RemeGen's groundbreaking phase II clinical trial results, presented at the 2025 ASCO Genitourinary Cancers Symposium in San Francisco, mark a significant advancement in bladder cancer treatment. The study evaluated the combination of Disitamab Vedotin (DV), a HER2-targeting antibody-drug conjugate, with Toripalimab immunotherapy as a neoadjuvant treatment for muscle-invasive bladder cancer (MIBC).
Unprecedented Efficacy Results
The trial (NCT05297552) demonstrated remarkable outcomes, with a pathological complete response (pCR) rate of 63.6% (95% CI: 45.1% - 79.6%), substantially surpassing the 36-42% response rates typically seen with traditional neoadjuvant chemotherapies. The study enrolled 47 patients with varying HER2 expression levels, including 10.6% with HER2 IHC 1+, 57.4% with IHC 2+, and 31.9% with IHC 3+.
Professor Xinan Sheng from Peking University Cancer Hospital, who presented the findings, highlighted that patients with baseline T2N0 stage disease achieved an exceptional pCR rate of 85.7%. The treatment's efficacy proved consistent across different patient subgroups, with HER2 IHC 3+ patients showing a particularly impressive 84.6% pCR rate.
Survival Benefits and Safety Profile
The combination therapy demonstrated strong durability, with a 12-month event-free survival (EFS) rate of 92.5% and an 18-month EFS rate of 85.9% among patients who underwent radical cystectomy. Notably, the treatment maintained efficacy regardless of PD-L1 status or HER2 expression levels.
Safety data revealed a manageable adverse event profile, with grade 3 or higher treatment-emergent adverse events (TEAEs) occurring in only 27.7% of patients. This represents a significant improvement over conventional chemotherapy regimens, which typically show 40-50% severe adverse event rates.
Future Directions
Based on these promising results, the China National Medical Products Administration (NMPA) granted breakthrough therapy designation to Disitamab Vedotin in May 2024. RemeGen is now expanding its research program to explore DV-based regimens across different treatment lines and combinations.
The company plans to investigate the potential of DV in combination with various immunotherapies and chemotherapy agents for urothelial cancer treatment. Additionally, research will extend to studying DV's role throughout the entire perioperative period for MIBC patients.
