or other anticancer agents known to be myelosuppressive: for agents not listed, the duration of this interval must be discussed with the study chair and the study-assigned research coordinator prior to enrollment >= 21 days after the last dose of cytotoxic or myelosuppressive chemotherapy (42 days if prior nitrosourea)
• Anticancer agents not known to be myelosuppressive (e.g. not associated with reduced platelet or absolute neutrophil counts [ANC]): >= 7 days after the last dose of agent; for agents not listed, the duration of this interval must be discussed with the study chair and the study-assigned research coordinator prior to enrollment
• 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
• Corticosteroids: If used to modify immune adverse events related to prior therapy, >= 14 days must have elapsed since last dose of corticosteroid
• Hematopoietic growth factors: >= 14 days after the last dose of a long-acting growth factor (e.g. Neulasta) or 7 days for short-acting growth factor; for agents that have known adverse events occurring beyond 7 days after administration, this period must be extended beyond the time during which adverse events are known to occur; the duration of this interval must be discussed with the study chair and the study-assigned research coordinator
• Interleukins, interferons and cytokines (other than hematopoietic growth factors): >= 21 days after the completion of interleukins, interferon or cytokines (other than hematopoietic growth factors)
• Stem cell infusions (with or without total-body irradiation [TBI]):
• Allogeneic (non-autologous) bone marrow or stem cell transplant, or any stem cell infusion including donor lymphocyte infusion (DLI) or boost infusion: >= 84 days after infusion and no evidence of graft versus host disease (GVHD)
• Autologous stem cell infusion including boost infusion: >= 42 days
• Cellular therapy: >= 42 days after the completion of any type of cellular therapy (e.g. modified T cells, natural killer (NK) cells, dendritic cells, etc.)
• X-ray therapy (XRT)/External Beam Irradiation including Protons: >= 14 days after local XRT; >= 150 days after TBI, craniospinal XRT or if radiation to >= 50% of the pelvis; >= 42 days if other substantial bone marrow (BM) radiation; note: radiation may not be delivered to "measurable disease" tumor site(s) being used to follow response to subprotocol treatment
• Radiopharmaceutical therapy (e.g., radiolabeled antibody, 131I-MIBG): >= 42 days after systemically administered radiopharmaceutical therapy
• GENERAL INCLUSION CRITERIA FOR SUBPROTOCOLS: For patients with solid tumors without known bone marrow involvement:
• Peripheral absolute neutrophil count (ANC) >= 1000/mm^3
• Platelet count >= 100,000/mm^3 (transfusion independent, defined as not receiving platelet transfusions for at least 7 days prior to enrollment)
• GENERAL INCLUSION CRITERIA FOR SUBPROTOCOLS: Patients with known bone marrow metastatic disease will be eligible for study provided they meet the blood counts (may receive transfusions provided they are not known to be refractory to red cell or platelet transfusions); these patients will not be evaluable for hematologic toxicity
• GENERAL INCLUSION CRITERIA FOR SUBPROTOCOLS: 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: 1 to < 2 years; maximum serum creatinine (mg/dL): male 0.6; female 0.6
• Age: 2 to < 6 years; maximum serum creatinine (mg/dL): male 0.8; female 0.8
• Age: 6 to < 10 years; maximum serum creatinine (mg/dL): male 1; female 1
• Age: 10 to < 13 years; maximum serum creatinine (mg/dL): male 1.2; female 1.2
• Age: 13 to < 16 years; maximum serum creatinine (mg/dL): male 1.5; female 1.4
• Age: >= 16 years; maximum serum creatinine (mg/dL): male 1.7; female 1.4
• GENERAL INCLUSION CRITERIA FOR SUBPROTOCOLS: Bilirubin (sum of conjugated + unconjugated) =< 1.5 x upper limit of normal (ULN) for age
• GENERAL INCLUSION CRITERIA FOR SUBPROTOCOLS: Serum glutamate pyruvate transaminase (SGPT) (alanine transferase [ALT]) =< 135 U/L (for the purpose of this study, the ULN for SGPT is 45 U/L)
• GENERAL INCLUSION CRITERIA FOR SUBPROTOCOLS: Patients must be able to swallow intact capsules/tablets, unless otherwise specified in the subprotocol to which they are assigned
• GENERAL INCLUSION CRITERIA FOR SUBPROTOCOLS: Agent specific limitations on prior therapy will be included with specific treatment subprotocols
• GENERAL EXCLUSION CRITERIA FOR SUBPROTOCOLS: Pregnant or breast-feeding women will not be entered on this study due to risks of fetal and teratogenic adverse events as seen in animal/human studies, or because there is currently no available information regarding human fetal or teratogenic toxicities; pregnancy tests must be obtained in females who are post-menarchal; males or females of reproductive potential may not participate unless they have agreed to use an effective contraceptive method
• GENERAL EXCLUSION CRITERIA FOR SUBPROTOCOLS: Concomitant medications
• Corticosteroids: at the time of consent and enrollment to regimen specific subprotocols, patients receiving corticosteroids who have not been on a stable or decreasing dose of corticosteroid for at least 7 days prior to enrollment to the subprotocol will not be eligible; if used to modify immune adverse events related to prior therapy, >= 14 days must have elapsed since last dose of corticosteroid
