China-based CStone Pharmaceuticals (HKG: 2616) has announced that the prestigious journal Nature Cancer has published the overall survival (OS) interim analysis from the registrational clinical study GEMSTONE-302. The study evaluates the programmed death-ligand 1 (PD-L1) inhibitor sugemalimab as a first-line treatment for stage IV non-small cell lung cancer (NSCLC). GEMSTONE-302 is a multicenter, randomized, double-blind Phase III trial that assesses sugemalimab in combination with chemotherapy for treatment-naïve stage IV NSCLC patients.
Primary and Secondary Endpoints Achieved in GEMSTONE-302 Trial
The primary endpoint of the study was progression-free survival (PFS), with secondary endpoints including OS, PFS in patients with PD-L1 expression ≥1%, objective response rate (ORR), duration of response (DoR), and safety. As of the data cutoff date of November 22, 2021, among 479 enrolled patients, 51 patients remained on the sugemalimab regimen versus 7 for placebo. The median follow-up durations were 25.4 months for the sugemalimab group and 24.9 months for the placebo group. The median OS was 25.4 months versus 16.9 months, with a hazard ratio (HR) of 0.65. The 2-year OS rates were 51.7% versus 35.6%. In patients with baseline brain metastasis, sugemalimab improved OS compared to the placebo group, with median OS of 22.1 months vs 9.0 months (HR=0.45). Additionally, OS benefits were observed in all subgroups, including different tumor histology subtypes and PD-L1 expression levels. In the intention-to-treat population, the median PFS was 9.0 months for sugemalimab compared to 4.9 months for placebo (HR=0.49). The 2-year PFS rates were 20.8% versus 7.3%, while subgroup analysis showed that in patients with PD-L1≥1%, the median PFS was 10.9 months for sugemalimab vs 4.9 months (HR=0.48). The safety data were consistent with previous reports.
Sugemalimab’s Approvals and Regulatory Progress
The in-house developed sugemalimab, first approved in China in December 2021, has since garnered approvals for use in the first-line treatment of epidermal growth factor receptor (EGFR) gene mutation negative and anaplastic lymphoma kinase (ALK) negative metastatic non-squamous non-small cell lung cancer (NSCLC) combined with pemetrexed plus carboplatin; in combination with pemetrexed plus carboplatin in the first-line treatment of metastatic squamous NSCLC; and for unresectable stage III NSCLC without disease progression after platinum-based synchronous or sequential chemotherapy and radiotherapy in the country. The drug is awaiting regulatory decisions in China for use in extranodal NK/T-cell lymphoma (R/R ENKTL), first-line gastric/gastroesophageal junction adenocarcinoma in combination with chemotherapy, first-line esophageal squamous cell carcinoma, and first-line NSCLC combined with chemotherapy in the UK.-Fineline Info & Tech
