Results of a phase III clinical trial with anti-PDL1 treatment in combination with chemotherapy for extensive stage small cell lung cancer.

Abstract

8095 Background: In China, small cell lung cancer (SCLC) accounts for over 15% of lung cancers. The morbidity of SCLC has been continuously increasing. SCLC is invasive, fast-growing cancer that distinctly differs from other cancers. Approximately 70% of cases present with metastasis at diagnosis and the median overall survival rate is about 8 to 11 months with a 5-year survival rate of less than 5%. Although being sensitive to chemotherapy and radiotherapy, SCLC patients are liable to relapse and often present with drug resistance. Here we study the combination of Socazolimab, an anti-PDL1 antibody, carboplatin and etoposide to treat extensive stage small cell lung cancer. Methods: The study is a randomized, double-blinded, placebo-controlled multicenter Phase III clinical trial. Patients who have extensive-stage SCLC are eligible to the trial. Patients are randomly assigned to the study group (Socazolimab + carboplatin + etoposide) or control group (placebo + carboplatin + etoposide) at 1:1 ratio, with a treatment cycle of every 3 weeks. There are 4 cycles of chemotherapy followed by Socazolimab or placebo alone until termination events occurred or for up to 2 years. The primary endpoint is overall survival (OS). The major secondary endpoint is progression free survival (PFS). Results: There were a total of 498 patients recruited for the study with average age of 61.9 amount which 449 patients were diagnosed with stage IV SCLC. All the analysis was based on intent-to-treat (ITT). The median baseline performance status score was 1.0. The median OS of study group and control group are 13.90 months (95% CI: 12.22-15.34) and 11.58 months (95% CI: 10.64-12.81) respectively, with a P-value of 0.0316. The 24 month survival rate of study group and control group are 20.7% (95% CI:14.8-27.3) and 5.9 %(95% CI: 0.8-18.9). The median PFS of the two groups are 5.55 months (95% CI:5.06-5.82) and 4.37 months (95% CI: 4.27-4.70) with a P-value < 0.0001. The treatment related adverse event were similar in both groups. Conclusions: These results show that Socazolimab plus chemotherapy continued to provide clinically meaningful improvements in OS for patients with extensive stage small cell lung cancer. Clinical trial information: NCT04878016 .