Clover Biopharmaceuticals Announces Positive Phase 2 Data for Respiratory Virus Vaccines

Clover Biopharmaceuticals has announced positive preliminary data from a Phase 2 clinical trial in Australia, evaluating its RSV (respiratory syncytial virus) and hMPV (human metapneumovirus) combination vaccine candidates, with the addition of PIV3 (para-influenza virus 3) in some formulations. The trial, involving 420 older adults aged 60 to 85, found robust immune responses to the vaccines, with no drop-off in antibody levels among the oldest participants.

The company's SCB-1022 and SCB-1033 candidates demonstrated strong neutralizing antibody responses against RSV, hMPV, and PIV3. Antibody titers were in line with or higher than those observed in a previous Phase 1 trial. Specifically, the vaccines showed approximately a six to nine-fold increase in RSV-neutralizing antibodies and a six to eight-fold increase in hMPV-neutralizing antibodies. PIV3-neutralizing antibodies showed a greater than three-fold increase, with a significant boost in participants with baseline PIV3 antibodies.

The study also revealed that the vaccines were well-tolerated. The most common side effects were mild fatigue, headache, and injection site pain, with symptoms resolving within two days. There were no serious adverse events reported, and no vaccine-related discontinuations. The company noted a 62% lower rate of respiratory tract infections in vaccinated participants compared to the placebo group within 28 days of vaccination.

Notably, the trial took place during an RSV outbreak in Australia, which co-circulated with hMPV and PIV3. This real-world scenario helped validate the vaccine's effectiveness in a complex viral environment.

Clover Biopharmaceuticals' SCB-1022 and SCB-1033 vaccines leverage the company's Trimer-Tag platform, which stabilizes viral proteins in a prefusion state, ensuring a strong immune response. The successful commercial-scale 2,000-liter bioreactor production of the vaccine components further de-risks late-stage development and commercialization.

"These positive Phase 2 clinical data strengthen the potential of our RSV + hMPV ± PIV3 combination vaccines," said Joshua Liang, Chief Executive Officer and Board Director of Clover Biopharmaceuticals. "The ability to re-vaccinate individuals previously receiving approved RSV vaccines to restore and broaden protection is particularly promising."

The results from this Phase 2 trial are significant as they continue to validate Clover Biopharmaceuticals' Trimer-Tag platform for the development of multi-valent protein-based respiratory vaccines. The company plans to continue evaluating the mid- and late-stage development plans for these vaccines and explore potential global collaboration opportunities to maximize their value.