Camrelizumab plus apatinib in patients with advanced or recurrent endometrial cancer after failure of at least one prior systemic therapy: A single-arm phase II trial

5516 Background: The first stage results of a Simon’s two-stage single-arm phase II trial showed promising antitumor activity and manageable safety of camrelizumab (a humanized anti-PD-1 monoclonal antibody) plus apatinib (a highly selective VEGFR2 inhibitor) in patients with advanced or recurrent endometrial cancer after failure of prior systemic therapy. Here, we report the primary results of this trial. Methods: This open-label, single-arm, phase II trial used a minimax Simon’s two-stage design. Patients with advanced or recurrent endometrial cancer that had progressed after at least one prior systemic therapy were treated with camrelizumab (200 mg, intravenously, every two weeks) and apatinib (250 mg, orally, daily) on a four-week cycle until disease progression or intolerable toxicity. The primary endpoint was the objective response rate per Response Evaluation Criteria In Solid Tumors (RECIST) version 1.1. Other assessed endpoints were disease control rate, time to response, duration of response, time to treatment failure, progression-free survival, overall survival, and treatment-related adverse events. Results: Between January 20, 2020 and October 14, 2022, 36 patients (median age: 60 [range: 29, 76] years; 17 [47.2%] had Eastern Cooperative Oncology Group [ECOG] performance status 1; 15 [41.7%] had received at least two prior systemic therapies) were enrolled. At the date of data cutoff (December 31, 2022), the median follow-up time was 13.9 (interquartile range: 5.8-23.2) months. All 36 patients were evaluable for efficacy, the confirmed objective response rate was 44.4% (95% CI: 27.9%, 61.9%) and the conformed disease control rate was 88.9% (95% CI: 73.9%, 96.9%), with two complete response, 14 partial response, and 16 stable disease. The median progression-free survival was 6.4 (95% CI: 5.2, 13.0) months. The treatment-related adverse events of grade 3 or greater occurred in 19 (52.8%) patients, with increased gamma-glutamyltransferase (8 [22.2%]), hyperglycemia (4 [11.1%]), hypertension (4 [11.1%]) and increased direct bilirubin (4 [11.1%]) being most common. Reactive cutaneous capillary endothelial proliferation occurred in 6 (16.7%) patients and all were grade 1 or 2. No treatment-related death occurred. Conclusions: Camrelizumab plus apatinib show promising antitumor activity and manageable toxicity in patients with advanced or recurrent endometrial cancer after failure of prior systemic therapy and warrant further investigation. Clinical trial information: ChiCTR2000031932 .