A Study of Rucaparib and Nivolumab in People With Leiomyosarcoma

Inclusion Criteria: * Male or female age ≥ 18 years at the time of informed consent * Be willing and able to provide written informed consent/assent for the trial * Be willing to comply with treatment protocol * Subjects must have a histologically confirmed unresectable/metastatic LMS * Availability of archival tissue for correlative studies. Either a paraffin block or at least 20 unstained slides are acceptable * Adequate performance status: ECOG 0 - 2 * Subjects must have had at least 1 but not more than 3 prior lines of systemic therapy (e.g. chemotherapy, immunotherapy, targeted or biological therapy) for their LMS. Patients who decline the standard of care first-line systemic therapy will be eligible for this trial. Prior adjuvant therapy will not count provided it was completed more than 6 months previously. * Presence of measurable disease per RECIST v1.1. Target lesions must not be chosen from a previously irradiated field unless there has been radiographically and/or pathologically documented tumor progression in that lesion prior to enrollment. * Adequate organ function determined within 14 days of treatment initiation, defined as per Hematological * Absolute neutrophil count (ANC) ≥1.5 K/mcL * Platelets ≥100 K/ mcL * Hemoglobin ≥9 g/dL Renal * Serum creatinine OR Measured or calculated creatinine clearance Estimated glomerular filtration rate (eGFR) ≥ 30 mL/min/1.73 m2. For calculated CrCL, the Cockcroft Gault formula or institutional standard formula can be used.…