Brigatinib in Pediatric and Young Adult Patients With ALK+ ALCL, IMT or Other Solid Tumors

This is an open-label, phase I-II dose-escalation and expansion study designed to define the recommended dose of brigatinib as monotherapy in pediatric and young adult patients with ALK+ ALCL, IMT or other solid tumors and to evaluate the pharmacokinetics (PK), (long-term) safety, and efficacy of brigatinib in these children.

Phase 1 part will be a dose escalation part using a rolling-6 design, aiming to accrue a minimum of 6 and a maximum of 18 evaluable patients in two dose-levels (and minus 1), at least 2/3 of included patients will be ≤18 years.

Phase 2 will be the tumor cohort expansion part of the study to further evaluate the safety, tolerability, and clinical activity/efficacy of brigatinib as monotherapy in two tumor-specific cohorts:

* Cohort B1: ALK+ IMT Planned sample size for Phase 2 is 12 patients with IMT. Patients who are included in the monotherapy Phase 1 IMT dose-escalation portion of the study will be included in the expansion cohort analysis if they receive the RP2D, and will count towards the total sample size of 12 patients. * Cohort B2: ALK+ ALCL Planned sample size for Phase 2 is 22 patients with ALCL. Patients who are included in the monotherapy Phase 1 ALCL dose-escalation portion of the study will be included in the expansion cohort analysis if they receive the RP2D, and will count towards the total sample size of 22 patients.