Ribociclib and Everolimus in Treating Children With Recurrent or Refractory Malignant Brain Tumors

PRIMARY OBJECTIVES: I. To estimate the maximum tolerated dose (MTD) and/or the recommended phase II dose (RP2D) of ribociclib and everolimus in children with refractory or recurrent central nervous system (CNS) tumors. (Phase I) II. To describe the toxicity profile and define the dose-limiting toxicities (DLTs) of ribociclib and everolimus in children with refractory or recurrent CNS tumors. (Phase I) III. To characterize the pharmacokinetics of ribociclib and everolimus in children with refractory or recurrent CNS tumors, and the potential for drug-drug interactions between the two compounds in this population. (Phase I) IV. To characterize ribociclib concentrations in tumor, and plasma in children with refractory or recurrent CNS malignancies undergoing neurosurgical procedures. (Surgical Study) SECONDARY OBJECTIVES: I. To describe the response rate of relapsed and refractory malignant brain tumors to ribociclib and everolimus in the context of a phase I study. (Phase I) II. To explore the effect of ribociclib treatment on Ki-67 by immunohistochemistry (IHC) by comparing archival and post-treatment tumor tissue. (Surgical Study) TERTIARY OBJECTIVES: I. To increase knowledge of the genomic landscape of treatment-refractory pediatric CNS tumors, including mechanisms of resistance and response. OUTLINE: This is a dose-escalation study. Patients receive ribociclib orally (PO) once daily (QD) on days 1-21 of course 1 and subsequent courses and days 2-21 of course 2, and everolimus PO QD on days 3-28 of course 1 and days 1-28 of subsequent courses. Patients who are undergoing surgery also receive ribociclib PO QD on days 7-10 before surgery. Treatment repeats every 28 days for up to 13 courses in the absence of disease progression or unacceptable toxicity. Patients with stable disease after 13 courses may continue receiving ribociclib and everolimus every 28 days for up to 13 additional courses in the absence of disease progression or unacceptable toxicity. After completion of study treatment, patients are followed up at 30 days.