RemeGen Co., Ltd. (RemeGen) has announced new efficacy and safety data from the Phase II clinical trial (NCT05297552, Study ID: RC48-C017) evaluating Disitamab Vedotin (DV) in combination with Toripalimab as a neoadjuvant therapy for HER2-expressing muscle-invasive bladder cancer (MIBC). The results were presented in an oral session at the 2025 American Society of Clinical Oncology Genitourinary Cancers Symposium (ASCO GU) by Professor Xinan Sheng from Peking University Cancer Hospital. This marks the first public disclosure of clinical results from a prospective study investigating antibody-drug conjugate (ADC) therapy combined with immunotherapy as a perioperative treatment for MIBC.

The study demonstrated a pathological complete response (pCR) rate of 63.6%, representing a significant improvement over traditional neoadjuvant chemotherapy (36%-42%). These results highlight the potential of combining targeted ADC therapy with immunotherapy to enhance treatment outcomes for MIBC patients.

Phase II Clinical Trial Findings

The NCT05297552 study was designed to assess the efficacy and safety of the HER2-targeting ADC Disitamab Vedotin (DV) and the PD-1 inhibitor Toripalimab in the perioperative setting for MIBC. This novel combination therapy builds upon RemeGen’s ongoing research into innovative treatment regimens for bladder cancer.

Key study results as of December 3, 2024, include:

• pCR rate of 63.6% (95% CI: 45.1% - 79.6%), nearly doubling the response rate of traditional neoadjuvant chemotherapies.
• Pathological response rate of 75.8% (95% CI: 57.7% - 88.9%).
• Postoperative pCR rate of 85.7% in patients with T2N0 clinical stage and 55.6% in patients with other urothelial carcinoma subtypes.
• High response rates across all HER2 expression levels, including a pCR rate of 84.6% in HER2 IHC 3+ patients.
• 12-month event-free survival (EFS) rate of 92.5% and 18-month EFS rate of 85.9%.
• Favorable safety profile, with grade 3 or higher treatment-emergent adverse events (TEAEs) occurring in only 27.7% of patients, significantly lower than the 40%-50% typically observed with traditional chemotherapy.

Regulatory Advancements and Future Research

The promising results from this study have gained regulatory recognition, with the Center for Drug Evaluation (CDE) of China’s National Medical Products Administration (NMPA) granting breakthrough therapy designation to DV in May 2024. The initial findings presented at the 2024 ASCO Annual Meeting garnered significant attention from the global oncology community, and the updated data at ASCO GU 2025 further validate the clinical potential of this therapeutic approach.

RemeGen remains committed to advancing targeted and personalized therapies for bladder cancer, with ongoing research exploring the feasibility of expanding DV-based regimens from later-line to front-line treatment for locally advanced or metastatic urothelial cancer. The company also aims to broaden DV's role in the perioperative setting, investigating combinations with chemotherapy and other immunotherapies to further enhance treatment efficacy.

Driving Innovation in Bladder Cancer Treatment

The latest findings reinforce RemeGen’s position as a leader in ADC and immunotherapy innovation. By pioneering new treatment approaches and expanding research collaborations, RemeGen continues to push the boundaries of precision oncology for genitourinary cancers.