SHANGHAI, China, 22 May 2026
Mabwell announced that new clinical data for its investigational Nectin-4-targeting antibody-drug conjugate (ADC) 9MW2821 (Bulumtatug Fuvedotin, BFv) will be presented at the ASCO Annual Meeting 2026. The presentations will include both oral and poster sessions highlighting promising efficacy results for urothelial carcinoma and muscle-invasive bladder cancer (MIBC) when 9MW2821 is combined with the PD-1 inhibitor toripalimab. The latest data further strengthen Mabwell’s position in the rapidly growing ADC oncology market and support the advancement of 9MW2821 toward potential regulatory filings in multiple cancer indications.
Strong Response Rates in Advanced Urothelial Carcinoma
The Phase Ib/II clinical study evaluating 9MW2821 plus toripalimab in patients with locally advanced or metastatic urothelial carcinoma enrolled 52 patients, with 47 included in the efficacy analysis as of December 1, 2025. The combination demonstrated a highly encouraging overall objective response rate (ORR) of 83.0%, while the confirmed ORR reached 74.5%. The study also reported a complete response (CR) rate of 12.8% and a disease control rate (DCR) of 89.4%.
Results were even stronger in previously untreated patients, where ORR increased to 87.5%, confirmed ORR reached 80.0%, and DCR climbed to 92.5%. Median progression-free survival (PFS) reached 12.9 months, while median duration of response (DoR) and overall survival (OS) had not yet been reached at the time of analysis. Importantly, investigators reported no new safety concerns associated with either 9MW2821 or toripalimab, reinforcing the manageable safety profile of the combination regimen.
Early Perioperative Bladder Cancer Data Shows High pCR Rates
Mabwell will also present Phase II data for 9MW2821 combined with toripalimab in perioperative muscle-invasive bladder cancer patients. The study enrolled 32 subjects, with seven patients completing neoadjuvant therapy as of January 4, 2026. Among the six patients who underwent radical cystectomy and lymph node dissection, the study achieved a pathological complete response (pCR) rate of 66.7% and a pathological downstaging (pDS) rate of 83.3%.
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One patient declined surgery after achieving a clinical complete response following neoadjuvant therapy, further highlighting the potential strength of the regimen in earlier-stage disease settings. No unexpected safety signals were identified during the trial, supporting continued development in bladder cancer treatment.
Mabwell Expands Global ADC Development Strategy
9MW2821 is a next-generation Nectin-4-targeting ADC developed using Mabwell’s proprietary ADC platform and is currently being investigated across multiple tumor types including urothelial carcinoma, cervical cancer, esophageal cancer, and breast cancer. According to the company, it is the world’s first Nectin-4 ADC to enter Phase III clinical trials for both cervical cancer and triple-negative breast cancer (TNBC). Mabwell currently has four pivotal Phase III trials ongoing globally.
The therapy has already received multiple regulatory designations from the US Food and Drug Administration and China’s National Medical Products Administration, including FDA Fast Track Designation for three indications, Orphan Drug Designation for one indication, and Breakthrough Therapy Designation from China’s CDE for two indications.
Mabwell stated that interim analyses for Phase III studies in urothelial carcinoma monotherapy, combination therapy, and cervical cancer are expected during 2026, with potential pre-NDA discussions planned based on those results. The company also expects to complete a Phase Ib/II cervical cancer combination study later this year before advancing into Phase III development.
Source: Mabwell press release
