Commercial-stage biotechnology company Clover Biopharmaceuticals Ltd (HKEX:02197) on Tuesday reported additional positive data from a Phase I clinical trial in the United States evaluating re-vaccination with the company's RSV PreF vaccine candidate (SCB-1019) compared head-to-head with GSK's RSV vaccine (AREXVY) in older adults who previously received AREXVY at least 2 seasons prior to enrolling.

Data showed a trend of approximately 60-80% higher RSV neutralising antibodies (nAbs) for Clover's RSV vaccine compared head-to-head versus AREXVY. Re-vaccination with Clover's RSV vaccine boosted RSV nAbs to approximately 120-135% of the peak levels observed after an initial dose of AREXVY (cross-trial comparison).

The results are from 62 participants, whereas the results announced in October 2025 were from 34 participants.

Participants in the trial were aged 60-85 years. They were randomised to receive either a heterologous SCB-1019 (Clover RSV PreF) revaccination dose, a homologous AREXVY (GSK RSV PreF) revaccination dose or saline placebo. The study is assessing safety, reactogenicity and immunogenicity.