The study consists of Phase I -part A (dose finding) and Phase I - part B (multiple expansion cohorts). Phase II may begin after evaluation of Phase I data (safety, tolerability, efficacy, pharmacokinetics and biomarker data), with consideration of other emerging data that may impact on the treatment landscape, before initiating Phase II in patients with relapsed or refractory NB and/or other tumors studied in Phase I.~Phase I-Part A (dose finding): a dose finding to determine the maximum tolerated dose (MTD) and/or recommended Phase II dose (RP2D) of ribociclib in combination with TOTEM.~Phase I- Part B (multiple expansion cohorts): it will be initiated to confirm RP2D identified from Phase I-part A. Multiple expansion cohorts have been planned to assess the preliminary antitumor activity and safety of ribociclib in combination with TOTEM in participants with r/r NB (cohort 1), MB (cohort 2), HGG (cohort 3), MRT (cohort 4), and RMS (cohort 5)~Phase II- Double-blind, randomized, placebo controlled in r/r NB: It is a two-arm randomized, double blinded, placebo controlled, parallel group trial in participants with r/r NB.
This is a Phase I/II study to assess the efficacy and safety of ribociclib in combination with topotecan and temozolomide (TOTEM) in pediatric patients with relapsed or refractory (r/r) neuroblastoma (NB), and other solid tumors, including medulloblastoma (MB), high-grade glioma (HGG), malignant rhabdoid tumors (MRT), and rhabdomyosarcoma (RMS).