• 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 Inclusion Criteria
• Patients ≥6 months and up to 60 months (1800 days) of age at time of dosing following diagnostic confirmation during screening period by genotype who demonstrate the ability to sit unassisted for 10 or more seconds but cannot stand or walk
• Diagnostic confirmation by genotype includes lab documentation of homozygous absence of SMN1 exon 7; with exactly three copies of SMN2
• Negative gene testing for SMN2 gene modifier mutation (c.859G>C)
• Onset of clinical signs and symptoms consistent with spinal muscular atrophy (SMA) at < 12 months of age
• Able to sit independently and not standing or walking independently. Definition of sitting independently is defined by the World Health Organization Multicentre Growth Reference Study (WHO-MGRS) criteria of being able to sit up unsupported with head erect for at least 10 seconds. Child should not use arms or hands to balance body or support position (Wijnhoven 2004)
• Be up-to-date on childhood vaccines that include palivizumab prophylaxis (also known as Synagis) to prevent respiratory syncytial virus (RSV) infections are also recommended in accordance with American Academy of Pediatrics (AAP 2009) Key Exclusion Criteria
• Current or historical ability to stand or walk independently
• Contraindications for spinal tap procedure or administration of intrathecal therapy or presence of an implanted shunt for the drainage of CSF or an implanted central venous (CNS) catheter
• Severe contractures as determined by designated Physical Therapist(s) at screening that interfere with either the ability to attain/demonstrate functional measures or interferes with ability to receive intrathecal (IT) dosing
• Severe scoliosis (defined as ≥ 50° curvature of spine) evident on X-ray examination
• Previous, planned or expected scoliosis repair surgery/procedure within 1 year of dose administration
• Use of invasive ventilatory support (tracheotomy with positive pressure) or pulse oximetry < 95% saturation at screening while the patient is awake, or for high altitudes > 1000 m, oxygen saturation < 92% while the patient is awake
• Pulse oximetry saturation must not decrease ≥ four (4) percentage points between screening and highest value on day of dosing
• Use or requirement of non-invasive ventilatory support for 12 or more hours daily over the two (2) weeks prior to dosing
• Medical necessity for a gastric feeding tube, where the majority of feedings are given by non-oral methods (i.e., nasogastric tube or nasojejunal tube) or patients whose weight-for-age falls below the 3rd percentile based on WHO Child Growth Standards (Onis 2006). Placement of a permanent gastrostomy prior to screening is not an exclusion
• Use or requirement of non-invasive ventilatory support for 12 or more hours daily over the two (2) weeks prior to dosing
• Medical necessity for a gastric feeding tube, where the majority of feedings are given by non-oral methods or patients whose weight-for-age falls below the 3rd percentile based on WHO Child Growth Standards (Onis 2006). Placement of a permanent gastrostomy prior to screening is not an exclusion
• Active viral infection (includes human immunodeficiency virus (HIV) or serology positive for hepatitis B or C, or Zika virus)
• Serious non-respiratory tract illness requiring systemic treatment and/or hospitalization within two (2) weeks prior to study entry
• Respiratory infection requiring medical attention, medical intervention or increase in supportive care of any manner within four (4) weeks prior to study entry
• Severe non-pulmonary/respiratory tract infection within four (4) weeks before study dosing or concomitant illness that in the opinion of the Principal Investigator (PI) creates unnecessary risks for gene transfer such as:
• Major renal or hepatic impairment
• Known seizure disorder
• Diabetes mellitus
• Idiopathic hypocalciuria
• Symptomatic cardiomyopathy
• History of bacterial meningitis or brain or spinal cord disease, including tumors, or abnormalities by magnetic resonance imaging (MRI) or computerized tomography (CT) that would interfere with the lumbar puncture (LP) procedures or CSF circulation
• Known allergy or hypersensitivity to prednisolone or other glucocorticosteroids or their excipients
• Known allergy or hypersensitivity to iodine or iodine-containing products
• Concomitant use of any of the following: drugs for treatment of myopathy or neuropathy, agents used to treat diabetes mellitus, or ongoing immunosuppressive therapy, plasmapheresis, immunomodulators such as adalimumab, or immunosuppressive therapy within 3 months of study dosing
• Inability to withhold use of laxatives or diuretics in the 24 hours prior to dose administration
• Anti-AAV9 antibody titers >1:50 as determined by Enzyme-linked Immunosorbent Assay (ELISA) binding immunoassay
• Should a potential patient demonstrate anti AAV9 antibody titer > 1:50, he or she may receive retesting within 30 days of the screening period and will be eligible to participate if the anti AAV9 antibody titer upon retesting is ≤ 1:50
• Clinically significant abnormal laboratory values (GGT, ALT, and AST, or total bilirubin > 2 × ULN, creatinine ≥ 1.0 mg/dL, hemoglobin [Hgb] < 8 or > 18 g/dL; white blood cell [WBC] > 20,000 per cmm) prior to gene replacement therapy. Patients with an elevated bilirubin level that is unequivocally the result of neonatal jaundice shall not be excluded
• Participation in recent SMA treatment clinical trial or receipt of an investigational or approved compound product or therapy received with the intent to treat SMA at any time prior to screening for this study
• Oral beta agonists must be discontinued 30 days prior to dosing.
• Inhaled albuterol specifically prescribed for the purposes of respiratory (bronchodilator) management is acceptable and not a contraindication at any time prior to screening for this study
• Expectation of major surgical procedures during the 1-year study assessment period

• Completed study drug treatment in a parent study; or had study drug interruption(s) in a parent study but completed study visits up to the last scheduled visit of the Treatment Period in the parent study.
• History of drug intolerance in a parent study that would pose an additional risk to the subject in the opinion of the investigator.
• Current participation in an investigational drug trial (other than a parent study) Other protocol defined Inclusion/Exclusion criteria may apply.

Key
• Subjects will be 1 to less than 2 years of age on Day 1 of the relevant part of the study.
• Homozygous for F508del (F/F). Key
• Any clinically significant laboratory abnormalities at the Screening Visit that would interfere with the study assessments or pose an undue risk for the subject.
• Solid organ or hematological transplantation. Other protocol defined Inclusion/Exclusion criteria may apply.

