Pediatric Nasal RSV Vaccine Candidate Found Safe with Robust Serum Antibody Response

Meissa Vaccines announced positive safety and immunogenicity data for MV-012-968, the company's intranasal live attenuated Respiratory syncytial virus (RSV) vaccine candidate.

Meissa is developing MV-012-968 as a needle-free, adjuvant-free vaccine to protect infants and toddlers from the respiratory syncytial virus (RSV).

The company says RSV is the leading cause of infant hospitalization in the United States and is considered a "missing" pediatric vaccine.

The clinical study in RSV-naïve (seronegative) participants between the ages of six and 36 months enrolled 79 participants at multiple sites in the U.S. to evaluate the safety and immunogenicity of MV-012-968 (NCT04909021).

At the highest dose tested, no serious adverse events related to vaccination were reported with no evidence of any lower respiratory tract symptoms, no Grade 2 or 3 fever observed, and low level, transient vaccine shedding detected.

All RSV-naïve infants and toddlers demonstrated a vaccine response to two doses of 107 PFU.

Serum-neutralizing antibody responses to MV-012-968 were robust and comparable to those seen with previous live attenuated RSV vaccine candidates demonstrating high efficacy against medically-attended RSV disease.

Moreover, MV-012-968 demonstrated significantly greater tolerability to date than these previous candidates.

"With this outstanding safety and robust serum antibody response, we believe Meissa's live attenuated vaccine has the potential to be a best-in-class solution to protect infants and toddlers from RSV, and we are now preparing to advance MV-012-968 into a Phase 2/3 clinical trial next year (2024)," said Martin Moore, Ph.D., co-founder and Chief Scientific Officer, Meissa Vaccines, in a press release on August 8, 2023.

"These data also demonstrate the power of our AttenBlock platform to generate live attenuated vaccines with outstanding safety and immunogenicity – something that we've not seen with other platforms."

As of August 10, 2023, the U.S. FDA has approved RSV vaccines for seniors and antibody therapies for infants.