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 CS5007 (EGFR/HER3 bispecific 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.
CS5007 is a bispecific ADC targeting both EGFR and HER3, developed with CStone’s proprietary ADC platform. It is composed of EGFR/HER3 bispecific antibody backbone (CS2011), a hydrophilic β-glucuronide linker and a clinically validated topoisomerase I inhibitor, Exatecan. This integrated approach, featuring precise targeting, optimized linker stability, and proven therapeutic payload, positions CS5007 as a potential best-in-class candidate for precision oncology.
Key Highlights：
1. CS5007 targets almost all human epidermal growth factor receptor (HER) family signaling except for HER2 homodimers, covering broad tumor types and effectively addressing tumor heterogeneity.
2. CS5007 demonstrated high-affinity binding to EGFR single-positive, HER3 single-positive, and EGFR/HER3 double-positive tumor cells.
3. CS5007 triggered high-rate internalization on tumor cells.
4. CS5007 demonstrated potent, antigen-dependent cytotoxicity against tumor cells in vitro across varying EGFR and HER3 expression levels and showed robust tumor-growth inhibition in CDX models.
5. CS5007 exhibited superior in vitro stability compared to ADCs conjugated with tetrapeptide and dipeptide linkers. After 7 days of incubation in human/monkey serum, it retained approximately 70% of its drug payload, indicating a minimal release rate.
6. CS5007 exhibited comparable pharmacokinetic (PK) profile to those ADCs composed of monoclonal antibodies in rodents.
CS5007 demonstrates strong affinity for EGFR- and/or HER3-positive tumor cells and induces efficient internalization. Preclinical studies have shown excellent antitumor activity, favorable safety, and pharmacokinetic profiles. The patent of CS5007 has been filed in March 2025. Preclinical findings support further IND-enabling studies and clinical investigations in various advanced solid tumors.
Poster Information:
【Title】CS5007: A novel EGFR and HER3 dual-targeted antibody-drug conjugate (ADC) with potent antitumor activity in preclinical studies
【Session Title】Growth Factor Receptors and Other Surface Antigens as Targets for Therapy 2
【Abstract Number】2954
【Date & Time】Monday, April 28, 2025, 2:00 PM - 5:00 PM ET
【Location】Poster Section 18, Board #6
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
Forward-looking statements
The forward-looking statements made in this article only relate to events or information as of the date when the statements are made in this article. Except as required by law, we undertake no obligation to update or publicly revise any forward-looking statements, whether as a result of new information, future events or otherwise, after the date on which the statements are made or to reflect the occurrence of unanticipated events. You should read this article completely and with the understanding that our actual future results or performance may be materially different from what we expect. All statements in this article are made on the date of publication of this article and may change due to future developments.
Disclaimer: only for communication and scientific use by medical and health professionals, it is not intended for promotional purposes.
Your privacy is important for us. We use cookies to enhance your experience when visiting our websites: performance cookies show us how you use this website, functional cookies remember your preferences and targeting cookies help us to share content relevant to you. Select “Accept all” for giving your consent to all cookies or select “Reject all” for using only strictly necessary cookies.
