• 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.

• Liveborn infants 22 0/7
•28 6/7 weeks gestation or 401
•1000 grams (inclusive) birth weight
• Clinical decision to give surfactant
• Less than or equal to 48 hours postnatal age
• Terminal illness (heart rate < 100 beats per minute, unresponsiveness to resuscitation) or unlikely to survive as judged by the clinician
• Decision to redirect or limit support
• Use of surfactant before enrollment (first dose of surfactant must be study drug)
• Infant received systemic steroids prior to enrollment
• Use of indomethacin, either received by the mother within 24 hours prior to delivery,received by the infant prior to enrollment, or intent to administer to the infant for IVH prophylaxis or PDA management from enrollment up to 7 days of final dose of study drug
• Serious chromosomal abnormalities or major malformations
• Known congenital infections including, but not limited to, confirmed sepsis, congenital CMV, etc.
• Infants with a permanent neuromuscular condition that affects respiration
• Enrollment in a conflicting clinical trial

• 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.

Inclusion Criteria 1. Neonates or infants >33 weeks gestational age with NOWS who have withdrawal scores requiring morphine replacement therapy 2. Clinically stable or on minimal respiratory support (continuous positive airway pressure [CPAP], nasal cannula, or room air) 3. Stable neonates who are dependent on opioids following extracorporeal membrane oxygenation, severe illness, or brain injury will be included in this study as these neonates represent a population in which tAN could minimize withdrawal while not adding burden of pharmacotherapies 4. Congenital syndromes may be included if the infants do not have major, unrepaired anomalies Exclusion Criteria 1. Unstable infants or those requiring significant respiratory support 2. Repeated episodes of autonomic instability (apnea or bradycardia) which are not self-resolving 3. Major unrepaired congenital anomalies impacting respiratory or cardiovascular system 4. Cardiomyopathy 5. Abnormal ear anatomy preventing the device to fit 6. Infants diagnosed with iatrogenic NOWS without intrauterine exposure 7. Infants two weeks of age or older (after birth) 8. Neonates who have received more than 6 methadone doses or 24 hours of methadone dosing 9. Infants who are wards of the state 10. Participant has any other significant disease or disorder which, in the opinion of the Investigator, may either put the participants at risk because of participation in the trial, or may influence the result of the trial, or the participant's ability to participate in the trial

• 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.

• Younger than 2 years (chronological age)
• Scheduled for anaesthesia that is expected to last at least 2 hours (and/or total operating room time is scheduled to be at least 2.5 hours)
• Has a legally acceptable representative capable of understanding the informed consent document and providing consent on the participant's behalf.
• Known neurologic, chromosomal or congenital anomaly which is likely to be associated with poor neurobehavioural outcome
• Existing diagnosis of behavioural or neurodevelopmental disability
• Prematurity (defined as < 36 weeks gestational age at birth)
• Birth weight less than 2 kg.
• Congenital cardiac disease requiring surgery
• Intracranial neurosurgery and intracranial craniofacial surgery (isolated cleft lip is not an exclusion)
• Previous cumulative exposure to general anaesthesia exceeding 2 hours
• Planned future cumulative exposure to anaesthesia exceeding 2 hours before the age of 3 years.
• Any specific contra-indication to any aspect of the protocol
• Previous adverse reaction to any anaesthetic
• Circumstances likely to make long term follow-up impossible
• Living in a household where the primary language spoken at home is not a language in which we can administer the Wechsler Preschool and Primary School Intelligence Scale
• Planned postoperative sedation with any agent except opioids (e.g. benzodiazepines, dexmedetomidine, ketamine, barbiturates, propofol, clonidine, chloral hydrate, and other non-opioid sedatives). For example if such sedation is planned for post-operative ventilation

1. Male or female ≥ 2 and ≤ 45 years of age at the Screening Visit. 2. Documentation of a CF diagnosis as evidenced by one or more clinical features consistent with the CF phenotype and one or more of the following criteria: 1. sweat chloride ≥ 60 milliequivalents/liter by quantitative pilocarpine iontophoresis test (QPIT) 2. two well-characterized mutations in the cystic fibrosis transmembrane conductive regulator (CFTR) gene 3. abnormal nasal potential difference(NPD) (change in NPD in response to a low chloride solution and isoproteronol of less than -5 mV) 3. First OR early MRSA colonization defined as: 1. First MRSA colonization: first documented isolation of MRSA from respiratory tract occurred ≤ 6 months prior to screening 2. Early MRSA colonization: MRSA was previously isolated from the respiratory tract ≤ 2 times over the past 3.5 years, but this was followed by at least 1 year of documented negative cultures for MRSA 4. MRSA is available to the central laboratory
•either the incident MRSA isolate from the clinic visit or the subject is MRSA positive at the screening visit 5. Clinically stable with no significant changes in health status within the 14 days prior to screening 6. Written informed consent (and assent when applicable) obtained from subject or subject's legal representative and ability for subject to comply with the requirements of the study 1. Received antibiotics with activity against MRSA within 28 days prior to screening 2. Use of an investigational agent within 28 days prior to screening 3. For subjects ≥ 6 years of age: FEV1 at screening < 25% of predicted for age based on the Wang (males < 18 years, females < 16 years) or Hankinson (males ≥ 18 years, females ≥ 16 years) standardized equations 4. MRSA from the screening culture or the most recent clinical care visit within 6 months prior to screening resistant to TMP/SMX 5. History of intolerance to topical chlorhexidine or mupirocin 6. History of intolerance to both TMP/SMX and minocycline 7. < 8 years of age and allergic or intolerant to TMP/SMX 8. ≥ 8 years of age and allergic or intolerant to TMP/SMX and MRSA isolate (from screening or clinical care visit)is resistant to minocycline 9. For females of child bearing potential: pregnant, breastfeeding, or unwilling to use barrier contraception through Day 42 of the study 10. Subjects with history of abnormal renal function will need screening labs showing normal function Abnormal renal function is defined as estimated creatinine clearance <50 mL/min using the: 1. Bedside Schwartz Equation for subjects <18 years of age, and 2. Levey Glomerular filtration rate (GFR) Equation for subjects ≥ 18 years of age. 11. Subjects with a history of abnormal liver function will need to have screening labs showing normal transaminases. Liver dysfunction is defined as ≥3x upper limit of normal (ULN), of serum aspartate transaminase (AST) or serum alanine transaminase (ALT) or abnormal synthetic function 12. History of solid organ or hematological transplantation 13. Presence of a condition or abnormality that in the opinion of the Investigator would compromise the safety of the patient or the quality of the data.