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

• All B-ALL patients must be enrolled on APEC14B1 and consented to Eligibility Screening (Part A) prior to treatment and enrollment on AALL1731. APEC 14B1 is not a requirement for B-LLy patients. B-LLy patients may directly enroll on AALL1731.
• Age at diagnosis:
• Patients must be >= 365 days and < 10 years of age (B-ALL patients without DS).
• Patients must be >= 365 days and =< 31 years of age (B-ALL patients with DS).
• Patients must be >= 365 days and =< 31 years of age (B-LLy patients with or without DS).
• B-ALL patients without DS must have an initial white blood cell count < 50,000/uL (performed within 7 days prior to enrollment).
• B-ALL patients with DS are eligible regardless of the presenting white blood cell count (WBC) (performed within 7 days prior to enrollment).
• Patient has newly diagnosed B-cell ALL, with or without Down syndrome: > 25% blasts on a bone marrow (BM) aspirate;
• OR if a BM aspirate is not obtained or is not diagnostic of B-ALL, the diagnosis can be established by a pathologic diagnosis of B-ALL on a BM biopsy;
• OR a complete blood count (CBC) documenting the presence of at least 1,000/uL circulating leukemic cells;
• OR patient has newly diagnosed B-cell LLy Murphy stages I or II, with or without Down syndrome.
• Note: For B-LLy patients with tissue available for flow cytometry, the criterion for diagnosis should be analogous to B-ALL. For tissue processed by other means (i.e., paraffin blocks), the methodology and criteria for immunophenotypic analysis to establish the diagnosis of B-LLy defined by the submitting institution will be accepted (diagnostic biopsy for B-LLy must be performed within 14 days prior to enrollment).
• All institutional, Food and Drug Administration (FDA), and National Cancer Institute (NCI) requirements for human studies must be met.
• All patients and/or their parents or legal guardians must sign a written informed consent.
• Patient must not have secondary ALL that developed after treatment of a prior malignancy with cytotoxic chemotherapy. Note: patients with Down syndrome with a prior history of transient myeloproliferative disease (TMD) are not considered to have had a prior malignancy. They would therefore be eligible whether or not the TMD was treated with cytarabine.
• With the exception of steroid pretreatment or the administration of intrathecal cytarabine, patients must not have received any prior cytotoxic chemotherapy for either the current diagnosis of B ALL or B LLy or for any cancer diagnosed prior to initiation of protocol therapy on AALL1731.
• For patients receiving steroid pretreatment, the following additional exclusion criteria apply:
• Non-DS B-ALL patients must not have received steroids for more than 24 hours in the 2 weeks prior to diagnosis without a CBC obtained within 3 days prior to initiation of the steroids.
• DS and non-DS B-LLy patients must not have received > 48 hours of oral or IV steroids within 4 weeks of diagnosis.
• Patients who have received > 72 hours of hydroxyurea.
• B-ALL patients who do not have sufficient diagnostic bone marrow submitted for APEC14B1 diagnostic testing and who do not have a peripheral blood sample submitted containing > 1,000/uL circulating leukemia cells.
• Patient must not have acute undifferentiated leukemia (AUL).
• Non-DS B-ALL patients with central nervous system [CNS]3 leukemia (CNS status must be known prior to enrollment).
• Note: DS patients with CNS3 disease are eligible but will be assigned to the DS-High B-ALL arm. CNS status must be determined based on a sample obtained prior to administration of any systemic or intrathecal chemotherapy, except for steroid pretreatment.
• Non-DS B-ALL patients with testicular leukemia. (Note: DS patients with testicular disease are eligible but will be assigned to the DS-High B-ALL arm).
• For LLy patients, the following additional exclusion criteria apply:
• T-Lymphoblastic Lymphoma.
• Morphologically unclassifiable lymphoma.
• Absence of both B-cell and T-cell phenotype markers in a case submitted as lymphoblastic lymphoma.
• CNS positive disease or testicular involvement.
• M2 (5%
•25% blasts) or M3 (> 25% blasts) marrow.
• Patients with known Charcot-Marie-Tooth disease.
• Patients with known MYC translocation associated with mature (Burkitt) B-cell ALL, regardless of blast immunophenotype.
• Patients requiring radiation at diagnosis.
• 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.

Key
• Completed study drug treatment in parent study (VX18-445-104); or had study drug interruption(s) in parent study but completed study visits up to the last scheduled visit of the Treatment Period in the parent study Key
• History of study drug intolerance in parent study Other protocol defined Inclusion/Exclusion criteria may apply

• 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.

Each patient must meet the following criteria to be enrolled in this study. 1. Is a child or an adolescent of 10 to <18 years old, at Visit 1 (Screening) 2. Has been diagnosed with type 2 diabetes mellitus per American Diabetes Association diagnostic criteria 3. HbA1c of 6.5% to 11.0%, inclusive, in patients not taking insulin/SU, and of 6.5% to 12.0%, inclusive, in patients taking insulin/SU, at Visit 1 (Screening) 4. Has a C-peptide of >0.6 ng/L at Visit 1 (Screening) 5. Has been treated with diet and exercise alone or in combination with a stable dose of an oral antidiabetic agent (e.g., metformin and/or SU) and/or insulin for their type 2 diabetes for at least 2 months prior to Visit 1 (Screening) 6. Has a fasting plasma glucose concentration <280 mg/dL (15.5 mmol/L) at Visit 1 (Screening) Patients who meet any of the following criteria will be excluded from the study. 1. Has a clinically significant medical condition that could potentially affect study participation and/or personal well-being, as judged by the Investigator, including but not limited to the following conditions: 1. Hepatic disease (defined by aspartate or alanine transaminase >3.0 times the upper limit of normal (ULN) 2. Renal disease or serum creatinine >1.5 mg/dL (132.6 µmol/L) (males) or 1.4 mg/dL (123.8 µmol/L) (females) 3. Gastrointestinal disease deemed significant by the Investigator 4. Organ transplantation 5. Chronic infection (e.g., tuberculosis, human immunodeficiency virus, hepatitis B virus, or hepatitis C virus) 6. Clinically significant malignant disease (with the exception of basal and squamous cell carcinoma of the skin) within 5 years of Visit 1 (Screening) 2. Has positive antibody titers to glutamic acid decarboxylase (GAD65) or islet cell antigen (ICA512) at Visit 1 (Screening) 3. Has a personal or family history of elevated calcitonin, calcitonin >100 ng/L, medullary thyroid carcinoma, or multiple endocrine neoplasia-2 4. Has ever used exenatide (exenatide once weekly [exenatide LAR], exenatide BID, BYETTA, or any other formulation) or any glucagon-like peptide-1 (GLP-1) receptor agonist (e.g., liraglutide [Victoza®]) 5. Is pregnant

• Eligible subjects will be as follows: 1. 4 weeks to 17 years of age, 2. fulfill the American Heart Association case definition for complete or incomplete KD, 3. have had fever (T ≥38°C) for 3 to 10 days prior to initial IVIG treatment, 4. have fever (T ≥38°C orally or rectally) between 36 hours and 7 days after end of the first IVIG infusion without other likely cause 1. Patient treated with infliximab or steroids for present illness (pts who received oral steroids as outpatients prior to KD diagnosis but who otherwise qualify for the study will not be excluded) 2. Known prior infection with tuberculosis, coccidiomycosis, or histoplasmosis.

• 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 A2, 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
• This criteria apply ONLY to patients who will receive chemotherapy (all groups other than Groups A1 and 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

1. ≥ 12 years of age at the time Informed Consent/ Assent is signed. 2. Weight ≥ 40 kg. 3. FEV1 ≥ 40% predicted and < 100% predicted in the last 12 months. 4. Physician-initiated treatment with an IV antibiotic 2 or 3 times in the last 12 months for a new PEx or physician-initiated treatment with an IV antibiotic 1 time in the last 12 months plus physician-initiated treatment with oral antibiotic(s) 1 or more times in the past 12 months for a new PEX. 1. Severe or unstable CF at screening or Visit 1. 2. Any of the following values for laboratory tests at screening: 1. A positive pregnancy test. 2. Hemoglobin < 10 g/dL in males and < 9 g/dL in females. 3. Neutrophils < 1.0 x 10^9 /L. 4. Platelets < 75 x 10^9/L. 5. Creatinine clearance < 50 mL/min according to Modification of Diet in Renal Disease (MDRD) Study equation. 6. Serum transaminases > 2.5 x upper limit of normal. 3. Any medical condition or concurrent medical therapies at screening or Visit 1 that may put the subject at greater safety risk, influence response to study drug or interfere with study assessments.

• 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

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

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).

