Bivalent RSV Vaccine Candidate For Young Adults Demonstrates Neutralizing Antibody Responses

Clover Biopharmaceuticals, Ltd. today announced positive preliminary immunogenicity and safety data in the initial young adult cohort from its Phase I trial evaluating SCB-1019, a bivalent RSV prefusion-stabilized F (PreF)-Trimer subunit vaccine candidate.

Clover's preliminary immunogenicity data across RSV-A and RSV-B neutralization appear to be in line or potentially favorable compared to other protein subunit RSV PreF vaccines.

These data support Clover's bivalent RSV-A/B approach, given that other monovalent RSV-A vaccines have previously observed lower immune responses and/or efficacy against RSV-B.

The results also confirm that Clover's PreF antigens in SCB-1019 are in the stabilized prefusion and trimeric form, further supported by exploratory immunogenicity results demonstrating significant increases in Site Ø neutralizing antibody-competitive titers.

Additionally, the SCB-1019 vaccination did not observe any notable safety or reactogenicity issues in this initial young adult cohort, enabling the planned enrollment of older adults to proceed in the Phase I clinical trial.

"We are encouraged by the progress and positive preliminary Phase I results for our bivalent RSV PreF vaccine candidate utilizing our validated Trimer-Tag platform, demonstrating broad and significant neutralizing antibody responses against both RSV-A and RSV-B," said Joshua Liang, Chief Executive Officer & Board Director of Clover, in a press release on April 8, 2024.

"As the first RSV PreF vaccine candidate developed in China to enter the clinical trial stage and now the first to generate clinical data, we look forward to the additional Phase I clinical data in our initial target older adult population in the second half of 2024 as planned."

As of April 2024, first-generation RSV vaccines have been approved in Canada, Europe, Japan, the United States, and the United Kingdom. The U.S. CDC estimated the percentage of adults 60+ was 23.6% (22.8-24.5).