Meissa Vaccines has begun dosing patients with its investigational vaccine for respiratory syncytial virus (RSV). MV-012-968 is an intranasal live attenuated RSV vaccine candidate being developed as a needle-free, adjuvant-free vaccine to protect infants and at-risk, older adults from RSV. There is currently no approved vaccination for RSV, which hospitalizes 1% of US infants annually and kills more than 66,000 per year.

The Phase 1c study has enrolled up to 45 seronegative participants between the ages of six and 24 months at three sites in the US to evaluate the safety and immunogenicity of MV-012-968 ( Identifier: NCT04909021).

According to the company, preliminary data from a Phase 1b study in RSV-seropositive participants between the ages of 15 and 59 months showed that a single intranasal dose of either 104 or 105 PFU of MV-012-968 was well-tolerated, did not result in detectable shed vaccine virus, indicating appropriate attenuation, and stimulated RSV-specific mucosal IgA in a dose-dependent manner ( Identifier NCT04444284). Data from a completed Phase 1a study showed a 106 PFU dose of MV-012-968 was safe and well-tolerated among healthy RSV sero-low adults and resulted in no detectable nasal shedding of infectious vaccine virus, while inducing RSV-specific mucosal IgA in the majority of vaccine recipients, despite pre-existing immunity to RSV ( Identifier NCT04227210).

“We believe that our intranasal live attenuated RSV vaccine candidate, developed on Meissa’s AttenuBlock vaccine platform, offers the potential to finally immunize against RSV, which has evaded other vaccine technologies for more than 60 years,” said Martin Moore, PhD, CEO and cofounder of Meissa Vaccines. “We have initiated this study in seronegative infants and young children based on supportive data from studies in seropositive adults and children showing MV-012-968 is well-tolerated and induces mucosal (IgA) antibodies, which protect against RSV infection. The development of a safe and effective RSV vaccine is a significant global health priority that could save thousands of lives and protect the health of millions of people around the world.”