• Patients in Group F must have a body surface area (BSA) >= 0.6 m^2
• Patients must have a performance status corresponding to Eastern Cooperative Oncology Group (ECOG) scores of 0, 1, or 2; use Karnofsky for patients > 16 years of age and Lansky for patients =< 16 years of age; patients who are unable to walk because of paralysis, but who are up in a wheelchair, will be considered ambulatory for the purpose of assessing the performance score
• Patients must be newly diagnosed with histologically-proven primary pediatric hepatic malignancies including hepatoblastoma or hepatocellular carcinoma, except as noted below; patients with a diagnosis of hepatocellular neoplasm, not otherwise specified, should be classified and treated per hepatoblastoma treatment arms; note that rapid central pathology review is required in some cases; please note: all patients with histology as assessed by the institutional pathologist consistent with pure small cell undifferentiated (SCU) HB will be required to have testing for INI1/SMARCB1 by immunohistochemistry (IHC) according to the practices at the institution
• Patients with histology consistent with pure SCU must have positive INI1/SMARCB1 staining
• For all Group A patients, WDF status as determined by rapid review will be used to further stratify patients to Group A1 or A2
• For Groups B, C and D, rapid review is required if patients are either >= 8 years of age or have an alphafetoprotein (AFP) =< 100 at diagnosis
• For all Groups E and F patients, rapid central pathology review is required
• In emergency situations when a patient meets all other eligibility criteria and has had baseline required observations, but is too ill to undergo a biopsy safely, the patient may be enrolled without a biopsy
• Clinical situations in which emergent treatment may be indicated include, but are not limited to, the following circumstances:
• Anatomic or mechanical compromise of critical organ function by tumor (e.g., respiratory distress/failure, abdominal compartment syndrome, urinary obstruction, etc.)
• Uncorrectable coagulopathy
• For a patient to maintain eligibility for AHEP1531 when emergent treatment is given, the following must occur:
• The patient must have a clinical diagnosis of hepatoblastoma, including an elevated alphafetoprotein (AFP), and must meet all AHEP1531 eligibility criteria at the time of emergent treatment
• Patient must be enrolled on AHEP1531 prior to initiating protocol therapy; a patient will be ineligible if any chemotherapy is administered prior to AHEP1531 enrollment
• Note: If the patient receives AHEP1531 chemotherapy emergently PRIOR to undergoing a diagnostic biopsy, pathologic review of material obtained in the future during either biopsy or surgical resection must either confirm the diagnosis of hepatoblastoma or not reveal another pathological diagnosis to be included in the analysis of the study aims
• Patients may have had surgical resection of the hepatic malignancy prior to enrollment; all other anti-cancer therapy for the current liver lesion is prohibited
• Creatinine clearance or radioisotope glomerular filtration rate (GFR) >= 60 mL/min/1.73 m^2 or
• A serum creatinine based on age/gender as follows:
• Age: maximum serum creatinine (mg/dL)
• 1 month to < 6 months: 0.4 (male and female)
• 6 months to < 1 year: 0.5 (male and female)
• 1 to < 2 years: 06 (male and female)
• 2 to < 6 years: 0.8 (male and female)
• 6 to < 10 years: 1 (male and female)
• 10 to < 13 years: 1.2 (male and female)
• 13 to < 16 years: 1.5 (male), 1.4 (female)
• >= 16 years: 1.7 (male), 1.4 (female)
• Total bilirubin =< 5 x upper limit of normal (ULN) for age
• Aspartate aminotransferase (AST) (serum glutamic-oxaloacetic transaminase [SGOT])/alanine aminotransferase (ALT) (serum glutamate pyruvate transaminase [SGPT]) < 10 x upper limit of normal (ULN) for age
• Shortening fraction of >= 28% by echocardiogram (for patients on doxorubicin-containing regimens [Groups C, D, E2, and F] assessed within 8 weeks prior to study enrollment) or
• Ejection fraction of >= 47% by echocardiogram or radionuclide angiogram (for patients on doxorubicin-containing regimens [Groups C, D, E2, and F] assessed within 8 weeks prior to study enrollment)
• Group F patients only: QT/corrected QT (QTc) interval =< 450 milliseconds for males and =< 470 milliseconds for females (assessed within 8 weeks prior to study enrollment)
• Normal pulmonary function tests (including diffusion capacity of the lung for carbon monoxide [DLCO]) if there is clinical indication for determination (e.g. dyspnea at rest, known requirement for supplemental oxygen) (for patients receiving chemotherapy [Groups A, B, C, D, E2, F]); for patients who do not have respiratory symptoms or requirement for supplemental oxygen, pulmonary function tests (PFTs) are NOT required
• 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
• Prior chemotherapy or tumor directed therapy (i.e. radiation therapy, biologic agents, local therapy (embolization, radiofrequency ablation, and laser); therefore, patients with a pre-disposition syndrome who have a prior malignancy are not eligible
• Patients who are currently receiving another investigational drug
• Patients who are currently receiving other anticancer agents
• Patients with uncontrolled infection
• Patients who previously received a solid organ transplant, other than those who previously received an orthotopic liver transplantation (OLT) as primary treatment of their hepatocellular carcinoma
• Patients with hypersensitivity to any drugs on their expected treatment arm
• Group C: Patients who have known deficiency of dihydropyrimidine dehydrogenase (DPD)
• Group D:
• Patients with chronic inflammatory bowel disease and/or bowel obstruction
• Patients with concomitant use of St. John's wort, which cannot be stopped prior to the start of trial treatment
• Group F:
• Patients with peripheral sensitive neuropathy with functional impairment
• Patients with a personal or family history of congenital long QT syndrome
• These criteria apply ONLY to patients who may receive chemotherapy (all groups other than Group E1):
• 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
• Note for Group F: patients of childbearing potential should use effective birth control during treatment with sorafenib and for at least 2 weeks after stopping treatment

• Postnatal age 48 hours -21 days
• Infant 22 0/7 to 28 6/7 weeks gestation at birth
• sPDA, as defined as: 1. Mild, Moderate, or Severe Clinical Criteria with Small or Moderate size PDA on echocardiogram 2. Mild or Moderate Clinical Criteria with Large PDA on echocardiogram
• Cardiopulmonary compromise
• Known congenital heart disease (besides atrial septal defect or ventricular septal defect)
• Known pulmonary malformation (e.g. congenital lobar emphysema, congenital pulmonary adenomatous malformation)
• Any condition which, in the opinion of the investigator, would preclude enrollment

• Inborn and outborn infants of 29 0/7 to 33 6/7 weeks gestational age at birth
• admitted to hospitals of the NICHD NRN who, are at time of enrollment:
• ≤35 6/7 weeks post-menstrual age at the time of randomization
• Receiving caffeine with plan to discontinue treatment or just discontinued caffeine treatment
• Receiving feeds at a volume of ≥120 ml/kg/day by oral and/or tube feeding
• Ability to start study medication within 72 hours after stopping caffeine
• On respiratory therapy (oxygen more than room air equivalent for high altitude sites, nasal cannula, continuous positive pressure ventilation, and/or mechanical ventilation)
• Infants who would otherwise be discharged home on apnea monitor due to underlying disease or family history, including history of a sibling with sudden infant death syndrome
• Parental request for apnea monitor
• Congenital heart disease other than atrial septal defect, ventricular septal defect, or patent ductus arteriosus
• Neuromuscular conditions affecting respiration
• Major congenital malformation and/or genetic disorder
• Plans to transfer to a non-NRN site before discharge
• Unable to obtain parental or guardian consent

• Signed informed consent given by the subject or the subject's parent/legal guardian for those under 18 years of age or the age of consent by local regulation.
• Male and female subjects with a suspected or confirmed UCD diagnosis of any subtype, except NAGS deficiency.
• Suspected diagnosis is defined as having experienced a HAC or a documented high ammonia of >=100 µmol/L
• Confirmed diagnosis is determined via enzymatic, biochemical, or genetic testing.
• Requires nitrogen-binding agents according to the judgment of the Investigator
• Birth and older.
• All females of childbearing potential and all sexually active males must agree to use an acceptable method of contraception from signing the informed consent throughout the study and for 30 days after the last dose of study drug. Acceptable forms of contraception are (oral, injected, implanted or transdermal), tubal ligation, intrauterine device, hysterectomy, vasectomy, or double barrier methods. Abstinence is an acceptable form of birth control, though appropriate contraception must be used if the subject becomes sexually active.
• Subject has received chronic treatment with an oral phenylbutyrate (RAVICTI, NaPBA, Pheburane, or other) longer than 14 consecutive days within one year prior to enrollment.
• Temporary use of NaPBA for acute management of a hyperammonemic crisis in the past is acceptable.
• Any concomitant illness (e.g., malabsorption or clinically significant liver or bowel disease) which would preclude the subject's safe participation, as judged by the Investigator.
• Has undergone liver transplantation, including hepatocellular transplant.
• Subjects on NaBz at Baseline will be excluded if they are viewed by the Investigator as being unable to undergo NaBz transition to a PAA prodrug during the Initial Treatment Period.
• Known hypersensitivity to PBA or any excipients of the NaPBA/PBA formulations.
• Pregnant or breast-feeding patients. Women of childbearing potential must have a pregnancy test performed at the Baseline Visit prior to the start of study drug.

