CStone Submits Application to the European Medicines Agency for New Indication of Sugemalimab in Stage III Non-Small Cell Lung Cancer

SUZHOU, China, March 24, 2025 /PRNewswire/ -- CStone Pharmaceuticals ("CStone", HKEX: 2616), a biopharmaceutical company dedicated to developing innovative cancer therapies, today announced the submission of a Type II variation application to the European Medicines Agency (EMA) for sugemalimab. The application seeks approval for the treatment of patients with unresectable stage III non-small cell lung cancer (NSCLC) who have not progressed following concurrent or sequential platinum-based chemoradiotherapy (CRT). This marks CStone's second regulatory submission for sugemalimab to the EMA, following its initial approval in Europe for metastatic squamous and non-squamous NSCLC in 2024. If this new indication is approved, sugemalimab would address a critical unmet need in stage III NSCLC, where only one PD-L1 antibody is currently approved in Europe. The drug's dual utility in stage III and IV NSCLC could solidify its role as a cornerstone immunotherapy in lung cancer.

The submission is supported by data from the GEMSTONE-301 Phase III trial, a multicenter, randomized, double-blind study evaluating sugemalimab as consolidation therapy in patients with unresectable stage III NSCLC post-CRT. Results published in The Lancet Oncology demonstrated:

• 36% reduction in risk of disease progression or death, significantly improved progression-free survival (PFS).
• 56% reduction in risk of death, with a strong positive trend toward overall survival (OS) benefit.
• Consistent clinical benefits across subgroups, regardless of prior CRT modality (concurrent or sequential).
• Favorable safety profile, no new safety signals identified.

Dr. Jason Yang, CEO, President of R&D, and Executive Director at CStone, commented: "Following sugemalimab's approval in Europe for stage IV NSCLC, we are working closely with EMA to expand its indications in earlier stage lung cancer and other malignancies. With its demonstrated outstanding efficacy and safety profile, sugemalimab is poised to address critical unmet needs for stage III NSCLC patients. We remain steadfast in expanding global access through strategic partnerships and collaborations with regulatory authorities, ensuring this innovative therapy reaches patients worldwide."

About Sugemalimab

The anti-PD-L1 monoclonal antibody sugemalimab was developed by CStone using OmniRat^® transgenic animal platform, which allows creation of fully human antibodies in one step. Sugemalimab is a fully human, full-length anti-PD-L1 immunoglobulin G4 (IgG4) monoclonal antibody, which may reduce the risk of immunogenicity and toxicity for patients, a unique advantage over similar drugs.

The European Commission (EC) and the Medicines and Healthcare products Regulatory Agency (MHRA) have approved sugemalimab in combination with platinum-based chemotherapy for the first-line treatment of patients with metastatic NSCLC with no sensitizing EGFR mutations, or ALK, ROS1 or RET genomic tumor aberrations.

The National Medical Products Administration (NMPA) of China has approved sugemalimab for five indications:

• In combination with chemotherapy as first-line treatment of patients with metastatic squamous and non-squamous NSCLC with no EGFR or ALK genomic tumor aberrations and metastatic squamous NSCLC;
• For the treatment of patients with unresectable Stage III NSCLC whose disease has not progressed following concurrent or sequential platinum-based chemoradiotherapy;
• For the treatment of patients with relapsed or refractory extranodal NK/T-cell lymphoma;
• In combination with fluorouracil and platinum-based chemotherapy as first-line treatment of patients with unresectable locally advanced, recurrent or metastatic ESCC; and
• In combination with fluoropyrimidine- and platinum-containing chemotherapy as first-line treatment for unresectable locally advanced or metastatic gastric or gastroesophageal junction (G/GEJ) adenocarcinoma with a PD-L1 expression CPS ≥5.

About CStone

CStone Pharmaceuticals (HKEX: 2616), founded in late 2015, is an innovation-driven biopharmaceutical company focused on advancing cutting-edge oncology therapies. Committed to addressing unmet medical needs globally, the company has achieved remarkable milestones since its inception, including the successful launch of four novel therapeutics and securing 16 regulatory approvals across nine indications.

CStone's robust pipeline features 16 high-potential candidates, including first-in-class and best-in-class assets such as antibody-drug conjugates (ADCs), multispecific antibodies, immunotherapies, and precision medicines. The company further distinguishes itself through a seasoned leadership team with comprehensive expertise in drug development—from preclinical research and clinical trials to manufacturing, business development, and commercialization.

For more information about CStone, please visit www.cstonepharma.com.
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