Camrelizumab plus apatinib in patients with advanced or recurrent endometrial cancer after failure of at least one prior systemic therapy (CAP 04): a single-arm phase II trial

The combination of anti-programmed death 1 (PD-1) inhibitors and tyrosine kinase inhibitors is an effective treatment strategy in endometrial cancer. We aimed to explore the efficacy and safety of camrelizumab plus apatinib as an alternative therapeutic option in patients with previously treated endometrial cancer. This single-arm Simon's two-stage phase II trial was conducted at the Fudan University Shanghai Cancer Center. Patients with advanced or recurrent endometrial cancer who had failed at least one prior systemic therapy were screened for potential participation. Eligible patients were treated with intravenous camrelizumab (200 mg d1 q2w) and oral apatinib (250 mg qd) every 4 weeks. The primary end point was the objective response rate (ORR) per RECIST v1.1 in the intention-to-treat principle. Between January 20, 2020, and October 14, 2022, 36 patients (29 with microsatellite stability/mismatch repair proficient MSS/pMMR tumors; two with microsatellite instability-high/mismatch repair deficient MSI-H/dMMR tumors) were enrolled and treated. The confirmed ORR was 44.4% (95% CI: 27.9, 61.9) and the disease control rate was 91.7% (95% CI: 77.5, 98.2). The median duration of response was 9.3 (95% CI: 4.3, not reached) months, the median progression-free survival was 6.2 (95% CI: 5.3, 11.1) months, and the median overall survival was 21.0 (95% CI: 13.4, not reached) months during a median follow-up of 14.2 (interquartile range: 10.3, 27.6) months. Treatment-related adverse events of grade 3 or 4 occurred in 20 (55.6%) patients, with the most common being increased γ-glutamyl transferase (27.8%), alanine aminotransferase (16.7%) and aspartate aminotransferase (13.9%), and hypertension (11.1%). No treatment-related death occurred. Camrelizumab plus apatinib showed promising antitumor activity with manageable toxicity in patients with advanced or recurrent endometrial cancer who had failed at least one prior systemic therapy. The findings of this study support further investigation of camrelizumab plus apatinib as an alternative therapeutic option, especially for patients with MSS/pMMR tumors. This trial was retrospectively registered with ChiCTR.org.cn, number ChiCTR2000031932.