Criteria for Inclusion of Subjects: Hand and forearm amputees: 1. Male or female, age 18 and older, of any race or ethnicity 2. Able and willing to sign Consent 3. Able and willing to participate in all study activities including implantation, testing and explantation of the study device. 4. Able to communicate effectively in English without an interpreter After preliminary screening subjects will be assessed for the following inclusion criteria: 1. Patient has an existing myoelectric hand prosthesis and demonstrates proficiency during daily use 2. Overall and phantom pain are well-controlled and not incapacitating Criteria for Exclusion of Subjects: 1. If MR neurogram and EMG/NCS study show nerve or muscle dysfunction/injury at a higher level than anticipated based on the appearance of the physical amputation stump, the subject may be excluded from the study due to adverse neuromuscular anatomy which would preclude use of the proposed experimental electrode implants. The radiographs will be used to confirm suitability of the amputation stump configuration. If the bony anatomy of the amputation stump is found to be unsuitable, the patient may be excluded from the study. 2. Subjects who have a history of cardiac arrhythmia will be excluded from the study.

• Histologically or cytologically-confirmed Ewing sarcoma, rhabdomyosarcoma, neuroblastoma, or osteosarcoma
• Disease progression after prior therapy in locally advanced or metastatic setting
• Measurable or evaluable disease based on the Response Evaluation Criteria in Solid Tumors (RECIST v1.1) criteria
• Age 12 months to <21 years
• Adequate bone marrow reserves, hepatic function, and renal function
• Recovered from effects of any prior surgery or cancer therapy
• Patients 18 years or older will provide written consent. A parent or legal guardian of a patient <18 years of age will provide informed consent and patients 11 to 18 years of age will provide written assent or as per participating institutional policy.
• Clinically significant gastrointestinal disorders
• NYHA Class III or IV congestive heart failure, ventricular arrhythmias or uncontrolled blood pressure
• Active infection or unexplained fever
• Known hypersensitivity to any of the components of MM-398 or other liposomal products
• Recent Investigational therapy
• Pregnant or breast feeding; females of child-bearing potential must test negative for pregnancy at the time of enrollment

Key For Phase 1:
• Participants with a locally advanced or metastatic solid tumor that:
• Has progressed on or is intolerant to standard therapy, or
• For which no standard therapy exists, or in the opinion of the Investigator, are not candidates for or would be unlikely to tolerate or derive significant clinical benefit from standard therapy, or
• Decline standard therapy
• Prior multikinase inhibitors (MKIs) with anti-RET activity are allowed
• A RET gene alteration is not required initially. Once adequate PK exposure is achieved, evidence of RET gene alteration in tumor and/or blood is required as identified through molecular assays, as performed for clinical evaluation
• Measurable or non-measurable disease as determined by RECIST 1.1 or RANO as appropriate to tumor type
• Eastern Cooperative Oncology Group (ECOG) score of 0, 1, or 2 or Lansky Performance Score (LPS) greater than or equal to (≥) 40 percent (%) (age less than [<] 16 years) with no sudden deterioration 2 weeks prior to the first dose of study treatment
• Adequate hematologic, hepatic and renal function
• Life expectancy of at least 3 months For Phase 2: As for phase 1 with the following modifications:
• For Cohort 1: Participants must have received prior standard therapy appropriate for their tumor type and stage of disease, or in the opinion of the Investigator, would be unlikely to tolerate or derive clinical benefit from appropriate standard of care therapy
• Cohorts 1 and 2:
• Enrollment will be restricted to participants with evidence of a RET gene alteration in tumor
• At least one measurable lesion as defined by RECIST 1.1 or RANO, as appropriate to tumor type and not previously irradiated
• Cohorts 3 and 4: Enrollment closed
• Cohort 5:
• Cohorts 1-4 without measurable disease
• MCT not meeting the requirements for Cohorts 3 or 4
• MTC syndrome spectrum cancers (e.g., MTC, pheochromocytoma), cancers with neuroendocrine features/differentiation, or poorly differentiated thyroid cancers with other RET alteration/activation may be allowed with prior Sponsor approval
• cfDNA positive for a RET gene alteration not known to be present in a tumor sample
• Cohort 6: Participants who otherwise are eligible for Cohorts 1, 2 or 5 who discontinued another RET inhibitor may be eligible with prior Sponsor approval
• Cohort 7: Participants with a histologically confirmed stage IB-IIIA NSCLC and a RET fusion; determined to be medically operable and tumor deemed resectable by a thoracic surgical oncologist, without prior systemic treatment for NSCLC Key Exclusion Criteria (Phase 1 and Phase 2):
• Phase 2 Cohorts 1 and 2: an additional known oncogenic driver
• Cohorts 3 and 4: Enrollment closed
• Cohorts 1, 2 and 5: prior treatment with a selective RET inhibitor Notes: Participants otherwise eligible for Cohorts 1, 2, and 5 who discontinued another selective RET inhibitor may be eligible for Phase 2 Cohort 6 with prior Sponsor approval
• Investigational agent or anticancer therapy (including chemotherapy, biologic therapy, immunotherapy, anticancer Chinese medicine or other anticancer herbal remedy) within 5 half-lives or 2 weeks (whichever is shorter) prior to planned start of LOXO-292 (selpercatinib). In addition, no concurrent investigational anti-cancer therapy is permitted Note: Potential exception for this exclusion criterion will require a valid scientific justification and approval from the Sponsor
• Major surgery (excluding placement of vascular access) within 2 weeks prior to planned start of LOXO-292 (selpercatinib)
• Radiotherapy with a limited field of radiation for palliation within 1 week of planned start of LOXO-292 (selpercatinib), with the exception of participants receiving radiation to more than 30% of the bone marrow or with a wide field of radiation, which must be completed at least 4 weeks prior to the first dose of study treatment
• Any unresolved toxicities from prior therapy greater than Common Terminology Criteria for Adverse Events (CTCAE) Grade 1 at the time of starting study treatment with the exception of alopecia and Grade 2, prior platinum-therapy related neuropathy
• Symptomatic primary CNS tumor, metastases, leptomeningeal carcinomatosis, or untreated spinal cord compression. Participants are eligible if neurological symptoms and CNS imaging are stable and steroid dose is stable for 14 days prior to the first dose of LOXO-292 (selpercatinib) and no CNS surgery or radiation has been performed for 28 days, 14 days if stereotactic radiosurgery (SRS)
• Clinically significant active cardiovascular disease or history of myocardial infarction within 6 months prior to planned start of LOXO-292 (selpercatinib) or prolongation of the QT interval corrected (QTcF) greater than (>) 470 milliseconds (msec)
• Participants with implanted pacemakers may enter the study without meeting QTc criteria due to nonevaluable measurement if it is possible to monitor for QT changes.
• Participants with bundle branch block may be considered for study entry if QTc is appropriate by a formula other than Fridericia's and if it is possible to monitor for QT changes.
• Required treatment with certain strong cytochrome P450 3A4 (CYP3A4) inhibitors or inducers and certain prohibited concomitant medications
• Phase 2 Cohort 7 (neoadjuvant treatment): Participant must not have received prior systemic therapy for NSCLC.

Cystic Fibrosis Main Study
• Must have CF diagnosis confirmed by sweat test or genotype analysis
• Subjects (and parents/legal guardians as applicable) must have the ability to read and write in English Sub-study
• No CF diagnosis
• Men or women without osteoporosis
• Less than 18 years of age
• Unwilling to return annually for study visits for up to 5 years
• Unwilling and/or medically unable to take denosumab

• Stratum I
• Patients must be less than 18 years of age at the time of diagnosis.
• Patients must have histological verification of the diagnosis of Langerhans cell histiocytosis according to the criteria described in Section 6.1
• Signed informed consent form
• Stratum II
• Patients of Stratum I who have:
• Progressive disease (AD worse) in non-risk organs after 6 weeks (Initial Course
• AD intermediate or worse in non-risk organs or AD better in risk organs after 12 weeks (Initial Course 2)
• Disease progression (AD worse) in non-risk organs at any time during continuation treatment
• Active disease at the end of Stratum I treatment
• Disease reactivation in non-risk organs at any time after completion of Stratum I treatment
• Stratum III
• Patients from Stratum I who fulfill the following criteria:
• AD worse in risk organs after week 6 (after Initial Course 1), or AD worse or AD intermediate in risk organs after week 12 (after Initial Course 2).
• Presence of unequivocally severe organ dysfunction at the above mentioned evaluation points (hematological dysfunction, liver dysfunction, or both of them) as
• Hb <70 g/L (<7.0 g/dl) and/or transfusion dependency
• PLT <20 x109/L (20,000/μL) and/or transfusion dependency (both criteria have to be fulfilled) AND/OR
• Liver dysfunction (or digestive involvement with protein loss)
• Total protein <55 g/L or substitution dependency
• Albumin <25 g/L or substitution dependency (at least one of the two criteria to be fulfilled)
• Stratum IV
• Patients from Stratum I or Stratum III who fulfill the following criteria:
• AD worse in risk organs after week 6 (after Initial Course 1), or AD worse or AD intermediate in risk organs after week 12 (after Initial Course 2) of Stratum I OR
• AD worse after the 2nd and 3rd 2-CdA/Ara-C course, and those AD worse or AD intermediate after the 4th 2-CdA/Ara-C course of Stratum III AND
• Presence of unequivocally severe organ dysfunction at the above mentioned evaluation points (hematological dysfunction, liver dysfunction, or both of them) as defined in Table XI (see Section 10.3.1).
• Informed consent: All patients or their legal guardians (if the patient is <18 years of age) must sign an Ethics or institutional Review Board approved consent form indicating their awareness of the investigational nature and the risks of this study. When appropriate, younger patients will be included in all discussions in order to obtain assent.
• Adequate organ function: Patients should have adequate hepatic, renal, cardiac and pulmonary function to undergo reduced intensity HCT based upon local institutional guidelines, or at a minimum meet requirements noted in eligibility checklist Appendix A-VIII_1. However, significant hepatic and pulmonary dysfunction, if secondary to underlying LCH disease activity, will not exclude patients from protocol enrollment and should be discussed with the National PI Coordinator and the Coordinating Principal Investigator.
• Stratum V
• All patients with verified diagnosis of LCH and MRI findings consistent with ND-CNSLCH irrespective of previous treatments (also those not registered to other Strata ofLCH-IV).
• Patients with isolated tumorous CNS-LCH (including isolated DI with mass lesion in the hypothalamus-pituitary axis). In patients with already established diagnosis of LCH and radiologic finding of CNS lesions compatible with LCH, a biopsy of the lesion is not obligatory. In all other cases a biopsy of the lesion is needed for inclusion into the study
• Stratum VI -- Patients with newly diagnosed SS-LCH and localization other than "multifocal bone",isolated tumorous CNS lesion, or isolated "CNS-risk" lesion.
• Stratum VII -- All patients registered in LCH IV (regardless of treatment) as long as consent for longterm follow-up has not been withheld.
• Stratum I
• Pregnancy (patients of child-bearing age must be appropriately tested before chemotherapy)
• LCH-related permanent consequences (e.g. vertebra plana, sclerosing cholangitis, lung fibrosis, etc.) in the absence of active disease
• Prior systemic therapy
• Stratum II
• Patients with progressive disease in risk organs
• Permanent consequences (e.g. sclerosing cholangitis, lung fibrosis, etc.) without evidence of active LCH in the same organ or in any other locations
• No written consent of the patient or his/her parents or legal guardian
• Stratum III
• The presence of any of the following criteria will exclude the patient from the study:
• Isolated sclerosing cholangitis without evidence of active hepatic LCH as the only evidence of risk organ involvement.
• Inadequate renal function as defined by serum creatinine > 3x normal for age
• Stratum IV
• Pulmonary failure (requiring mechanical ventilation) not due to active LCH.
• Isolated liver sclerosis or pulmonary fibrosis, without active LCH.
• Uncontrolled active life-threatening infection.
• Decreased renal function with a GFR of less than 50ml/1.73m2/min.
• Pregnancy or active breast feeding
• Failure to provide signed informed consent
• Stratum VI
• Patients with SS-LCH who have an isolated tumorous CNS lesion (they are eligible for Stratum V),
• Patients with isolated "CNS-risk" or multifocal bone lesions (they are eligible for Stratum I, Group 2)