• Investigational drugs: patients must meet criteria for prior therapy at the time of consent and enrollment to a subprotocol; other investigational agents may not be administered to patients while they are receiving study drug as part of a subprotocol
• Anticancer agents: patients must meet criteria for prior therapy at the time of consent and enrollment to a subprotocol; other investigational agents may not be administered to patients while they are receiving study drug as part of a subprotocol
• Anti-GVHD agents post-transplant: patients who are receiving cyclosporine, tacrolimus or other agents to prevent graft-versus-host disease post bone marrow transplant are not eligible
• GENERAL EXCLUSION CRITERIA FOR SUBPROTOCOLS: Patients who have an uncontrolled infection are not eligible
• GENERAL EXCLUSION CRITERIA FOR SUBPROTOCOLS: Patients who have had a prior solid organ transplant are not eligible
• GENERAL EXCLUSION CRITERIA FOR SUBPROTOCOLS: Additional agent specific criteria will be included with specific treatment subprotocols

INCLUSION CRITERIA: 1. Diagnosis: Refractory or relapsed neuroblastoma with original diagnosis based on tumor histopathology or elevated urine catecholamines with typical tumor cells in the bone marrow, OR pheochromocytoma or paraganglioma (less than 12 years of age) not amenable to curative surgery. 2. Age ≥12 months and able to cooperate with radiation safety restrictions during therapy period with/without pharmacologic anxiolysis. 3. Disease status: Failure to respond to standard therapy (usually combination chemotherapy with or without radiation and surgery) or development of progressive disease at any time (any new lesion or an increase in size of >25% of a pre-existing lesion). Disease evaluation must be completed within 8 weeks of study entry. If possible, the disease evaluation should take place subsequent to any intervening therapy; if intervening therapy does occur, evaluations should be done as clinically indicated. If patient has received prior treatment with MIBG, they must have a response or stable disease after the most recent MIBG infusion. Patient may have PD after showing an initial response to MIBG therapy (at [or around] the day 35-63 post-MIBG therapy evaluation). 4. Stem cells: Patients must have a hematopoietic stem cell product available for re-infusion after 131I-MIBG treatment at doses of 12 mCi/kg. If no stem cells are available, then the dose of 131I-MIBG should be <12 mCi/kg. 5. Prior Therapy: Patients may enter this study with or without re-induction therapy for recurrent tumor. Patients must have fully recovered from the toxic effects of any prior therapy, meeting the following criteria: 1. At least 2 weeks should have elapsed since any anti-tumor therapy and the patient must meet certain hematologic criteria. 2. 3 months should have elapsed in the case of completing external beam radiation for total abdominal, whole lung, total body irradiation (spot irradiation to skull-based metastases is NOT a contraindication). Patients who receive localized emergency radiation to sites of life-threatening or function-threatening disease prior to or immediately after establishment of the definitive diagnosis are not contraindicated for treatment on this protocol. 3. Cytokine therapy (e.g. G-CSF, GM-CSF, IL-6, erythropoietin) must be discontinued a minimum of 24 hours prior to 131I-MIBG therapy. 4. Minimum of six weeks from previous 131I-MIBG therapy. 5. The lifetime cumulative injected activity should be evaluated by the Investigator on a case-by-case basis with special attention to any recovery from past 131I-MIBG dose(s). 6. For patients who received a stem cell infusion for a previous 131I-MIBG therapy but do NOT have remaining stored stem cells: i. If the stem cell reinfusion was protocol driven but not based upon the development of profound cytopenias (e.g. automatic stem cell reinfusion on Day 14), the patient is eligible for retreatment with MIBG at a dose <12 mCi/kg at the investigators discretion; ii. If the stem cell reinfusion was given based upon the development of profound cytopenias, decisions for re-treatment with 131I-MIBG will require a case-by-case evaluation by the Investigator. 6. Organ Function: 1. Liver function: Bilirubin ≤ 2x upper limit of normal; AST/ALT ≤ 10x upper limit of normal. 2. Kidney function: i. Serum Creatinine ≤ 2x upper limit of normal OR ii. 24-hr creatinine clearance OR GFR ≥ 60 ml/min/1.73m2. c. Hematologic Criteria: ANC ≥750/uL; Platelets ≥ 50,000/uL without transfusion if stem cells are not available (ANC ≥ 500 and any platelet count allowed if stem cells available). Patient must be off myeloid growth factors for at least 24 hours. If the patient has received prior treatment with MIBG, they may be thrombocytopenic, but requiring no more than 2 platelet transfusions per week to maintain counts above 20,000/uL. Hemoglobin must be ≥ 10gm/dL (transfusion allowed) regardless of stored stem cell availability. d. Normal lung function, as manifested by no dyspnea at rest or exercise intolerance, no oxygen requirement. e. No clinically significant cardiac dysfunction. 7. Signed informed consent/assent has been obtained. EXCLUSION CRITERIA: 1. Patients 12 years and older with iobenguane scan positive, unresectable, locally advanced or metastatic pheochromocytoma or paraganglioma and marketed product is available. 