• Gestational age 29 0/7 to 33 6/7 weeks at birth
• Birth weight less than 1600 grams
• Greater than 48 hours of age
• Current weight less than 1540 grams
• In an incubator
• Receiving phototherapy
• Receiving respiratory support (including CPAP, ventilation, HFNC > 2 LPM)
• Receiving blood pressure support
• Designated for transfer to referral hospital while in incubator
• Known major congenital or chromosomal anomaly

• Patients must have constitutional trisomy 21 (Down syndrome) or trisomy 21 mosaicism (by karyotype or fluorescence in situ hybridization [FISH])
• Patient has one of the following:
• Patient has previously untreated de novo AML and meets the criteria for AML with >= 20% bone marrow blasts as set out in the World Health Organization (WHO) Myeloid Neoplasm classification
• Attempts to obtain bone marrow either by aspirate or biopsy must be made unless clinically prohibitive; in cases where it is clinically prohibitive, peripheral blood with an excess of 20% blasts and in which adequate flow cytometric and cytogenetics/FISH testing is feasible can be substituted for the marrow exam at diagnosis
• Patient has cytopenias and/or bone marrow blasts but does not meet the criteria for the diagnosis of AML (WHO Myeloid Neoplasm classification) because of < 20% marrow blasts and meets the criteria for a diagnosis of myelodysplastic syndrome (MDS)
• Patient has a history of transient myeloproliferative disorder (which may or may not have required chemotherapy intervention), who:
• Are > 8 weeks since resolution of transient myeloproliferative disease (TMD) with >= 5% blasts, OR
• Patients who have an increasing blast count (>= 5%) in serial bone marrow aspirates performed at least 4 weeks apart
• Children who have previously received chemotherapy, radiation therapy or any anti-leukemic therapy are not eligible for this protocol, with the exception of cytarabine for the treatment of TMD
• There are no minimal organ function requirements for enrollment on this study
• Note: Previous cardiac repair with sufficient cardiac function is not an exclusion criteria
• Each patient's 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 subjects research must be met
• Patients with promyelocytic leukemia (French-American-British [FAB] M3)
• Prior therapy
• Patients =< 30 days from the last dose of cytarabine used for treatment of TMD

• Patients must have had histologic verification of juvenile myelomonocytic leukemia (JMML) at original diagnosis and currently have relapsed or refractory disease; the diagnosis is made based on the following criteria
• JMML category 1 (all of the following): the diagnostic criteria must include all features in category 1 and EITHER (i) one of the features in category 2 OR (ii) two features from category 3 to make the diagnosis
• Splenomegaly
• > 1000 (1 x 10^9/uL) circulating monocytes
• < 20% blasts in the bone marrow or peripheral blood
• Absence of the t(9;22) or BCR/ABL fusion gene
• JMML category 2 (at least one of the following if at least two category 3 criteria are not present):
• Somatic mutation in RAS or PTPN11
• Clinical diagnosis of NF1 or NF1 gene mutation
• Homozygous mutation in CBL
• Monosomy 7
• JMML category 3 (at least two of the following if no category 2 criteria are met):
• Circulating myeloid precursors
• White blood cell count, > 10 000 (10 x 10^9/ uL)
• Increased hemoglobin F for age
• Clonal cytogenetic abnormality
• GM-CSF hypersensitivity
• Patients with refractory or relapsed JMML must have had at least one cycle of intensive frontline therapy or at least 2 cycles of a deoxyribonucleic acid (DNA) demethylating agent with persistence of disease, defined by clinical symptoms or the presence of a clonal abnormality; frontline therapy is defined as one cycle of intravenous chemotherapy that includes of any of the following agents: fludarabine, cytarabine, or any anthracycline but specifically excludes oral 6-mercaptopurine; frontline therapy will also include any conditioning regimen as part of a stem cell transplant; patients who transform to AML at any point with more than 20% blasts are not eligible for this trial
• Patients must have a Lansky or Karnofsky performance status score of >= 50, corresponding to Eastern Cooperative Oncology Group (ECOG) categories 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 have fully recovered from the acute toxic effects of all prior chemotherapy, immunotherapy, or radiotherapy prior to study enrollment
• Myelosuppressive chemotherapy: patients must have completely recovered from all acute toxic effects of chemotherapy, immunotherapy or radiotherapy prior to study enrollment; at least 14 days must have elapsed since the completion of cytotoxic therapy, with the exception of hydroxyurea
• Note: cytoreduction with hydroxyurea can be initiated and continued for up to 24 hours prior to the start of protocol therapy
• Hematopoietic growth factors: at least 14 days after the last dose of a long-acting growth factor (e.g., pegfilgrastim) 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
• Biologic (anti-neoplastic agent): at least 7 days must have elapsed since completion of therapy with a biologic agent; for agents that have known adverse events occurring beyond 7 days after administration, this period prior to enrollment must be extended beyond the time during which adverse events are known to occur
• Monoclonal antibodies:
• At least 30 days after the completion of any type of immunotherapy, e.g. tumor vaccines
• At least 3 half-lives must have elapsed since prior therapy that included a monoclonal antibody
• Radiotherapy:
• >= 2 weeks must have elapsed since local palliative external radiation therapy (XRT) (small port)
• >= 6 months must have elapsed if prior craniospinal XRT was received, if >= 50% of the pelvis was irradiated, or if traumatic brain injury (TBI) was received
• >= 4 weeks must have elapsed if other substantial bone marrow irradiation was given
• Stem cell transplant or rescue without TBI: no evidence of active graft versus (vs.) host disease and >= 3 months must have elapsed since transplant; >= 4 weeks must have elapsed since any donor lymphocyte infusion
• Patients must not be known to be refractory to red blood cell or platelet transfusions
• 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: Maximum serum creatinine (mg/dL)
• 1 month to < 6 months: 0.4 (male) 0.4 (female)
• 6 months to < 1 year: 0.5 (male) 0.5 (female)
• 1 to < 2 years: 0.6 (male) 0.6 (female)
• 2 to < 6 years: 0.8 (male) 0.8 (female)
• 6 to < 10 years: 1 (male) 1 (female)
• 10 to < 13 years: 1.2 (male) 1.2 (female)
• 13 to < 16 years: 1.5 (male) 1.4 (female)
• >= 16 years: 1.7 (male) 1.4 (female)
• Total bilirubin =< 1.5 x upper limit of normal (ULN) for age
• Serum glutamate pyruvate transaminase (SGPT) (alanine aminotransferase [ALT]) =< 3 x ULN (=< 135 U/L) (for the purpose of this study, the ULN for SGPT is 45 U/L)
• Serum albumin >= 2 g/dL
• Shortening fraction of >= 27% by echocardiogram OR ejection fraction of >= 50% by multi-gated acquisition (MUGA)
• Corrected QT (by Bazett's formula [QTcB]) interval < 450 msecs
• Patients must be able to swallow tablets or liquid; use of a nasogastric or gastrostomy (G) tube is also allowed
• Patients who are pregnant or breast-feeding are not eligible for this study as there is yet no available information regarding human fetal or teratogenic toxicities; negative pregnancy tests must be obtained in girls who are post-menarchal; patients of reproductive potential may not participate unless they have agreed to use an effective contraceptive method for the duration of study therapy; women of childbearing potential should be advised to use effective contraception for 4 months after the last dose of trametinib; trametinib may also potentially be secreted in milk and therefore breastfeeding women are excluded; female patients should not breastfeed during treatment with trametinib, and for 4 months following the last dose; male patients must use a condom during intercourse and agree not to father a child during therapy and for 4 months following discontinuation of trametinib to avoid unnecessary exposure of trametinib to the fetus
• Concomitant Medications
• Corticosteroids: patients requiring corticosteroids who have not been on a stable or decreasing dose of corticosteroid for the 7 days prior to enrollment are not eligible; if used to modify immune adverse events related to prior therapy, >= 14 days must have elapsed since last dose of corticosteroid
• Note: hydrocortisone used as a pre-medication to prevent transfusion related reactions is not considered a concomitant corticosteroid
• Investigational drugs: patients who are currently receiving another investigational drug are not eligible
• Anti-cancer agents: patients who are currently receiving other anti-cancer agents are not eligible (except patients receiving hydroxyurea, which may be continued until 24 hours prior to start of protocol therapy)
• Anti-graft versus host disease (GVHD) or agents to prevent organ rejection post-transplant: patients who are receiving cyclosporine, tacrolimus or other agents to prevent either graft-versus-host disease post bone marrow transplant or organ rejection post-transplant are not eligible for this trial
• Cardiac medications: any medications for treatment of left ventricular systolic dysfunction
• Patients who have an uncontrolled infection are not eligible
• Patients who in the opinion of the investigator may not be able to comply with the safety monitoring requirements of the study are not eligible
• Patients with a history of hepatic sinusoid obstructive syndrome (veno-occlusive disease) within the prior 3 months are not eligible
• Patients with a history of or current evidence/risk of retinal vein occlusion (RVO) or central serous retinopathy (CSR) are not eligible
• Patients with a history of RVO or CSR, or predisposing factors to RVO or CSR (e.g., uncontrolled glaucoma or ocular hypertension
• Patients with uncontrolled systemic disease(s) such as hypertension or diabetes mellitus are not eligible; blood pressure must be =< the 95th percentile for age, height, and gender
• Patients with a history of allergic reaction attributed to compounds of similar chemical or biologic composition to the MEK inhibitor, trametinib are not eligible
• Patients with a clinical diagnosis of Noonan syndrome are not eligible; Note: patients with Casitas B-lineage lymphoma (CBL) syndrome, also known as Noonan-like syndrome, are eligible to enroll