Inclusion criteria: Intubated and mechanically ventilated with moderate-severe PARDS for <48 hours per PALICC guidelines (chest imaging consistent with acute pulmonary parenchymal disease and OI ≥12 or OSI ≥10). We require two blood gases meeting moderate-severe PARDS criteria (separated by at least 4 ± 2 hours during which time the clinical team is actively working to recruit lung volume and optimize the patient's hemodynamic status per PALICC guidelines; specifically, incremental and decremental PEEP changes to optimize lung volume). A second blood gas is not required for OI ≥16. Exclusion criteria:
• Perinatal related lung disease
• Congenital diaphragmatic hernia or congenital/acquired diaphragm paralysis
• Respiratory failure explained by cardiac failure or fluid overload
• Cyanotic heart disease
• Cardiomyopathy
• Unilateral lung disease
• Primary pulmonary hypertension
• Intubated for status asthmaticus
• Obstructive airway disease (e.g., Severe airways disease without parenchymal involvement or disease characterized by hypercapnia with FiO2 <0.30 and/or evidence of increased resistance visible on the flow
•time scalar and/or presence of intrinsic PEEP)
• Active air leak
• Bronchiolitis obliterans
• Post hematopoietic stem cell transplant; specifically, patients receiving continuous supplemental oxygen for three or more days prior to intubation; receiving noninvasive ventilation for more than 24 hours prior to intubation; receiving more than one vasoactive medication at time of meeting inclusion criteria; spending more than four days in the PICU prior to intubation; supported on or with immediate plans for renal replacement therapies; with two or more allogeneic transplants; who relapsed after the transplant; or with diffuse alveolar hemorrhage
• Post lung transplant
• Home ventilator (including noninvasive) or home oxygen dependent (exception: night-time noninvasive ventilation (CPAP/BiPAP) or oxygen for obstructive sleep apnea is permitted)
• Neuromuscular respiratory failure
• Critical airway (e.g., post laryngotracheal surgery or new tracheostomy) or anatomical obstruction of the lower airway (e.g., mediastinal mass)
• Facial surgery or trauma in previous 2 weeks
• Head trauma (managed with hyperventilation)
• Intracranial bleeding
• Unstable spine, femur or pelvic fractures
• Acute abdominal process/open abdomen
• Morbid obesity (2w-24 months: WHO weight-for-length/height z-score ≥+3; ≥2 years: WHO body mass index (BMI)-for-age z-score ≥+3)
• Currently receiving either prone positioning or any high-frequency mode of MV with current illness (Up to 4 hours of prone positioning and/or any mode of high-frequency mode of MV is allowed as long as the therapies are off for least 4 hours prior to the subject meeting oxygenation criteria.)
• Supported on ECMO during the current admission
• Family/medical team not providing full support (patient treatment considered futile)
• Previously enrolled in current study
• Enrolled in any other interventional clinical trial not approved for co-enrollment
• Known pregnancy

• Diagnosis of Down syndrome
• Age 10-21 years
• Prior adenotonsillectomy
• Severe OSA (AHI > 10, AHI < 50, no more than 25% AHI attributable to central events) based on prior in-lab PSG performed after adenotonsillectomy and within 18 months of enrollment
• Approval from at least two of the three physician reviewers based upon the results of a routine drug-induced sleep endoscopy (DISE) having occurred within 12 months of enrollment
• Subjects must have either tracheotomy or be ineffectively treated with CPAP due to non-compliance, discomfort, un-desirable side effects, persistent symptoms despite compliance use, or refusal to use the device
• Children and their parents/guardians must be willing to have stimulation hardware permanently implanted, and be willing to participate in follow-up visits, postoperative PSG, and questionnaire completion
• Children's parents/guardians must complete a questionnaire confirming that their child is capable of communicating feelings of pain or discomfort. They must also confirm they are able to assess their child for adverse effects related to device implantation
• Children and their parents/guardians must be proficient in English
• Body mass index (BMI) above the 95th percentile for subject's age
• Circumferential airway collapse at the level of the velopharynx observed during DISE
• Other medical conditions resulting in medical instability (eg. congestive heart failure, recent open heart surgery, immunosuppression, or chronic lung disease or aspiration)
• Presence of another medical condition requiring future magnetic resonance imaging (MRI) of the chest
• Patients with another implantable device which could interact unintentionally with the Inspire system
• Any contraindication for general anesthesia
• History of bleeding or clotting disorders and those on blood thinning or NSAID medications for the week prior to implantation surgery. Subjects will be asked to refrain from the use of NSAIDS for two weeks after implantation or any revision surgeries
• Subject is currently taking muscle relaxant medication
• Life expectancy less than 12 months
• Subject's inability to communicate pain or discomfort to their caretaker/parent, based on parental or investigator assessment
• Nonverbal candidates will be excluded due to an inability to complete testing procedures including expressive language sampling
• Subjects with a co-occurring diagnosis of autism spectrum disorder
• Subjects that have a positive β-HCG
• Subjects deemed unfit for participation by the investigator for any other reason

Eligibility criteria: Infants are eligible if they meet all of the following criteria:
• ≥ 36 0/7 weeks PMA by best obstetric estimate AND birth weight of ≥ 2000g
• postnatal age ≤7 days (168 hours of age)
• invasive mechanical ventilation (defined as ventilation with an endotracheal tube) and
• one arterial blood gas with an OI ≥ 10 (after tracheal tube obstruction and other easily resolvable mechanical causes for increased OI are ruled out) on the most recent arterial blood gas within 12 hours prior to the time of randomization.
• if an arterial blood gas is not available at the time of randomization, a preductal OSI of ≥ 5 can be used as an inclusion criterion instead of OI ≥ 10; (the OSI should be based on the most recent preductal pulse oximetry recording and must be within 12 hours of randomization)
• postnatal blood gas with PCO2 ≤ 80 mmHg (arterial, capillary or venous blood gas) on the most recent blood gas sample obtained within 12 hours prior to randomization Note: Criteria (iv) to (vi) must be met at the most recent analysis within 12 hours prior to randomization. Infants are ineligible if they meet any of the following criteria:
• known hypertrophic cardiomyopathy
• Note 1: infants of diabetic mothers with asymmetric septal hypertrophy can be included as long as there is no evidence of obstruction to left ventricular outflow tract on echocardiogram,
• Note 2: infants with other acyanotic congenital heart disease (CHD) and CDH may be included in the study and will be a predetermined subgroup for analysis)
• cyanotic CHD
•transposition of great arteries (TGA), total anomalous pulmonary venous return (TAPVR), partial anomalous pulmonary venous return (PAPVR), truncus arteriosus (TA), tetralogy of Fallot (TOF), single ventricle physiology
•hypoplastic left heart syndrome (HLHS), tricuspid atresia, critical pulmonic stenosis or atresia etc.,
• enrolled in conflicting clinical trials (such as a randomized controlled blinded trial of another pulmonary vasodilator therapy); Note: mothers enrolled in fetal tracheal occlusion studies such as FETO may be enrolled if permitted by investigators of the fetal tracheal occlusion study; [FETO refers to fetoscopic endoluminal tracheal occlusion and involves occlusion of fetal trachea with a balloon device at mid-gestation and subsequent removal in later gestation]
• infants with bilateral CDH o Note 3: infants with anterior and central defects are included in the study
• associated abnormalities of the trachea or esophagus (trachea-esophageal fistula, esophageal atresia, laryngeal web, tracheal agenesis)
• renal dysfunction (with serum creatinine > 2 mg/dL not due to maternal factors) or severe oligohydramnios associated with renal dysfunction at randomization; renal dysfunction may be secondary to renal anomalies or medical conditions such as acute tubular necrosis
• severe systemic hypotension (mean blood pressure < 35 mm Hg for at least 2 h with a vasoactive inotrope score of > 30)
• decision is made to provide comfort/ palliative care and not full treatment
• Intracranial bleed (including the following findings on the cranial ultrasound)
• Cerebral parenchymal hemorrhage
• Blood/echodensity in the ventricle with distension of the ventricle
• Periventricular hemorrhagic infarction
• Posterior fossa hemorrhage
• Cerebellar hemorrhage
• persistent thrombocytopenia (platelet count < 80,000/mm3) despite blood product administration on the most recent blood draw prior to randomization
• coagulopathy (PT INR > 1.7) despite blood product administration on the most recent blood draw (if checked
•there is no reason to check PT for the purpose of this study)
• aneuploidy associated with short life span (such as trisomy 13 or 18) will not be included in the study (infants with trisomy 21 can be included in the study)
• elevated arterial, venous or capillary PCO2 > 80 mmHg in spite of maximal ventilator support (including high frequency ventilation) on the most recent blood gas obtained within 12 hours prior to randomization
• use of milrinone infusion prior to randomization (the use of other inhaled pulmonary vasodilators such as iNO, inhaled epoprosternol, inhaled PGE1 and oral such as endothelin receptor antagonists is permitted
•Note: it is unlikely to be on oral pulmonary vasodilators early in the course of CDH)
• ongoing therapy with parenteral (intravenous or subcutaneous) pulmonary vasodilators such as IV/SQ prostacyclin analogs (Epoprostenol
•Flolan or Treprostinil
•Remodulin or PGE1
•Alprostadil) or IV phosphodiesterase 5 inhibitors (sildenafil
•Revatio) at the time of randomization. In addition, initiation of therapy with these two classes of parenteral medications during the first 24 hours of study drug initiation is not permitted and will be considered a protocol deviation. The risk of systemic hypotension is high during the first 24 hours of study-drug (milrinone) infusion and hence parenteral administration of other pulmonary vasodilators is avoided to minimize risk of hypotension.
• Subjects already on ECMO or patients who are being actively considered for ECMO by the neonatal or surgical team
• attending (neonatal, critical care or surgical) refusal for participation in the trial (including concern about presence of hemodynamic instability)