Participant(s) must meet all of the following criteria to be eligible for this study: 1. Diagnosis of Multiple Sclerosis (MS) according to the 2017 McDonald Criteria 2. (Kurtzke) Expanded Disability Status Scale (EDSS) ≤ 6.0 at the time of randomization (Day 0) 3. T2 abnormalities on brain Magnetic Resonance Imaging (MRI) that fulfill the 2017 McDonald MRI criteria for dissemination in space --A detailed MRI report or MRI images must be available for review by the site neurology investigator. 4. Highly active treatment-resistant relapsing MS, defined as ≥ 2 episodes of disease activity in the 36 months prior to the screening visit (Visit -2). The two disease activity episodes will be a clinical MS relapse or MRI evidence of MS disease activity and must meet all the criteria as described below: 1. At least one episode of disease activity must occur following ≥ 1 month of treatment with an oral DMT approved by the FDA or MHRA for the treatment of relapsing MS, or a monoclonal antibody, specifically: dimethyl fumarate (Tecfidera®), diroximel fumarate, teriflunomide (Aubagio®), cladribine (Mavenclad®), daclizumab (Zinbryta®), siponimod (Mayzent®), ozanimod, fingolimod (Gilenya®), rituximab (Rituxan®), ocrelizumab (Ocrevus®), natalizumab (Tysabri®), alemtuzumab (Campath®, Lemtrada®), or ofatumumab (Arzerra®), and 2. At least one episode of disease activity must have occurred within the 12 months prior to the screening visit (Visit -2), and 3. At least one episode of disease activity must be a clinical MS relapse (see item c.i. below). The other episode(s) must occur at least one month before or after the onset of the clinical MS relapse, and must be either another clinical MS relapse or MRI evidence of disease activity (see item d.ii. below): i. Clinical MS relapse must be confirmed by a neurologist's assessment and documented contemporaneously in the medical record. If the clinical MS relapse is not documented in the medical record, it must be approved by the study adjudication committee, and ii. MRI evidence of disease activity must include ≥ 2 unique active lesions on a brain or spinal cord MRI. A detailed MRI report or MRI images must be available for review by the site neurology investigator. A unique active lesion is defined as either of the following:
• A gadolinium-enhancing lesion, or
• A new non-enhancing T2 lesion compared to a reference scan obtained not more than 24 months prior to the screening visit (Visit -2). 5. Candidacy for treatment with at least one of the following high efficacy DMTs: Cladribine, natalizumab, alemtuzumab, ocrelizumab, rituximab, and ofatumumab (after approval by the FDA for relapsing MS). Candidacy for treatment for each DMT is defined as meeting all of the following:
• No prior disease activity with the candidate DMT, and
• No contraindication to the candidate DMT, and
• No treatment with the candidate DMT in the 12 months prior to screening. 6. Completion of SARS-CoV-2 vaccination series ≥ 14 days prior to randomization (Day 0). 7. Positive for VZV antibodies, or completion of at least one dose of the varicella zoster glycoprotein E (gE) Shingrix vaccine at least 4 weeks prior to randomization (Day 0). 8. Insurance or public funding approval for MS treatment with at least one candidate DMT, and 9. Ability to comply with study procedures and provide informed consent, in the opinion of the investigator. Subject(s) who meet any of the following criteria will not be eligible for this study: 1. Diagnosis of primary progressive Multiple Sclerosis (MS) according to the 2017 McDonald criteria 2. History of neuromyelitis optica or anti-myelin oligodendrocyte glycoprotein (anti-MOG) antibodies associated encephalomyelitis 3. Prior treatment with an investigational agent within 3 months or 5 half-lives, whichever is longer. Agents authorized by the FDA or MHRA for prevention or treatment of SARS-CoV-2 are not considered investigational. 4. Either of the following within one month prior to randomization (Day 0): 1. Onset of acute MS relapse, or 2. Treatment with intravenous methylprednisolone 1000 mg/day for 3 days or equivalent. 5. Initiation of natalizumab, alemtuzumab, ocrelizumab, or rituximab between screening visit (Visit -2) and randomization (Day 0) 6. Brain MRI or Cerebrospinal fluid (CSF) examination indicating a diagnosis of progressive multifocal leukoencephalopathy (PML) 7. History of cytopenia consistent with the diagnosis of myelodysplastic syndrome (MDS) 8. Presence of unexplained cytopenia, polycythemia, thrombocythemia or leukocytosis 9. History of sickle cell anemia or other hemoglobinopathy 10. Evidence of past or current hepatitis B or hepatitis C infection, including treated hepatitis B or hepatitis C -Note: Hepatitis B surface antibody following hepatitis B immunization is not considered to be evidence of past infection. 11. Presence or history of mild to severe cirrhosis 12. Hepatic disease with the presence of either of the following: 1. Total bilirubin ≥ 1.5 times the upper limit of normal (ULN) or total bilirubin
• 3.0 times the ULN in the presence of Gilbert's syndrome, or 2. Alanine Aminotransferase (ALT) or Aspartate Aminotransferase (AST) ≥ 2.0 times the ULN. 13. Positive SARS-CoV-2 PCR test, or alternative nucleic acid amplification test (NAAT) per institutional standards, within 14 days prior to randomization (Day 0). 14. Evidence of HIV infection 15. Positive QuantiFERON
•TB Gold, TB Gold Plus, or T-SPOT®.TB test results (e.g., blood test results. Purified Protein Derivative (PPD) tuberculin test may be substituted for QuantiFERON
•TB Gold, TB Gold Plus, or T-SPOT®.TB test results. 16. Active viral, bacterial, endoparasitic, or opportunistic infections 17. Active invasive fungal infection 18. Hospitalization for treatment of infections or parenteral (IV or IM) antibacterials, antivirals, antifungals, or antiparasitic agents within the 30 days prior to randomization (Day 0) unless clearance is obtained from an Infectious Disease specialist 19. Receipt of live or live-attenuated vaccines within 6 weeks of randomization (Day 0) 20. Presence or history of clinically significant cardiac disease including: 1. Arrhythmia requiring treatment with any antiarrhythmia therapy, with the exception of low dose beta blocker for intermittent premature ventricular contractions 2. Coronary artery disease with a documented diagnosis of either:
• Chronic exertional angina, or
• Signs or symptoms of congestive heart failure. 3. Evidence of heart valve disease, including any of the following:
• Moderate to severe valve stenosis or insufficiency,
• Symptomatic mitral valve prolapse, or
• Presence of prosthetic mitral or aortic valve. 21. Left ventricular ejection fraction (LVEF) < 50% 22. Impaired renal function defined as Estimated glomerular filtration rate (eGFR) < 60 mL/min/1.73 m^2 according to the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) formula 23. Forced expiratory volume in one second (FEV1) <70% predicted (no bronchodilator) 24. Diffusing capacity of the lungs for carbon monoxide (DLCO) (corrected for Hgb) < 70% predicted 25. Poorly controlled diabetes mellitus, defined as HbA1c >8% 26. History of malignancy, with the exception of adequately treated localized basal cell or squamous skin cancer, or carcinoma in situ of the cervix. -Note:Malignancies for which the participant is judged to be cured prior to randomization (Day 0) will be considered on an individual basis by the study adjudication committee. 27. Presence or history of any moderate to severe rheumatologic autoimmune disease requiring treatment, including but not limited to the following:
• systemic lupus erythematous
• systemic sclerosis
• rheumatoid arthritis
• Sjögren's syndrome
• polymyositis
• dermatomyositis
• mixed connective tissue disease
• polymyalgia rheumatica
• polychondritis
• sarcoidosis
• vasculitis syndromes, or
• unspecified collagen vascular disease. 28. Presence of active peptic ulcer disease, defined as endoscopic or radiologic diagnosis of gastric or duodenal ulcer 29. Prior history of AHSCT 30. Prior history of solid organ transplantation 31. Positive pregnancy test or breast-feeding 32. Inability or unwillingness to use effective means of birth control 33. Failure to willingly accept or comprehend irreversible sterility as a side effect of therapy 34. Psychiatric illness, mental deficiency, or cognitive dysfunction severe enough to interfere with compliance or informed consent 35. History of hypersensitivity to mouse, rabbit, or Escherichia coli-derived proteins 36. Any metallic material or electronic device in the body, or condition that precludes the participant from undergoing MRI with gadolinium administration 37. Presence or history of ischemic cerebrovascular disorders, including but not limited to transient ischemic attack, subarachnoid hemorrhage, cerebral thrombosis, cerebral embolism, or cerebral hemorrhage 38. Presence or history of other neurological disorders, including but not limited to:
• central nervous system (CNS) or spinal cord tumor
• metabolic or infectious cause of myelopathy
• genetically-inherited progressive CNS disorder
• CNS sarcoidosis, or
• systemic autoimmune disorders potentially causing progressive neurologic disease or affecting ability to perform the study assessments. 39. Presence of any medical comorbidity that the investigator determines will significantly increase the risk of treatment mortality, or 40. Presence of any other concomitant medical condition that the investigator deems incompatible with trial participation.

1. Able to understand the potential risks and benefits, the study requirements, and provide written informed consent before enrollment into the study; or if unable, the subject's Legally Authorized Representative (LAR) may provide written informed consent. 2. Male or female ≥18 to maximum of 80 years of age, inclusive. 3. Lower limb spasticity due to stroke, traumatic brain injury, or spinal cord injury that occurred ≥6 months prior to randomization. Eligible subjects may have lower limb monoplegia or hemiplegia. Subjects with cerebral palsy are eligible for study enrollment. 4. Ambulatory (with or without the use of a walking assistive device). 5. Modified Ashworth Scale (MAS) score ≥2 in the ankle plantar flexors of the affected lower limb at screening and at baseline. 6. In the Investigator's opinion, the subject will be available and able to comply with the study requirements for at least 1 year, based on the subject's overall health and disease prognosis. 7. In the Investigator's opinion, the subject will be willing and able to comply with all requirements of the protocol, including completion of study questionnaires. A caregiver may be designated to assist with the physical completion of questionnaires/scales. 1. Quadriplegia/tetraplegia, lower limb diplegia or triplegia. 2. Uncontrolled epilepsy or any type of seizure disorder with a seizure(s) within the previous year. 3. Neuromuscular disorders including, but not limited to, amyotrophic lateral sclerosis (ALS), primary lateral sclerosis (PLS), multiple sclerosis (MS), myasthenia gravis, or muscular dystrophy. 4. History of major joint contracture(s), in which, based on the Investigator's assessment, the contracture(s) significantly contribute(s) to joint immobility in the affected lower limb. 5. Unresolved fracture(s) in the affected lower limb. 6. Severe atrophy in the affected lower limb. 7. Known hypersensitivity to botulinum toxins type A or B or to any MYOBLOC solution components. 8. Concomitant use or exposure within 5 half-lives of randomization of the following: aminoglycoside antibiotics, curare-like agents, or other agents that may interfere with neuromuscular function. 9. Treatment with a neurolytic agent (e.g., phenol, alcohol blocks) to the affected lower limb within 1 year before randomization. 10. Presence of a spinal stimulator or intrathecal baclofen pump that has not been turned off within 30 days before screening. 11. Changes to treatment regimen or any new treatment with oral antispasmodics and/or muscle relaxants within 30 days before randomization. 12. Initiation of physical and/or occupational therapy <30 days before randomization. Subjects receiving physical and/or occupational therapy ≥30 days before randomization must be willing to maintain their therapy regimen through Week 4 of the DBP. 13. Application of an ankle-foot orthosis (AFO) <30 days before randomization. Subjects regularly using an AFO ≥30 days before randomization must be willing to maintain use of the AFO through Week 4 of the Double-Blind Period. 14. Prior botulinum toxin type A (BoNT/A) or B (BoNT/B) treatment in the affected lower limb within 24 weeks before screening. Prior BoNT/A or BoNT/B treatment in areas other than the affected lower limb is not exclusionary but must have occurred at least 12 weeks before screening. Prior toxin exposure must have been well tolerated and without any significant long-term side effects in the case of repeated prior exposure. 15. Subjects should not receive nor have any plans to receive any botulinum toxin treatment, other than the study drug (MYOBLOC), from the point informed consent is obtained until participation in the study is complete. 16. Severe dysphagia (i.e., inability to swallow liquids, solids or both without choking or medical intervention), or dysphagia with a history of aspiration pneumonia, within 6 months before screening. 17. Prior surgery to treat spasticity in the affected lower limb (i.e., tendon lengthening or tendon transfer). 18. Any anticipated or scheduled surgery during the study period, with the exception of dermatological procedures performed under local anesthesia for the purposes of removing precancerous and cancerous lesions. 19. Major surgery within 3 months before screening. 20. Pregnancy or breastfeeding. 21. Females of childbearing potential must agree to practice a medically acceptable method of contraception (e.g., intrauterine device, hormonal contraception started at least one full cycle before study enrollment or barrier method in conjunction with spermicide) for the duration of the study (including 2 months after study completion). For the purposes of this study, all females are considered to be of childbearing potential unless they are confirmed by the Investigator to be post-menopausal (at least 1 year since last menses and laboratory test confirmation), biologically sterile, or surgically sterile (e.g., hysterectomy with bilateral oophorectomy, tubal ligation). 22. History of drug or alcohol abuse within 6 months before screening. 23. Obstructive pulmonary disease with forced expiratory volume in 1 second (FEV1)/forced vital capacity (FVC) <70%. 24. Slow vital capacity (SVC) <60% of predicted. 25. Chronic or current use of inhaled corticosteroids. 26. Ventilator dependence (i.e., 24-hour ventilator dependence when intubated, or due to a failure to wean the subject from the ventilator while hospitalized in the intensive care unit or respiratory care center). Subjects who use oxygen on an as-needed basis or during sleeping hours only via a nasal cannula are eligible for the study. 27. Infection at the planned sites of injection. 28. Treatment with an investigational drug, device, or biological agent within 30 days before screening or while participating in this study. 29. Malignancy diagnosed 3 months before screening. 30. Has one or more screening clinical laboratory test values outside the reference range that, in the opinion of the Investigator, are clinically significant, or any of the following :
• Serum creatinine >1.5 times the upper limit of normal (ULN);
• Serum total bilirubin > 1.5 times ULN;
• Serum alanine aminotransferase or aspartate aminotransferase >2 times ULN. 31. Has any of the following cardiology findings at screening:
• Abnormal ECG that is, in the Investigator's opinion/evaluation, clinically significant;
• PR interval >220 ms;
• QRS interval >130 ms;
• QTcF interval >450 ms (for men), or >470 ms (for women) (QT corrected using Fridericia's method);
• Second-or third-degree atrioventricular block;
• Any rhythm, other than sinus rhythm, that is interpreted or assessed by the Investigator to be clinically significant. 32. Any other medical illness, condition, or clinical finding that, in the opinion of the Investigator and/or the Sponsor, would put the subject at undue risk.