• Age ≤6 weeks (≤42 days) at time of dose
• Ability to tolerate thin liquids as demonstrated through a formal bedside swallowing test
• Compound muscle action potential (CMAP) ≥2mV at Baseline; centralized review of CMAP data will be conducted
• Gestational age of 35 to 42 weeks • Patients with pre-symptomatic SMA Type 1 as determined by the following features:
• 2 copies of SMN2 Patients with 2 copies of SMN2 (n ≥12) • Patients with pre-symptomatic SMA Type 2 as determined by the following features:
• 3 copies of SMN2
• Weight at screening visit <2 kg
• Hypoxemia (oxygen saturation <96% awake or asleep without any supplemental oxygen or respiratory support) at the screening visit or for altitudes >1000 m, oxygen saturation <92% awake or asleep without any supplemental oxygen or respiratory support at the screening visit
• Any clinical signs or symptoms at screening or immediately prior to dosing that are, in the opinion of the Investigator, strongly suggestive of SMA
• Tracheostomy or current prophylactic use or requirement of noninvasive ventilatory support at any time and for any duration prior to screening or during the screening period
• Patients with signs of aspiration/inability to tolerate nonthickened liquids based on a formal swallowing test performed as part of screening or patients receiving any non-oral feeding method
• Clinically significant abnormalities in hematology or clinical chemistry parameters as determined by investigator or medical monitor
• Treatment with an investigational or commercial product, including nusinersen, given for the treatment of SMA. This includes any history of gene therapy, prior antisense oligonucleotide treatment, or cell transplantation.
• Patients whose weight-for-age is below the third percentile based on World Health Organization (WHO) Child Growth Standards
• Biological mother with active viral infection as determined by screening laboratory samples (includes human immunodeficiency virus [HIV] or positive serology for hepatitis B or C) • Biological mothers with clinical suspicion of Zika virus that meet Centers for Disease Control and Prevention (CDC) Zika virus epidemiological criteria including history of residence in or travel to a geographic region with active Zika transmission at the time of travel will be tested for Zika virus RNA. Positive results warrant confirmed negative Zika virus RNA testing in the patient prior to enrollment.
• Serious nonrespiratory tract illness requiring systemic treatment and/or hospitalization within 2 Weeks prior to screening
• Upper or lower respiratory infection requiring medical attention, medical intervention, or increase in supportive care of any manner within 4 Weeks prior to dosing
• Severe nonpulmonary/respiratory tract infection within 4 Weeks before administration of gene replacement therapy or concomitant illness that, in the opinion of the Investigator or Sponsor medical monitor, creates unnecessary risks for gene replacement therapy such as:
• Major renal or hepatic impairment
• Known seizure disorder
• Diabetes mellitus
• Idiopathic hypocalciuria
• Symptomatic cardiomyopathy
• Known allergy or hypersensitivity to prednisolone or other glucocorticosteroids or their excipients
• Previous, planned or expected major surgical procedure including scoliosis repair surgery/procedure during the study assessment period
• Concomitant use of any of the following: drugs for treatment of myopathy or neuropathy, agents used to treat diabetes mellitus, or ongoing immunosuppressive therapy, plasmapheresis, immunomodulators such as adalimumab, immunosuppressive therapy within 4 Weeks prior to gene replacement therapy
• AntiAAV9 antibody titer >1:50 as determined by Enzyme-linked Immunosorbent Assay (ELISA) binding immunoassay • Should a potential patient demonstrate AntiAAV9 antibody titer >1:50, he or she may receive retesting inside the 30-Day screening period and will be eligible to participate if the AntiAAV9 antibody titer upon retesting is ≤1:50, provided the <6 Week age requirement at the time of dosing is still met
• Biological mother involved with the care of the child refuses anti-AAV9 antibody testing prior to dosing