Inclusion Criteria Age -Patients must be ≥ 1 and ≤ 21 years of age at the time of enrollment. Diagnosis
• Cohort A: Patients must have a diagnosis of acute lymphoblastic leukemia (ALL) or mixed phenotypic acute leukemia with ≥ 5% blasts in the bone marrow (M2 or M3), with or without extramedullary disease) or a diagnosis of lymphoblastic lymphoma.
• Cohorts B & C: Patients must have a diagnosis of acute lymphoblastic leukemia (ALL), lymphoblastic lymphoma, or mixed phenotypic acute leukemia with any level of detectable disease (minimal residual disease level acceptable) with or without extramedullary disease Performance Level -Karnofsky > 50% for patients > 16 years of age and Lansky > 50% for patients ≤ 16 years of age. Prior Therapy
• Patients must have recovered from the acute toxic effects (≤ Grade 2 or baseline) of all prior chemotherapy, immunotherapy, or radiotherapy prior to entering this study, unless otherwise specified. Subjects with disease related cytopenias will be eligible.
• Patients must have relapsed or refractory disease after attaining at least a first remission. They may be in first to third relapse..
• Patients with Philadelphia chromosome t(9;22) positive disease must have received at least two prior tyrosine kinase inhibitors.
• Patients who have experienced their relapse after a Hematopoietic stem cell transplantation (HSCT) are eligible, provided they have no evidence of graft-versus-host disease (GVHD) and are at least 100 days post-transplant at the time of enrollment.
• Prior anthracycline lifetime cumulative exposure: Patients must have less than 320 mg/m2 (or 400 mg/m2 if prior cardioprotection) lifetime exposure of anthracycline chemotherapy. 1. Cohort A: Patients must have less than 320 mg/m2 (or 400 mg/m2 if prior cardioprotection) lifetime exposure of anthracycline chemotherapy (See Appendix 2 for anthracycline calculation worksheet). 2. Cohorts B & C: There is no limit on prior anthracycline exposure.
• Hematopoietic growth factors: It must have been at least seven days since the completion of therapy with granulocyte colony-stimulating factor (GCSF) or other growth factors at the time of enrollment. It must have been at least 14 days since the completion of therapy with pegfilgrastim (Neulasta®).
• Biologic anti-neoplastic agents: At least seven days after the last dose of a biologic agent. For agents that have known adverse events occurring beyond seven 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 or vice chair.
• Monoclonal antibodies: At least three half-lives (or 30 days—whichever is longer) of the antibody must have elapsed after the last dose of monoclonal antibody. (e.g., Rituximab = 66 days, Epratuzumab = 69 days)
• Immunotherapy: At least 30 days after the completion of any type of immunotherapy, e.g. tumor vaccines, chimeric antigen receptor T-cells.
• Recent prior chemotherapy: At least 10 days after standard vincristine and the completion of any type of chemotherapy induction regimen. At least 3 weeks after radiation therapy. At least 30 days after the completion of any investigational neoplastic agent is also required. An investigational agent is defined as any drug that is not approved and licensed for sale by the FDA for institutions in the United States, by Health Canada for institutions in Canada and by The Therapeutic Goods Administration for institutions in Australia. Exceptions:
• There is no time restriction in regard to prior intrathecal chemotherapy provided there is complete recovery from any acute toxic effects of such; it is allowable to enroll a patient that has received IT Cytarabine (ARA-C), IT Methotrexate (MTX) or triple IT therapy within 14 days of enrollment as part of their evaluation to diagnose disease relapse. The IT therapy given within 14 days of initiation of protocol specified chemotherapy, may substitute for the day 1 IT in cohorts A and B
• Subjects with rapidly progressive disease may receive hydroxyurea until they begin study therapy;
• Patients who relapse while on maintenance-type ALL therapy or are receiving maintenance therapy for disease stabilization will not require a wash-out period before entry into this study. However, there must be at least 10 days after any dose of standard vincristine. Renal and Hepatic Function
• Renal function: Patient's serum creatinine must be ≤ 1.5 x institutional upper limit of normal (ULN) according to age. If the serum creatinine is greater than 1.5 times normal, the patient must have a calculated creatinine clearance or radioisotope glomerular filtration rate (GFR) ≥ 70milliliter/min/1.73m2. Alternatively, a 24-hour creatinine clearance may also be used.
• Hepatic function: alanine aminotransferase (ALT) and aspartate aminotransferase (AST) must be < 5 x institutional upper limit of norm ULN. Total bilirubin must be ≤ 1.5 x ULN (except in the case of subjects with documented Gilbert's disease ≤ 5 × ULN). Cardiac Function -Patients must have a shortening fraction ≥ 27% or an ejection fraction ≥ 55% by echocardiogram, cardiac MRI or multigated acquisition scan (MUGA). Reproductive Function
• Female patients must not be pregnant and those of childbearing potential must have a negative urine or serum pregnancy test confirmed within one week prior to enrollment.
• Female patients with infants must agree not to breastfeed their infants while on this study.
• Male and female patients of childbearing potential must agree to use an effective method of contraception during the study. Exclusion Criteria Patients will be excluded if they have isolated testicular disease. Patients will be excluded if they have previously received Marqibo®. Patients will be excluded if they have a known allergy to any of the drugs used in the study, with the exception that patients with an allergy to PEG-asparaginase who can receive Erwinia asparaginase are eligible. Patients unable to receive any formulation of asparaginase may only enroll on cohort C Patients will be excluded if they have active, uncontrolled systemic fungal, bacterial, viral or other infection despite appropriate antibiotics or other treatment. Patients who require azole antifungal agents will be excluded. Azoles must be discontinued at least one week prior to the start of Marqibo®. Patients will be excluded if there is a plan to administer non-protocol chemotherapy, radiation therapy, another investigational agent or immunotherapy during the study period. Patients with pre-existing, persistent grade 2 or greater sensory or motor neuropathy from any cause will be excluded. Patients will be excluded if they have, significant concurrent disease, illness, psychiatric disorder or social issue that would compromise patient safety or adherence with the protocol treatment or procedures or interfere with consent, study participation, follow up, or interpretation of study results.Patients with Down syndrome will not be eligible for enrollment on Cohort A Patients with a known history of human immunodeficiency virus (HIV) will will be excluded due to the increased risk of complications such as severe infection and unknown interaction of Marqibo® with antiretroviral drugs. Active hepatitis B or C infection as defined by seropositive for hepatitis B (hepatitis B surface antigen (HBsAg)) or hepatitis C and elevated liver transaminases (defined as above the ULN per the institution normal ranges).

• Patients less than 12 months of age
• Clinical signs of moderate to severe bronchiolitis defined by American Academy of Pediatrics
• Requires ICU level of care by clinicians' discretion
• Requiring HFNC support
• Infants who required immediate need for respiratory support such as non-invasive positive pressure ventilation (NIPPV) or invasive ventilation
• Congenital heart disease,
• Immunocompromised state
• Upper airway obstruction
• Chronic lung disease
• Bronchopulmonary dysplasia,
• Home oxygen therapy requirement
• Acute trauma patients
• Baseline craniofacial malformations
• Admitted to the neonatal or cardiac ICUs
• Patients who are admitted to the floor

Key
• Heterozygous for F508del and a minimal function mutation (F/MF genotype)
• Forced expiratory volume in 1 second (FEV1) value >=40% and <=90% of predicted mean for age, sex, and height for participants currently receiving ELX/TEZ/IVA therapy; FEV1 >=40% and <=80% for participants not currently receiving ELX/TEZ/IVA Key
• History of solid organ or hematological transplantation
• Hepatic cirrhosis with portal hypertension, moderate hepatic impairment (Child Pugh Score 7 to 9), or severe hepatic impairment (Child Pugh Score 10 to 15)
• Lung infection with organisms associated with a more rapid decline in pulmonary status
• Pregnant or breast-feeding females Other protocol defined Inclusion/Exclusion criteria may apply

Key
• Participant has one of the following genotypes:
• Homozygous for F508del;
• Heterozygous for F508del and a gating (F/G) mutation;
• Heterozygous for F508del and a residual function (F/RF) mutation;
• At least 1 other TCR CFTR gene mutation identified as responsive to ELX/TEZ/IVA and no F508del mutation
• Forced expiratory volume in 1 second (FEV1) value >=40% and <=90% of predicted mean for age, sex, and height for participants currently receiving CFTR protein modulator therapy; FEV1 >=40% and <=80% for participants not currently receiving CFTR protein modulator therapy Key
• History of solid organ or hematological transplantation
• Hepatic cirrhosis with portal hypertension, moderate hepatic impairment (Child Pugh Score 7 to 9), or severe hepatic impairment (Child Pugh Score 10 to 15)
• Lung infection with organisms associated with a more rapid decline in pulmonary status
• Pregnant or breast-feeding females Other protocol defined Inclusion/Exclusion criteria may apply

• infants/ children with midshaft or distal hypospadias undergoing primary single stage repair in one of the Pediatric Regional Anesthesia Network participating centers.
• prior hypospadias surgery,
• proximal or penoscrotal hypospadias,
• abnormal caudal anatomy or spinal dysraphism,
• cyanotic congenital heart disease,
• infection or rash at the block injection site.

