Open-Label Study of the CDK4/6 Inhibitor SPH4336 in Subjects With Locally Advanced or Metastatic Liposarcomas

Inclusion Criteria: * Informed consent * ≥ 18 years of age * ECOG performance status 0 or 1 * Histologically confirmed, locally advanced or metastatic sarcoma * Dedifferentiated or well-differentiated/dedifferentiated liposarcomas * No more than 3 prior lines of treatment * Evidence of progression as evidenced by at least one of the following within the past 3 months: * An increase of at least 20% in measurable tumors * The appearance of new lesions * Unequivocal progression of non-measurable lesions * Measurable disease per RECIST v1.1 * If residual treatment-related toxicity from prior therapy: * All treatment-related toxicity resolved to Grade 1 or baseline (alopecia excepted) * ANC ≥ 1,500/μL * Platelets ≥ 100,000/μL * Hgb ≥ 9.0 g/dL (in the absence of pRBC transfusion over the prior 4 weeks) * Estimated glomerular filtration rate of ≥ 60 mL/min (based on the Cockcroft and Gault formula for individualized estimates of GFR) * Total bilirubin ≤ 1.5 x the Upper Limit of Normal (ULN) or ≤ 3 x ULN if known Gilbert's disease * AST and ALT ≤ 3 x ULN or ≤ 5 x ULN if malignant involvement of the liver * Sterile or willing to use effective contraception (approved hormonal contraceptive such as oral contraceptives, patches, implants, injections, rings or hormonally-impregnated intrauterine device (IUD), or an IUD in women of childbearing potential and a condom in men) during the study and for 3 months following the last dose of study drug * Availability of archived tum…