Mabwell (688062.SH), an innovative biopharmaceutical company with entire industry chain, announced the first patient dosing in the U.S. for a clinical study of its novel nectin-4-targeting antibody-drug conjugate (Bulumtatug Fuvedotin, or BFv, R&D code: 9MW2821) in triple-negative breast cancer (TNBC) patients previously treated with antibody-drug conjugate (ADC). This is the first overseas clinical study of 9MW2821, representing a significant step in Mabwell's global development of ADC therapeutics.

The multicenter clinical study (NCT06908928) aims to evaluate the efficacy and safety of BFv in TNBC patients previously treated with a taxane and an antibody-drug conjugate with a topoisomerase inhibitor payload. The first subject has been dosed at Memorial Sloan Kettering Cancer Center.

So far, treatment options for TNBC remain limited. While topoisomerase inhibitor-based ADCs (TOPi-ADCs) are emerging as a mainstream post-standard therapy option, a high proportion of patients progress after TOPi-ADC treatment, indicating significant unmet clinical needs due to the lack of alternative therapies.

BFv is a novel Nectin-4 targeting ADC leveraging next-generation site-specific conjugation technology. Composed of a novel antibody, an optimized linker, and cytotoxic payload MMAE (Monomethyl auristatin E), it has good profile of tumor binding and target specificity. BFv is protected by multiple patents in China and internationally through the PCT. Studies demonstrate its superior characteristics including more homogeneous components, significantly lower toxin release in plasma and enhanced cytotoxic payload delivery efficiency which leads to substantially increased intratumoral drug concentration.

Considering high expression of Nectin-4 in TNBC, BFv's clinical study on TNBC imposes no biomarker screening requirements, holding potential for broad patient coverage and offering a novel therapeutic option for TNBC patients.