Fruquintinib plus sintilimab in patients with advanced endometrial cancer with mismatch-repair proficient status: a multicenter, single-arm, phase Ib/II trial

This report presents the primary analysis of the endometrial cancer (EMC) cohort of FRUSICA-1 (ClinicalTrials.gov identifier, NCT03903705), a multicenter, single-arm, phase Ib/II study evaluating fruquintinib plus sintilimab. The cohort included Chinese patients with inoperable or advanced mismatch-repair proficient (pMMR) EMC who had progressed on or could not tolerate up to two prior platinum-based therapies, and comprised exploratory and pivotal phases. Patients received fruquintinib (5 mg orally once daily on a 2 weeks on/1 week off schedule) plus sintilimab (200 mg intravenously once every 3 weeks). The primary endpoint was objective response rate (ORR) assessed by an independent review committee (IRC). Secondary endpoints included ORR as assessed by the investigator, disease control rate, time to response, duration of response, progression-free survival (PFS) and tumor shrinkage as assessed by both the IRC and investigator, overall survival, and safety. By May 15, 2024, 98 patients with pMMR EMC were enrolled and treated. IRC-assessed ORR was 32.7% (95% confidence interval [CI] 23.5–42.9) for the total pMMR population (n = 98) and 31.6% (95% CI 21.4–43.3) for the pivotal population (n = 76). Median PFS was 8.6 months (95% CI 5.5–16.6) for the total population and 7.1 months (95% CI 5.4–16.6) for the pivotal population. The most common grade ≥3 treatment-related adverse event was hypertension (17.3%). In conclusion, fruquintinib plus sintilimab showed promising efficacy and tolerable safety in previously treated, advanced pMMR EMC.