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.

• Age Patients must be ≤21 years of age at the time of enrollment. 1. Phase 1
•Initial enrollment will be restricted to patients < 18 years of age until 9 such patients are enrolled 2. Phase 2
•Initial enrollment will be restricted to patients < 18 years of age until 6 such patients are enrolled
• Diagnosis Patients must have a diagnosis of relapsed/refractory ALL or LLy with or without extramedullary disease (including CNS2 and CNS3). Patient with mixed phenotype ALL or mature B (Burkitt-like) leukemia are not eligible. 1. Patients with ALL must have ≥ 5% blasts by morphology. 2. Patients with LLy must have measurable disease documented by clinical, radiologic or histologic criteria
• Performance Level Karnofsky ≥ 50% for patients > 16 years of age and Lansky ≥ 50% for patients ≤ 16 years of age.
• Prior Therapy A. Prior therapeutic attempts
• Phase 1
•Any patients with relapsed/refractory ALL or LLy
• Phase 2 1. B-cell ALL/LLy: all patients must have failed two or more therapeutic attempts. 2. T-cell ALL/LLy: all patients must have failed one or more therapeutic attempts. B. Recent prior chemotherapy Patients must have fully recovered from the acute toxic effects of all prior chemotherapy, immunotherapy, or radiotherapy prior to entering this study.
• Cytoreduction with hydroxyurea Hydroxyurea can be initiated and continued for up to 24 hours prior to the start of protocol therapy.
• Patients who relapsed while they are receiving cytotoxic therapy At least 14 days must have elapsed since the completion of the last dose of chemotherapy,except Intrathecal chemotherapy, and/or maintenance therapy such as vincristine, mercaptopurine, methotrexate or glucocorticoids. There is no waiting period for those relapsing on maintenance therapy. C. Hematopoietic stem cell transplant: Patients who have experienced their relapse after a HSCT are eligible, provided they have no evidence of acute or chronic Graft-versus-Host Disease (GVHD), are not receiving GVHD prophylaxis or treatment, and are at least 90 days post-transplant at the time of enrollment. D. Hematopoietic growth factors: It must have been at least 7 days since the completion of therapy with G-CSF or other growth factors at the time of enrollment. It must have been at least 14 days since the completion of therapy with pegfilgrastim (Neulasta®). E. Biologic (anti-neoplastic agent): At least 7 days since the last dose of a biologic agent. 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 1. Monoclonal antibodies: At least 3 half-lives of the antibody must have elapsed after the last dose of monoclonal antibody. (i.e., blinatumomab = 6 hours,44 inotuzumab = 37 days, rituximab = 66 days) 2. Immunotherapy: At least 30 days after the completion of any type of immunotherapy, e.g., tumor vaccines, CAR T cells. F. XRT: Craniospinal XRT is prohibited during protocol therapy. No washout period is necessary for radiation given to any extramedullary site other than CNS; ≥90 days must have elapsed if prior total body irradiation (TBI) or craniospinal XRT. G. Anthracyclines: Patients must have had a lifetime exposure of <400 mg/m2 of doxorubicin equivalents of anthracyclines. H. Proteasome inhibitors: Patients with a prior exposure to proteasome inhibitors (e.g., bortezomib, carfilzomib) are eligible as long as the patient demonstrated at least a partial response to a proteasome inhibitor with chemotherapy combination. -Renal and hepatic function Patients must have adequate renal and hepatic functions as indicated by the following laboratory values: A. Adequate renal function defined as: Patient must have a calculated creatinine clearance or radioisotope GFR 70ml/min/1.73m2 OR a normal serum creatinine based on age/gender B. Adequate Liver Function Defined as: Direct bilirubin ≤ 1.5 x upper limit of normal (ULN) for age or normal (except in the presence of Gilbert's syndrome), AND alanine transaminase (ALT) ≤ 5 x ULN for age. The hepatic requirements are waived for patients with known or suspected liver involvement by leukemia or lymphoma. This must be reviewed by and approved by the study chair or vice chair.
• Adequate Cardiac Function Defined as: Shortening fraction of more than or equal to 27% by echocardiogram, OR ejection fraction of equal to or more than 50% by radionuclide angiogram (MUGA).
• Reproductive Function A. Female patients of childbearing potential must have a negative urine or serum pregnancy test confirmed within 2 weeks prior to enrollment. B. Female patients with infants must agree not to breastfeed their infants while on this study. C. Male and female patients of child-bearing potential must agree to use an effective method of contraception approved by the investigator during the study and for a minimum of 6 months after study treatment.
• Informed Consent Patients and/or their parents or legal guardians must be capable of understanding the investigational nature, potential risks and benefits of the study. All patients and/or their parents or legal guardians must sign a written informed consent. Age appropriate assent will be obtained per institutional guidelines. To allow non-English speaking patients to participate in this study, bilingual health services will be provided in the appropriate language when feasible.
• All institutional, FDA, and OHRP requirements for human studies must be met. Patients will be excluded if they have isolated CNS or testicular disease. Patients will be excluded if they have ≥grade 2 peripheral sensory or motor neuropathy (defined by the Modified "Balis" Pediatric Scale of Pediatric Neuropathies) at the time of enrollment (see section 4.7.1.1). Patients will be excluded if they have a known allergy or intolerance to any of the drugs used in the study
•except for PEG-asparaginase for which erwinia asparaginase may be substituted Patients will be excluded if they have a systemic fungal, bacterial, viral or other infection that is exhibiting ongoing signs/symptoms related to the infection without improvement despite appropriate antibiotics or other treatment. The patient needs to be off pressors and have negative blood cultures for 48 hours. Patients will be excluded if there is a plan to administer non-protocol chemotherapy, radiation therapy, or immunotherapy during the study period. Patients will be excluded if they have significant concurrent disease, illness, psychiatric disorder or social issue that would compromise patient safety or compliance with the protocol treatment or procedures, interfere with consent, study participation, follow up, or interpretation of study results. Patients with DNA fragility syndromes (such as Fanconi anemia, Bloom syndrome) are excluded. Patients will be excluded if they have had a lifetime exposure of ≥400 mg/m2 doxorubicin equivolents of anthracyclines (anthracycline equivalence to doxorubicin conversion see appendix iv) . Concomitant medications Investigational drugs: Patients currently receiving another investigational drug are not eligible. Anti-GVHD agents post transplant: patients who are receiving cyclosporine, tacrolimus or other agents to prevent graft-versus-host disease post hematopoetic stem cell transplant are not eligible. CYP3A4 agents: patients who are currently receiving drugs that are strong inducers of CYP3A4 are not eligible. Strong inducers of CYP3A4 should be avoided from 14 days prior to enrollment to the end of the study. See appendix ii for a list of agents which fall into this category. Patients with Ph+ALL and Ph-like ALL who are currently receiving TKI therapy Infants or Patients with Down Syndrome will be excluded in phase 2 of the study

