MVA-BN RSV is our product candidate for the prevention of RSV (Respiratory Syncytial Virus). The vaccine incorporates five different RSV antigens to stimulate a broad immune response against both RSV subtypes (A and B), thus mimicking the immune response observed following a natural response to an RSV infection.
We have advanced the clinical development of the vaccine and have generated highly promising Phase 2 results, confirming both broad and durable antibody and T cell responses against RSV, as well as mucosal immune responses that may be important for protection against RSV. The Phase 2 program in elderly included a revaccination of subjects after one year, following which the immune responses were rapidly and significantly increased, notably in subjects with the weakest immunity prior to the booster vaccination.
In 2021, a human challenge trial of MVA-BN RSV was conducted. The phase 2 double-blinded, placebo-controlled trial enrolled healthy adult volunteers, 18-50 years of age who were randomized to receive either a single vaccination of MVA-BN RSV or placebo. Volunteers were challenged intranasally with an RSV type A strain 28 days after vaccination. A total of 61 subjects were evaluable. The study demonstrated a significant reduction in viral load in vaccinated subjects (n=30) versus placebo (n=31), thus meeting the primary endpoint of this pivotal study. At the same time, the vaccinated subjects showed a significant reduction in clinical symptoms typically associated with RSV infections. The MVA-BN RSV vaccine demonstrated a vaccine efficacy of up to 79% in preventing symptomatic RSV infections. No vaccine-related serious adverse events were observed, and the vaccine was well tolerated, consistent with the safety profile previously reported in phase 1 and phase 2 clinical studies.
Pending further analysis of the current RSV infection rates, discussions with regulatory authorities about the Phase 3 design, and funding/partnering considerations, the Company will determine the immediate next steps and expects to communicate these during fourth quarter of 2021.
RSV (respiratory syncytial virus) has been recognized as a significant cause of respiratory illness in all age groups. It is highly infectious and the most common cause of lower respiratory tract infection in infants and children worldwide, resulting in a high number of hospitalizations. RSV infections are also a serious health concern in the elderly and in adults with cardiopulmonary disease.
According to estimates from WHO, RSV infects more than 64 million people globally each year and causes a similar number of deaths as influenza, yet unlike influenza, there is no vaccine to prevent RSV.
There are only two subtypes of RSV, A and B, which are typically present either simultaneously or alternately during yearly epidemics.