Study of Safety and Efficacy in Patients With Malignant Rhabdoid Tumors (MRT) and Neuroblastoma

Inclusion Criteria: * Confirmed diagnosis of MRT or, neuroblastoma or in dose escalation part, other tumors with documented evidence of D-cyclin-CDK4/6-INK4a-Rb pathway abnormalities (dose escalation part only), * Patients with CNS disease should be on stable doses of steroids for at least 7 days prior to first dose of LEE011 with no plans for escalation. * In expansion part, patients must have at least one measurable disease as defined by RECIST v1.1. * Patients must have a Lansky (≤ 16 years) or Karnofsky (\> 16 years) score of at least 50. Exclusion Criteria: * Prior history of QTc prolongation or QTcF \> 450 ms on screening ECG. * Patients with the following laboratory values during screening: * Serum creatinine \> 1.5 x upper limit of normal (ULN) for age * Total bilirubin \>1.5 x ULN for age * Alanine aminotransferase (ALT)/serum glutamic pyruvic transaminase (SGPT) \> 3 x ULN for age; aspartate aminotransferase (AST)/serum glutamic oxaloacetic transaminase(SGOT) \> 3 x ULN for age except in patients with tumor involvement of the liver who must have AST/SGOT and ALT/SGPT ≤ 5 x ULN for age. For the purpose of this study, the ULN for SGPT/ALT is 45 U/L. * Patients who are currently receiving treatment with agents that are metabolized predominantly through CYP3A4/5 and have a narrow therapeutic window and/or agents that are known strong inducers or inhibitors CYP3A4/5 are prohibited. In particular, enzyme-inducing antiepileptic drugs (EIAEDs). * Other severe acut…