Efficacy and Safety of Benmelstobart Plus Anlotinib in Advanced Endometrial Cancer: Results of a Multi‐Cohort, Phase II Study (ETER200)

Patients with advanced endometrial cancer (EC) have a poor prognosis and limited therapeutic options after failure of prior systemic therapy. In this multi‐cohort Phase II study (ETER200), patients with metastatic or recurrent EC who had received at least one chemotherapy regimen were enrolled. Based on MSI/MMR status, patients received benmelstobart plus anlotinib (Cohort 1), benmelstobart (Cohort 2), or anlotinib (Cohort 3) every 3 weeks. Primary endpoint was objective response rate (ORR) assessed by independent review committee (IRC) per RECIST v1.1. Here, the results of Cohort 1 expansion stage were reported. As of May 9, 2024, 85 of the 107 non‐MSI‐H/pMMR EC patients enrolled in Cohort 1 constituted the expansion stage population for primary efficacy analysis. The IRC‐assessed ORR was 34.1% (95% CI, 24.2–45.2), with a median duration of response of 15.2 months (95% CI, 6.9–not evaluable). Median progression‐free and overall survival were 8.8 months (95% CI, 5.8–15.2) and 21.8 months (95% CI, 19.5–29.1), respectively. Grade ≥ 3 treatment‐related adverse events occurred in 69.2% of patients, most commonly hypertension (21.2%) and palmar‐plantar erythrodysesthesia syndrome (9.4%). Overall, benmelstobart plus anlotinib showed promising anti‐tumor activity and an acceptable safety profile in advanced non‐MSI‐H/pMMR EC, supporting further evaluation of this combination in randomized Phase III studies. Trial Registration: ClinicalTrials.gov, NCT04574284.