Mabwell, a biopharmaceutical company based in Shanghai, is set to unveil promising Phase II clinical trial results for its innovative Nectin-4-targeting antibody-drug conjugate (ADC), 9MW2821, at the 2026 European Society for Medical Oncology (ESMO) Congress. The study focuses on patients with locally advanced or metastatic triple-negative breast cancer (TNBC) who have previously been treated with ADCs carrying a topoisomerase I inhibitor payload.
The trial, identified as CTR20242376, evaluates the efficacy and safety of 9MW2821, either as a standalone treatment or in combination with a PD-1 monoclonal antibody. As of April 10, 2026, data from 60 patients showed an objective response rate of 30%, a disease control rate of 80%, and a median progression-free survival of 3.7 months. The median duration of response was recorded at 8.7 months, while the median overall survival remains immature. Importantly, no new safety concerns emerged during the trial.
Breast cancer remains a significant health challenge in China, with an estimated 375,800 new cases and 73,000 deaths reported in 2024. TNBC, a particularly aggressive form of breast cancer, accounts for 15% to 20% of all cases and is associated with a poor prognosis. Current treatments for TNBC primarily involve ADCs with topoisomerase I inhibitor payloads, but once these treatments fail, chemotherapy is the standard option, underscoring the urgent need for new therapies.
9MW2821 and Its Clinical Progress
Developed independently by Mabwell, 9MW2821 is a Nectin-4-targeting ADC that is undergoing multiple clinical trials for various cancers, including urothelial carcinoma (UC), cervical cancer (CC), TNBC, and esophageal cancer. The cumulative clinical enrollment for these trials exceeds 2,200 patients. Notably, 9MW2821 has received Breakthrough Therapy Designation from the Center for Drug Evaluation (CDE) for UC, both as a monotherapy and in combination therapy.
Currently, four pivotal Phase III trials are in progress, focusing on UC and CC, as well as TNBC patients pretreated with topoisomerase I inhibitor-payload ADCs. These trials are expected to undergo interim analyses in 2026, with potential applications for pre-New Drug Application (NDA) meetings anticipated based on the interim data.
Parallel to these developments, Phase I/II trials are advancing rapidly, and the TNBC monotherapy has entered Phase Ib trials in the United States. Mabwell's comprehensive approach to clinical development reflects its commitment to addressing unmet medical needs in oncology.
Mabwell, listed on both the Shanghai and Hong Kong stock exchanges, is dedicated to innovation across the pharmaceutical value chain. The company's mission, "Explore Life, Benefit Health, " emphasizes its focus on providing effective and accessible therapies for global medical challenges, particularly in oncology and aging-related diseases.
The company acknowledges the inherent uncertainties in clinical testing and the regulatory process. It remains cautious about forward-looking statements, which are subject to various risks and factors beyond its control. These include environmental, political, economic, and societal influences, as well as reliance on third-party vendors and the ability to protect intellectual property.
