YANTAI, China, Feb. 15, 2025 — At the 2025 American Society of Clinical Oncology Genitourinary Cancers Symposium (ASCO GU) in San Francisco, USA, Professor Xinan Sheng presented phase II trial data (NCT05297552, Study ID: RC48-C017) on Disitamab Vedotin (DV) plus Toripalimab as neoadjuvant therapy for HER2-expressing muscle-invasive bladder cancer (MIBC). This is the first published data from a prospective study using an antibody-drug conjugate (ADC) with immunotherapy perioperatively for MIBC. The pathological complete response (pCR) rate was a notable 63.6%, significantly exceeding that of traditional neoadjuvant chemotherapies (36%-42%). ASCO GU is a leading urologic oncology conference.

The NCT05297552 study evaluated the combined effect of DV, a HER2-targeting ADC from RemeGen Co., Ltd. (RemeGen), and Toripalimab, a PD-1 inhibitor, in the perioperative setting for MIBC. In May 2024, the Center for Drug Evaluation (CDE) of China’s National Medical Products Administration (NMPA) granted breakthrough therapy designation to DV based on this study. Preliminary results, presented at the 2024 ASCO Annual Meeting, generated considerable interest. The updated ASCO GU data reinforce these findings.

The NCT05297552 study enrolled 47 patients (10.6% HER2 IHC 1+, 57.4% IHC 2+, and 31.9% IHC 3+) who received the neoadjuvant therapy; 33 underwent radical cystectomy and pelvic lymph node dissection (RC + PLND). Data cutoff was December 3, 2024. Results showed encouraging efficacy and manageable safety:

• The pCR rate was 63.6% (95% CI: 45.1% – 79.6%), almost double that of standard neoadjuvant chemotherapy (36%-42%). The pathological response rate was 75.8% (95% CI: 57.7% – 88.9%). For patients with baseline clinical stage T2N0, the postoperative pCR rate was 85.7%. A 55.6% pCR rate was observed in patients with other urothelial carcinoma subtypes. Benefits were seen regardless of PD-L1 status or HER2 expression level (IHC 1+/2+/3+), with an 84.6% pCR rate in HER2 IHC 3+ patients.
• The 12-month event-free survival (EFS) rate for patients undergoing radical cystectomy was 92.5%; the 18-month rate was 85.9%.
• The treatment was well-tolerated. Grade 3 or higher treatment-emergent adverse events (TEAEs) occurred in only 27.7% of patients, significantly less than with standard chemotherapy (40%-50%).

RemeGen is expanding DV research in bladder cancer, aiming to offer better treatment options globally. Studies are underway to evaluate DV-based regimens in earlier-line treatments for locally advanced or metastatic urothelial cancer. Further research will explore DV’s use throughout the perioperative period for MIBC and examine its synergy with chemotherapy or other immunotherapies for urothelial cancer.

SOURCE RemeGen Co., Ltd

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