• Be male at any age.
• Be scheduled to undergo surgery, chemotherapy, drug treatment and/or radiation for the treatment or prevention of a medical condition or malignancy with risk of causing permanent and complete loss of subsequent testicular function.
• Or, have a medical condition or malignancy that requires removal of all or part of one or both testicles.
• Have newly diagnosed or recurrent disease. Those who were not enrolled at the time of initial diagnosis (i.e., patients with recurrent disease) are eligible if they have not previously received therapy that is viewed as likely to result in complete and permanent loss of testicular function.
• Have two testicles if undergoing elective removal of all or part of a testicle for fertility preservation only. Note: removal of both testicles will limit fertility preservation options.
• Sign an approved informed consent and authorization permitting the release of personal health information. The patient and/or the patient's legally authorized guardian must acknowledge in writing that consent for specimen collection has been obtained, in accordance with institutional policies approved by the U.S. Department of Health and
• Consent for serum screening tests for infectious diseases [HIV-1, HIV-2, Hepatitis B, Hepatitis C], to be performed at the time of testicular tissue harvesting.
• Undergo a full history and physical examination and obtain standard pre-operative clearance (based on the most recent ACC/AHA Guideline for Perioperative Cardiovascular Evaluation for Noncardiac Surgery) as determined by their primary surgeon.
• Participating in long term follow-up is a requirement of the protocol.
• Diagnosed with psychological, psychiatric, or other conditions which prevent giving fully informed consent.
• Diagnosed with an underlying medical condition that significantly increases their risk of complications from anesthesia and surgery.

• Note: Patients enrolled on AOST2031 are eligible for enrollment in the present study. Patients are eligible to be included in the study only if all the following criteria apply: Age and Weight 1. Between 12 years of age and 39 years of age at the time the Informed Consent/ Assent form is signed. 2. Weight at least 40 kg. Diagnosis 3. Has histologic confirmation of osteosarcoma at diagnosis. 4. Has at least one episode of disease recurrence in the lungs without limitation on the number of episodes of recurrence as long as the following criteria are met: 1. Surgical resection of all possible sites of suspected pulmonary metastases to achieve a complete remission within 8 weeks prior to study enrollment 2. Pathological confirmation of osteosarcoma from at least one resected tumor. 3. Patients will not require radiographic confirmation of complete remission for enrollment. However, a postoperative CT chest scan is required as a baseline for future comparisons. https://members.childrensoncologygroup.org/files/Disc/surgery/handbooks/OsteoBoneHandb ook.pdf) Performance Status 5. Patient must have a performance status corresponding to ECOG scores of 0, 1, or 2. Use Karnofsky scale for patients > 16 years of age and Lansky scale for patients < years of age Prior Therapy 6. Patient must have fully recovered from the acute toxic effects of all prior chemotherapy, immunotherapy, radiotherapy, or surgery prior to entering this study. Organ Function Requirements 7. Patient has adequate organ function as defined below: a. Hematological: i. Absolute neutrophil count (ANC) is at least 1,000/µL without transfusion or growth factor support. ii. Platelet count ≥ 50,000/µL without transfusion or growth factor support. b. Adequate renal function defined as: i. Creatine clearance or radioisotope glomerular filtration rate (GFR) > 70 mL/min/1.73 m2 or ii. A serum creatine based on age/gender as follows: Maximum Serum Creatinine (mg/dL) Age: 12 to < 13 years Male :1.2 Female:1.2 Age:13 to < 16 years Male :1.5 Female:1.4 Age: ≥ 16 years Male :1.7 Female:1.4 Note: the threshold for creatinine values in this table were derived from the Schwartz formula for estimating GFR. c. Adequate liver function defined as: i. Total bilirubin < 1.5 x upper limit of normal (ULN) for age ii. Serum glutamic-pyruvic transaminase (SGPT) / alanine aminotransferase (ALT) < 110 U/L (for the purpose of this study the ULN for SGPT is 45 U/L) iii. Serum albumin > 2 g/dL d. Adequate coagulation i. International normalized ratio (INR) or prothrombin time (PT) < 1.5 x ULN unless patient is receiving anticoagulant therapy as long as PT or INR is within therapeutic range of intended use of anticoagulants. ii. Activated partial thromboplastin time (aPTT) < 1.5 x ULN unless patient is receiving anticoagulant therapy as long as aPTT is within therapeutic range of intended use of anticoagulants. e. Adequate cardiac function defined as: i. Shortening fraction of > 27% by echocardiogram, or ii. Ejection fraction of > 50% by radionuclide angiogram or echocardiogram f. Adequate pulmonary function defined as: i. No evidence of dyspnea at rest, no history of exercise intolerance, and a pulse oximetry of > 94%. g. Central nervous system (CNS) function defined as: i. Patients with a known seizure disorder may be enrolled if on anticonvulsants and/or are well-controlled. ii. CNS toxicity including peripheral neuropathy < Grade 2. 8. Patient and/or patient's parent or legal guardian must be capable of understanding the investigational nature, potential risks, and benefits of the study. The patient and/or the parent or legal guardian must sign a written informed consent. Age-appropriate assent will be obtained per institutional guidelines. Contraception: Female patients : 9. A female patient is eligible to participate if she is not pregnant, not breastfeeding, and at least one of the following conditions applies: 1. Not a woman of childbearing potential (WOCBP) as defined in the protocol OR 2. A WOCBP who agrees to follow the contraceptive guidance in the protocol during the treatment period and for at least 120 days after the last dose of study treatment. 10. A female patient of childbearing potential must have a negative urine or serum pregnancy test within 72 hours prior to receiving any dose of study treatment. If the urine test is positive or cannot be confirmed as negative, a serum pregnancy test will be required. Male patients: 11. A male patient is eligible to participate if he agrees to follow the contraceptive guidance in the protocol during the study treatment period and for at least 120 days after the last dose of study treatment. 1. Has clinically evident metastatic or recurrent disease. 2. Has concurrent pulmonary recurrence and local recurrence at the primary tumor site. 3. Has primary refractory disease with progression of the primary tumor on initial-therapy. 4. Has CNS or any extrapulmonary disease involvement at the time of the most recent episode of disease recurrence proceeding enrollment. 5. Has active infection requiring systemic therapy or is dependent on or is currently receiving systemic antibiotics that cannot be discontinued before dosing. (Note: Patients who discontinue an antibiotic prior to dosing must wait at least 5 half-lives after the last dose of antibiotic before receiving any OST31-164 infusion). Inhaled prophylactic PJP (pneumocystis jiroveci pneumonia) treatment is acceptable per Investigator discretion. 6. Is currently dependent on or has received corticosteroids within the past 4 weeks (topical corticosteroids and occasional inhaled corticosteroids are allowed). 7. Is currently participating in or has participated in a study of an investigational agent or is using an investigational device within 4 weeks of the first dose of treatment. 8. Has a history of other active malignancy for < 2 years prior to enrollment. Basal cell carcinoma of the skin, squamous cell carcinoma of the skin, or in situ cervical cancer that has undergone potentially curative therapy or is felt by the Investigator to be at low risk for recurrence is allowed. 9. Has an active autoimmune disease requiring systemic treatment within the past 3 months or a documented history of clinically severe autoimmune disease, or a syndrome that requires systemic steroids or immunosuppressive agents. Replacement therapy (e.g., thyroxine, insulin, or physiologic corticosteroid replacement therapy for adrenal or pituitary insufficiency) is not considered a form of systemic treatment. Patients with vitiligo or resolved childhood asthma/atopy would be an exception to this rule. Patients who require intermittent use of bronchodilators or local steroid injections will not be excluded from the study. Patients with hypothyroidism stable on hormone replacement or Sjogren's syndrome will not be excluded from the study. 10. Has known psychiatric or substance abuse disorders that would interfere with cooperation with the requirements of the trial. 11. Is pregnant or breastfeeding or expecting to conceive or father children within the projected duration of the trial, starting with the pre-screening or screening visit through 120 days after the last dose of study treatment. 12. Has a known allergy to any component of the study treatment(s) formulations. 13. Has a contraindication (e.g., sensitivity/allergy) to both trimethoprim/ sulfamethoxazole and amoxicillin. 14. Has contraindication to administration of NSAIDs. 15. Is currently receiving or will be receiving any chemotherapy, including PI3K inhibitors, during the treatment phase. 16. Has had a prior monoclonal antibody therapy within 2 weeks prior to study Day 1. 17. Requires or anticipates requiring tumor necrosis factor (TNF) blocking agent (e.g., infliximab) therapy for diagnosis of rheumatologic disease or inflammatory bowel disease (e.g., ankylosing spondylitis, Crohn's disease, plaque psoriasis, psoriatic arthritis, rheumatoid arthritis, or ulcerative colitis). 18. Has previous history of listeriosis. 19. Has a known history of human immunodeficiency virus (HIV) (HIV 1/2 antibodies). 20. Has known active hepatitis B (e.g., HBsAg reactive) or hepatitis C (e.g., HCV RNA [qualitative] is detected). 21. Has received a live vaccine within 30 days prior to Study Day 1. 22. Patient is or has an immediate family member (spouse, children, or parent) who is directly involved with this study or is employed by the investigational site or Sponsor, unless prospective Institutional Review Board (IRB) approval (by chair or designee) is given allowing exception to this criterion for a specific patient. Regulatory Requirements: 1. All patients and/or their parents or legal guardians must sign a written informed consent. 2. All institutional, FDA, and NCI requirements for human studies must be met.

• Age -- Age ≤ 30 years at time of initial qualifying solid tumor diagnosis
• Diagnosis -- Histologic diagnosis of solid malignancy (excluding brain tumors and lymphoma) that meets at least one of the following criteria:
• Refractory, defined as tumor progression after initiation of standard first line therapy without having achieved a prior partial or complete remission OR Biopsy proven residual disease at the completion of planned standard initial front-line therapy.
• Recurrent, defined as tumor progression after achieving a prior partial or complete remission
• Newly diagnosed high risk disease, defined as having an expected event free survival of < 50% at 2 years.
• Lacks definitive diagnosis or classical genomic findings after histologic review and standard molecular testing (rare tumor group).
• Examples include (eligibility not limited to these examples):
• Histology typically associated with a fusion in which fusion is not detected.
• Ewing-like sarcoma
• Undifferentiated sarcoma
• Inflammatory myofibroblastic tumor without ALK fusion
• Infantile fibrosarcoma without NTRK fusion
• Specimen Samples
• Sufficient tumor specimen available to meet the minimum requirements for profiling from diagnosis or progression / recurrence --- OR
• Surgery / biopsy planned as part of clinical care that is anticipated to yield sufficient material to meet the minimum requirements for profiling; OR
• Patient has already had molecular profiling and patient has not yet started matched targeted therapy based on the report .
• No Therapy Planned -- Patients who have declined further anticancer therapy will be excluded.
• Performance Status -- Patients with Lansky (age < 16 years) or Karnofsky (age ≥16 years) score < 50 will be excluded.
• Life Expectancy -- Patients with anticipated life expectancy < 3 months will be excluded.

