8846威尼斯(中国百科)有限公司

Suzhou, China, July 7 2025 – CStone Pharmaceuticals (“CStone”, HKEX: 2616), an innovation-driven biopharmaceutical company focused on anti-cancer therapies, announced today that clinical progress update on CS2009, a potential first-in-class/best-in-class PD-1/VEGF/CTLA-4 trispecific antibody independently developed by CStone. It features balanced and monovalent PD-1 and CTLA-4 arms and a bivalent anti-VEGFA arm, which leads to potent multi-target synergy and preferential targeting of tumor tissue to reduce systemic toxicity.

CS2009 preferentially blocks PD-1 and CTLA-4 on double-positive tumor-infiltrating T cells via avidity-driven engagement, while minimizing interference with CTLA-4 signaling in peripheral T cells, thus potentially offering enhanced efficacy with lower systemic toxicity. In the tumor micro-environment (TME), CS2009’s anti-PD-1 and anti-CTLA-4 activities are further enhanced significantly by crosslinking with VEGFA dimers that are upregulated in the TME.

Key Highlights

• The global multicenter Phase I/II study is actively enrolling patients in Australia and China, with planned expansion to the United States for Phase II enrollment. With strong interests from investigators and patients, the trial is enrolling speedily and expected to exceed 100 patients by the end of this year.
• The Phase Ia dose escalation study has evaluated four dose levels in patients with advanced and heavily pretreated solid tumors. Dose level 4 at 20 mg/kg, Q3W has just passed safety evaluation by the Safety Monitoring Committee (SMC) without identifying any Dose Limiting Toxicity (DLT). The study is currently enrolling at Dose Level 5 (30 mg/kg, Q3W) to establish a wide safety margin over potential recommended phase 2 dose (RP2D), while backfilling is ongoing for prior dose levels (1–20 mg/kg, Q3W). Phase Ib/II dose expansion/pivotal extension studies are anticipated to commence in the second half of 2025.
• To date, CS2009 is found to be well tolerated across all evaluated dose levels, with excellent pharmacokinetic (PK) profile supporting Q3W dosing, with pharmacodynamic (PD) responses indicating both T cell activation from PD-1 and CTLA-4 blockade and VEGFA neutralization. Anti-tumor activities have been observed from lower-dose cohorts in patients with “cold” tumors and PD-(L)1 pretreated tumors.
• Phase Ia data (including safety, PK, PD, and antitumor activity) are targeted for presentation at an international conference in Q4 2025.

CS2009's Global Multicenter Study

The Phase I trial of CS2009 is a global multicenter study. The Phase Ia study involves dose escalation and cohort backfilling to evaluate safety, tolerability, PK, PD and antitumor activity in patients with advanced solid tumors. The Phase Ib/II study comprises dose expansion and pivotal extension, assessing safety, tolerability, PK, and efficacy through multiple parallel cohorts investigating both monotherapy and combination regimens across various solid tumors.

This trial will thoroughly evaluate the clinical potential of CS2009 in a wide range of advanced solid tumors, including but not limited to non-small cell lung cancer, hepatocellular carcinoma, gastric adenocarcinoma, endometrial cancer, ovarian cancer, renal cell carcinoma, colorectal cancer, and cervical cancer, in efforts to advance the development of next-generation immuno-oncology therapeutics.

About CS2009 (PD-1/VEGF/CTLA-4 Trispecific Antibody)

CS2009 is a novel trispecific antibody targeting PD-1, VEGFA, and CTLA-4 to achieve multidimensional antitumor effects through synergistic mechanisms. It is independently developed by CStone from molecular inception, with the potential to be first- or best-in-class. Its differentiated molecular design combines these validated targets, preferentially invigorating exhausted tumor infiltrating lymphocytes (TILs) while demonstrating VEGF neutralization comparable to existing anti-VEGF antibodies. CS2009 covers a wide range of cancers, including but not limited to non-small cell lung cancer, hepatocellular carcinoma, gastric adenocarcinoma, endometrial cancer, ovarian cancer, renal cell carcinoma, cervical cancer and etc.

About CStone

CStone (HKEX: 2616), established in late 2015, is an innovation-driven biopharmaceutical company focused on the research and development of anti-cancer therapies. Dedicated to addressing patients’ unmet medical needs in China and globally, the Company has made significant strides since its inception. To date, the Company has successfully launched 4 innovative drugs and secured approvals for 16 new drug applications (NDAs) covering 9 indications. The company’s pipeline is balanced by 16 promising candidates, featuring potentially first-in-class or best-in-class antibody-drug conjugates (ADCs), multispecific antibodies, immunotherapies and precision medicines. CStone also prides itself on a management team with comprehensive experiences and capabilities that span the entire drug development spectrum, from preclinical and translational research to clinical development, drug manufacturing, business development, and commercialization. For more information about CStone, please visit www.cstonepharma.com.

IR contact: ir@cstonepharma.com

PR contact: pr@cstonepharma.com

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