First-line benmelstobart plus anlotinib and chemotherapy in advanced or metastatic/recurrent esophageal squamous cell carcinoma: a multi-center phase 2 study

Although first-line immunochemotherapy has improved prognosis for patients with advanced esophageal squamous cell carcinoma (ESCC), more effective strategies still require further investigation. This multi-center, phase II study (ClinicalTrials.gov NCT05013697) assessed the feasibility of benmelstobart (a novel PD-L1 inhibitor) plus anlotinib (multitargeted TKI) and chemotherapy in advanced or metastatic/recurrent ESCC. Eligible patients received 4-6 cycles (21-day) of benmelstobart (1200 mg), anlotinib (10 mg) plus paclitaxel (135 mg/m²)/cisplatin (60-75 mg/m²), then maintained with benmelstobart and anlotinib. Primary endpoint was progression-free survival (PFS) assessed according to RECIST v1.1. Secondary endpoints were tumor response, overall survival (OS), and safety assessed by adverse events (AEs). From September 2021 to November 2023, 50 patients were enrolled and received study treatment. With median follow-up of 23.7 months as of April 1, 2024, median PFS was 14.9 months (95% CI, 11.4-not estimable [NE]) and the 1-year PFS was 58.5% (95% CI, 41.9%-71.9%). Among 50 patients, confirmed objective response rate was 72.0% and disease control rate was 84.0%. Median duration of response of 36 responders was 16.2 months (95% CI, 10.2-NE). At the cutoff date, 31 patients remained alive; median OS was not reached (95% CI, 13.2 months-NE) with 1-year OS of 74.8% (95% CI, 59.8%-84.8%). Forty-six (92.0%) patients reported treatment-related AEs, with 37 (74.0%) were grade ≥3. Overall, benmelstobart plus anlotinib and chemotherapy showed promising efficacy and acceptable toxicity in advanced or metastatic/recurrent ESCC.