• STEP I REGISTRATION CRITERIA
• Histologically documented renal cell carcinoma with clear cell component, including patients who have sarcomatoid or rhabdoid features
• Any metastatic disease, including visceral, lymph node, other soft tissue and bone, measurable per RECIST 1.1.
• Measurable disease as defined in the protocol.
• Must be intermediate or poor risk patient per International Metastatic Renal Cell Carcinoma Database (IMDC) criteria (1 or more of the following): Karnofsky performance status [KPS] < 80, < 1 year from diagnosis [including initial nephrectomy] to systemic treatment for metastatic disease, hemoglobin less than lower limit of normal [LLN], corrected calcium concentration greater than upper limit of normal [ULN], absolute neutrophil count greater than ULN, platelet count > ULN).
• Central nervous system (CNS) disease permitted, if stable and not otherwise causing symptoms or needing active treatment.
• Karnofsky performance status >= 70%.
• No prior treatment with PD-1, PD-L1, or CTLA-4 targeting agents (including but not limited to nivolumab, pembrolizumab, pidilizumab, durvalumab, atezolizumab, tremelimumab, and ipilimumab), or any other drug or antibody specifically targeting T-cell co-stimulation or checkpoint pathways. The only exception is for prior treatment with nivolumab or other PD-1/PD-L1/CTLA-4 targeting therapy on pre- or post-operative trials, as long as > 1 year since completion of systemic therapy.
• No prior previous systemic therapy for renal cell carcinoma (prior HD IL-2 [> 28 days] and prior adjuvant sunitinib > 180 days since completion and prior immunotherapy as above are allowed).
• No systemic cancer therapy less than 28 days prior to registration; no radiation therapy less than 14 days prior to registration. There must be a complete recovery and no ongoing complications from radiotherapy.
• Not pregnant and not nursing, because this study involves an agent that has known genotoxic, mutagenic and teratogenic effects. Therefore, for women of childbearing potential only, a negative serum or urine pregnancy test done =< 14 days prior to registration is required.
• Age >= 18 years
• Absolute neutrophil count (ANC) >= 1,500/mm^3.
• Platelet count >= 100,000/mm^3.
• Hemoglobin >= 8 g/dL.
• Calculated (Calc.) creatinine clearance >= 30 mL/min.
• Urine protein =< 1+ or urine protein to creatinine (UPC) ratio < 1.
• Total bilirubin =< 1.5 x upper limit of normal (ULN) (except for patients with known or likely Gilbert's syndrome, for whom total bilirubin up to 3 mg/dL is allowed with direct bilirubin =< 20% total bilirubin)
• Aspartate aminotransferase/alanine aminotransferase (AST/ALT) =< 2.5 x upper limit of normal (ULN) or < 5 x ULN if hepatic metastases present.
• STEP 2 REGISTRATION ELIGIBILITY CRITERIA
• Successful completion of at least 1 cycle of ipilimumab/nivolumab.
• Resolution of any treatment-related adverse events to grade 1 or less per dose modification section (this criteria does not include any adverse events [AEs] not attributable to treatment which are present due to disease), with prednisone-equivalent dosing at 10 mg daily or less. Exceptions for this criteria include patients receiving replacement hormone treatments (such as levothyroxine for treatment-related hypothyroidism or glucocorticoid replacement for adrenal insufficiency). Please contact study chair if further discussion is needed.
• No more than 80 days from last dose of ipilimumab/nivolumab.
• Active autoimmune disease requiring ongoing therapy.
• Ongoing acute toxicity > grade 2 from previous treatment.
• History of severe allergic, anaphylactic or other hypersensitivity reactions to chimeric or humanized antibodies.
• Active hepatitis B/C, or active tuberculosis (PPD response without active TB is allowed)
• Human immunodeficiency virus (HIV) -infected patients with detectable viral load within 6 months prior to registration. Patients on effective anti-retroviral therapy with undetectable viral load within 6 months prior to registration are eligible.
• Concurrent use of immunosuppressive medication including prednisone above 10 mg daily.
• Uncontrolled adrenal insufficiency.
• Uncontrolled hypertension (systolic blood pressure [BP] >150 mmHg or diastolic BP > 90 mmHg).
• Major surgery less than 28 days prior to registration.
• Any serious non-healing wound, ulcer, or bone fracture within 28 days prior to registration.
• Any arterial thrombotic events within 180 days prior to registration.
• Clinically significant hematuria, hematemesis, or hemoptysis within 12 weeks prior to registration.
• Cavitating pulmonary lesions or known endotracheal or endobronchial disease manifestations.
• Lesions encasing or invading any major blood vessels (this does not include tumor thrombus extending into/through renal vein/inferior vena cava [IVC]). Patients with tumor thrombus extending into/through renal vein are considered eligible.
• Moderate of severe hepatic impairment (Child-Pugh B or C).
• Any history of untreated pulmonary embolism or deep venous thrombosis (DVT) in the 180 days prior to registration. (Any asymptomatic, treated pulmonary embolism or asymptomatic, treated deep venous thrombosis > 30 days prior to registration allowed).
• Corrected QT interval calculated by the Fridericia formula (QTcF) > 500 ms.
• Unstable cardiac arrhythmia within 6 months prior to registration.
• Any gastrointestinal (GI) bleeding =< 180 days, hemoptysis, or other signs of pulmonary hemorrhage =< 90 days prior to registration.
• History of abdominal fistula, gastrointestinal perforation, intra-abdominal abscess, bowel obstruction, or gastric outlet obstruction within 180 days prior to registration.
• Active peptic ulcer disease, inflammatory bowel disease, or malabsorption syndrome within 28 days prior to registration.
• Untreated hypothyroidism (treated hypothyroidism on thyroid replacement therapy is allowed. Abnormal thyroid-stimulating hormone (TSH) is acceptable with normal T3/free T4 if treated on thyroid replacement therapy)
• Evidence of pancreatitis, history of organ transplant, or history of congenital QT syndrome.
• Active treatment with coumarin agents (e.g., warfarin), direct thrombin inhibitors (e.g., dabigatran), direct Xa inhibitor betrixaban or platelet inhibitors (e.g., clopidogrel) within 5 days of registration. Allowed anticoagulants include: prophylactic use of low-dose aspirin for cardio-protection (per local applicable guidelines) and low-dose low molecular weight heparins (LMWH), therapeutic doses of LMWH or anticoagulation with direct factor Xa inhibitors rivaroxaban, edoxaban, apixaban. Allowed also in patients with known brain metastases who are on a stable dose of the anticoagulant for at least 1 week prior to registration without clinically significant hemorrhagic complications from the anticoagulation regimen or the tumor.
• Significant cardiac ischemia events (ST elevation myocardial infarction [STEMI] or non-ST elevation myocardial infarction [NSTEMI]) within 6 months or active NY Heart Association class 3-4 heart failure symptoms

• Diagnosis of EBV+ disorder
• Eastern Cooperative Oncology Group performance status <= 3 for participants aged >= 16 years; Lansky score >= 20 for participants from 1 year to < 16 years
• Adequate organ function test results, unless organ dysfunction is considered to be due to the underlying EBV-associated disease by the investigator Cohort-specific
• For participants with PID LPD:
• Newly diagnosed or relapsed/refractory LPD confirmed by biopsy-proven EBV+ LPD or positive cerebrospinal fluid (CSF) cytology with or without radiographically measurable intracranial disease with EBV detected in CSF
• Participant must have systemic measurable disease and/ or CNS measurable disease
• Definitive therapy (eg, allogeneic HCT, gene therapy) for the underlying PID is planned
• Participants with newly diagnosed disease should be ineligible for standard first-line therapy for EBV+ LPD, as determined by the investigator
• For participants with AID LPD:
• Newly diagnosed or relapsed/refractory LPD confirmed by biopsy-proven EBV+ LPD or positive CSF cytology, with or without radiographically measurable intracranial disease, with EBV detected in CSF
• Participant must have systemic measurable disease and/ or CNS measurable disease
• Participants who are human immunodeficiency virus positive (HIV+) must meet both of the following criteria: Have an HIV viral load assessed by reverse transcription-polymerase chain reaction (RT-PCR) below the lower limit of detection and CD4 >= 50 cells/μL within 6 months prior to the first dose of tabelecleucel
• Participants with newly diagnosed disease should be ineligible for standard first-line therapy for EBV+ LPD, as determined by the investigator
• For participants with CNS PTLD:
• Newly diagnosed or relapsed/refractory EBV+ CNS PTLD histologically confirmed by biopsy-proven EBV+ CNS PTLD or positive CSF cytology with or without radiographically measurable intracranial disease with EBV detected in CSF
• Participant may have systemic and CNS disease or CNS disease only
• Participants with newly diagnosed disease should be ineligible for standard first-line therapy for EBV+ LPD, as determined by the investigator
• For participants with EBV+ PTLD, where standard first line therapy (rituximab and/or chemotherapy) is not appropriate, including CD20-negative disease:
• Newly diagnosed, biopsy-proven EBV+ PTLD
• Ineligible for standard first-line therapy for EBV+ PTLD, as determined by the investigator
• Participants must have systemic disease measurable per Lugano Classification criteria, except when contraindicated or mandated by local practice, then MRI may be used.
• For participants with sarcoma, including LMS:
• Newly diagnosed or failed systemic first-line therapy for EBV+ sarcoma. Participants with newly diagnosed disease should be ineligible for standard first-line therapy for EBV+ sarcoma, as determined by the investigator.
• Biopsy-proven EBV+ sarcoma
• Measurable disease using diagnostic PET/CT and/or MRI following RECIST 1.1 criteria
• For participants with CAEBV:
• Newly diagnosed or previously treated CAEBV
• Detectable EBV viremia on at least 2 occasions at a minimum of 90 days apart
• At least 3 active clinical findings (per Kimura H, et al. Front Immunol. 2017;8:1867) as: Fever >= 38.5°C; splenomegaly, lymphadenopathy, and/or hepatomegaly; cytopenia affecting at least 2 or 3 lineages in the peripheral blood (hemoglobin < 9 g/dL, platelets < 100 × 10^3/mL, neutrophils < 1 × 10^3/mL); hypogammaglobulinemia; hemophagocytosis; hepatitis; neuropathy; rash; and hydroa vacciniforme
• For participants with EBV+ viremia with HLH:
• Newly diagnosed or previously treated EBV+ viremia with HLH
• A molecular diagnosis consistent with HLH-2004 trial (per Henter JI, et al. Pediatr Blood Cancer. 2007;48:124-31) OR 5 or more of the clinical symptoms (per Jordan MB, et al. Blood. 2011;118:4041-4052): Fever >= 38.5°C; splenomegaly; cytopenia affecting at least 2 or 3 lineages in the peripheral blood (hemoglobin < 9 g/dL, platelets < 100 × 10^3/mL, neutrophils < 1 × 10^3/mL); hypertriglyceridemia (fasting >= 265 mg/dL) and/or hypofibrinogenemia (<= 150 mg/dL); hemophagocytosis in bone marrow, spleen, lymph nodes, or liver; low or absent natural killer cell (NK-cell) activity; ferritin >= 500 ng/mL; and elevated soluble CD25
• Burkitt, T-cell (except in the setting of HLH), natural killer/T-cell lymphoma/LPD, Hodgkin, or transformed lymphoma
• Serious known active infections, defined as ongoing uncontrolled adenovirus infection or infections requiring systemic therapy at the time of enrollment
• Suspected or confirmed Grade >= 2 acute graft-versus-host disease (GvHD) per the Center for International Blood and Marrow Transplant Research (CIBMTR) consensus grading system or extensive chronic GvHD per National Institutes of Health (NIH) consensus criteria at the time of the enrollment
• Need for vasopressor or ventilatory support
• Prior therapy (in order of increasing washout period) prior to enrollment as:
• Within 4 weeks or 5 half-lives (whichever is shorter) for any investigational product and/ or any chemotherapy (systemic or intrathecal), targeted small molecule therapy, or antibody/biologic therapy. Note: prior anti-CD20 antibody use is permitted within the washout period if a subsequent disease response assessment indicates disease progression
• Within <= 8 weeks for cellular therapies (EBV-CTLs, chimeric antigen receptor therapies directed at T cells or T-cell subsets, donor lymphocyte infusion, other CTLs); and/or therapies which could impact tabelecleucel function (anti-thymocyte globulin, alemtuzumab)
• Unwilling to use protocol specified contraceptive methods
• Women who are pregnant or breastfeeding
• Ongoing need for daily steroids of > 0.5 mg/kg prednisone or glucocorticoid equivalent, ongoing methotrexate, or extracorporeal photopheresis (protocol-specified dexamethasone is permitted and concludes by the time of enrollment)
• For participants with PID LPD or AID LPD: history of prior allogeneic HCT or solid organ transplant

