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  • CStone Announces Oral Presentation of Translational Data for CS5001, A Potentially Best-in-Class ROR1-Targeting ADC, at the 13th World ADC London Conference

    Times:2023.03.20   Author:CStone

    • Profiling CS5001 against cancer cell lines showed potent cytotoxicity in both hematological cancer and solid tumor cell lines expressing ROR1
    • CS5001 also demonstrated significant ROR1- dependent in vivo anti-tumor activity in cell line and human xenograft mouse models of triple-negative breast cancer
    • As one of the most clinically advanced ROR1 ADCs globally, CS5001 is advancing through Phase I dose-escalation


    Suzhou, China, March 20th, 2023--CStone Pharmaceuticals (HKEX: 2616), a leading biopharmaceutical company focused on the research, development, and commercialization of innovative immuno-oncology therapies and precision medicines, today announced the delivery of an oral presentation entitled “Translational considerations in the development of CS5001, a PBD-based ADC against ROR1, a tumor-specific target” at the 13th World Antibody Drug Conjugate Conference (World ADC London) .

    Tumor-specific cell killing by ADCs relies on target-mediated internalization and release of cytotoxic payload. CS5001 is an ADC armed with an ultra-potent pyrrolobenzodiazepine (PBD) payload to maximize cytotoxicity mediated by receptor tyrosine kinas-like orphan receptor 1 (ROR1), a tumor-specific receptor for both hematologic malignancies and solid tumors. This translational study of CS5001 aims to explore the potential of developing CS5001 in solid tumors, including the evaluation of ROR1 expression in human samples of various solid tumor, in vitro cytotoxicity and in vivo efficacy of CS5001 and their correlation with ROR1 expression, validating ROR1 expression as a potential predictive biomarker in subsequent clinical development of CS5001. The results showed that ROR1 was expressed in multiple solid tumors, and CS5001 exhibited potent cytotoxicity against both hematological and solid tumor cells expressing ROR1. CS5001 also showed significant ROR1-dependent tumor growth inhibition in mouse xenografts of solid tumors and human TNBC PDX models. CS5001 is a promising candidate drug with precision treatment potential in both hematologic tumors and malignant solid tumors.

    “We are delighted to present the translational data of CS5001 at the World ADC London conference in March 2023.” said, Dr. Archie Tse, Chief Scientific Officer of CStone. “The encouraging results demonstrate the target-dependent efficacy of CS5001, even at relatively low expression levels. This observation, together with the significant bystander killing effect we have seen with CS5001, highlights its therapeutic potential in ROR1-expressing solid tumors. These findings support the continued clinical development of CS5001. At present, the global multi-regional Phase I clinical trial of CS5001 is making rapid progress. We are committed to advancing the global development of CS5001 swiftly, with the goal of bringing better treatment options for patients as soon as possible.”

    The global multi-regional dose finding phase I clinical trial of CS5001 has completed safety evaluation of several dose levels, with results indicating good safety and tolerability. Previously, preclinical data of CS5001 was presented in a late-breaking abstract (LBA) session at the 33rd International Molecular Targets and Cancer Therapeutics Symposium in 2021. The data indicated that CS5001 exhibits strong selective cytotoxicity in various ROR1-expressing tumor cell lines and significant in vivo anti-tumor activity in both blood and solid tumor xenograft mouse models.


    About CS5001 (ROR1 ADC) 

    CS5001 is now a clinical-stage antibody-drug conjugate (ADC) targeting ROR1 (receptor tyrosine kinase-like orphan receptor 1). CS5001 has uniquely designed and LCB’s proprietary tumor-cleavable linker and pyrrolobenzodiazepine (PBD) prodrug. Only after reaching the tumor, the linker and prodrug are cleaved to release the PBD toxin, resulting in lethal DNA cross-links in cancer cells. The use of the linker plus PBD prodrug effectively helps addressing the toxicity problem associated with traditional PBD payloads, leading to a better safety profile. Additionally, CS5001 utilizes site-specific conjugation for a precise drug antibody ratio of which enables homogeneous production and large-scale manufacturing. 

    In October 2020, CStone signed a licensing agreement with LegoChem Biosciences, Inc. (LCB) for the development and commercialization of CS5001 which was originally generated by collaboration of LCB and ABL Bio, both South Korea-based leading biotech companies. Under the agreement, CStone obtains the exclusive global right to develop and commercialize CS5001 outside the Republic of Korea. 


    About CStone

    CStone (HKEX: 2616) is a biopharmaceutical company focused on research, development, and commercialization of innovative immuno-oncology and precision medicines to address the unmet medical needs of cancer patients in China and worldwide. Established in 2015, CStone has assembled a management team with extensive experience in innovative drug development, clinical research, and commercialization. The company has built an oncology-focused pipeline of 15 drug candidates with a strategic emphasis on immuno-oncology combination therapies. Currently, CStone has received ten NDA approvals for its four drugs. Multiple late-stage drug candidates are now under pivotal clinical trials or registration. CStone’s vision is to become globally recognized as a world-renowned biopharmaceutical company by bringing innovative oncology therapies to cancer patients worldwide. 

    For more information about CStone, please visit


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