1. Age (at the time of consent/assent): ≥6 months to <18 years
•Cohort 4 only: ≥10 years to <18 years 2. Performance Status:
• If <12 years of age: Lanksy Performance Status >50%
• If ≥12 years of age: Karnofsky Performance Status >50% NOTE: If subject is unable to walk due to paralysis, but is mobile in a wheelchair, subject is considered to be ambulatory for the purpose of assessing their performance status. 3. Has provided signed written informed consent/assent 4. Has a life expectancy of >3 months 5. Has relapsed or refractory disease and no standard treatment options as determined by locally or regionally available standards of care and treating physician's discretion 6. Is ineligible or inappropriate for other treatment regimens known to have effective potential 7. Has a documented local diagnostic pathology of original biopsy confirmed by a Clinical Laboratory Improvement Amendments (CLIA)/College of American Pathologists (CAP) or equivalent laboratory certification 8. Has all prior treatment (i.e., chemotherapy, immunotherapy, radiotherapy) related clinically significant toxicities resolve to ≤ Grade 1 per CTCAE, version 4.03 or are clinically stable and not clinically significant, at time of enrollment 9. Has completed a prior therapy (ies) according to the criteria below:
• Other investigational study agent (any medicinal product that is not approved in the country of treatment for any indication, adult or pediatric) (At least 30 days or five half-lives, whichever is longer, since last dose prior to the first dose of tazemetostat)
• Chemotherapy: cytotoxic (At least 14 days since last dose of chemotherapy prior to first dose of tazemetostat)
• Chemotherapy: nitrosoureas (At least 6 weeks since last dose of nitrosoureas prior to first dose of tazemetostat)
• Chemotherapy: non-cytotoxic (e.g., small molecule inhibitor) (At least 14 days since last dose of non-cytotoxic chemotherapy prior to first dose of tazemetostat)
• Monoclonal antibody (ies) (At least 28 days since the last dose of any monoclonal antibody prior to first dose of tazemetostat)
• Immunotherapy (e.g., tumor vaccine) At least 6 weeks since last dose of immunotherapy agent(s) prior to first dose of tazemetostat)
• Radiotherapy (RT) (At least 14 days from last local site RT prior to first dose of tazemetostat/At least 21 days from stereotactic radiosurgery prior to first dose of tazemetostat/At least 12 weeks from craniospinal, ≥ 50% radiation of pelvis, or total body irradiation prior to first dose of tazemetostat)
• Hematopoietic growth factor (At least 14 days from last dose of hematopoietic growth factor prior to first dose of tazemetostat)
• Hematopoietic cell transplantation (At least 60 days from infusion of hematopoietic cells prior to first dose of tazemetostat) 10. Has adequate hematologic (bone marrow and coagulation factors), renal and hepatic function as defined by criteria below:
• Hematologic (BM Function):
• Hemoglobin ≥ 8 g/dL
• Platelets ≥100,000/mm^3 (≥100 x 10^9/L)
• ANC ≥1,000/mm^3 (≥1.0 x 10^9/L)
• Hematologic (Coagulation Factors):
• INR/ PTd ≤1.5 ULN
• PTT ≤1.5 ULN
• Fibrinogen ≥0.75 LLN
• Renal Function (creatinine clearance or serum creatinine):
• Calculated creatinine clearance ≥50 mL/min/1.73m^2
• Serum creatinine 6 months to 1 year: male 0.6 mg/dL (53 µmol/L) female 0.5 mg/dL (44 µmol/L)
• Serum creatinine 1 to < 2 years: male 0.6 mg/dL (53 µmol/L) female 0.6 mg/dL (53 µmol/L)
• Serum creatinine 2 to < 6 years: male 0.8 mg/dL (71 µmol/L) female 0.8 mg/dL (71 µmol/L)
• Serum creatinine 6 to <10 years: male 1 mg/dL (88 µmol/L) female 1 mg/dL (88 µmol/L)
• Serum creatinine 10 to <13 years: male 1.2 mg/dL (106 µmol/L) female 1.2 mg/dL (106 µmol/L)
• Serum creatinine 13 to <16 years: male 1.5 mg/dL (133 µmol/L) female 1.4 mg/dL (125 µmol/L)
• Serum creatinine ≥16 years: male 1.7 mg/dL (150 µmol/L) female 1.4 mg/dL (125 µmol/L)
• Hepatic Function:
• Total bilirubin <1.5 x ULN
• ALT or AST <3 x ULN Eligibility can be determined by either total or conjugated bilirubin 11. For subjects with CNS involvement: Subjects must have deficits that are stable for a minimum of 14 days prior to enrollment, or seizures that are stable, not increasing in frequency or severity and controlled on current anti-seizure medication(s) for a minimum of 7 days prior to enrollment NOTE: Subjects with leptomeningeal disease or brian tumors with positive cerebral spinal fluid cytology are eligible for this study. Subjects may receive glucocorticoids (at stable or tapering dose) to control CNS symptoms prior to enrollment; however, subjects should receive a stable or tapering dose for at least 7 days prior to enrollment. 12. Has a shortening fraction of >27% or an ejection fraction of ≥50% by echocardiogram or multi-gated acquisition scan and New York Heart Association Class<2 13. Has a QT interval corrected by Fridericia's formula (QTcF) ≤450 msec 14. Is able to swallow and retain orally administered medication and does not have any uncontrolled gastrointestinal (GI) condition such as nausea, vomiting, or diarrhea, or any clinically significant GI abnormalities that may alter absorption such as malabsorption syndromes, hereditary fructose intolerance, glucose-galactose malabsorption, sucrose-isomaltase insufficiency, or major resection of stomach and/or bowels NOTE: Nasogastric and gastrostomy tube administration of the oral suspension formulation of study drug is permitted. 15. Has sufficient tumor tissue (slides or blocks) available for central confirmatory testing of immunohistochemistry and/or cytogenetics/fluorescence in situ hybridization (FISH) and/or deoxyribonucleic acid mutation analysis (required for study entry but enrollment based on local results) 16. Is willing and able to comply with all aspects of the protocol as judged by Investigator 17. For female subjects of childbearing potential: Subject must:
• Have a negative beta-human chorionic gonadotropin (β-hCG) pregnancy test at time of Screening and within 72 hours prior to planned first dose of tazemetostat (urine or serum test is acceptable however, positive urine tests must be confirmed with serum testing), and
• Agree to use effective contraception, as defined in Section 8.6.11 start of Screening until 6 months following the last dose of study treatment and have a male partner who uses a condom, or
• Practice true abstinence (when this is in line with the preferred and usual lifestyle of the subject, see Section 8.6.11, or
• Have a male partner who is vasectomized with confirmed azoospermia 18. For male subjects with a female partner of childbearing potential: Subject must:
• Be vasectomized or
• Agree to use condoms as defined in Section 8.5.11 from first dose of tazemetostat until 3 months following the last dose of tazemetostat, or
• Have a female partner who is NOT of childbearing potential For Dose Escalation Only: To be eligible for enrollment in dose escalation, a subject must meet ALL of the following criteria in addition to the inclusion criteria listed above for all subjects: 1. Has evaluable disease as defined as lesions that can be accurately measured at least in one dimension by radiographic examination or physical examination and other lesions such as bone lesions, leptomeningeal disease, ascites, hepatosplenomegaly from disease. 2. Has one of the following histologically confirmed tumors: (NOTE: Evidence of diagnostic pathology of original biopsy confirmed by a CLIA/CAP certified laboratory must be available)
• Rhabdoid tumor:
• ATRT (Closed to enrollment)
• MRT
• RTK
• Selected tumors with rhabdoid features
• NI1-negative tumor:
• Epithelioid sarcoma
• Epithelioid malignant peripheral nerve sheath tumor
• Extraskeletal myxoid chondrosarcoma
• Myoepithelial carcinoma
• Renal medullary carcinoma
• Other INI1-negative malignant tumors (e.g., dedifferentiated chordoma) with Sponsor approval
• Synovial sarcoma with SS18-SSX rearrangement (NOTE: Evidence of diagnostic pathology of original biopsy confirmed by a CLIA/CAP certified laboratory must be available) (Closed to enrollment) 3. For subjects with ATRT, MRT, RTK, or selected tumors with rhabdoid features only: the following test results must be available: Morphology and immunophenotypic panel consistent with rhabdoid tumor and Loss of INI1 or SMARCA4 confirmed by IHC, or Molecular confirmation of tumor bi-allelic INI1 or SMARCA4 loss/mutation when INI1 or SMARCA4 IHC is equivocal or unavailable 4. For subjects with INI1 negative tumor only: the following test results must be available: Morphology and immunophenotypic panel consistent with INI1-negative tumors, and Loss of INI1 confirmed by IHC, or Molecular confirmation of tumor bi-allelic INI1 loss/mutation when INI1 IHC is equivocal or unavailable 5. For subjects with synovial sarcoma only: The following test results must be available: Morphology consistent with synovial sarcoma, and Cytogenetics or FISH and/or molecular confirmation (e.g., DNA sequencing) of SS18 rearrangement t(X;18)(p11;q11) For Dose Expansion Only: Note: To be eligible for enrollment in Dose Expansion, a subject must meet ALL of the following criteria in addition to the inclusion criteria for ALL subjects listed above 1. Has measurable disease 2. Has one of the following histologically confirmed tumors:
• Cohort 1
•ATRT (Closed to enrollment)
• Cohort 2
•MRT/RTK/selected tumors with rhabdoid features
• Cohort 3
•INI-negative tumors:
• Epithelioid sarcoma
• Epithelioid malignant peripheral nerve sheath tumor
• Extraskeletal myxoid chondrosarcoma(EMC)
• Myoepithelial carcinoma
• Renal medullary carcinoma
• Chordoma (poorly differentiated or de-differentiated)
• Other INI1-negative malignant tumors (e.g., dedifferentiated chordoma) with Sponsor approval
• Cohort 4
•Tumor types eligible for Cohorts 1 through 3 or synovial sarcoma with SS18-SSX rearrangement (Closed to enrollment) NOTE: Evidence of diagnostic pathology of original biopsy confirmed by a CLIA/CAP or other Sponsor-approved certified laboratory must be available. 3. For subjects with ATRT/MRT/RTK only
•have the following test results available:
• Morphology and immunophenotypic panel consistent with rhabdoid tumor, and
• Loss of INI1 or SMARCA4 confirmed by IHC, or
• Molecular confirmation of tumor bi-allelic INI1 or SMARCA4 loss/mutation when INI1 or SMARCA4 IHC is equivocal or unavailable 4. For subjects with INI1-negative tumors only: The following test results must be available:
• Morphology and immunophenotypic panel consistent with INI1-negative tumors, and
• Loss of INI1 confirmed by IHC, or
• Molecular confirmation of tumor bi-allelic INI1 loss/mutation when INI1 IHC is equivocal or unavailable 5. For subjects with synovial sarcoma with SS18-SSX rearrangement (in Cohort 4 ONLY - Closed to enrollment): The following test results must be available:
• Morphology consistent with synovial sarcoma, and
• Cytogenetics or FISH and/or molecular confirmation (e.g., deoxyribonucleic acid [DNA] sequencing) of SS18 rearrangement t(X;18)(p11;q11) 6. For subjects to be enrolled in Cohort 4 (Closed to enrollment): Able to swallow and retain orally administered tablets 1. Has had prior exposure to tazemetostat or other inhibitor(s) of EZH2 2. Is being actively treated for another concurrent malignancy or is less than five years from completion of treatment for another malignancy 3. Has participated in another interventional clinical study and received investigational drug within 30 days or 5 half-lives, whichever is longer, prior to the planned first dose of tazemetostat 4. Has had major surgery within 2 weeks prior to enrollment NOTE: Minor surgery (e.g., minor biopsy of extracranial site, central venous catheter placement, shunt revision) is permitted within 2 weeks prior to enrollment. 5. Has thrombocytopenia, neutropenia, or anemia of Grade ≥3 (per CTCAE 4.03 criteria) or any prior history of myeloid malignancies, including myelodysplastic syndrome (MDS). Has abnormalities known to be associated with MDS (e.g. del 5q, chr 7 abn) and MPN (e.g. JAK2 V617F) observed in cytogenetic testing and DNA sequencing. Note: Bone marrow aspirate/biopsy will be conducted following abnormal peripheral blood smear morphology assessment conducted by central lab at screening. Cytogenetic testing and DNA sequencing will be conducted following an abnormal result of bone marrow aspirate/biopsy. 6. Has a prior history of T-LBL/T-ALL. 7. Has clinically active heart disease including prolonged corrected QTcF (>450 msec) 8. Is currently taking any prohibited medication(s) as described in Section 7.3. 9. Is unwilling to exclude grapefruit juice, Seville oranges and grapefruit from the diet and all foods that contain those fruits from time of enrollment to while on study 10. Has an active infection requiring systemic treatment 11. Is immunocompromised (i.e. congenital immunodeficiencies), including subjects known history of infection with human immunodeficiency virus (HIV) 12. Has known history of chronic infection with hepatitis B virus (hepatitis B surface antigen positive) or hepatitis C virus (detectable HCV RNA) 13. Has had a symptomatic venous thrombosis within the 14 days prior to study enrollment NOTE: Subjects with a history of a deep vein thrombosis 14 days prior to study enrollment who are on anticoagulation therapy with low molecular weight heparin are eligible for this study 14. For subjects with CNS involvement (primary tumor or metastatic disease): Have any active bleeding, or new intratumoral hemorrhage of more than punctate size on Screening MRI obtained within 14 days of starting study drug,or known bleeding diathesis or treatment with anti-platelet or anti-thrombotic agents 15.15. Has known hypersensitivity to any of the components of tazemetostat or other inhibitor(s) of EZH2, or hypersensitivity to Ora-sweet or methylparaben 16. Has an uncontrolled intercurrent illness including, but not limited to, uncontrolled infection, or psychiatric illness/social situations that would limit compliance with study requirements 17. For female subjects of childbearing potential: Is pregnant or nursing For male subjects: Is unwilling to adhere to contraception criteria from time of enrollment in study to at least 30 days after last dose of tazemetostat.