2. Patients eligible for the Phase II (OPTIMUM) trial. 3. Patients with disease of any major organ system that would compromise their ability to withstand therapy. Any significant organ impairment should be discussed with the Principal Investigator prior to patient entry. 4. Because of the teratogenic potential of the study medications, no patients who are pregnant or lactating will be allowed. Patients of childbearing potential, who are sexually active, must practice an effective method of birth control while participating on this study, to avoid possible damage to the fetus . [e.g. intrauterine device, double-barrier method (i.e., diaphragm, or a cervical cap) with intravaginal spermicidal foam, cream or gel], or male partner sterilization throughout the study]. 5. Patients who are on hemodialysis 6. Proteinuria, in the absence of urinary infection, within 4 weeks prior to the planned treatment date is a relative contraindication to receiving therapy for patients with pheochromocytoma/paraganglioma. Patients with pheochromocytoma/paraganglioma with any clinically significant proteinuria must have a 24-hr urine protein determination. If proteinuria is confirmed as being above the institutional upper limit of normal, the patient is ineligible for MIBG therapy. 7. Patients with active infections that meet grade 3-4 according to the current version of the NCI CTCAE. 8. Patients with known MIBG-avid parenchymal brain metastases are not eligible. (Patients with leptomeningeal or skull-based metastases are eligible.)

1. Participant is able and willing to provide informed consent (≥18 years), or informed consent is obtained by the parent or legal guardian for minor participants, with the minor providing age appropriate assent, according to local law and regulations; 2. Life expectancy ≥ 12 weeks; 3. Known high-risk neuroblastoma OR previously intermediate-risk neuroblastoma that has relapsed or progressed to high-risk, with failure to achieve complete response with standard therapy (defined as at least 4 cycles of aggressive multi-drug induction chemotherapy with or without radiation and surgery, or according to a standard high-risk treatment/neuroblastoma protocol), OR who are medically ineligible to receive standard treatment OR who are intolerant to standard treatment; 4. Adequate recovery from acute toxic effects of any prior therapy, as deemed by the Investigator or treating Sub-Investigator; 5. Adequate liver function as defined by the following laboratory values obtained within 28 days prior to administration of 64Cu-SARTATE: Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) < 3.0 x upper limit of normal (ULN); 6. Adequate renal function; 7. Adequate laboratory parameters: Absolute neutrophil count > 1.0 x 10 9/L; Platelet count > 50 x 10 9/L; Total bilirubin <1.5 x ULN; 8. Karnofsky or Lansky performance status ≥50; 9. All participants must have a hematopoietic stem cell product available (minimum CD34+ cell dose is ≥2 x 10 6 cells/kg); 10. Sexually active participants of reproductive potential must practice an effective method of birth control while participating on this study, to avoid possible damage to the fetus. Abstinence is considered acceptable; 11. 64Cu-SARTATE uptake on the 4 hour scan (SUVmax) of any lesion equal to or higher than that of the liver in order to move on to the therapy phase of the study. 1. Participants with disease of any major organ system that would compromise their ability to tolerate therapy, as deemed by the Investigator or treating Sub-Investigator; 2. Any other active malignancy, or a history of prior malignancy within the past 3 years; 3. History of cardiac failure as evidenced by: dyspnea at rest, exercise intolerance, oxygen requirement, clinically significant cardiac dysfunction; 4. Planned administration of chemotherapy, anti-cancer cytokine therapy, immunotherapy or radiotherapy within 2 weeks prior to the administration of 64Cu-SARTATE; 5. Administration of therapeutic dose of 131I-MIBG within 8 weeks prior to the administration of 64Cu-SARTATE; 6. External beam radiation therapy (EBRT) to both kidneys or a single functioning kidney within 12 months prior to the administration of 64Cu-SARTATE; 7. Administration of any investigational agents within 21 days prior to administration of 64Cu-SARTATE; 8. Treatment with long acting somatostatin analogues (administered within 28 days prior to the administration of 64Cu-SARTATE), or short acting somatostatin analogues (administered within 24 hours prior to the administration of 64Cu-SARTATE); 9. Known sensitivity or allergy to somatostatin analogues; 10. Previous peptide receptor radionuclide therapy (PRRT); 11. Female participants who are pregnant or lactating; 12. Participants who are on hemodialysis; 13. QTc interval ≥ 0.45 seconds as measured by Screening ECG; 14. Participants with uncontrolled infection(s); 15. Any medical condition which the Investigator feels may interfere with the procedures or evaluations of the study; 16. Participants 12 months and younger will be excluded from cohorts where the planned single or cumulative administered activity is modelled to deliver a radiation dose to the marrow that exceeds 2 Gy.

• 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