• Patients must be < 50 years at the time of enrollment.
• Patient must have eligibility confirmed by rapid central imaging review.
• Patients must have =< 4 nodules per lung consistent with or suspicious for metastases, with at least one of which being >= 3 mm and all of which must be =< 3 cm size.
• Lung nodules must be considered resectable by either open thoracotomy or thoracoscopic surgery. Determination of resectability is made by the institutional surgeon.
• Patients must have a histological diagnosis of osteosarcoma.
• Patients must have evidence of metastatic lung disease at the time of initial diagnosis, or at time of 1st recurrence following completion of therapy for initially localized disease.
• Patients with newly diagnosed disease must have completed successful gross tumor resection for their primary tumor or surgical local control of primary tumor must be planned to be performed simultaneously with thoracic surgery.
• Newly diagnosed patients must be receiving systemic therapy considered by the treating physician as at least equivalent to methotrexate, doxorubicin and cisplatin (MAP) at the time of enrollment on this study.
• Patients at time of 1st recurrence must have previously completed initial systemic therapy for their primary tumor, considered by the treating physician as at least equivalent to MAP.
• Patients with unresectable primary tumor.
• Patients with pulmonary metastatic lesions that would require anatomic resection (lobectomy or pneumonectomy) or lesions that are defined as "central" (i.e., central lesion involves or is proximal to segmental bronchi and peripheral is lesion distal to segmental bronchi).
• Patients with pleural or mediastinal based metastatic lesions, or with pleural effusion.
• Patients with disease progression at either the primary or pulmonary metastatic site while on initial therapy. Note: Once the patient has been enrolled on the study, additional computed tomography (CT) scans are not anticipated prior to thoracic surgery. Note: Some variation in nodule size measurements over the course of pre-operative therapy is anticipated and does not qualify for exclusion unless deemed true disease progression by the primary treatment team.
• Patients with evidence of extrapulmonary metastatic disease.
• Patients who received pulmonary surgery for lung metastasis prior to enrollment.
• 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.

Key
• Diagnosis of sporadic or familial ALS
• Less than 3 years since ALS symptom onset
• Stable doses of approved ALS treatments (riluzole and/or edaravone) for at least 2 months prior to screening
• Participants must be able to swallow the study intervention
• Vital capacity >50% predicted at screening
• Women must have been surgically sterilized or be postmenopausal
• Men, and sex partner if a woman of childbearing potential, must use highly effective contraception Key
• Any history of unstable or poorly controlled psychiatric, endocrine, pulmonary, cardiovascular, gastrointestinal, hepatic, pancreatic, renal, metabolic, hematologic, immunologic, or allergic disease, or other major disorders
• Positive serum pregnancy test or currently lactating or breastfeeding
• History of malignancy within 5 years
• History of clinically significant neurologic disorders other than ALS

1. Must have provided informed consent in a manner approved by the Investigator's Institutional Review Board (IRB) prior to any study-related procedure being performed. If a participant is unable to provide informed consent due to his/her medical condition, the participant's legally authorized representative may consent on behalf of the study participant, as permitted by local law and institutional Standard Operating Procedures; 2. Aged greater than or equal to 18 years at the time of informed consent; 3. Recent use of an FDA-approved immune checkpoint inhibitor (ICI, defined as administered an immune checkpoint inhibitor ≤ 6 months of myocarditis diagnosis), alone or in combination with other cancer therapies (i.e. chemotherapy, radiation therapy or targeted therapy). The FDA-approved ICI could be given as part of a clinical trial but not in combination with a new investigational agent which may cause myocarditis; 4. A diagnosis of myocarditis. 5. Hospitalized at the time of randomization; 6. On 1000 mg of solumedrol per day for myocarditis or with an intent to initiate 1000 mg of solumedrol per day for myocarditis within 24 hours of first administration of study drug; 7. Serum evidence of ongoing myocardial injury: Serum evidence of ongoing myocardial injury will be defined as an institutional troponin (either conventional or high-sensitivity troponin I or T, using the standard institutional assay) with a value that is ≥5 times the upper limit of the reference standard normal for that institution. The troponin assay may be adjusted based on sex depending on institutional standards. This value of troponin of ≥5 times above the institutional upper limits of normal value must be noted within 10 days prior to potential randomization. The 10-day period can be in the outpatient or inpatient setting. For example, a participant with a troponin value that on one occasion was ≥5 times the upper limits of institutional normal in the 10-day window prior to potential randomization (whether in the inpatient or outpatient setting), but later decreases below that threshold, typically due to starting corticosteroids, would still be considered eligible; 8. The following laboratory parameters, not older than 48 hours at the time of randomization, and measured as part of usual care:
• Total white blood cell (WBC) count >2,500/μl
• Absolute neutrophil count (ANC) >1,500/μL
• Alanine aminotransferase (ALT) or aspartate aminotransferase (AST) <20 times the upper limit of the institutional normal ranges; 9. Women of childbearing potential (i.e., not postmenopausal, or surgically sterilized) must have a negative highly sensitive urine or serum pregnancy test prior to randomization. Participating women of childbearing potential must be willing to consistently use effective methods of contraception from screening until at least 90 days after administration of the last dose of study drug. Participating men must also be willing to consistently use effective methods of contraception from screening until at least 90 days after administration of the last dose of study drug; and 10. Must be willing and able to abide by all study requirements and restrictions. 1. Must not have experienced any of the following (as defined in the section on the primary endpoint) in the 30-day period prior to randomization:
• A sudden cardiac arrest
• Cardiogenic shock as defined. A significant bradyarrhythmia (Mobitz type II second degree atrioventricular block or third degree (complete) atrio-ventricular (AV) block, for which an intervention with a temporary or permanent pacemaker is completed or recommended).
• A significant tachyarrhythmia (ventricular fibrillation of any duration or sustained ventricular tachycardia (>30 seconds, >120 beats per minute); or a ventricular tachyarrhythmia requiring intervention. 2. Recent (≤2 month) exposure to abatacept or belatacept. 3. Concurrent or recent (≤2 month) use of the following non-corticosteroid immunosuppressive therapies prior to randomization: mycophenolate, JAK STAT inhibitors (including but not limited to upadacitinib, tofacitinib, baricitinib, and filgotinib), tacrolimus, anti-thymocyte globulin, alemtuzumab, infliximab, and plasma exchange. The use of intravenous immunoglobulin is permitted prior to randomization and during study treatment. 4. Currently enrolled in another interventional study utilizing systemic agents for the management of ICI-related toxicities. 5. Female who is pregnant, breastfeeding, or is considering becoming pregnant during the study or for approximately 90 days after the last dose of study drug. 6. Male who is considering fathering a child or donating sperm during the study or for approximately 30 days after the last dose of study drug. 7. Any active, chronic, or recurrent viral infection that, based on the investigator's clinical assessment, makes the participant an unsuitable candidate for the study. These may include hepatitis B virus (HBV) or hepatitis C virus (HCV), recurrent or disseminated (even a single episode) herpes zoster, and disseminated (even a single episode) herpes simplex. Active HBV and HCV are defined as: HBV: hepatitis B surface antigen (HBs Ag) positive (+) or detected sensitivity on the HBV deoxyribonucleic acid (DNA) polymerase chain reaction (PCR) qualitative test for Hepatitis B core antibody (HBc Ab) positive (+) participants; HCV: HCV ribonucleic acid (RNA) detectable in any participant with anti-HCV antibody (HCV Ab). Patients with active Covid-19 infection will be excluded. This is defined as the period of ongoing symptoms in the setting of a positive Covid-19 test, or until 10 days after symptom onset and after resolution of fever for at least 24 hours, without the use of fever-reducing medications. 8. Known active tuberculosis (TB), history of incompletely treated TB, suspected or known extrapulmonary TB, suspected or known systemic bacterial or fungal infections; 9. Receipt of any live vaccine within four weeks prior to the first dose of study drug, or expected need of live vaccination during study participation including at least 90 days after the last dose of IV study drug. 10. Any medical condition that could interfere with, or for which the treatment might interfere with, the conduct of the study or interpretation of the study results, or that would, in the opinion of the Investigator, increase the risk of the participant by participating in the study. 11. Any factors that, in the Investigator's opinion, are likely to interfere with study procedures, such as history of noncompliance with scheduled appointments.

• Aged =>50 years to <85 years
• Shoulder pain and/or loss of range of active motion, strength or function
• MRI-confirmed partial- or full-thickness supraspinatus and/or infraspinatus tear of 4cm or less in longitudinal dimension
• Medically fit for surgery, defined as Category I-III per American Society of Anesthesiologists (ASA) Physical Status Classification
• Ability and willingness to provide informed consent
• Primary diagnosis is something other than a rotator cuff tear
• History (in last 2 years) of shoulder fracture involving the humeral head on affected side
• Previous rotator cuff surgery on affected side
• Isolated subscapularis &/or teres minor tear on affected side
• Acute rotator cuff tear caused by a severe trauma
• Shoulder used as a weight-bearing joint
• Contraindication to MRI (claustrophobia, pacemaker, pregnancy, shoulder implant, etc.)
• Glenohumeral osteoarthritis on xrays/MRI
• Grade 4 fatty infiltration of rotator cuff (any tendons)
• Candidate for shoulder arthroplasty at baseline
• Non-English speaking

• Subjects with moderate hemophilia A (baseline factor VIII activity 1-5%) or severe hemophilia A (baseline factor VIII activity <1%) on prophylactic standard half-life FVIII infusions OR subjects with moderate or severe hemophilia A who have not started prophylactic treatment
• Less than 18 years of age
• Subjects with documented FVIII inhibitor
• Subjects with a history of ≥ 2 target joints
• Subjects with a history of synovectomy
• Currently using medications known to impact bone and mineral metabolism (e.g., bisphosphonates, corticosteroids, estrogen, testosterone, calcitonin, thyroid hormone therapy);
• Disease states known to affect bone integrity (e.g., primary hyperparathyroidism, Paget's disease, clinically significant liver disease)

1. ≥ 18 years of age 2. Histopathological or cytologically documented locally advanced or metastatic solid tumors who have no available standard therapeutic treatment options 3. At least one measurable lesion as defined by RECIST V1.1 criteria for solid tumors 4. Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1 5. Adequate organ function confirmed at screening and within 10 days of initiating treatment, as evidenced by:
• Absolute neutrophil count (ANC) ≥ 1.5 x 10^9/L
• Hemoglobin (Hgb) ≥ 8 g/dl
• Platelets (plt) ≥ 75 x 10^9/L
• AST/SGOT and ALT/SGPT ≤ 2.5 x Upper Limit of Normal (ULN) or ≤ 5.0 x ULN if liver metastases are present
• Total bilirubin ≤ 1.5 x ULN
• Calculated creatinine clearance ≥ 50 mL/min (Cockcroft Gault formula) 6. Negative pregnancy test within 72 hours before starting study treatment in all premenopausal women and women < 12 months after the onset of menopause 7. Must agree to take sufficient contraceptive methods to avoid pregnancy during the study and until at least 6 months after ceasing study treatment 8. Able to sign informed consent and comply with the protocol 1. Women who are pregnant or lactating 2. Women of child-bearing potential (WOCBP) who do not use adequate birth control 3. Patients with any hematologic malignancy, including leukemia (any form), lymphoma, and multiple myeloma 4. Patients with a history of primary central nervous system tumors or carcinomatous meningitis. 5. Patients with the following mood disorders as judged by the Investigator or a psychiatrist:
• Medically documented history of or active major depressive episode, bipolar disorder (I or II), obsessive-compulsive disorder, schizophrenia; a history of suicidal attempt or ideation, or homicidal ideation (immediate risk of doing harm to others)
• ≥ CTCAE grade 3 anxiety 6. Impaired cardiac function or significant diseases, including but not limited to any of the following:
• left ventricular ejection fraction (LVEF) < 45% as determined by multigated acquisition (MUGA) scan or echocardiogram (ECHO)
• Congenital long QT syndrome
• QTcF ≥ 480 msec on screening ECG
• Unstable angina pectoris ≤ 3 months prior to starting study drug
• Acute myocardial infarction ≤ 3 months prior to starting study drug 7. Patients with:
• unresolved diarrhea ≥ CTCAE grade 2, or
• impairment of gastrointestinal (GI) function, or
• GI disease that may significantly alter the absorption of TT-00420 8. Other concurrent severe and/or uncontrolled concomitant medical conditions (e.g., uncontrolled hypertension, uncontrolled hypertriglyceridemia, or active or uncontrolled infection) that could cause unacceptable safety risks or compromise compliance with the protocol 9. Patients who have received chemotherapy, targeted therapy, or immunotherapy ≤ 4 weeks (6 weeks for nitrosourea or mitomycin-C) prior to starting study drug or who have not recovered from side effects of such therapy 10. Patients who have received wide field radiotherapy ≤ 4 weeks or limited field radiation for palliation ≤ 2 weeks prior to starting study drug or who have not recovered from side effects of such therapy 11. Patients who have undergone major surgery ≤ 4 weeks prior to starting study drug or who have not recovered from side effects of such therapy 12. Patients who have been treated with any hematopoietic colony-stimulating growth factors (e.g., G-CSF, GM-CSF) ≤ 4 weeks prior to starting study drug. 13. Patients who are currently receiving treatment with therapeutic doses of warfarin sodium or any other coumarin-derivative anticoagulants 14. Patients who have received systemic corticosteroids ≤ 2 weeks prior to starting study drug or who have not recovered from the side effects of such treatment. 15. Patients who are currently receiving treatment with strong CYP3A inhibitors or inducers ≤ 2 weeks prior to starting study drug. 16. Known diagnosis of human immunodeficiency virus (HIV) infection (HIV testing is not mandatory; patients with well controlled HIV might be enrolled) 17. Known history of active infection with Hepatitis B or Hepatitis C 18. Has received a live-virus vaccination within 30 days of planned first dose 19. Inability to swallow or tolerate oral medication 20. Has a history or current evidence of any condition, therapy, or laboratory abnormality that, in the opinion of the investigator, might confound the results of the trial, interfere with the patient's safe participation and compliance in the trial.