• Patients must be >= 2 years and =< 21 years at the time of enrollment
• Patients must have a body surface area (BSA) of >= 0.5 m^2 at enrollment
• Patients must have neurofibromatosis type 1 (NF1) based on clinical criteria and/or germline genetic testing
• Patients must be newly diagnosed or have previously diagnosed NF-1 associated LGG that has not been treated with any modality other than surgery
• For patients with optic pathway gliomas (OPGs):
• Newly-diagnosed patients with OPG are eligible if there are neurologic symptoms (including visual dysfunction, as defined below) or other exam findings associated with the tumor
• Previously-diagnosed patients with OPG are eligible if they have new or worsening neurologic symptoms (including visual dysfunction, as defined below) or have tumor growth
• For both newly-diagnosed and previously-diagnosed OPG, the patient may be eligible, irrespective of whether there has been tumor growth or other neurological symptoms or worsening, if they meet at least one of the following visual criteria:
• Visual worsening, defined as worsening of visual acuity (VA) or visual fields (VF) documented within the past year (by examination or history); OR
• Significant visual dysfunction (defined as VA worse than normal for age by 0.6 logMAR [20/80, 6/24, or 2.5/10] or more in one or both eyes)
• For patients with LGG in other locations (i.e., not OPGs):
• Newly-diagnosed patients with LGG are eligible if there are neurologic symptoms or other exam findings associated with the tumor
• NOTE: Newly-diagnosed patients with LGG without associated neurologic symptoms or exam findings are not eligible
• Previously-diagnosed patients with LGG are eligible if they have new or worsening neurologic symptoms or have tumor growth
• Although not required, if a biopsy/tumor resection is performed, eligible histologies will include all tumors considered LGG or low-grade astrocytoma (World Health Organization [WHO] grade I and II) by 5th edition WHO classification of central nervous system (CNS) tumors with the exception of subependymal giant cell astrocytoma
• Patients must have two-dimensional measurable tumor >= 1 cm^2
• Patients with metastatic disease or multiple independent primary LGGs are allowed on study
• Creatinine clearance or radioisotope glomerular filtration Rate (GFR) >= 70 mL/min/1.73 m^2 OR a serum creatinine based on age/gender (within 7 days prior to enrollment) as follows:
• Age; maximum serum creatinine (mg/dL)
• 2 to < 6 years; 0.8 (male) and 0.8 (female)
• 6 to < 10 years; 1 (male) and 1 (female)
• 10 to < 13 years; 1.2 (male) and 1.2 (female)
• 13 to < 16 years; 1.5 (male) and 1.4 (female)
• >= 16 years; 1.7 (male) and 1.4 (female)
• Total bilirubin =< 1.5 x upper limit of normal (ULN) for age (within 7 days prior to enrollment) (children with a diagnosis of Gilbert's syndrome will be allowed on study regardless of their total and indirect [unconjugated] bilirubin levels as long as their direct [conjugated] bilirubin is < 3.1 mg/dL)
• Serum glutamate pyruvate transaminase (SGPT) (alanine aminotransferase [ALT]) =< 3 x upper limit of normal (ULN) = 135 U/L (within 7 days prior to enrollment). For the purpose of this study, the ULN for SGPT is 45 U/L
• Albumin >= 2 g/dL (within 7 days prior to enrollment)
• Left ventricular ejection fraction (LVEF) >= 53% (or institutional normal; if the LVEF result is given as a range of values, then the upper value of the range will be used) by echocardiogram (within 4 weeks prior to enrollment)
• Corrected QT (QTc) interval =< 450 msec by electrocardiography (EKG) (within 4 weeks prior to enrollment)
• Absolute neutrophil count >= 1,000/uL (unsupported) (within 7 days prior to enrollment)
• Platelets >= 100,000/uL (unsupported) (within 7 days prior to enrollment)
• Hemoglobin >= 8 g/dL (may be supported) (within 7 days prior to enrollment)
• Patients with a known seizure disorder should be stable and should have not experienced a significant increase in seizure frequency within 2 weeks prior to enrollment
• Patients 2-17 years of age must have a blood pressure that is =< 95th percentile for age, height, and gender at the time of enrollment. Patients >= 18 years of age must have a blood pressure =< 130/80 mmHg at the time of enrollment (with or without the use of antihypertensive medications).
• Note: Adequate blood pressure can be achieved using medication for the treatment of hypertension
• All patients must have ophthalmology toxicity assessments performed within 4 weeks prior to enrollment
• For all patients, an MRI of the brain (with orbital cuts for optic pathway tumors) and/or spine (depending on the site(s) of primary disease) with and without contrast must be performed within 4 weeks prior to enrollment
• For patients who undergo a surgery on the target tumor (not required), a pre- and post-operative* MRI of the brain (with orbital cuts for optic pathway tumors) or spine (depending on the site(s) of primary disease) with and without contrast must also be performed within 4 weeks prior to enrollment
• The post-operative MRIs should be performed ideally within 48 hours after surgery if possible
• Patients must have a performance status corresponding to Eastern Cooperative Oncology Group (ECOG) scores of 0, 1, or 2. Use Karnofsky for patients > 16 years of age and Lansky for patients =< 16 years of age
• Patients must have the ability to swallow whole capsules
• Patients must have receptive and expressive language skills in English or Spanish to complete the quality of life (QOL) and neurocognitive assessments
• 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 must not have received any prior tumor-directed therapy including chemotherapy, radiation therapy, immunotherapy, or bone marrow transplant. Prior surgical intervention is permitted
• Patients with a concurrent malignancy or history of treatment (other than surgery) for another tumor within the last year are ineligible
• Patients may not be receiving any other investigational agents
• Patients with any serious medical or psychiatric illness/ condition, including substance use disorders likely in the judgement of the investigator to interfere or limit compliance with study requirements/treatment are not eligible
• Patients who, in the opinion of the investigator, are not able to comply with the study procedures are not eligible
• Female patients who are pregnant are not eligible since fetal toxicities and teratogenic effects have been noted for several of the study drugs. A pregnancy test is required for female patients of childbearing potential
• Lactating females who plan to breastfeed their infants are not eligible
• Sexually active patients of reproductive potential who have not agreed to use an effective contraceptive method for the duration of their study participation and for 12 weeks after stopping study therapy are not eligible
• Note: Women of child-bearing potential and males with sexual partners who are pregnant or who could become pregnant (i.e., women of child-bearing potential) should use effective methods of contraception for the duration of the study and for 12 weeks after stopping study therapy to avoid pregnancy and/or potential adverse effects on the developing embryo
• Cardiac conditions:
• Known genetic disorder that increases risk for coronary artery disease. Note: The presence of dyslipidemia in a family with a history of myocardial infarction is not in itself an exclusion unless there is a known genetic disorder documented
• Symptomatic heart failure
• New York Heart Association (NYHA) class II-IV prior or current cardiomyopathy
• Severe valvular heart disease
• History of atrial fibrillation
• Ophthalmologic conditions:
• Current or past history of central serous retinopathy
• Current or past history of retinal vein occlusion or retinal detachment
• Patients with uncontrolled glaucoma
• If checking pressure is clinically indicated, patients with intraocular pressure (IOP) > 22 mmHg or ULN adjusted by age are not eligible
• Ophthalmological findings secondary to long-standing optic pathway glioma (such as visual loss, optic nerve pallor, or strabismus) or longstanding orbito-temporal plexiform neurofibroma (PN), such as visual loss, strabismus) will NOT be considered a significant abnormality for the purposes of the study
• Treatments and/or medications patient is receiving that would make her/him ineligible, such as:
• Supplementation with vitamin E greater than 100% of the daily recommended dose. Any multivitamin containing vitamin E must be stopped prior to study enrollment even if less than 100% of the daily recommended dosing for vitamin E
• Surgery within 2 weeks prior to enrollment, with the exception of surgical placement for vascular access or cerebrospinal fluid (CSF) diverting procedures such as endoscopic third ventriculostomy (ETV) and ventriculo-peritoneal (VP) shunt.
• Note: Patients must have healed from any prior surgery prior to enrollment
• Patients who have an uncontrolled infection are not eligible

• clinical and/or electrographic seizures
• life expectancy of less than 24 hours
• anoxic brain injury or an uncontrolled metabolic condition as primary cause of SE
• treatment of current SE episode with IV anesthetics

