Suzhou, China, May 7, 2025 – CStone Pharmaceuticals (“CStone”, HKEX: 2616), an innovation-driven biopharmaceutical company focused on anti-cancer therapies, announced today that a poster presentation of preclinical data of CS5006 (integrin β4 [ITGB4] antibody drug conjugate [ADC]), a key asset in CStone Pipeline 2.0, has been delivered at the 2025 American Association for Cancer Research (AACR) Annual Meeting.
CS5006 is a first-in-class antibody-drug conjugate (ADC) targeting the novel antigen integrin β4 (ITGB4), developed using CStone’s proprietary ADC platform. Leveraging an internally developed machine learning-based bioinformatics algorithm alongside rigorous in-house experimental validation, CStone identified elevated ITGB4 expression across multiple tumor types—including non-small cell lung cancer (NSCLC), colorectal cancer (CRC), esophageal squamous cell carcinoma (ESCC), and head and neck squamous cell carcinoma (HNSCC)—with minimal expression observed in normal tissues. Preclinical in vivo and in vitro studies have demonstrated CS5006’s promising therapeutic potential, highlighting its ability to effectively killing tumor cells.
Key Highlights：
1. Bioinformatics analysis identified high ITGB4 expression in colorectal tumor tissues, supporting ITGB4 as a promising tumor-associated antigen for CRC. In the tumor microenvironment, ITGB4 was selectively overexpressed on tumor cells while remaining low expression in normal tissues.
2. Immunohistochemistry (IHC) staining confirmed limited ITGB4 expression in normal tissue but high expression in tumor tissues from patients with CRC, sq-NSCLC, HNSCC and ESCC.
3. ITGB4 antibody demonstrated high affinity and internalization rate.
4. CS5006 preclinical proof-of-concept models using ITGB4-vedotin and ITGB4-DXd showed potent antitumor activity in both in vitro and in vivo studies, along with favorable pharmacokinetic (PK) profiles.
（1）ITGB4-vedotin exhibited strong antigen-dependent cytotoxicity in ITGB4-positive tumor cell lines in vitro and demonstrated potent antigen-dependent tumor inhibition in CDX models in vivo.
（2）ITGB4-DXd also exhibited potent antigen-dependent cytotoxicity in vitro and strong tumor-inhibitory effects in vivo CDX tumor models.
（3）Both ITGB4-vedotin and ITGB4-DXd exhibited favorable PK characteristics.
In summary, CS5006 is a first-in-class ADC targeting the novel tumor antigen ITGB4 and is currently undergoing comprehensive preclinical evaluation. Preclinical data have demonstrated strong antitumor activity across multiple animal models, particularly in solid tumors such as non-small cell lung cancer, head and neck squamous cell carcinoma, and esophageal squamous cell carcinoma. The compound also exhibited good tolerability, providing strong support for its further clinical development. The patent of CS5006 has been filed in April 2023.
Poster Information:
【Title】CS5006: A novel integrin β4-targeted antibody-drug conjugate (ADC) with robust antitumor activity in preclinical studies
【Session Title】Growth Factor Receptors and Other Surface Antigens as Targets for Therapy 2
【Abstract Number】2953
【Date & Time】Monday, April 28, 2025, 2:00 PM - 5:00 PM ET
【Location】Poster Section 18, Board #5
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 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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