• All patients must be enrolled on APEC14B1 (NCT02402244) and consented to the Molecular Characterization Initiative (Part A) prior to enrollment and treatment on ARST2032 (this trial).
• Patients must be =< 21 years at the time of enrollment.
• Patients must have newly diagnosed embryonal rhabdomyosarcoma (ERMS), spindle cell/sclerosing RMS, or FOXO1 fusion negative alveolar rhabdomyosarcoma (ARMS) (institutional FOXO1 fusion results are acceptable). RMS types included under ERMS include those classified in the 1995 International Classification of Rhabdomyosarcoma (ICR) as ERMS (classic, spindle cell, and botryoid variants), which are reclassified in the 2020 World Health Organization (WHO) classification as ERMS (classic, dense and botryoid variants) and spindle cell/sclerosing RMS (encompassing the historical spindle cell ERMS variant and the newly recognized sclerosing RMS variant). Enrollment in APEC14B1 is required for all patients.
• All patients will be evaluated for stage and clinical group. Note that clinical group designation assigned at the time of enrollment on study remains unchanged regardless of any second-look operation that may be performed.
• Patients will be eligible for the very low-risk stratum (Regimen VA) if they have Stage 1, CG I disease.
• Patients will be eligible for the low-risk stratum (Regimen VAC/VA) if they have Stage 1, CG II disease, Stage 2, CG I or II disease, or Stage 1, CG III (orbit only) disease.
• Paratesticular Tumors: Staging ipsilateral retroperitoneal lymph node sampling (SIRLNS) is required for all patients >= 10 years of age with paratesticular tumors who do not have gross nodal involvement on imaging.
• Extremity Tumors: Regional lymph node sampling is required for histologic evaluation in patients with extremity tumors.
• Clinically or radiographically enlarged nodes must be sampled for histologic evaluation.
• Patients must have a Lansky (for patients =< 16 years of age) or Karnofsky (for patients > 16 years of age) performance status score of >= 50. 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 performance score.
• Peripheral absolute neutrophil count (ANC) >= 750/uL (within 7 days prior to enrollment).
• Platelet count >= 75,000/uL (transfusion independent) (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 (within 7 days prior to enrollment) based on age/gender as follows:
• Age: 1 month to < 6 months; Maximum serum creatinine (mg/dL): 0.4 (male) : 0.4 (female)
• Age: 6 months to < 1 year; Maximum serum creatinine (mg/dL): 0.5 (male) : 0.5 (female)
• Age: 1 to < 2 years; Maximum serum creatinine (mg/dL): 0.6 (male) : 0.6 (female)
• Age: 2 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 (within 7 days prior to enrollment), and
• If there is evidence of biliary obstruction by the tumor, then the total bilirubin must be < 3 x ULN for age.
• Note: For the purpose of this study, the ULN for SGPT (ALT) has been set to the value of 45 U/L.
• Serum glutamate pyruvate transaminase (SGPT) (alanine aminotransferase [ALT]) =< 135 U/L (within 7 days prior to enrollment).
• 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.
• Patients who have received prior chemotherapy and/or radiation therapy for cancer prior to enrollment. Surgical resection alone of previous cancer(s) is permitted.
• Patients who have received chemotherapy or radiation for non-malignant conditions (e.g., autoimmune diseases) are eligible. Patients must discontinue chemotherapy for non-malignant conditions prior to starting protocol therapy.
• Vincristine is sensitive substrate of the CYP450 3A4 isozyme. Patients must not have received drugs that are moderate to strong CYP3A4 inhibitors and inducers within 7 days prior to study enrollment.
• Patients unable to undergo radiation therapy, if necessary, as specified in the protocol.
• Evidence of uncontrolled infection.
• Female patients who are pregnant 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.

• Have advanced breast cancer or another solid tumor with the presence of a PIK3CA H1047R mutation (or other Sponsor and SRC-approved, activating PIK3CA mutations other than H1047R mutation)
• Have adequate archival tumor tissue sample available or be approved by the Sponsor for enrollment if no tumor sample is available.
• Have stopped all cancer treatment and have recovered from the major side effects
• Have adequate organ function, as measured by blood tests
• Have a performance status of 0 or 1 on the Eastern Cooperative Oncology Group (ECOG) scale
• Patients must have
• Measurable disease --- Patients with non-breast tumor types must have at least 1 measurable lesion
• Non-measurable bone disease (at least one bone lesion in breast cancer patients only)
• For patients with an ER+ breast cancer diagnosis:
• If female, must be postmenopausal
• If male, must agree to use hormone suppression
• Phase 1a: -- Dose escalation and backfill patients:
• Advanced solid tumor
• Patients may have had up to 5 prior regimens for advanced disease
• Phase 1b:
• Part A:
• ER+/HER2- advanced breast cancer
• Patients may have had up to 2 prior regimens for advanced disease
• Prior cyclin dependent kinase (CDK)4/6 inhibitor therapy required
• Part B:
• ER+/HER2- advanced breast cancer
• Patients may have had up to 2 prior regimens for advanced disease.
• Part C:
• ER+/HER2- advanced breast cancer
• Patients may have had up to 5 prior regimens for advanced disease. ---- Prior CDK4/6 inhibitor therapy required.
• Have a diagnosis of diabetes mellitus Type 2
• Part D:
• Advanced breast cancer
• Patients may have had up to 5 prior regimens for advanced disease.
• Part E:
• Advanced solid tumor
• Patients may have had up to 3 prior regimens for advanced disease
• Medical Conditions
• Colorectal cancer
• Endometrial cancers with specific concurrent oncogenic alterations
• A history of known active or suspected
• Diabetes mellitus Type 1 or
• Diabetes mellitus Type 2 requiring antidiabetic medication (Phase 1a and all parts of Phase 1b except Part C).
• Serious concomitant systemic disorder
• Known or suspected history of untreated or uncontrolled central nervous system (CNS) involvement.
• Active uncontrolled systemic bacterial, viral, fungal, or parasitic infection, or other clinically significant active disease process
• Prior exposure to PI3K/AKT/mTOR inhibitor(s), except in certain circumstances

Inclusion Criteria 1. Biopsy-proven non-hematopoietic malignancy, except for small cell lung cancer, germ cell cancer, or unknown primary tumor. 2. Radiographic evidence by MRI (or by CT scan with CT contrast if ineligible or intolerant of MRI) of brain metastasis. (If patient is unable to tolerate MRI contrast, an MRI without contrast is acceptable if lesions are visible) 3. All brain metastases must be outside the brain stem (midbrain, pons and medulla). 4. Patient must have 10 or less brain metastases. 5. The maximum diameter of any lesion must be less than or equal to 3.0 cm. 6. Previous treatment with surgery, radiation, chemotherapy, immunotherapy or any targeted agents are allowed provided that:
• Radiation was not to the brain.
• Surgery to the brain was > 7 days prior to SRS and there remains at least one additional brain metastasis that can be targeted with SRS 7. Age ≥ 18 years. 8. ECOG Performance Score of 2 or better/Karnofsky Performance Status score of 50-60 or better. 9. All men, as well as women of child-bearing potential must agree to use adequate contraception (hormonal or barrier method of birth control; abstinence) prior to study entry and for the duration of study participation. Should a woman become pregnant or suspect she is pregnant while participating in this study, she should inform her treating physician immediately. A female of child-bearing potential is any woman (regardless of sexual orientation, marital status, having undergone a tubal ligation, or remaining celibate by choice) who meets the following criteria:
• Has not undergone a hysterectomy or bilateral oophorectomy; or
• Has not been naturally postmenopausal for at least 12 consecutive months (i.e., has had menses at any time in the preceding 12 consecutive months). Medically acceptable birth control (contraceptives) includes:
• Approved hormonal contraceptives (such as birth control pills, patch, or ring: Depo-Provera, Implanon), or
• Barrier methods (such as a condom or diaphragm) used with a spermicide (a substance that kills sperm) 10. Ability to understand and the willingness to sign a written informed consent. Exclusion Criteria 1. Patients had craniotomy and surgery to the brain within 7 days from the date of SRS. 2. Patients with leptomeningeal metastasis. NOTE: For the purposes of exclusion, LMD is a clinical diagnosis, defined as positive CSF cytology and/or equivocal 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, unless a parenchymal lesion can adequately explain the neurologic symptoms and/or signs. 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. 3. Patients with a contraindication to both MRI (with or without contrast) and CT scan (with contrast) 4. Patients with life expectancy < 3 months. 5. Uncontrolled intercurrent illness including, but not limited to, ongoing or active infection, symptomatic congestive heart failure, unstable angina pectoris, cardiac arrhythmia, or psychiatric illness/social situations that, in the opinion of the investigator, would limit compliance with study requirements. 6. Subjects must not be pregnant or nursing at the time of SRS treatment due to the potential for congenital abnormalities and the potential of this regimen to harm nursing infants.