• Adolescents ages 13 through 18 years, and
• Adolescents must be experiencing an elevated level of depressive symptoms (PHQ-9 = 5-18), and
• Adolescents will be included if they have had past depressive episode/s, but not if they are in a current depressive episode. 1. Outside age range: 1. 12 or younger 2. 19 or older 2. Adolescent is a non-English speaker/reader 3. On the PHQ-9 screening, depression symptom level is: 1. PHQ-9 = 4 or lower 2. PHQ-9 =19 or higher 4. As assessed by the MINI Kid, a current depressive episode 5. As assessed by the MINI Kid, adolescent meets DSM-5 criteria for a psychotic or bipolar disorder. 6. Currently using medication therapy for depression, anxiety, or other internalizing disorders. 7. Currently engaged in individual treatment for a mood disorder (assessed by BCC during phone screen) 8. Currently engaged in a cognitive-behavioral group or therapy (assessed by BCC during phone screen) 9. Any past psychiatric hospitalizations 10. Any past suicide attempt or incident of self-harm with moderate or greater lethality 11. Extreme, current drug/alcohol abuse (determined by clinician follow up following a score of 3 or greater on the CRAFFT) 12. Current suicidal thoughts 1. Eligibility will be determined on a case-by-case basis during the baseline PhQ-9 and MINI Kid assessment process and after a consultation with a licensed mental health clinician has taken place. If adolescent report suicidal ideation on the baseline PhQ-9, and found ineligible, the MINI Kid assessment may not be required. 2. Adolescents with current (within the past 6 months), active suicidal feelings will be excluded. 3. Adolescents with passive thoughts of death or suicide but report to the mental health clinician that they would never act on these thoughts may be admitted, depending on the severity of the risk. 4. Adolescents with past (greater than 6 months ago) ideation who are determined to be low risk will be admitted into the study if there has never been an attempt of moderate or greater lethality. 13. Significant reading impairment (a minimum sixth-grade reading level based on parental report) and/or significant intellectual or developmental disabilities 14. Not willing to comply with the study protocol 15. Did not complete phone assessment with MINI Kid by BCC 16. Not affiliated with any of the sites listed in Appendix A. 17. Parent/guardian does not speak English or Spanish 18. Parent/guardian has a cognitive or intellectual impairment 19. Participant Declined/Changed Mind/Uninterested in participating

• STEP 0: Patients must be >= 12 months and =< 21 years of age at the time of enrollment on Step 0.
• Please note:
• This age range includes pre-screening for all HGG patients. Individual treatment protocols may have different age criteria.
• Non-DIPG patients with tumors that do not harbor an H3K27M-mutation and are >= 18 years of age will not be eligible to enroll on ACNS1821 (Step 1).
• STEP 0: Patient is suspected of having localized, newly diagnosed HGG, excluding metastatic disease, OR patient has an institutional diagnosis of DIPG
• STEP 0:
• For patients with non-pontine tumors: Patient and/or their parents or legal guardians have signed informed consent for eligibility screening on APEC14B1 Part A.
• For patients with DIPG: Patient and/or their parents or legal guardians have signed informed consent for ACNS1821.
• STEP 0:
• For patients with non-pontine tumors only, the specimens obtained at the time of diagnostic biopsy or surgery must be submitted through APEC14B1 ASAP, preferably within 5 calendar days of definitive surgery
• STEP 1: Patients must be >= 12 months and =< 21 years of age at the time of enrollment
• STEP 1: Patients must have newly-diagnosed DIPG or HGG (including DMG).
• STEP 1: Stratum DIPG
• Patients with newly-diagnosed typical DIPG, defined as tumors with a pontine epicenter and diffuse involvement of at least 2/3 of the pons on at least 1 axial T2 weighted image, are eligible. No histologic confirmation is required.
• Patients with pontine tumors that do not meet radiographic criteria for typical DIPG (e.g., focal tumors or those involving less than 2/3 of the pontine cross-sectional area with or without extrapontine extension) are eligible if the tumors are biopsied and proven to be high-grade gliomas (such as anaplastic astrocytoma, glioblastoma, high-grade glioma not otherwise specified [NOS], and/or H3 K27M-mutant) by institutional diagnosis.
• STEP 1: Stratum DMG (with H3 K27M mutation)
• Patients must have newly-diagnosed non-pontine H3 K27M-mutant HGG without BRAF V600 or IDH1 mutations as confirmed by Rapid Central Pathology and Molecular Screening Reviews performed on APEC14B1
• Note: Patients need not have either measurable or evaluable disease, i.e., DMG patients may have complete resection of their tumor prior to enrollment. Primary spinal tumors are eligible for enrollment. For rare H3 K27M-mutant HGG in non-midline structures (e.g., cerebral hemispheres), these patients will be considered part of Stratum DMG.
• STEP 1: Stratum HGG (without H3 K27M mutation)
• Patients must have newly-diagnosed non-pontine H3 K27M-wild type HGG without BRAF V600 or IDH1 mutations as confirmed by Rapid Central Pathology and Molecular Screening Reviews performed on APEC14B1
• Please note:
• Patients who fall in this category and who are >= 18 years of age are not eligible due to another standard-of-care regimen (radiation/temozolomide) that is available
• Patients need not have either measurable or evaluable disease, i.e., HGG patients may have complete resection of their tumor prior to enrollment. Primary spinal tumors are eligible for enrollment
• STEP 1: Patients must have a performance status corresponding to Eastern Cooperative Oncology Group (ECOG) scores of 0, 1 or 2. Use Karnofsky for patients > 16 years of age and Lansky for patients =<16 years of age. Patients 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.
• STEP 1: Peripheral absolute neutrophil count (ANC) >= 1000/uL (within 7 days prior to step 1 enrollment)
• STEP 1: Platelet count >= 100,000/uL (transfusion independent) (within 7 days prior to step 1 enrollment)
• STEP 1: Hemoglobin >= 8.0 g/dL (may receive red blood cell [RBC] transfusions) (within 7 days prior to step 1 enrollment)
• STEP 1: Creatinine clearance or radioisotope glomerular filtration rate (GFR) >= 70 mL/min/1.73 m^2 (within 7 days prior to step 1 enrollment) or A serum creatinine based on age/gender as follows (within 7 days prior to step 1 enrollment):
• Age / Maximum Serum Creatinine (mg/dL)
• 1 to < 2 years / male: 0.6; female: 0.6
• 2 to < 6 years / male: 0.8; female: 0.8
• 6 to < 10 years / male: 1; female: 1
• 10 to < 13 years / male: 1.2; female: 1.2
• 13 to < 16 years / male: 1.5; female: 1.4
• >= 16 years / male: 1.7; female: 1.4
• STEP 1: Total bilirubin =< 1.5 x upper limit of normal (ULN) for age
• STEP 1: Serum glutamate pyruvate transaminase (SGPT) (alanine aminotransferase [ALT]) =< 135 U/L. For the purpose of this study, the ULN for SGPT is 45 U/L.
• STEP 1: Serum amylase =< 1.5 x ULN
• STEP 1: Serum lipase =< 1.5 x ULN
• STEP 1: No evidence of dyspnea at rest, no exercise intolerance, and a pulse oximetry > 94% if there is clinical indication for determination.
• STEP 1: Patients with seizure disorder may be enrolled if on anticonvulsants and well controlled.
• STEP 1: Patients must be enrolled and protocol therapy must begin no later than 31 days after the date of radiographic diagnosis (in the case of non-biopsied DIPG patients only) or definitive surgery, whichever is the later date (Day 0). For patients who have a biopsy followed by resection, the date of resection will be considered the date of definitive diagnostic surgery. If a biopsy only was performed, the biopsy date will be considered the date of definitive diagnostic surgery.
• STEP 1: Patients must not have received any prior therapy for their central nervous system (CNS) malignancy except for surgery and steroid medications.
• STEP 1: Patients who are currently receiving another investigational drug are not eligible.
• STEP 1: Patients who are currently receiving other anti-cancer agents are not eligible.
• STEP 1: Patients >=18 years of age who have H3 K27M-wild type HGG.
• STEP 1: Patients who have an uncontrolled infection.
• STEP 1: Patients who have received a prior solid organ transplantation.
• STEP 1: Patients with grade > 1 extrapyramidal movement disorder.
• STEP 1: Patients with known macular degeneration, uncontrolled glaucoma, or cataracts.
• STEP 1: Patients with metastatic disease are not eligible; MRI of spine with and without contrast must be performed if metastatic disease is suspected by the treating physician.
• STEP 1: Patients with gliomatosis cerebri type 1 or 2 are not eligible, with the exception of H3 K27M-mutant bithalamic tumors.
• STEP 1: Patients who are not able to receive protocol specified radiation therapy.
• STEP 1:
• Female patients who are pregnant are ineligible since there is yet no available information regarding human fetal or teratogenic toxicities.
• Lactating females are not eligible unless they have agreed not to breastfeed their infants. It is not known whether selinexor is excreted in human milk.
• Female patients of childbearing potential are not eligible unless a negative pregnancy test result has been obtained.
• Sexually active patients of reproductive potential are not eligible unless they have agreed to use two effective methods of birth control (including a medically accepted barrier method of contraception, e.g., male or female condom) for the duration of their study participation and for 90 days after the last dose of selinexor. Abstinence is an acceptable method of birth control.

