• Sugemalimab is the world's first anti-PD-L1 monoclonal antibody approved for use in combination with fluorouracil and platinum-based chemotherapy for unresectable locally advanced, recurrent or metastatic esophageal squamous cell carcinoma.
• This marks the 13^th NDA approval obtained by CStone and sugemalimab's fourth indication approved in China, following stage III and IV non-small cell lung cancer and relapsed or refractory extranodal NK/T-cell lymphoma.
• The GESMTONE-304 study met its pre-specified dual primary endpoints. Treatment of sugemalimab in combination with fluorouracil plus cisplatin demonstrated a statistically significant and clinically meaningful improvement in the progression-free survival and overall survival of patients with unresectable locally advanced, recurrent, or metastatic esophageal squamous cell carcinoma in the first-line setting

Dr. Jason Yang, CEO of CStone, said, "We are excited about the approval of sugemalimab for the fourth indication in first-line ESCC, which further demonstrates its clinical significance and potential. In additional to the approved indications such as non-small cell lung cancer (NSCLC), NK/T-cell lymphoma, and ESCC, sugemalimab is currently under review for its sBLA for the first-line treatment of gastric cancer. We are keeping active and productive communication with the NMPA to secure early approval in China and will also work with the FDA and EMA to explore registration pathways in the U.S, Europe and other territories. We look forward to benefiting more patients with ESCC around the world with sugemalimab."

Professor Li Jin, Principal Investigator of the GEMSTONE-304 study and Director of the Department of Oncology, East Hospital, Tongji University, said, "Esophageal cancer is a prevalent malignancy in China, with ESCC being the most common in terms of pathological type. About 70% of patients with esophageal cancer have progressed to locally advanced or advanced stages at the time of initial diagnosis. In addition, 50%-60% of patients with resectable esophageal cancer relapse or develop distant metastases after radical surgery. The GEMSTONE-304 study demonstrated that sugemalimab in combination with chemotherapy significantly improved progression-free survival (PFS) and overall survival (OS) compared to first-line chemotherapy for ESCC, with a manageable safety profile. We believe, with this approval, sugemalimab will provide a new first-line treatment option to patients with advanced ESCC."

This sBLA of sugemalimab was approved based on the data from the GEMSTONE-304 study. It is a randomized, double-blind, multi-center, placebo-controlled phase 3 registrational clinical trial designed to evaluate the efficacy and safety of sugemalimab in combination with 5-fluorouracil plus cisplatin as first-line treatment in patients with unresectable locally advanced, recurrent, or metastatic ESCC. The primary endpoints are Blinded Independent Central Review (BICR)-assessed PFS and OS, and secondary endpoints include investigator-assessed PFS, BICR and investigator-assessed objective response rate (ORR) and duration of response (DoR).

The GEMSTONE-304 study results were presented at the 2023 ESMO World Congress on Gastrointestinal Cancer (ESMO GI 2023) in an oral presentation. The study met its pre-specified dual primary endpoints. The results showed that sugemalimab in combination with chemotherapy demonstrated a statistically significant and clinically meaningful improvement in BICR-assessed PFS and OS compared with placebo in combination with chemotherapy. Sugemalimab in combination with chemotherapy showed good tolerability and safety, with no new safety signal observed. The safety profile was consistent with previous findings across studies in other diseases with sugemalimab. The BICR-assessed median PFS in the sugemalimab treatment group is 6.2 months compared with 5.4 months in the placebo group, with a hazard ratio (HR) of 0.67 (95% CI, 0.54-0.82), and a p-value of 0.0002. The median OS in the sugemalimab treatment group is 15.3 months compared with 11.5 months in the placebo group, with an HR of 0.70 (95% CI, 0.55-0.90), and a p-value of 0.0076. Subgroup analysis demonstrated that consistent clinical benefits were observed across almost all predefined subgroups regardless of PD-L1 expression level. The BICR- assessed ORR is 60.1% vs 45.2%, with a difference of 14.9%. The DoR is 6.0 months vs 4.5 months.