Clover Biopharmaceuticals Announces Promising Phase I Clinical Trial Results for RSV Vaccine Re-Vaccination in Older Adults

Promising Phase I Clinical Data from Clover Biopharmaceuticals

Clover Biopharmaceuticals, a biotechnology leader in vaccine development, has released encouraging results from a Phase I clinical trial evaluating the re-vaccination of older adults with its RSV PreF vaccine candidate (SCB-1019). This data highlights a significant increase in RSV neutralizing antibodies (nAbs), suggesting improved immunity levels for those previously vaccinated with GSK's AREXVY.

The latest findings, which involved a larger cohort of 62 participants compared to the previous report's cohort of 34, indicate that SCB-1019 can boost RSV nAbs by approximately 60-80% in comparison to AREXVY. Specifically, this re-vaccination also restored antibody levels to about 120-135% of the peak observed after the initial dose of AREXVY. In contrast, the homologous re-vaccination with AREXVY only reached about 75% of peak levels. This marks a significant development for older adults, who are particularly vulnerable to respiratory diseases caused by viruses like RSV.

Joshua Liang, CEO of Clover, emphasized the importance of these findings: "The ability to effectively re-vaccinate older adults previously receiving an approved RSV vaccine is a key differentiator for our candidates. Current vaccines have limitations in preventing respiratory diseases caused by related viruses, making our development critical for public health."

The Trial Structure and Expectations

The trial focused on older adults (ages 60-85) who had received their first dose of AREXVY at least two seasons prior to the study. Participants were divided into three groups: those receiving SCB-1019, those receiving a second dose of AREXVY, and one group receiving a placebo. The primary objectives were to assess the safety, side effects, and immune responses of the candidates.

Preliminary results show that participants who received Clover's SCB-1019 exhibited a robust immune response, significantly surpassing those who received the homologous AREXVY re-vaccination. Surprisingly, individuals receiving the placebo showed no significant changes in their antibody levels. Additionally, the AREXVY group showed a substantial increase in off-target antibodies against a specific strain of the vaccine used.

Broader Implications of Clover's Vaccine Candidates

Given that over 40% of U.S. adults over 60 have already been vaccinated with protein-based RSV vaccines, and considering the current vaccines have not effectively supported re-vaccination recommendations, Clover's encouraging data suggests a promising opportunity. This could potentially lead to broader protective measures not only against RSV but also other respiratory viruses like human metapneumovirus and parainfluenza virus type 3, for which there are currently few effective vaccines.

Currently, Clover's RSV+hMPV±PIV3 vaccine candidates are under investigation in a Phase II trial, which began enrolling participants in early 2026. As Clover continues to push the boundaries of vaccine development, the hope is to ultimately provide a multi-viral defense against common respiratory infections that severely impact older adults.

About Clover Biopharmaceuticals

Clover Biopharmaceuticals, based in Shanghai, is at the forefront of global biotechnology innovation, with a mission to harness the power of vaccines to improve health outcomes worldwide. Focused on diverse vaccine development, Clover aims to address ongoing health challenges and contribute significantly to preventing vaccine-preventable diseases. With strong collaborative partnerships and a commitment to research and development, Clover is strategically positioned to lead advancements in vaccine technology.

As clinical trials continue, Clover remains optimistic about the potential of its vaccine candidates not only to enhance individual protection but also to address broader public health challenges across various populations globally.