Inclusion: 1. Histologically confirmed relapsed or refractory solid tumor as follows:
• For dose escalation and dose determination parts: Histologically confirmed relapsed or refractory solid tumor (including CNS tumors but not lymphomas). Patients with Diffuse Intrinsic Pontine Glioma do not require histological only radiographic confirmed relapse to enroll.
• For dose expansion and tumor specific cohorts: Histologically confirmed relapsed or refractory solid tumor including but not limited to EWS, rhabdoid tumor, rhabdomyosarcoma, neuroblastoma, and medulloblastoma. Patients with Diffuse Intrinsic Pontine Glioma do not require histological only radiographic confirmed relapse to enroll. EWS is not eligible for TOPO and CTX tumor-specific cohorts.
• For randomized Phase 2 part: Histologically confirmed Ewing sarcoma at diagnosis or at relapse, with presence of EWSR1-ETS or FUS-ETS rearrangement. Histopathology confirmation of both EWSR1-ETS or FUS-ETS rearrangement partners is required OR availability of formalin fixed paraffin embedded (FFPE) tumor tissue sample for central testing. Patient must have relapsed or have refractory disease and at least evaluable disease in at least one site other than bone marrow that can be followed by imaging. 2. Age ≥2 and <21 years at the time of study entry. 3. Lansky performance status ≥50% for patients ≤16 years of age, or Eastern Cooperative Oncology Group (ECOG) 0, 1 or 2 for patients >16 years of age. 4. Adequate bone marrow function.
• Absolute neutrophil count ≥1000/mm3;
• Platelet count ≥100,000/mm3 (transfusion independent, no platelet transfusion in past 7 days prior study entry);
• Hemoglobin ≥8.5 g/dL (transfusion allowed). 5. Adequate renal function: Serum creatinine level based on age/gender must within protocol specified limits. 6. Adequate liver function, including:
• Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) ≤2.5 × upper limit of normal (ULN) or ≤5 × ULN for age, if attributable to disease involvement of the liver;
• Total bilirubin ≤1.5 × ULN for age, unless the patient has documented Gilbert's syndrome. 7. Patients enrolled to Phase 1 portion of the study and tumor specific cohorts must have measurable disease as defined by RECIST version 1.1 or modified RANO criteria for CNS disease or INRC for neuroblastoma. Patients with EWS enrolled to Phase 2 portion of the study are eligible with evaluable disease (eg, bone only disease with no soft tissue component). 8. Recovered to CTCAE Grade ≤1, or to baseline, from any non-hematological acute toxicities of prior surgery, chemotherapy, immunotherapy, radiotherapy, differentiation therapy or biologic therapy, with the exception of alopecia. 9. Serum/urine pregnancy test (for all girls ≥8 years of age) negative at screening and at the baseline visit. Exclusion: 1. Phase 1 and tumor specific cohorts: For palbociclib with IRN and TMZ combination, prior treatment with a CDK4/6 inhibitor or progression while on treatment with an IRN-containing regimen that includes TMZ. Patients who have received the combination of IRN and TMZ and did not progress while on these medications are eligible. For patients enrolling in the palbociclib with TOPO and CTX combination, prior treatment with a CDK4/6 inhibitor or progression while on treatment with a TOPO-containing regimen that includes CTX. Patients who have received the combination of TOPO and CTX and did not progress while on these medications are eligible. Phase 2 portion: prior treatment with a CDK4/6 inhibitor or progression while on treatment with an IRN-containing or TMZ-containing regimen. Patients who have received IRN and/or TMZ and did not progress while on these medications are eligible. 2. Prior intolerability to IRN and/or TMZ plus/minus palbociclib with IRN and TMZ combination and prior intolerability to TOPO and/or CTX for TOPO and CTX combination. 3. Use of strong cytochrome P450 (CYP) 3A inhibitors or inducers. Patients who are receiving strong uridine diphosphate-glucuronosyl transferase 1A1 (UGT1A1) inhibitors within 12 days of Cycle 1 Day 1 (C1D1) are not eligible for the palbociclib with IRN and TMZ combination. Patients who are receiving strong UGT1A1 inhibitors within 12 days of C1D1 are eligible for the palbociclib with TOPO and CTX combination (See Section 5.7.1 for list of products.) 4. Systemic anti cancer therapy within 2 weeks prior to study entry and 6 weeks for nitrosoureas. 5. Prior irradiation to >50% of the bone marrow (see Appendix 9). 6. Participation in other studies involving investigational drug(s) within 2 weeks or 5 half lives, whichever is longer, prior to study entry. 7. Major surgery within 4 weeks prior to study entry. Surgical biopsies or central line placement are not considered major surgeries. 8. For IRN and TMZ with/without palbociclib combinations: known or suspected hypersensitivity to palbociclib, IRN and/or TMZ. For combination of palbociclib with TOPO and CTX: known or suspected hypersensitivity to palbociclib, TOPO and/or CTX. 9. Patients with known symptomatic brain tumors or brain metastases and require steroids, unless they have been on a stable or on a decreasing steroid dose for >14 days. 10. Patients with previously diagnosed brain metastases are eligible if they have completed their prior treatment and have recovered from the acute effects of radiation therapy or surgery prior to study entry for these metastases for at least 14 days post radiation and 4 weeks post-surgery and are neurologically stable. 11. Hereditary bone marrow failure disorder. 12. QTc >470 msec. 13. History of clinically significant or uncontrolled cardiac disease, including:
• History of or active congestive heart failure; if patient had congestive heart failure resolve and >1 year from resolution, patient will be considered eligible;
• Clinically significant ventricular arrhythmia (such as ventricular tachycardia, ventricular fibrillation or Torsades de Pointes);
• Diagnosed or suspected congenital or acquired prolonged QT syndrome;
• Need for medications known to prolong the QT interval;
• Uncorrected hypomagnesemia or hypokalemia because of potential effects on the QT interval;
• Left ventricular ejection fraction <50% or shortening fraction <28%. 14. Recent or ongoing clinically significant gastrointestinal disorder that may interfere with absorption of orally administered drugs (eg, gastrectomy). 15. Severe acute or chronic medical or laboratory test abnormality that may increase the risk associated with study participation or investigational product administration or may interfere with the interpretation of study results, and in the judgment of the Investigator, would make the patient inappropriate for entry into this study. 16. Investigator site staff members directly involved in the conduct of the study and their family members, site staff members otherwise supervised by the investigator, or patients who are Pfizer employees, including their family members, directly involved in the conduct of the study.

• Participants must have had a histologic diagnosis of osteosarcoma at original diagnosis
• Disease Status: Patients with an isolated pulmonary recurrence of osteosarcoma can be enrolled on this study.
• Any history of metastatic disease at a site other than lung would make the patient ineligible for this study.
• The patient's treating team must consider the patient's disease to be resectable and the patient must be willing to undergo resection of all disease, including any lung lesion meeting criteria for likely metastatic disease, defined as: 3 or more lesions ≥ 3 mm in diameter OR a single lesion ≥ 5 mm.
• Patients with bilateral disease are eligible provided their disease is considered resectable. Resectable pulmonary nodules are defined as nodules that can be removed without performing a pneumonectomy (e.g., nodules immediately adjacent to the main stem bronchus or main pulmonary vessels).
• Must have a performance status corresponding to Eastern Cooperative Oncology Group (ECOG) scores of 0, 1 or 2, using the Karnofsky scale for patients > 16 years of age and the Lansky scale for patients ≤ 16 years of age
• Prior Therapy: Participants must have fully recovered from the acute toxic effects of all prior chemotherapy, immunotherapy, or radiotherapy prior to the start of protocol therapy.
• Participants must have normal organ and marrow function within 7 days of starting protocol therapy
• All participants and/or their parents or legal guardians must have the ability to understand and the willingness to sign a written informed consent/assent document
• Additional criteria may apply
• Pregnancy or Breast Feeding
• Males and females of reproductive potential may not participate unless they have agreed to the use of, at minimum, two methods of contraception, with one method being highly effective and the other method being either highly effective or less effective as outlined in study protocol documentation
• Concomitant Medications: Patients receiving the following are not eligible:
• Corticosteroids or other immunosuppressive medications
• Patients who are currently receiving other investigational agents or other anti-cancer therapy
• Intercurrent Illnesses: Patients with uncontrolled intercurrent illness including, but not limited to:
• Ongoing or active infection
• Symptomatic congestive heart failure
• Unstable angina pectoris
• Cardiac arrhythmia
• Psychiatric illness/social situations that would limit compliance with study requirements
• Autoimmune disorders: Patients with a history of any Grade autoimmune disorder are not eligible.
• Asymptomatic laboratory abnormalities (e.g., ANA, rheumatoid factor, altered thyroid function studies) will not render a patient ineligible in the absence of a diagnosis of an autoimmune disorder.
• Patients with ≥ Grade 2 hypothyroidism due to history of autoimmunity are not eligible. Note: Hypothyroidism due to previous irradiation or thyroidectomy will not impact eligibility
• Allergies: Patients with a history of allergic reactions attributed to compounds of similar chemical or biologic composition to Nivolumab (e.g., another humanized antibody) or Azacitidine are not eligible
• Safety and Monitoring: Patients who are considered unable to comply with the safety monitoring requirements of the study are not eligible
• Patients with known HIV or hepatitis B or C are excluded
• Patients who have received prior solid organ transplantation are not eligible
• Patients who have received prior anti-PD-1 directed therapy (mAb or small molecule) are not eligible

• Diagnosed with RRMS per revised McDonald criteria (2017) with an EDSS score ≤ 6.5 at screening
• Neurologically stable with no evidence of relapse within the 28 days before signing the informed consent form (ICF)
• Either not currently receiving disease modifying MS therapy, or currently using fumarate drugs (dimethyl fumarate or diroximel fumarate)
• Patients must use a highly effective method of birth control or are sterile or postmenopausal as confirmed by study Investigator
• Patient has signed and understands the ICF
• Diagnosis of primary progressive MS or secondary progressive MS
• Uncontrolled or significant medical conditions (including active infection or chronic hepatitis) which, in the opinion of the Investigator, preclude participation
• Patients treated with glatiramer acetate, parenteral steroids or adrenocorticotropic hormone, β-interferon, plasma exchange, fingolimod, ozanimod, or siponimod within the 3 months prior to first dose
• Patients treated with cytotoxic agents (including, but not limited to, cladribine, mitoxantrone, cyclophosphamide, azathioprine, and methotrexate), laquinimod, teriflunomide, or IV gamma globulin within 12 months prior to first dose
• Patients treated with monoclonal antibody therapy (including natalizumab, daclizumab, rituximab, ofatumumab, and ocrelizumab) within 24 months prior to first dose
• Patients previously treated with alemtuzumab, total lymphoid irradiation, mesenchymal stem cell or hematopoietic stem cell transplantation, or tolerance-inducing therapies for MS
• Contraindication to or inability to undergo gadolinium-enhanced magnetic resonance imaging (MRI) scan
• Use of any investigational drug or experimental procedure within previous 6 months that would interfere with the assessment of ANK-700
• Patients who are pregnant or breastfeeding

• Women and men of reproductive potential should agree to use an appropriate method of birth control throughout their participation in this study due to the teratogenic potential of the therapy utilized in this trial. Appropriate methods of birth control include abstinence, oral contraceptives, implantable hormonal contraceptives or double barrier method (diaphragm plus condom)
• Diagnosis of advanced cancer
• Patient-reported 2-month weight loss of at least 5 pounds (2.3 kilograms) and/or physician-estimated caloric intake of less than 20 calories/kilogram of body weight per day
• The patient must perceive loss of appetite and/or weight as a problem; and have an appetite score of 4 or worse on the "Please rate your appetite…." question that requires a patient response on a 0-10 numeric rating scale
• Not receiving ongoing tube feedings or parenteral nutrition at the time of registration
• Not currently using systemic adrenal steroids (with the exception of short-term dexamethasone within 3 days of chemotherapy for control of chemotherapy side effects)
• No use of androgens, progesterone analogs, or other appetite stimulants within the past month
• Patient should not have poorly controlled hypertension or congestive heart failure at registration
• Patient should not have an obstruction of the alimentary canal, malabsorption, or intractable vomiting (defined as vomiting more than 3 times per day over the preceding week)
• Not currently using olanzapine for another medical condition or had previously used olanzapine for chronic nausea or for any pre-existing psychotic disorder
• Patient should not have had a previous blood clot at any time in the past
• No history of poorly controlled diabetes
• No symptomatic leptomeningeal disease or known brain metastases as these patients may have difficulty taking oral medications
• No history of hypersensitivity to olanzapine or megestrol acetate
• No COVID-19 infection in the past that, in the opinion of the treating physician, had left patients with compromised taste, which has not resolved at the time of registration
• Not pregnant and not nursing, because this study involves an investigational agent whose genotoxic, mutagenic and teratogenic effects on the developing fetus and newborn are unknown. Therefore, for women of childbearing potential only, a negative urine or serum pregnancy test done =< 14 days prior to registration is required
• Age >= 18 years
• Eastern Cooperative Oncology Group (ECOG) performance status 0, 1 or 2
• Estimated life expectancy of 3 months or longer
• Serum creatinine =< 2.0 mg/dL
• Aspartate aminotransferase (AST) or alanine aminotransferase (ALT) =< 3 x upper limit of normal (ULN)
• Fasting glucose > 1410 mg/dl
• Granulocytes > 1000/hpf
• No treatment with another antipsychotic agent, such as risperidone, quetiapine, clozapine, butyrophenone within 30 days of enrollment
• In order to complete the mandatory patient-completed measures, participants must be able to speak and/or read English or Spanish. Sites seeking to enroll Spanish-speaking patients should have access to Spanish speaking staff on site or through the use of a translation service to be able to conduct the informed consent discussion in Spanish, and to conduct the weekly phone calls
• Psychiatric illness which would prevent the patient from giving informed consent
• Medical condition such as uncontrolled infection (including human immunodeficiency virus [HIV]), uncontrolled diabetes mellitus or cardiac disease which, in the opinion of the treating physician, would make this protocol unreasonably hazardous for the patient
• Patients who cannot swallow oral formulations of the agents
• Patients with impaired decision-making capacity (such as with a diagnosis of dementia or memory loss) are not eligible for this study
• No presence of a hormone-sensitive tumor, such as breast, endometrial, or prostate cancer (this exclusion criterion is intended to circumvent any confounding antineoplastic effects of megestrol acetate)

