Treatment of Milademetan Versus Trabectedin in Patient With Dedifferentiated Liposarcoma

Approximately 160 patients will be randomly assigned in a 1:1 ratio to receive milademetan or trabectedin. Randomization will be stratified by the ECOG performance status (0 or 1) and number of prior treatments (≤ 2 or \> 2) for the patient's liposarcoma. Patients will receive study drug (i.e., milademetan or trabectedin) until reaching unequivocal disease progression (RECIST v.1.1) as determined by the Investigator, experiencing unmanageable toxicity, or until other treatment discontinuation criteria are met. Patients may be treated beyond tumor progression if they are experiencing clinical benefit based on the assessment of the Investigator in discussion with the Medical Monitor. All patients will be followed for documentation of disease progression and survival information (i.e., date and cause of death) and subsequent treatment information (i.e., date/duration of treatment, response, and subsequent disease progression). Long-term follow-up will continue every 12 weeks (± 7 days) until the endpoint of death, the patient is lost to follow-up, or for 24 months following the final dose of study drug, whichever comes first.