Antibody levels maintained against multiple targets 6 months post vaccination.

Bavarian Nordic has announced 6-month follow-up data from the Phase I trial of MVA-BN RSV, its novel, broad spectrum vaccine against respiratory syncytial virus (RSV). The randomized, placebo-controlled trial, evaluated the safety, tolerability and immunogenicity of the recombinant vaccine in 63 healthy adults, including an elderly group of individuals and positive top line results were reported in May 2016.

The 6 month (30 weeks) analysis revealed that the antibody response induced by the vaccine candidate remained at similar levels previously reported, demonstrating that MVA-BN RSV induced a durable immune response lasting at least 6 months; a period spanning a normal RSV season. Specifically

• neutralizing antibodies against both RSV subtypes A & B remained at similar levels previously reported for 8 weeks post the vaccination
• blood IgG and IgA, the later a specialized antibody that is transported from blood to mucosal surfaces (e.g. throat, lungs etc.) remained elevated at the levels previously reported for 6-8 weeks post the initial vaccination.

Additionally, T cell responses have now been measured for all RSV proteins included in the vaccine. There was a 3-4 fold increase in the T cell response in the elderly volunteers to the RSV Matrix (M) protein and the surface glycoprotein (G) from RSV subtype B. Therefore, MVA-BN RSV has now induced a strong (3-5 fold) booster response to all five RSV proteins included in the vaccine (Fusion [F], G [from both subtype A & B], nucleocapsid [N] and M).

"These data are another important step in the development of an effective RSV vaccine, as we have shown this vaccine, based on our potent MVA platform, is able to induce a durable immune response spanning at least a whole RSV season. We are highly encouraged that our vaccine candidate has induced a robust and broad immune response against 5 RSV proteins, which remains a clearly differentiated approach to prior RSV vaccines based on using only a single RSV protein," said Paul Chaplin, President and CEO of Bavarian Nordic.

An ongoing Phase II trial is evaluating the safety and immunogenicity of two different doses, with or without a booster at day 28, of MVA-BN RSV in 400 healthy subjects aged 55 or older. Top-line results from the randomized, placebo controlled study are anticipated in mid-2017 and will provide essential information for subsequent, larger efficacy studies.