• Patients must be =< 50 years of age at the time of enrollment
• Patients with newly diagnosed RMS of any subtype, except adult-type pleomorphic, based upon institutional histopathologic classification are eligible to enroll on the study based upon Stage, Group, and age, as below. FOXO1 fusion status must be determined by week 4 (day 28) of therapy. RMS types included under embryonal RMS (ERMS) include those classified in the 1995 International Classification of Rhabdomyosarcoma (ICR) as ERMS (classic, spindle cell, and botryoid variants), which are reclassified in the 2020 World Health Organization (WHO) Classification as ERMS (classic, dense and botryoid variants) and spindle cell/sclerosing RMS (encompassing the historical spindle cell ERMS variant and the newly recognized sclerosing RMS variant). Classification of alveolar RMS (ARMS) in the 2020 WHO Classification is the same as in the ICR and includes classic and solid variants
• ERMS
• Stage 4, group IV, >= 10 years of age
• ARMS
• Stage 4, group IV Patients will be eligible to remain on protocol therapy based upon stage, group, and age
• Bone marrow metastatic disease is based on morphologic evidence of RMS based on hematoxylin and eosin (H&E) stains. In the absence of morphologic evidence of marrow involvement on H&E, patients with bone marrow involvement detected ONLY by flow cytometry, reverse transcriptase (RT)-polymerase chain reaction (PCR), fluorescence in situ hybridization (FISH), or immunohistochemistry will NOT be considered to have clinical bone marrow involvement for the purposes of this study
• 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 (must be performed within 7 days prior to enrollment):
• Age; Maximum serum creatinine (mg/dL)
• 1 month to < 6 months; 0.4 mg/dL (male); 0.4 mg/dL (female)
• 6 months to < 1 year; 0.5 mg/dL (male); 0.5 mg/dL (female)
• 1 to < 2 years; 0.6 mg/dL (male); 0.6 mg/dL (female)
• 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 (must be performed within 7 days prior to enrollment)
• If there is evidence of biliary obstruction by tumor, then total bilirubin must be < 3 x ULN for age
• 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
• Patients with evidence of uncontrolled infection are not eligible
• RMS that is considered a second malignancy and previous cancer(s) that were treated with chemotherapy and/or radiation. Surgical resection alone of previous cancer(s) is allowed
• Patients with central nervous system involvement of RMS as defined below:
• Malignant cells detected in cerebrospinal fluid
• Intra-parenchymal brain metastasis separate and distinct from primary tumor (i.e., direct extension from parameningeal primary tumors is allowed).
• Diffuse leptomeningeal disease
• Patients who have received any chemotherapy (excluding steroids) and/or radiation therapy for RMS prior to enrollment.
• Note: the following exception:
• Patients requiring emergency radiation therapy for RMS. These patients are eligible, provided they are consented to ARST2031 prior to administration of radiation
• Note: Patients who have received or are receiving chemotherapy or radiation for non-malignant conditions (e.g. autoimmune diseases) are eligible. Patients must discontinue chemotherapy for non-malignant conditions prior to starting protocol therapy
• Vincristine and vinorelbine are sensitive substrates of CYP450 3A4 isozyme. Patients must not have received drugs that are moderate to strong CYP3A4 inhibitors and inducers within 7 days prior to study enrollment
• Female patients who are pregnant 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

• Patient has confirmed diagnosis of a R/R solid or CNS tumor with a mutation in KIT or PDGFRA (confirmed by local mutational testing of tumor sample) that has progressed despite standard therapy and no alternative treatment option is available OR Confirmed diagnosis of H3K27M mutant glioma that has failed standard therapy or for which no standard therapy that may convey clinical benefit exists, as judged by the Investigator.
• Patients with CNS disease should be on a stable dose (≤10% change) of corticosteroids for at least 7 days prior to first dose of avapritinib, with no plans for dose escalation.
• Disease extent 1. Part 1: All patients must have at least 1 measurable lesion as defined by RECIST v1.1 or RANO (for CNS tumors). If radiation therapy has been administered, at least 1 measurable lesion must not have been irradiated, or must have clearly progressed since being irradiated. 2. Part 2: At least one measurable lesion as defined by RECIST v1.1 (RANO for CNS tumors). If radiation therapy has been administered, at least 1 measurable lesion must not have been irradiated within the previous 12 weeks, or must have clearly progressed since being radiated (per RANO). For up to 5 patients with H3K27M mutant gliomas where there is no standard therapy that may convey clinical benefit as judged by the investigator, progression of disease of a measurable lesion after irradiation is not required.
• A Lansky (≤16 years of age) or Karnofsky (>16 years of age) score of at least 50. If the patient is unable to walk due to paralysis, but is mobile in a wheelchair, the patient is considered ambulatory for the purpose of assessing their performance status.
• Patient agrees to utilize contraception consistent with local regulations
• Patient has any of the following within 14 days before the first dose of study treatment: 1. Platelet count <75 × 109/L (<100 × 109/L if a CNS tumor). 2. Absolute neutrophil count (ANC) <1.0 × 109/L. 3. Hemoglobin <8.0 g/dL (RBC transfusion ≥14 days before test is permitted to meet criterion). 4. Aspartate aminotransferase (AST) or alanine aminotransferase (ALT) >3 × the upper limit of normal (ULN) for age; except in patients with tumor involvement of the liver who must not have AST and ALT >5 × ULN for age. 5. Total bilirubin >1.5 mg/dL for age; and in presence of Gilbert's syndrome, total bilirubin. > 3 × ULN or direct bilirubin > 1.5 × ULN. 6. Serum creatinine >1.5 × ULN for age. 7. International normalized ratio (INR) or prothrombin time (PT) >ULN (>1.5 × ULN if on prophylactic reversible anticoagulants).
• Patient has a QT interval corrected using Fridericia's formula (QTcF) >470 msec. Patient has a familial or personal history of prolonged QT syndrome or Torsades de pointes.
• Patient has clinically significant, uncontrolled, cardiovascular disease including congestive heart failure Grade III or IV according to the New York Heart Association (NYHA) classification; myocardial infarction or unstable angina within the previous 6 months, uncontrolled hypertension (>99th percentile for age), or clinically significant, uncontrolled arrhythmias, including bradyarrhythmias that may cause QT prolongation (eg, Type II second degree heart block or third-degree heart block).
• Patient received the following systemic antineoplastic therapies: 1. Systemic antineoplastic therapy (including experimental therapy within 5 half-lives or 28 days [6 weeks if prior nitrosurea], whichever is shorter). 2. Focal external beam radiotherapy, including stereotactic radiosurgery, within 6 weeks prior to the first dose of avapritinib to either target or non-target lesions. Systemic radiopharmaceuticals, including nonstereotactic radiosurgery, within 2 weeks of the first dose of avapritinib (within 6 weeks for patients with CNS tumors). Craniospinal irradiation within 12 weeks prior to the first dose of avapritinib. 3. All AEs related to other antineoplastic therapies (eg, systemic antineoplastics, radiotherapy) must have resolved to Grade ≤1 (Grade ≤2 for peripheral neuopathy and/or ototoxicity) prior to the first dose of avapritinib.
• Patient has previously received treatment with avapritinib.
• Patient received autologous stem cell transplant (SCT) following myeloablative therapy or chimeric antigen receptor T cell (CAR-T) therapy within 3 months prior to the first dose of avapritinib or prior allogeneic SCT within 1 year and no evidence of Grade 1 or greater graft-versus-host disease and no immunosuppressants for graft-versus-host disease (steroids for primary malignancy being permitted). Patients who received stem cell reinfusion following nonmyeloablative therapy are eligible once they meet the peripheral blood count criteria in Exclusion Criterion #1.
• Patient requires on going treatment or has received treatment within 28 days before the start of avapritinib administration with drugs or foods that are strong CYP3A inhibitors or inducers or EIAEDs (eg, carbamazepine, phenytoin, phenobarbital, and primidone). Please refer to Appendix 1 for a list of these drugs and/or foods.
• Patient has had a major surgical procedure within 14 days of the first dose of study treatment (procedures such as central venous catheter placement, tumor needle biopsy, and feeding tube placement are not considered major surgical procedures).
• Patient has a history of another primary malignancy that has been diagnosed or required therapy within 3 years before the first dose of avapritinib. The following prior malignancies are not exclusionary: completely resected basal cell and squamous cell skin cancer, curatively treated localized prostate cancer, and completely resected carcinoma in situ of any site.
• Female subjects of childbearing potential who are unwilling, if not post-menopausal or surgically sterile, to abstain from sexual intercourse or employ highly effective contraception from the time of informed consent and for at least 6 weeks after the last dose of study treatment. Male subjects who are unwilling, if not surgically sterile, to abstain from sexual intercourse or employ highly effective contraception from the time of informed consent and for at least 6 weeks after the last dose of study treatment. Refer to Section 5.4.2 for acceptable methods of contraception.
• Patient is pregnant
• Patient is breastfeeding.
• Patient has prior or ongoing clinically significant illness, medical condition, surgical history, physical finding, or laboratory abnormality that, in the Investigator's opinion, could affect the safety of the patient; alter the absorption, distribution, metabolism, or excretion of the study drug; or impair the assessment of study results.
• History of thrombosis requiring treatment within the past 6 months.
• Patients who require anticoagulants, with the exception of stable doses of prophylactic reversible anticoagulants.
• Patients who are unable to swallow tablets (in Part 1) or mini-tablets (in Part 2) within the sprinkle capsules.
• Patients with a known risk of intracranial bleeding, such as a brain aneurysm that has not been removed or repaired, or a history of intracranial bleeding within the past year, or radiographic evidence of hemorrhage on Screening MRI. Exceptions are patients with primary CNS tumors who are eligible unless CNS bleeding has occurred within 2 weeks of the first dose of avapritinib and patients with punctate hemorrhages <3 mm.
• History of a seizure disorder that is not well controlled on current antiepileptic medications. EIAEDs carbamazepine, phenytoin, phenobarbital, and primidone are prohibited.
• Patient is unwilling or unable to comply with scheduled visits, treatment administration plan, laboratory tests, or other study procedures and study restrictions

• 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

• Patients with histologically confirmed solid tumor malignancies with residual tumors present that require standard of care chemotherapy for a minimum number of cycles. All anatomical sites and all tumor histologies are eligible including central nervous system tumors. Both newly diagnosed and/or newly relapsed patients are eligible.
• Patients ages 8
•25 years
• In the opinion of the investigator, patients must be thought to be able to lie still for imaging without sedation for 20
•30 minutes.
• Patients must have a performance status of > 50% (Lansky or Karnofsky).
• Patients of childbearing potential must have a negative urine or serum pregnancy test as per institution's standard of care within 7 days prior to [18F]FLT PET/CT imaging.
• Ability to understand and the willingness to sign a written informed consent/assent.
• Patients with known allergic or hypersensitivity reactions to previously administered radiopharmaceuticals of similar chemical or biologic composition to [18F]FLT
• Newly diagnosed subjects who had prior chemotherapy or radiotherapy before enrollment in the study. Relapsed patients are eligible prior to starting their relapsed chemotherapy regimen if they meet the other eligibility criteria.
• Subjects for whom chemotherapy is not a standard of care primary therapy option.
• Patients who are pregnant or breast-feeding.
• Patients with no residual tumor (i.e. complete resection at diagnosis or relapse).

• Advanced or metastatic solid or primary CNS tumor which has failed standard of care therapies
• Evidence of an activating RET gene alteration in the tumor and/or blood
• Measurable or non-measurable disease
• Karnofsky (participants 16 years and older) or Lansky (participants younger than 16) performance score of at least 50
• Participant with primary CNS tumors or cerebral metastases must be neurologically stable for 7 days prior and must not have required increasing doses of steroids within the last 7 days
• Adequate hematologic, hepatic and renal function.
• Ability to receive study drug therapy orally or via gastric access
• Willingness of men and women of reproductive potential to observe conventional and effective birth control
• Major surgery within two weeks prior to planned start of LOXO-292
• Clinically significant, uncontrolled cardiac, cardiovascular disease or history of myocardial infarction within 6 months prior to planned start of LOXO-292
• Active uncontrolled systemic bacterial, viral, fungal or parasitic infection
• Clinically significant active malabsorption syndrome
• Pregnancy or lactation
• Uncontrolled symptomatic hyperthyroidism or hypothyroidism (i.e. the participant required a modification to current thyroid medication in the 7 days before start of LOXO-292)
• Uncontrolled symptomatic hypercalcemia or hypocalcemia
• Known hypersensitivity to any of the components of the investigational agent, LOXO-292 or Ora-Sweet® SF and OraPlus®, for participants who will receive LOXO-292 suspension
• Prior treatment with a selective RET inhibitor(s) (including investigational selective RET inhibitor[s])