A Study Assessing Efficacy & Safety of Ribociclib in Patients With Advanced Well/Dedifferentiated Liposarcoma

Inclusion Criteria: * Written informed consent * Age ≥ 18 years * Histological confirmed diagnosis of WDL/DDL with metastatic or locally advanced disease not amenable to complete resection * WDL/DDL patients must have documentation of disease progression within 6 months prior to study entry * Eastern Cooperative Oncology Group (ECOG) performance status of 0-1 * Measurable disease by RECIST v1.1 criteria. At least one measurable lesion located outside of a previously irradiated area * Formalin fixed paraffin embedded tumor blocs and representative hematoxylin/eosin slides (preferably both) should be provided for immunohistochemistry staining and molecular analysis of 50 gene signature panel and must have increased CDK4 gene copy number (at least \>/=3) and proficient Rb gene * Patient has adequate bone marrow and organ function * Must be able to swallow ribociclib capsules/tablets Exclusion Criteria: * A known hypersensitivity to ribociclib or any of its excipients * A concurrent malignancy or malignancy within 3 years prior to starting study drug, with the exception of adequately treated, basal or squamous cell carcinoma, non-melanomatous skin cancer or curatively resected cervical cancer * Patients with central nervous system (CNS) involvement at least 4 weeks from prior therapy completion * Clinically significant, uncontrolled heart disease (including history of any cardiac arrhythmias, e.g., ventricular, supraventricular, nodal arrhythmias, or conduction abnormality wit…