Study of RXDX-101 in Children With Recurrent or Refractory Solid Tumors and Primary CNS Tumors, With or Without TRK, ROS1, or ALK Fusions

1. Disease status:

• Phase 1 portion (closed): Participants must have measurable or evaluable disease, as defined by RECIST v1.1
• Phase 2 portion:
• Part B: Participants must have measurable or evaluable disease, as defined by RANO
• Part C (closed): Participants must have measurable or evaluable disease, as defined by RECIST v1.1 ± Curie Scale
• Part D: Participants must have measurable or evaluable disease, as defined by RECIST v1.1
• Part E (closed): Participants must have measurable or evaluable disease, as defined by RECIST v1.1 ± Curie Scale or RANO

2. Tumor type:

• Phase 1 portion:

* Part A: Relapsed or refractory extracranial solid tumors

• Phase 2 portion
• Part B: Primary brain tumors with NTRK1/2/3 or ROS1 gene fusions; gene fusions are defined as those predicted to translate into a fusion protein with a functional TRKA/B/C or ROS1 kinase domain, without a concomitant second oncodriver as determined by a nucleic acid-based diagnostic testing method
• Part D: Extracranial solid tumors (including NB) with NTRK1/2/3 or ROS1 gene fusions; gene fusions are defined as those predicted to translate into a fusion protein with a functional TRKA/B/C or ROS1 kinase domain, without a concomitant second oncodriver as determined by a nucleic acid-based diagnostic testing method

3. Histologic/molecular diagnosis of malignancy at diagnosis or the time of relapse

4. Archival tumor tissue from diagnosis or, preferably, at relapse

5. Performance status: Lansky or Karnofsky score ≥ 60% and minimum life expectancy of at least 4 weeks

6. Prior therapy: Participants must have a disease that is locally advanced, metastatic, or where surgical resection is likely to result in severe morbidity, and who have no satisfactory treatment options for solid tumors and primary CNS tumors that are neurotrophic tyrosine receptor kinase (NTRK) or ROS1 fusion-positive

7. Participants must have recovered from the acute toxic effects of all prior chemotherapy, immunotherapy, or radiotherapy prior to enrollment

8. Adequate organ and neurologic function

9. Females of childbearing potential must have a negative serum pregnancy test during screening and be neither breastfeeding nor intending to become pregnant during study participation. Agreement to remain abstinent or use use combined contraceptive methods prior to study entry, for the duration of study participation and in the following 90 days after discontinuation of study treatment.

10. For male participants with a female partner of childbearing potential or a pregnant female partner: Agreement to remain abstinent or use a condom during the treatment period and for at least 3 months after the last dose of study drug

1. Receiving other experimental therapy

2. Known congenital long QT syndrome

3. History of recent (3 months) symptomatic congestive heart failure or ejection fraction ≤50% at screening

4. Known active infections

5. Familial or personal history of congenital bone disorders, bone metabolism alterations or osteopenia

6. Receiving Enzyme Inducing Antiepileptic Drugs (EIAEDs) within 14 days of first dose.

7. Prior treatment with approved or investigational TRK or ROS1 inhibitors

8. Known hypersensitivity to entrectinib or any of the other excipients of the investigational medicinal product

9. Patients with NB with bone marrow space-only disease

10. Incomplete recovery from acute effects of any surgery prior to treatment.

11. Active gastrointestinal disease or other malabsorption syndromes that would impact drug absorption.

12. Other severe acute or chronic medical or psychiatric condition or lab abnormality that may increase the risk associated with study participation, drug administration or may interfere with the interpretation of study results.