INCLUSION CRITERIA -Patients must be greater than or equal to 12 months and ≤ 21 years of age at the time of study enrollment. Patients must have one of the following: Leukemia
• Patients must have relapsed or refractory acute lymphoblastic leukemia (ALL) with greater than or equal to 25% blasts in the bone marrow (M3). OR
• Patients may have an M2 marrow (greater than or equal to 5% to < 25% blasts) with an extramedullary site of relapse; including CNS 2 and CNS 3.
• Refractory disease defined as no more than 1 prior failed salvage attempt following the current relapse, or no more than 2 additional treatment cycles after initial induction failure in newly diagnosed patients. Lymphoma
• Patient must have relapsed or refractory lymphoblastic lymphoma or peripheral T-cell lymphoma.
• Patient must have histologic verification of disease at original diagnosis.
• Patient must have evaluable or measurable disease documented by clinical or radiographic criteria or bone marrow disease present at study entry.
• Patients may have CNS 2 or 3 disease, if other sites of involvement. Karnofsky greater than or equal to 50% for patients > 16 years of age and Lansky greater than or equal to 50 for patients ≤ 16 years of age. Patients must have fully recovered from the acute toxic effects of all prior anti-cancer chemotherapy. Patients must have had 2 or more prior therapeutic attempts defined as:
• Relapse after going into remission from re-induction for the first or subsequent relapse (ie: 2nd , 3rd, 4th…relapse), or
• Patients with lymphoma may have refractory disease after first or greater relapse and a single re-induction attempt. Patients with leukemia or lymphoma who relapse while receiving maintenance chemotherapy will not be required to have a waiting period before enrollment onto this study. At least 14 days must have elapsed after the completion of cytotoxic therapy, with the exception of hydroxyurea. Hematopoietic growth factors: At least 14 days after the last dose of a long-acting growth factor (e.g. Neulasta) or 7 days for short-acting growth factor. Biologic (anti-neoplastic agent): At least 7 days after 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 Immunotherapy: At least 42 days after the completion of any type of immunotherapy, e.g. tumor vaccines. or chimeric antigen receptor T cell (CART) therapy. Monoclonal antibodies: At least 3 half-lives of the antibody must have elapsed after the last dose of a monoclonal antibody. (ie: Rituximab = 66 days, Epratuzumab = 69 days). Patients must have been off blinatumomab infusion for at least 7 days and all drug-related toxicity must have resolved to grade 2 or lower as outlined in the inclusion and exclusion criteria XRT: At least 14 days after local palliative XRT (small port); At least 84 days must have elapsed if prior TBI, craniospinal XRT or if greater than or equal to 50% radiation of pelvis; At least 42 days must have elapsed if other substantial marrow radiation. Stem Cell Infusion: No evidence of active graft vs. host disease and at least 84 days must have elapsed after transplant or stem cell infusion. Study specific limitations on prior therapy: Patient may not have received therapy with an mTOR inhibitor. Adequate Bone Marrow Function Defined as: Blood counts are not required to be normal prior to enrollment on trial. However, platelet count must be greater than or equal to 20,000/mm3 to initiate therapy (may receive platelet transfusions). Patients should not be known to be refractory to red blood cell or platelet transfusions. Adequate Renal Function Defined as:
• Creatinine clearance or radioisotope GFR greater than or equal to 70ml/min/1.73 m2 or
• Normal serum creatinine based on age and gender. Adequate Liver Function Defined as:
• Total bilirubin (sum of conjugated + unconjugated) must be less than or equal to 1.5 x normal per institutional normal values for age.
• SGPT (ALT) and SGOT (AST) must be less than 3 x institutional upper limit of normal (Grade 1 or less per CTCAE 4). --GGT must be less than 2.5 x institutional upper limit of normal (Grade 1 or less per CTCAE 4).
• Serum albumin greater than or equal to 2 g/dL.
• The hepatic requirements may be waived for patients with elevations clearly due to leukemic infiltration after consultation with the Study Chair or Vice Chair.
• Fasting or non-fasting serum triglyceride level ≤ 300 mg/dL and serum cholesterol level ≤ 300 mg/dL. Adequate Cardiac Function Defined As:
• Shortening fraction of ≥ 27% by echocardiogram, or
• Ejection fraction of ≥ 50% by gated radionuclide study. Adequate Pulmonary Function Defined as:
• Pulse oximetry > 94% on room air (> 90% if at high altitude)
• No evidence of dyspnea at rest and no exercise intolerance.
• Baseline chest x-ray with no evidence of active infectious disease or pneumonitis. Reproductive Function
• Female patients of childbearing potential must have a negative urine or serum pregnancy test confirmed prior to enrollment.
• Female patients with infants must agree not to breastfeed their infants while on this study.
• Male and female patients of child-bearing potential must agree to use an effective method of contraception approved by the investigator during the study.
• Random or fasting glucose within the upper limits of normal for age. If the initial blood glucose is non-fasting and above normal limits a fasting glucose can be obtained and must be within the upper limits of normal for age. EXCLUSION CRITERIA
• Corticosteroids: Patients receiving corticosteroids who have not been on a stable or decreasing dose of corticosteroid for at least 7 days prior to enrollment are not eligible.
• Investigational Drugs: Patients who are currently receiving another investigational drug are not eligible. The definition of "investigational" for use in this protocol means any drug that is not licensed by the FDA, Health Canada or the Therapeutic Goods Administration to be sold in the countries they govern. (United States, Canada and Australia)
• Anti-cancer Agents: Patients who are currently receiving or may receive while on therapy, other anti-cancer agents, radiation therapy or immunotherapy are not eligible [except leukemia patients receiving hydroxyurea, which may be continued until 24 hours prior to start of protocol therapy]. Intrathecal chemotherapy (at the discretion of the primary oncologist) may be given up to one week prior to the initiation of study therapy.
• Anti-GVHD or agents to prevent organ rejection post-transplant: Patients who are receiving cyclosporine, tacrolimus or other agents to prevent either graft-versus-host disease post bone marrow transplant or organ rejection post transplant are not eligible for this trial. At least 3 half-lives must have elapsed after the last dose of GVHD meds.
• Anticoagulants: Patients who are currently receiving therapeutic anticoagulants (including aspirin, low molecular weight heparin, and others) are not eligible. At least 3 half-lives must have elapsed after the last dose of anticoagulants.
• Angiotensin-converting enzyme (ACE) inhibitors: Patients who are currently receiving ACE inhibitors are not eligible due to the development of angioneurotic edema-type reactions in some subjects who received concurrent treatment with temsirolimus + ACE inhibitors. At least 3 half-lives must have elapsed after the last dose of ACE inhibitors.
• Enzyme inducing Anti-convulsants: Patients who are currently receiving enzyme inducing anticonvulsants (ie phenytoin, phenobarbitol, or carbamazepine) are not eligible. Stabilizing on a non-hepatic inducing metabolizing anti-convulsant (ie: gabapentin or levetiracetam) prior to study entry is acceptable. At least 3 half-lives must have elapsed after the last dose of enzyme inducing anti-coagulants.
• Patients receiving treatment with azoles such as fluconazole or voriconazole which are potent inhibitors of temsirolimus metabolism. At least 3 half-lives must have elapsed after the last dose of azoles. Infection Criteria Patients are excluded if they have:
• Positive blood culture within 48 hours of study enrollment;
• Fever above 38.2 within 48 hours of study enrollment with clinical signs of infection. Fever that is determined to be due to tumor burden is allowed if patients have documented negative blood cultures for at least 48 hours prior to enrollment and no concurrent signs or symptoms of active infection or hemodynamic instability.
• A positive fungal culture within 30 days.
• Active fungal, viral, bacterial, or protozoal infection requiring IV treatment. Chronic prophylaxis therapy to prevent infections is allowed. Patients with Down syndrome and Fanconi Anemia are excluded. Patients will be excluded if they have significant concurrent disease, illness, psychiatric disorder or social issue that would compromise patient safety or compliance with protocol treatment or required observations, interfere with consent, study participation, follow up, or interpretation of study results. Patients with known optic nerve and/or retinal involvement (because it may not be possible to safely delay irradiation) are not eligible. Patients presenting with visual disturbances by history or physical exam should have an ophthalmological exam and, if indicated, an MRI to determine optic nerve or retinal involvement.

