Mabwell Announces First Patient Dosed in the US Clinical Study of Bulumtatug Fuvedotin in TNBC Patients Previously Treated with ADCs

SHANGHAI, Aug. 12, 2025 /PRNewswire/ -- 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.

About Triple-negative breast cancer (TNBC)

TNBC accounts for approximately 15% to 20% of all breast cancer cases globally, and is generally thought as a subtype with the most malignancy due to the lack of specific therapeutic targets. The global number of incident cases of TNBC increased from 320.1 thousand in 2019 to 361.2 thousand in 2023, and is expected to further increase to 479.4 thousand in 2032. In China, the number of incident cases of TNBC increased from 49.5 thousand in 2019 to 54.8 thousand in 2023, and is expected to further increase to 65.4 thousand in 2032.

About Bulumtatug Fuvedotin

Bulumtatug Fuvedotin (BFv) is a novel Nectin-4 targeting ADC using Mabwell's proprietary next-generation IDDC™ platform. It stands out as the first clinical-stage drug candidate among Chinese companies for this specific target. And it's the first Nectin-4 targeting ADC to disclose clinical efficacy data in cervical, esophageal, and breast cancers. For urothelial carcinoma, both monotherapy and combination therapy with a PD-1 inhibitor have advanced to Phase III clinical studies, making it the first among Chinese candidates and second globally in this field, and have been granted Breakthrough Therapy Designation by CDE of NMPA in China. For cervical cancer, it is the first Nectin-4-targeting ADC worldwide to enter Phase III studies. BFv has been granted multiple Fast Track designations (including for locally advanced or metastatic Nectin-4-positive triple-negative breast cancer) and Orphan Drug designation by US FDA.

About Mabwell
Mabwell (688062.SH) is an innovation-driven biopharmaceutical company with the entire value chain of the pharmaceutical industry. The company provides more effective and accessible therapy and innovative medicines to fulfill global medical needs, focusing on oncology and aging-related disease indications. Mabwell's mission is "Explore Life, Benefit Health" and its vision is "Innovation, from ideas to reality". For more information, please visit .

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