Enlonstobart in patients with PD-L1 positive recurrent/metastatic cervical cancer: Updated survival results of the phase II study.

5522 Background: Enlonstobart is a PD-1 inhibitor that has demonstrated durable anti-tumor activity and acceptable safety in patients with PD-L1 positive recurrent/metastatic cervical cancer in a multicenter, single-arm, open-label, phase II study. At primary cutoff date (May 27, 2023), the overall survival (OS) was not reached. Here, we report results from a pre-planned further follow-up (August 20, 2024). Methods: Eligible patients were ≥18 years old with PD-L1-positive (combined positive score ≥ 1) cervical cancer who had progression during or after or intolerance to the first-line platinum-based therapy. A total of 107 patients received enlonstobart 240 mg every two weeks for up to 24 months or until disease progression, intolerable toxicities, or other study discontinuation criteria were met. At the updated cutoff date, analyses of progression-free survival (PFS) and OS in the full analysis set (FAS), which consisted of all patients who had received at least one dose of enlonstobart treatment, and the per protocol set (PPS), which consisted of all patients in the FAS who had at least one available postbaseline tumor assessment were conducted. Results: At the cutoff date of August 20 2024, the median follow-up time was 15.84 months (range 0.4 ~ 35.6 months). In FAS, the median PFS was 3.06 (95 % CI 2.23–6.90) months. The median OS was 19.38 (95 % CI 14.95–25.40) months and the estimated OS rate was 68.14 % (95 %CI 58.20–76.19) at 12 months, 50.78 % (95 % CI 40.46–60.20) at 18 months, and 42.84 % (95 % CI 32.76–52.53) at 24 months. In PPS, the median PFS was 3.81 (95 % CI 2.63–7.49) months. The median OS was 21.26 (95 % CI 15.44–27.66) months and the estimated OS rate was 71.53 % (95 %CI 61.48–79.40) at 12 months, 53.32 % (95 % CI 42.64–62.87) at 18 months, and 44.98 % (95 % CI 34.50–54.89) at 24 months. Conclusions: Enlonstobart monotherapy showed a promising survival in patients with PD-L1 positive recurrent/metastatic cervical cancer, whose disease experienced progression after first-line platinum-based therapy. Clinical trial information: NCT04886700 .