Core Business Strategy

CStone operates on a highly defined strategic framework centered on:

1. Immuno-Oncology (IO) Backbone Therapies: Developing proprietary monoclonal antibodies (such as anti-PD-L1 and anti-PD-1) to serve as the foundational therapeutic backbone for combination therapies.
2. Precision Medicine: Targeting specific genetic mutations and biomarkers (such as RET, IDH1, and FGFR) to deliver targeted small-molecule therapies to specific patient subpopulations.
3. Emerging Modalities: Investing in next-generation therapeutic modalities, notably Antibody-Drug Conjugates (ADCs) and multi-specific cell engagers, to address drug resistance and hard-to-treat cancers.
4. Commercialization through Partnerships: Collaborating with established global and domestic pharmaceutical companies to accelerate market access, optimize commercial execution, and scale therapeutic reach within China and internationally.

Product Portfolio and Commercialized Assets

CStone has successfully transitioned several high-value oncology therapies from clinical development to commercial availability in Greater China. The company's approved product portfolio includes both internally developed assets and in-licensed therapies.

1. Cejemly (Sugemalimab - CS1001)

Sugemalimab is an investigational fully human anti-PD-L1 monoclonal antibody developed internally by CStone using the OmniRat transgenic animal platform. It is designed to reduce the risk of immunogenicity and offer potential safety advantages. * Mechanism of Action: Blocks the interaction of PD-L1 with PD-1 and CD80 receptors, restoring T-cell activation against tumor cells. It also induces antibody-dependent cellular phagocytosis (ADCP) by macrophages, providing a dual mechanism of tumor clearance. * Approved Indications: Approved in China for the treatment of stage III and stage IV non-small cell lung cancer (NSCLC) in both squamous and non-squamous histologies, as well as for relapsed or refractory extranodal NK/T-cell lymphoma, esophageal squamous cell carcinoma (ESCC), and gastric/gastroesophageal junction adenocarcinoma. * Commercialization Partners: Partnered with Pfizer for commercialization rights within mainland China, and with EUSA Pharma for commercialization rights in select territories outside of Greater China.

2. Ayvakit (Avapritinib)

Licensed from Blueprint Medicines, Ayvakit is an orally active, highly potent, and selective kinase inhibitor. * Mechanism of Action: Targets KIT and PDGFRA mutational kinases, specifically inhibiting PDGFRA exon 18 mutations (including the D842V mutation) and KIT exon 17 mutations. * Approved Indications: Approved in Greater China (including mainland China, Taiwan, and Hong Kong) for the treatment of adults with unresectable or metastatic gastrointestinal stromal tumors (GIST) harboring a PDGFRA exon 18 mutation, as well as for advanced systemic mastocytosis (AdvSM).

3. Gavreto (Pralsetinib)

Also licensed from Blueprint Medicines, Gavreto is a once-daily, oral precision therapy. * Mechanism of Action: Highly selective inhibitor of RET (Rearranged during Transfection) receptor tyrosine kinase fusions and mutations. * Approved Indications: Approved in China for the treatment of adult patients with locally advanced or metastatic RET fusion-positive NSCLC, as well as RET-mutant medullary thyroid cancer and RET fusion-positive thyroid cancer. * Note: CStone has dynamically managed its rights to Gavreto, transitioning certain commercial and operational responsibilities to local partners like Servier and others to optimize therapeutic distribution.

4. Tibsovo (Ivosidenib)

Licensed from Servier (originally developed by Agios Pharmaceuticals), Tibsovo is a first-in-class oral targeted inhibitor. * Mechanism of Action: Inhibits mutant isocitrate dehydrogenase-1 (IDH1), preventing the accumulation of the oncometabolite 2-hydroxyglutarate (2-HG) and promoting the differentiation of malignant cells into normal mature cells. * Approved Indications: Approved in China for the treatment of adult patients with relapsed or refractory acute myeloid leukemia (AML) who have an IDH1 mutation, and for IDH1-mutant locally advanced or metastatic cholangiocarcinoma.

Clinical Pipeline and Research & Development

CStone maintains a deep, diversified pipeline of investigational drug candidates designed to address resistance mechanisms and expand therapeutic options beyond current standards of care.

Key Pipeline Candidates:

• Nofazinlimab (CS1003): A humanized IgG4 monoclonal antibody targeting programmed cell death protein 1 (PD-1). It is currently under global Phase III evaluation in combination with lenvatinib as a first-line treatment for advanced hepatocellular carcinoma (HCC).
• CS5001 (ROR1 ADC): An antibody-drug conjugate targeting Receptor Tyrosine Kinase-Like Orphan Receptor 1 (ROR1). Licensed from LegoChem Biosciences, CS5001 features a tumor-cleavable linker and a pyrrolobenzodiazepine (PBD) prodrug payload. It represents one of CStone's leading candidates in the emerging ADC space, currently undergoing Phase I clinical evaluation for various solid tumors and hematological malignancies.
• CS2011 (STING Agonist): An orally available Stimulator of Interferon Genes (STING) agonist designed to promote robust anti-tumor immune responses through the activation of the innate immune system, currently in early-stage clinical development.
• CS5006: A novel multi-specific antibody candidate targeting tumor-associated antigens to activate localized immune responses while minimizing systemic toxicities.

Strategic Partnerships and Business Model

CStone’s business model leverages collaborative partnerships to mitigate clinical development risks, access cutting-edge technologies, and maximize commercial potential. The company's key strategic relationships include:

• Pfizer: Strategic alliance established to commercialize sugemalimab in mainland China and to jointly select and develop additional oncology assets. Pfizer also made an equity investment in CStone as part of this partnership.
• Blueprint Medicines: Collaboration providing CStone with exclusive development and commercialization rights to avapritinib (Ayvakit) and pralsetinib (Gavreto) in Greater China.
• Servier: Partnership granting CStone the rights to develop and commercialize ivosidenib (Tibsovo) in Greater China.
• LegoChem Biosciences: License agreement granting CStone worldwide development and commercialization rights (excluding South Korea) for the ROR1 ADC, CS5001.

Manufacturing and Operational Infrastructure

To support its transition into an integrated biopharmaceutical entity, CStone has established state-of-the-art facilities designed to meet international Good Manufacturing Practice (GMP) standards:

• Suzhou Translational Medicine and Manufacturing Center: A modern facility built to support the commercial production of small molecule drug substances and formulations, as well as clinical-stage biologics. This facility enhances CStone’s supply chain independence, reduces manufacturing costs, and ensures long-term scalable production capacity for its pipeline assets.
• Translational Medicine Platform: Utilizing advanced biomarker discovery and clinical pharmacology tools to guide clinical development. This allows CStone to design biomarker-driven clinical trials, improving patient selection and maximizing clinical trial success rates.