Sacituzumab Govitecan in Combination With Cisplatin in Platinum Sensitive Recurrent Ovarian and Endometrial Cancer

This is an open-label, Phase 1 study with a dose expansion cohort (DEC), conducted in two separate disease groups (ovarian and endometrial cancer). The primary objective of the study is to determine the optimal dose of sacituzumab govitecan for use in combination with cisplatin for treatment of epithelial ovarian and endometrial cancers. For each disease group, there will be a safety run-in phase utilizing a 3+3 design with a de-escalated dose level if the starting dose shows toxicity and an expansion cohort to evaluate the preliminary efficacy and tolerability of the experimental regimen. The dose expansion cohort will consist of 14 patients in the ovarian cohort and 12 patients in the endometrial cohort with an additional 2 patients in each cohort to account for potential patient replacement. This will yield a total sample size of 22-28 patients in the ovarian cancer cohort and a total sample size of 20-26 patients in the endometrial cancer cohort. Phase 1, Safety Run-in with Dose De-escalation Scheme: Dose Level 0, starting level: Sacituzumab govitecan 7.5 mg/kg + Cisplatin 70 mg/m2 IV Dose -1: Sacituzumab govitecan 7.5 mg/kg + Cisplatin 70 mg/m2 IV In this stage, a minimum of 6 patients and a maximum of 12 patients will be required. The recommended dose expansion cohort (DEC) dose is defined as the highest dose at which no more than 1 out of 6 patients experience a Dose-Limiting Toxicity (DLT) Phase 2, Dose Expansion Cohort: Sacituzumab govitecan 5-7.5 mg/kg IV (depending on phase I result) + Cisplatin 70 mg/m2 IV. Drug product administration will continue until progressive disease (PD), unacceptable toxicity, or death. The primary endpoint of the safety run-in phase is to determine the recommended DEC dose of Sacituzumab in combination with a fixed schedule of cisplatin in patients with ovarian and endometrial cancers. In the safety run-in phase, the assessment of dose limiting toxicity (DLT) will be performed standard 3 + 3 design rules. The recommended DEC dose is defined as the highest dose of Sacituzumab in combination with Cisplatin at the fixed dose of 70 mg/m2 at which no more than 1 out of 6 patients experience DLT within the first cycle of therapy. The DEC is designed to indicate proof of concept regarding the overall response rate (ORR) and safety of the combination of sacituzumab with cisplatin at the dose established in the safety run-in phase of the study. Once the recommended DEC dose for sacituzumab and cisplatin combination has been established for each disease cohort, an additional 14 patients will be enrolled for the ovarian group and 12 patients for the endometrial group. An additional 2 patients will be added to each cohort to account for potential patient replacement for a total of 42-54 evaluable patients.