CStone Seeks EMA Approval for Sugemalimab in Stage III NSCLC

SUZHOU, China, March 23, 2025 – CStone Pharmaceuticals, a biopharmaceutical company prominent in developing innovative cancer treatments, recently filed a Type II variation application with the European Medicines Agency (EMA) for their drug sugemalimab. This application aims to obtain approval to treat patients with unresectable stage III non-small cell lung cancer (NSCLC) who have not experienced disease progression following concurrent or sequential platinum-based chemoradiotherapy.

This submission represents the second regulatory effort by CStone for sugemalimab in Europe, following the drug's initial approval for treating metastatic squamous and non-squamous NSCLC in 2024. Approval of this new application would mark a significant advancement in addressing critical unmet needs in stage III NSCLC, as it would offer an additional treatment option where currently only one PD-L1 antibody is approved in Europe. The dual applicability of sugemalimab in both stage III and IV NSCLC enhances its potential as a primary immunotherapy in lung cancer treatment.

The application is backed by robust data from the GEMSTONE-301 Phase III trial, an extensive multicenter, randomized, double-blind study. This trial assessed the efficacy of sugemalimab as a consolidation therapy for patients with unresectable stage III NSCLC following chemoradiotherapy. Published findings in The Lancet Oncology revealed a 36% reduction in the risk of disease progression or death, demonstrating significantly improved progression-free survival. The trial also showed a 56% decrease in the risk of death, indicating a strong positive trend towards improved overall survival. These benefits were consistent across various patient subgroups, irrespective of whether they underwent concurrent or sequential CRT. Additionally, the trial affirmed the drug's favorable safety profile, with no new safety concerns identified.

Dr. Jason Yang, CEO, President of R&D, and Executive Director at CStone, expressed the company's commitment to expanding the indications for sugemalimab in Europe. Following its approval for stage IV NSCLC, CStone is actively collaborating with the EMA to broaden its applications to address earlier stages of lung cancer and other related diseases. Dr. Yang reiterated the company's dedication to enhancing global access to this novel therapy through strategic partnerships and collaborations with regulatory bodies.

Sugemalimab, an anti-PD-L1 monoclonal antibody, was developed by CStone using the OmniRat® transgenic animal platform. This platform enables the creation of fully human antibodies in a single step, which may reduce the risk of immunogenicity and toxicity compared to similar treatments. Sugemalimab has already been approved by the European Commission and the Medicines and Healthcare products Regulatory Agency for use in combination with platinum-based chemotherapy for first-line treatment of metastatic NSCLC without specific genomic tumor aberrations.

In China, the National Medical Products Administration has approved sugemalimab for multiple indications, including its use in tandem with chemotherapy for both metastatic and unresectable locally advanced NSCLC. It is also approved for treating relapsed or refractory extranodal NK/T-cell lymphoma and other cancers such as ESCC and gastric or gastroesophageal junction adenocarcinoma with specific PD-L1 expressions.

CStone Pharmaceuticals, founded in 2015, is committed to advancing cutting-edge oncology therapies. The company has achieved significant milestones, including the launch of four novel therapeutics and 16 regulatory approvals across various indications. CStone's development pipeline features promising candidates, including antibody-drug conjugates, multispecific antibodies, and precision medicines, guided by a leadership team with extensive expertise in drug development and commercialization.