The study will consist of 4 parallel groups of participants, one for each of the following primary brain tumor types: high-grade glioma, medulloblastoma, ependymoma and DIPG. A Simon's Optimal two-stage study design will be applied to each group and enrollment will occur as follows:~Stage 1: Nine participants will be enrolled in each brain tumor type group~Stage 2: If during Stage 1, ≥ 2 participants achieves either an objective response (either complete response or partial response) within the first 6 cycles of treatment (or within the first 3 cycles for DIPG participants), or a long-term stable disease, an additional 11 participants shall be enrolled; otherwise no additional participants will be enrolled into that group.~If a total of 5 or more participants across all 20 participants in a given group (Stage 1 and 2) evaluable for the primary endpoint are observed as having either an objective response (either complete response or partial response) within the first 6 cycles of treatment (or within the first 3 cycles for DIPG participants) or a long-term stable disease, pomalidomide will be considered effective in that disease indication.~Once treatment has been discontinued, participants will be followed up for up to 5 years from enrollment of the last participant.~Participants who withdraw from either stage for reasons other than disease progression prior to completing Cycle 1 of study treatment will be replaced.
This study will assess the efficacy, safety and tolerability of pomalidomide in children and young adults aged 1 to < 21 years with recurrent or progressive primary brain tumors in one of four primary brain tumor types: high-grade glioma (HGG), medulloblastoma, ependymoma and diffuse intrinsic pontine glioma (DIPG).