• 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

• There is no age limit for the low risk stratum (stage I ovarian immature teratoma and stage I non-seminoma or seminoma malignant GCT [all sites])
• Standard risk 1: Patient must be < 11 years of age at enrollment
• Standard risk 2: Patients must be >= 11 and < 25 years of age at enrollment
• Patients enrolling on one of the low risk arms must be newly diagnosed with a stage I germ cell tumor; for the standard risk arms, patients must be newly diagnosed with metastatic germ cell tumor (stage II or higher); histologic confirmation of a primary extracranial germ cell tumor in any of the categories outlined below is required of all patients at enrollment except for those who were initially diagnosed with stage I non-seminoma malignant GCT and later recur during observation post surgery off study; for these patients, if elevated tumor markers rise to > 5 x upper limit of normal (ULN) on at least 2 measurements taken at least 1 week apart, a diagnostic biopsy is not required for enrollment
• Low risk stage I immature teratoma (IT); site: ovarian; stage: Children's Oncology Group (COG) stage I, Federation of Gynecology and Obstetrics (FIGO) stage IA and IB; grade: 2 or 3; histology: pure immature teratoma (may contain microscopic foci of yolk sac tumor), mixed immature and mature teratoma, (no pathological evidence of MGCT); tumor markers: alpha-FP =< 1,000 ng/mL, beta-HCG institutional normal; all ages
• Low risk stage I non-seminoma MGCT; site: ovarian, testicular, or extragonadal; stage: COG stage I, FIGO stage IA and IB, American Joint Committee on Cancer (AJCC) testicular stage IA, IB and IS; histology: must contain at least one of the following: yolk sac tumor, embryonal carcinoma, or choriocarcinoma (pure or mixed); all ages
• Low risk stage I seminoma-MGCT; site: testicular; stage: COG stage I; AJCC testicular stage IA IB, and IS; histology: must contain at least one of the following: may contain immature/mature teratoma; may NOT contain yolk sac tumor, embryonal carcinoma, or choriocarcinoma; all ages
• Standard risk 1 (SR1); site: ovarian, testicular, or extragonadal; stage: COG stage II-IV, FIGO stage IC, FIGO stage II-IV (International Germ Cell Consensus Classification [IGCCC] criteria DO NOT apply); histology: must contain at least one of the following: yolk sac tumor, embryonal carcinoma, or choriocarcinoma; age (years) < 11
• Standard risk 2 (SR2)
• Site: ovarian; stage: COG stage II and III, FIGO stage IC, II and III; histology: must contain at least one of the following: yolk sac tumor, embryonal carcinoma, or choriocarcinoma; age (years) >= 11 and < 25
• Site: testicular; stage: COG stage II-IV, AJCC stage II, III, IGCCC good risk; histology: must contain at least one of the following: yolk sac tumor, embryonal carcinoma, or choriocarcinoma; tumor markers: must be IGCCC good risk; post op: alpha-FP < 1,000 ng/mL, beta-HCG < 5,000 IU/mL and lactate dehydrogenase (LDH) < 3.0 x normal; age (years) >= 11 and < 25
• Site: extragonadal; stage: COG stage II; histology: must contain at least one of the following: yolk sac tumor, embryonal carcinoma, or choriocarcinoma; age (years) >= 11 and < 25
• Notes:
• IGCCC criteria only apply to SR2 patients with a testicular primary tumor
• Use post-op tumor marker levels to determine IGCCC risk group
• Stage 1 seminoma patients are not eligible for the standard risk arms of the study
• For the low risk stage I non-seminoma MGCT and the standard risk arms, components of yolk sac tumor, embryonal carcinoma, or choriocarcinoma can be mixed with other forms of GCT, such as seminoma or mature or immature teratoma; if yolk sac tumor is the only malignant component present, then it must be deemed by the pathologist to be greater than a "microscopic component" of yolk sac tumor
• Patients must have a performance status corresponding to Eastern Cooperative Oncology Group (ECOG) scores of 0, 1, 2 or 3; use Karnofsky for patients > 16 years of age and Lansky for patients =< 16 years of age
• Organ function requirements apply ONLY to patients who will receive chemotherapy (SR1 and SR2 patients)
• Adequate renal function defined as:
• Creatinine clearance or radioisotope glomerular filtration rate (GFR) >= 70 mL/min/1.73 m^2 (within 7 days prior to enrollment) OR
• A serum creatinine based on age/gender as follows (within 7 days prior to enrollment): (mg/dL)
• 1 month to < 6 months male: 0.4 female: 0.4
• 6 months to < 1 year male: 0.5 female: 0.5
• 1 to < 2 years male: 0.6 female: 0.6
• 2 to < 6 years male: 0.8 female: 0.8
• 6 to < 10 years male: 1 female: 1
• 10 to < 13 years male: 1.2 female: 1.2
• 13 to < 16 years: male: 1.5 female: 1.4
• >= 16 years male: 1.7 female: 1.4
• Total bilirubin =< 1.5 x upper limit of normal (ULN) for age (within 7 days prior to enrollment)
• Serum glutamic-oxaloacetic transaminase (SGOT) (aspartate aminotransferase [AST]) or serum glutamate pyruvate transaminase (SGPT) (alanine aminotransferase [ALT]) < 2.5 x upper limit of normal (ULN) for age (for the purpose of this study, the ULN for SGPT is 45 U/L) (within 7 days prior to enrollment)
• Peripheral absolute neutrophil count (ANC) >= 1,000/mm^3 (within 7 days prior to enrollment) AND
• Platelet count >= 100,000/mm^3 (within 7 days prior to enrollment)
• Patients enrolling on the standard risk arms must be medically fit to receive protocol treatment and with no contraindications to protocol treatment
• Eligibility criteria to participate in the pilot study of the AYA-Hears instrument (patient reported outcomes [PROs] of ototoxicity) Note: participants in group 1 will not receive AGCT1531 protocol-directed therapy; all other AYA-HEARS patients must be enrolled on the AGCT1531 SR2 arm in order to participate
• >= 11 and < 25 years old at enrollment
• Able to fluently speak and read English
• Has received prior cisplatin- or carboplatin-based chemotherapy regimen for malignancy including diagnoses other than germ cell tumor
• Followed for cancer or survivorship care at one of the following institutions:
• Baylor College of Medicine/Dan L Duncan Comprehensive Cancer Center
• Dana Farber/Harvard Cancer Center
• Hospital for Sick Children
• Children's Hospital of Eastern Ontario
• Oregon Health and Science University
• Seattle Children's Hospital
• Yale University
• Patients with any diagnoses not listed including:
• Stage I testicular cancer patients who have undergone primary RPLND (retroperitoneal lymph node dissection)
• Pure dysgerminoma
• Pure mature teratoma
• Pure immature teratoma COG stage I, grade I
• Pure immature teratoma COG stage I, grade 2,3 with alpha-fetoprotein (AFP) >= 1000 ng/mL
• Pure immature teratoma COG stage II
•IV or FIGO stage IC to IV
• "Poor risk" GCT (age >= 11 years old and COG stage IV ovarian, COG stage III or IV EG, or IGCCC intermediate or poor risk testicular), or
• Primary central nervous system (CNS) germ cell tumor
• Germ cell tumor with somatic malignant transformation
• Spermatocytic seminoma
• Patients must have had no prior systemic therapy for the current cancer diagnosis
• Patients must have had no prior radiation therapy with the exception of CNS irradiation of brain metastases; (this exception only applies to SR1 patients; any patients over age 11 with distant metastases to brain [stage IV disease] would be considered poor risk and therefore not eligible for this trial)
• Patients with significant, pre-existing co-morbid respiratory disease that contraindicate the use of bleomycin are ineligible for the standard risk arms of the trial
• 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; (this criteria applies ONLY to patients who will receive chemotherapy [SR1 and SR2 patients])
• Lactating females who plan to breastfeed their infants; (this criteria applies ONLY to patients who will receive chemotherapy [SR1 and SR2 patients])
• Sexually active patients of reproductive potential who have not agreed to use an effective contraceptive method for the duration of their study participation; (this criteria applies ONLY to patients who will receive chemotherapy [SR1 and SR2 patients])

• 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])