Abstract CT079: Efficacy and safety of sintilimab (anti-PD-1 mAb) for advanced cervical cancer: Results from a Phase II trial

Abstract Background: Patients (pts) with advanced cervical cancer who progressed on first-line treatment have no standard therapy and derive limited benefit from currently available treatment. More effective therapeutic strategies are required. This phase II trial was conducted to evaluate the efficacy and safety of IBI310 (anti-CTLA-4 mAb) plus sintilimab (sint) versus sint in pts with recurrent/metastatic cervical cancer. Here we present the efficacy and safety results for pts in sint plus placebo group. Methods: Pts aged 18-75 years, with histologically or cytologically confirmed cervical cancer who had progressed on or been intolerant to first-line or above platinum-based chemotherapy were enrolled. Pts in sint plus placebo group received sint (200mg) plus placebo IV Q3W for 4 cycles followed by sint monotherapy till disease progression, intolerable toxicity, withdrawal of informed consent, death, or for up to 24 months. The primary endpoint was objective response rate (ORR) assessed by IRRC per RECIST V1.1. The data cutoff date was April 20, 2022. Results: Overall, 101 pts were enrolled and received at least one dose of assigned treatment (median age of 53.0 years, 71.3% pts with PD-L1 CPS ≥1, 91.0% pts with squamous-cell carcinoma, and 36.6% pts with ≥2 lines of prior systemic therapy). The median treatment exposure was 18.0 weeks. The IRRC-assessed confirmed objective response rate (ORR) was 24.5% (95%CI: 16.4%-34.2%), disease control rate was 56.1% (95%CI: 45.7%-66.1%), and median duration of response was not reached. Pts with PD-L1 CPS ≥1 showed numerically higher ORR versus those with CPS <1 (32.9% vs 17.2%). With a median follow-up of 8.3 months, median PFS was 2.7 months (95%CI: 1.5-4.3). Median overall survival (OS) was not reached; OS rate was 89.6% (95%CI: 80.9%-94.5%) at 6 months and 65.5% (95%CI: 50.9%-76.7%) at 12 months. Treatment-related adverse events (TRAEs) occurred in 75.2% pts, with the most common being anaemia (13.9%), hypothyroidism (12.9%), white blood cell count decreased (12.9%), and hyperthyroidism (10.9%). 18.8% pts experienced CTCAE Grade 3 or higher TRAEs (no TRAE leading to death occurred). TRAEs leading to drug discontinuation occurred in 1 pt (myocarditis, grade 2). Conclusion: This study demonstrated favorable antitumor activity and acceptable safety with sintilimab alone over available therapies in ≥2 line advanced cervical cancer. ClinicalTrials.gov identifier: NCT04590599 Citation Format: Qinglei Gao, Jing Wang, Qin Xu, Ying Tang, Jieqing Zhang, Baoping Chang, Bairong Xia, Wei Duan, Danbo Wang, Lijing Zhu, Ruifang An, Guonan Zhang, Yaling Tang, Jianli Huang, Xiang Zhang, Hui Qiu, Wenting Ji, Li Li, Jianqing Zhu, Ding Ma. Efficacy and safety of sintilimab (anti-PD-1 mAb) for advanced cervical cancer: Results from a Phase II trial [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 2 (Clinical Trials and Late-Breaking Research); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(8_Suppl):Abstract nr CT079.