Testing Low-Dose Common Chemotherapy (Liposomal Doxorubicin) in Combination With an Anti-Cancer Drug, Peposertib, in Advanced Sarcoma

PRIMARY OBJECTIVES: I. To evaluate the safety and tolerability of peposertib in combination with low-dose pegylated liposomal doxorubicin hydrochloride (liposomal doxorubicin) as evaluated by the dose-limiting toxicity (DLT) rate at each tested dose level. II. To determine the recommended phase 2 dose (RP2D) of liposomal doxorubicin and peposertib combination and determine the maximal tolerated dose (MTD) if identified. SECONDARY OBJECTIVE: I. To assess the pharmacokinetics of peposertib and liposomal doxorubicin used in combination with each other. CORRELATIVE OBJECTIVES: I. To test the hypothesis that soft tissue sarcomas (STS) with homologous recombination deficiency (HRD) like leiomyosarcomas (LMS) will be more susceptible to DNA-protein kinase inhibitor (PKi) in combination with low-dose liposomal doxorubicin. II. To test the hypothesis that gammaH2AX and pNBS1 can be used as pharmacodynamic biomarkers of response to DNA-PKi in combination with low-dose liposomal doxorubicin. III. To test the hypothesis that disease activity correlates with circulating tumor DNA levels in the plasma. OUTLINE: This is a dose-escalation study of peposertib and liposomal doxorubicin. Patients receive peposertib orally (PO) twice daily (BID) on days 1-28 of each cycle and liposomal doxorubicin intravenously (IV) on day 1 of each cycle. Cycles repeat every 28 days in the absence of disease progression, unacceptable toxicity or withdrawal of consent. Patients undergo blood sample collection and computed tomography (CT) or magnetic resonance imaging (MRI) throughout the trial. Patients also undergo tissue biopsy and echocardiography (ECHO) or multigated acquisition scan (MUGA) during screening and on the trial. Patients are followed for 30 days after removal from study or until death, whichever occurs first.