Palbociclib Isethionate in Treating Younger Patients With Recurrent, Progressive, or Refractory Central Nervous System Tumors

PRIMARY OBJECTIVES: I. To determine the maximum tolerated dose (MTD)/phase II recommended dose and describe toxicities related to PD-0332991 (palbociclib isethionate) in children with retinoblastoma protein 1 (Rb1) positive recurrent, progressive or refractory primary central nervous system (CNS) tumors. II. To determine plasma pharmacokinetics of PD-0332991 in children with Rb1positive recurrent, progressive or refractory primary CNS tumors. SECONDARY OBJECTIVES: I. To record preliminary evidence of efficacy of PD-0332991 in children with recurrent CNS tumors. II. To evaluate cyclin-dependent kinase (CDK)4/6, cyclin D1-3, Ink4a-ARF copy-number variations in available tumor tissue by array comparative, genomic hybridization (aCGH). III. To explore the potential relationships between the pharmacokinetics of PD-0332991 and pharmacodynamic response (e.g. percentage change in absolute neutrophil count \[ANC\], platelet counts). IV. To explore the pharmacogenetic polymorphisms in PD-0332991 metabolizing enzymes and transporters and relate these polymorphisms to PD-0332991 pharmacokinetics. OUTLINE: This is a dose-escalation study. Patients receive palbociclib isethionate orally (PO) once daily (QD) on days 1-21. Treatment repeats every 4 weeks for 26 courses in the absence of disease progression or unacceptable toxicity. After completion of study treatment, patients are followed up for 30 days.