Inclusion Criteria 1. Subjects ≥ 6 years of age at time of Informed Consent Form (ICF) or Assent Form signing. 2. Confirmed diagnosis of CF, determined by having clinical features consistent with the CF phenotype, plus one of the following: 1. Positive sweat chloride test (value ≥ 60 mEq/L), 2. Genotype with 2 mutations consistent with CF (i.e., a mutation in each of the cystic fibrosis transmembrane conductance regulator [CFTR] genes). 3. Positive sputum culture or a throat swab culture for MRSA at Screening. 4. In addition to the Screening sample, have at least 2 prior sputum or throat swab cultures positive for MRSA, of which at least 1 sample is more than 6 months prior to Screening. At least 50% of all MRSA cultures (sputum or throat swab culture) collected from the time of the first positive culture (in the previous 1 year) must have tested positive for MRSA. (Note: Screening sample may count towards 50% positive count) 5. Forced expiratory volume in 1 second (FEV1) ≥ 30% and ≤ 90% of predicted that is normal for age, gender, race, and height, using the Global Lung Function Initiative (GLI) equation. 6. At least 1 episode of acute pulmonary infection treated with non-maintenance antibiotics within 12 months prior to the Baseline visit. (Initiation of treatment with intermittent inhaled anti-Pseudomonal therapy will not qualify as treatment with non-maintenance antibiotics). 7. If female of childbearing potential, an acceptable method of contraception must be used during the study and must be combined with a negative pregnancy test obtained during Screening; sexually active male subjects of reproductive potential who are non-sterile (i.e., male who has not been sterilized by vasectomy for at least 6 months, and were not diagnosed with infertility through demonstration of azoospermia in a semen sample and/or absence of vas deferens through ultrasound) must be willing to use a barrier method of contraception, or their female partner must use an acceptable method of contraception, during the study. For purposes of this study, the Sponsor defines "acceptable methods of contraception" as: 1. Oral birth control pills administered for at least 1 monthly cycle prior to administration of the study drug. 2. A synthetic progestin implanted rod (eg, Implanon®) for at least 1 monthly cycle prior to the study drug administration but not beyond the 4th successive year following insertion. 3. Intrauterine devices (IUDs), inserted by a qualified clinician for at least 1 monthly cycle prior to study drug administration. 4. Medroxyprogesterone acetate (eg, Depo-Provera®) administered for a minimum of 1 monthly cycle prior to administration of the study drug and continuing through 1 month following study completion. 5. Hysterectomy or surgical sterilization. 6. Abstinence. 7. Double barrier method (diaphragm with spermicidal gel or condoms with contraceptive foam). NOTE: For subjects prescribed Orkambi: Orkambi may substantially decrease hormonal contraceptive exposure, reducing the effectiveness and increasing the incidence of menstruation-associated adverse reactions. Hormonal contraceptives, including oral, injectable, transdermal, and implantable, should not be relied upon as an effective method of contraception when co-administered with Orkambi. 8. Able and willing to comply with the protocol, including availability for all scheduled study visits and able to perform all techniques necessary to use the AeroVanc inhaler and measure lung function. 9. Agree not to smoke during any part of the clinical trial (Screening visit through end of study). 10. Subjects with a P. aeruginosa co-infection must either be stable on a regular suppression regimen of inhaled antibiotics or must be, in the opinion of the Investigator, stable despite the lack of such treatment. Exclusion Criteria 1. Use of anti-MRSA treatments prescribed as maintenance therapy (intravenous [IV] or inhaled treatment within 28 days; oral treatment within 14 days) prior to the Baseline visit. 2. Use of non-maintenance antibiotic for pulmonary infection or extrapulmonary MRSA infection (IV or inhaled antibiotic within 28 days; oral antibiotic within 14 days) prior to the Baseline visit. 3. History of previous allergies or sensitivity to vancomycin, or other component(s) of the study drug or placebo except for a history of red-man syndrome. 4. Inability to tolerate inhaled products. 5. First time sputum culture or throat swab culture yielding B. cepacia, or nontuberculous Mycobacteria in the previous 6 months to Screening. 6. History of lung or other solid organ transplantation or currently on the list to receive lung or other solid organ transplantation. 7. Resistance to vancomycin at Screening (vancomycin resistant Staphylococcus aureus [VRSA], or vancomycin intermediate resistant Staphylococcus aureus [VISA], with minimum inhibitory concentration [MIC] ≥ 8 μg/mL). 8. Oral corticosteroids in doses exceeding 10 mg prednisone per day or 20 mg prednisone every other day, or equipotent doses of other corticosteroids. 9. Changes in antimicrobial, bronchodilator, anti-inflammatory or corticosteroid medications within 14 days, or changes in CFTR modulators within 28 days, prior to the Baseline visit. 10. Abnormal laboratory findings or other findings or medical history at Screening that, in the Investigator's opinion, would compromise the safety of the subject or the quality of the study data. 11. Inability to tolerate inhalation of a short acting beta2 agonist 12. SpO2 <90% at Screening. 13. Changes in physiotherapy technique or physiotherapy scheduled within 1 week of the Baseline visit. 14. Administration of any investigational drug or device within 4 weeks prior to the Screening visit and during the study 15. Female with positive pregnancy test result during Screening, pregnant (or intends to become pregnant), lactating or intends to breastfeed during the study. 16. Renal insufficiency, defined as creatinine clearance < 50 mL/min using the Cockcroft-Gault equation for adults or Schwartz equation for children at the Screening visit. 17. Abnormal liver function, defined as ≥ 4x upper limit of normal (ULN), of serum aspartate aminotransferase (AST) or serum alanine aminotransferase (ALT), or known cirrhosis at Screening. 18. Diagnosed with clinically significant hearing loss. 19. History of positive result for human immunodeficiency virus (HIV), hepatitis B virus (HBV) or hepatitis C virus (HCV). 20. Planned hospitalizations for prophylaxis antibiotic treatment within 28 days prior to Baseline visit or during the double-blind period (Period 1).

