A phase II evaluation of sacituzumab govitecan in platinum-resistant ovarian cancer (NCT06028932).

5575 Background: Patients with platinum-resistant ovarian cancer (PROC) have few therapeutic options. More than 60% of high-grade serous ovarian cancers overexpress (≥ 2+ by immunohistochemistry) Trop2, a key regulator of growth pathways and marker of aggressive disease. Sacituzumab govitecan (SG) is an antibody-drug conjugate consisting of a Trop-2–specific antibody conjugated with SN-38, an active metabolite of irinotecan. Methods: NCT06028932 is a single-institution open-label phase II study. Patients received SG at 10 mg/kg intravenously days 1 and 8 of a 21-day cycle until prohibitive toxicity or progression. The primary endpoint was objective response rate (ORR) by RECIST 1.1. Secondary endpoints included progression-free (PFS) and overall (OS) survival, as well as safety. Results: Twenty patients were enrolled. Median age was 67 years (range: 45-84). Most participants (85%, n=17) were White. The median number of prior lines prior to enrollment was 3 (range: 1-8). ECOG performance status was 0 (n=16) or 1 (n=4). Most patients had a poorly differentiated tumor (90%, n=18) with advanced disease (stage III/IV) at initial diagnosis (85%, n=17). Serous histology predominated (75%, n=15), followed by clear cell (15%, n=3), endometrioid (5%, n=1), and carcinosarcoma (5%, n=1). Across a median follow-up of 9.9 months, there were 15 progressions and 4 deaths. ORR was 35% (7/20); there were no complete responses, and stable disease was achieved in 40% (8/20). Median PFS was 8.0 months (95% CI: 3.8-14.8); median OS was not yet reached. No new safety signals were observed. The most common grade 3-4 treatment-emergent adverse events were neutropenia (n=15), hypokalemia (n=3), and anemia (n=2). The most frequent grade 1-2 events included diarrhea (n=59), fatigue (n=27), abdominal pain (n=20), nausea (n=20), alopecia (n=16), anorexia (n=14), and vomiting (n=13). Conclusions: SG exhibits encouraging efficacy for PROC with manageable toxicities. Future studies are warranted. Clinical trial information: NCT06028932 .