CStone Pharmaceuticals announced that the registrational clinical data from sugemalimab (the GEMSTONE-301 study) in stage III non-small cell lung cancer (NSCLC) were published in the world-leading clinical oncology journal, The Lancet Oncology. Sugemalimab as a consolidation therapy demonstrated a statistically significant and clinically meaningful improvement in progression-free survival in patients with unresectable stage III NSCLC without disease progression after concurrent or sequential chemoradiotherapy. After being selected as a late-breaking abstract (LBA) at the European Society of Medical Oncology (ESMO) Congress 2021, this study has been honored on the international academic stage, fully demonstrating its great academic value and clinical potential.

The leading principal investigator of GEMSTONE-301 is Professor Yi-Long Wu from Guangdong Provincial People's Hospital. This randomized, double-blind phase 3 trial was done in 50 hospitals and research centers in China. With an innovative study design, this study enrolled patients with either concurrent or sequential chemoradiotherapy to better reflect real-world clinical practice and covered a broad NSCLC patient population.

The GEMSTONE-301 study is designed to evaluate the efficacy and safety of sugemalimab as consolidation therapy in patients with unresectable stage III NSCLC without disease progression after concurrent or sequential chemoradiotherapy. GEMSTONE-301 study met its primary endpoint at a pre-planned interim analysis. The findings showed that sugemalimab demonstrated statistically significant and clinically meaningful improvement in progression-free survival (PFS) as assessed by blinded independent central review (BICR).

The BICR-assessed median PFS was 9.0 months vs 5.8 months, stratified HR=0.64 (95% CI:0.48, 0.85), p-value=0.0026. Consistent PFS benefit favoring sugemalimab was observed in patients who received either concurrent or sequential chemoradiotherapy prior to randomization. The median PFS was 10.5 months vs.

6.4 months in the concurrent radiotherapy group, HR=0.66 (95% CI: 0.44, 0.99), and 8.1 months vs. 4.1 months in the sequential radiotherapy group, HR=0.59 (95% CI: 0.39, 0.91). Sugemalimab had a well-tolerated safety profile with no new safety signals observed.

The NMPA of China has approved the NDA of sugemalimab (Cejemly®) in combination with chemotherapy for treatment-naïve metastatic (stage IV) NSCLC patients. Based on the positive data in patients with locally advanced (stage III) and metastatic (stage IV) NSCLC, sugemalimab has the potential to become the world's first anti-PD(L)1 monoclonal antibody approved for the treatment of all-comer patients from both stage III and stage IV NSCLC.