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. 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);
• 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. 7. Measurable disease as defined by RECIST version 1.1 or modified RANO criteria for CNS disease or INRC for neuroblastoma. 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. 10. Evidence of a personally signed and dated informed consent document indicating that the patient or a legally acceptable representative/parent(s)/legal guardian of minors, has been informed of all pertinent aspects of the study. Minor study patients also must provide age appropriate assent according to the local guidelines, where applicable. 11. Willing and able to comply with scheduled visits, treatment plan, laboratory tests, and other procedures. Exclusion: 1. 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. 2. Prior intolerability to IRN and/or TMZ, for palbociclib with IRN and TMZ combination and prior intolerability to TOPO and/or CTX for palbociclib with 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. Prior growth factors (including filgrastim) within 7 days before study entry or PEG-filgrastim within 14 days before study entry. 5. Radiation therapy within 14 days before study entry. 6. Systemic anti cancer therapy within 2 weeks prior to study entry and 6 weeks for nitrosoureas. 7. Previous high dose chemotherapy requiring stem cell rescue within 90 days or persistent AE >Grade 1. 8. Prior irradiation to >50% of the bone marrow (see Appendix 9). 9. Participation in other studies involving investigational drug(s) within 2 weeks or 5 half lives, whichever is longer, prior to study entry. 10. Major surgery within 4 weeks prior to study entry. Surgical biopsies or central line placement are not considered major surgeries. 11. Known or suspected hypersensitivity to palbociclib, IRN and/or TMZ. 12. 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. 13. 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. 14. Hereditary bone marrow failure disorder. 15. QTc >470 msec. 16. 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%. 17. Recent or ongoing clinically significant gastrointestinal disorder that may interfere with absorption of orally administered drugs (eg, gastrectomy). 18. Evidence of serious active or uncontrolled bacterial, fungal or viral infection or known history of hepatitis B virus, hepatitis C virus, or human immunodeficiency virus infection or acquired immunodeficiency syndrome-related illness. 19. Other 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. 20. 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. 21. Fertile male patients and female patients of childbearing potential who are unwilling or unable to use a highly effective method of contraception as outlined in this protocol for the duration of the study and for at least 90 after the last dose of investigational product.

• 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

• Age 5 through 21 years old at the time of screening for Cohorts 1 and 2; Age ≥2 years old at the time of screening for Cohort 3.
• Documented diagnosis of 5q SMA.
• Diagnosed as later-onset (e.g., Type 2 or Type 3) SMA prior to receiving any treatment with therapy approved for SMA.
• Non-ambulatory patients must be able to sit independently (sits up straight with head erect for at least 10 seconds; does not use arms or hands to balance body or support position) per World Health Organization (WHO) motor milestones definition at screening.
• Ambulatory patients must have the ability to independently ambulate without aids or orthotics over 10 meters in 30 seconds or less at screening.
• Receiving the same background SMA therapy (e.g., on an approved survival motor neuron (SMN) upregulator therapy such as nusinersen, or not on any SMA therapy) for at least 6 months prior to screening and anticipated to remain on that therapy throughout the duration of the study.
• If receiving the SMN upregulator therapy nusinersen, must have completed the loading regimen and initiated maintenance dosing (i.e., completed at least one maintenance dose) with at least 4 weeks after the first maintenance dose having elapsed prior to screening.
• Nutritional status stable over the past 6 months and anticipated to be stable throughout the duration of the study.
• Have no physical limitations that would prevent the patient from undergoing motor function outcome measures throughout the duration of the study.
• Able to receive study drug infusions and provide blood samples through the use of a peripheral intravenous (IV) or a long-term IV access device that the patient has placed for reasons independent from the study throughout the duration of the study.
• Able to adhere to the requirements of the protocol, including travel to the study center and completing all study procedures and study visits.
• For patients who are expected to have reached reproductive maturity by the end of the study, adhere to study specific contraception requirements.
• Use of tracheostomy with positive pressure.
• Use of chronic daytime non-invasive ventilatory support for >16 hours daily in the 2 weeks prior to dosing, or anticipated to regularly receive such daytime ventilator support chronically over the duration of the study.
• Any acute or co-morbid condition interfering with the well-being of the patient within 14 days of screening, including active systemic infection, the need for acute treatment or inpatient observation due to any reason.
• Severe scoliosis and/or contractures at screening. Based on clinical judgement, any scoliosis or contractures present must be stable over the past 6 months, anticipated to be stable for the duration of the study and not prevent the patient from being evaluated on any functional outcome measures throughout the duration of the study.
• Pregnant or breastfeeding.
• Major orthopedic or other interventional procedure, including spine or hip surgery, considered to have the potential to substantially limit the ability of the patient to be evaluated on any functional outcome measures, within 6 months prior to screening, or anticipated for the duration of the study.
• Prior history of a hypersensitivity reaction to a monoclonal antibody (mAb) or recombinant protein bearing an Fc domain (such as a soluble receptor- Fc fusion protein).
• Use of systemic corticosteroids within 60 days prior to screening. Inhaled or topical steroids are allowed.
• Treatment with investigational drugs within 3 months prior to screening.
• Use of therapies with potentially significant muscle effects (such as androgens, insulin-like growth factor, growth hormone, systemic betaagonist, botulinum toxin, or muscle relaxants) or muscle-enhancing supplements within 60 days prior to screening.
• Patient has any other condition, which in the opinion of the Investigator may compromise safety or compliance, would preclude the patient from successful completion of the study, or interfere with the interpretation of the results.

Key
• Subject has a confirmed diagnosis of CF and is heterozygous for F508del and either a gating or residual function mutation (F/G and F/RF genotypes)
• Forced expiratory volume in 1 second (FEV1) value ≥40% and ≤90% of predicted mean for age, sex, and height Key
• Clinically significant cirrhosis with or without portal hypertension
• Lung infection with organisms associated with a more rapid decline in pulmonary status
• Solid organ or hematological transplantation Other protocol defined Inclusion/Exclusion criteria may apply

• 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 7 days prior to enrollment
• Corrected QT (QTc) interval =< 450 msec by electrocardiography (EKG) within 7 days 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

Key
• Subjects From Study VX16-809-122 Part B (Study 122)
• Completed the 24-week Treatment Period and the Safety Follow-up Visit in Study 122B
• Subjects Not From Study 122
• Subjects will be 1 to less than 2 years of age
• Homozygous for the F508del mutation (F/F) Key
• Any clinically significant laboratory abnormalities that would interfere with the study assessments or pose an undue risk for the subject
• Solid organ or hematological transplantation Other protocol defined Inclusion/Exclusion criteria may apply.