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 within 12 months of screening)
* On screening, inability to determine the QTcF interval on the ECG (i.e.: unreadable or not interpretable) or QTcF \>450 msec
* Participation in a prior investigational study within 30 days prior to enrollment
* Patient has had major surgery within 14 days prior to starting study drug