Study Evaluating the Efficacy and Safety of IPI 504 in Patients With Advanced Dedifferentiated Liposarcoma

Inclusion Criteria: * At least 18 years of age at the time of signing informed consent. * Histologic diagnosis of dedifferentiated liposarcoma. * Available archival pathology specimen or tissue sample from a new biopsy for confirmation of diagnosis by central pathology reading. * At least one prior chemotherapy regimen for dedifferentiated liposarcoma. * No more than 2 prior chemotherapy regimens for dedifferentiated liposarcoma. Note: Any number of non-chemotherapy regimens is permitted. * Measurable disease on computed tomography (CT) or magnetic resonance imaging (MRI) as defined by RECIST (version 1.1) with at least one measurable lesion. * Eastern Cooperative Oncology Group (ECOG) performance status: 0 or 1. * Life expectancy ≥6 months. Exclusion Criteria: * Prior treatment with any heat shock protein 90 (Hsp90) inhibitor. * Surgery, radiotherapy, or lesion ablative procedure to the only area of measurable disease * Patients with prior hepatic resections or hepatic-directed therapy * Use of a medication or food that is a clinically relevant CYP3A inhibitor or inducer within 2 weeks prior to dosing.