Hengrui Medicine Launches Global First Phase III Trial of Hepatitis B siRNA Therapy HRS-5635

▎Armstrong

On May 26, 2026, Hengrui Pharma registered a Phase III clinical trial on ClinicalTrials.gov for the novel hepatitis B siRNA drug HRS-5635 for the treatment of chronic hepatitis B infection.

This Phase III clinical trial is planned to enroll 540 subjects with chronic hepatitis B and is expected to be completed in June 2028.

The primary endpoint of this Phase III clinical trial is the functional cure rate, defined as the proportion of patients achieving sustained HBV DNA suppression and HBsAg seroclearance 24 weeks after treatment discontinuation following a 24-week treatment regimen.

In September 2025, HRS-5635 was included in the Breakthrough Therapy Drug Program.

Summary

In recent years, the field of hepatitis B (HBV) has witnessed continuous major clinical breakthroughs. Internationally, GSK's Bepirovirsen has achieved success in Phase III clinical trials and has already submitted a marketing authorization application. As a country with a high burden of hepatitis B, China has seen a flourishing landscape in the development of novel HBV drugs. Huahui Health's HH-003 for hepatitis B and hepatitis D co-infection has demonstrated breakthrough efficacy and was granted marketing approval early this year. AusperBioAHB-137 has demonstrated a significantly improved HBsAg seroclearance rate, which remains markedly superior 24 weeks off-treatment, and is currently in Phase III clinical trials. CGE HEALTHCARE's therapeutic hepatitis B vaccine has advanced to Phase III clinical development. Hepa Thera's HBV siRNA therapy has secured two Breakthrough Therapy designations, including a neutralizing antibody combination regimen, and recently completed a Series B financing round exceeding RMB 400 million. Hengrui Pharma's HBV siRNA therapy has also rapidly progressed to Phase III clinical trials.