Bavarian Nordic RSV vaccine clears early clinical test

Bavarian Nordic

Bavarian Nordic (CPH:BAVA) has posted top-line data from a Phase I trial of its respiratory syncytial virus (RSV) vaccine. The early-phase data, which show the vaccine is safe and well tolerated, clear the path for Bavarian Nordic to advance the candidate into a larger study later this year and escalate its preparations for a planned pediatric program.

Kvistgaard, Denmark-based Bavarian Nordic tested the vaccine, named MVA-BN RSV, at two doses in 63 healthy adults aged 18 to 65 years old. Some participants experienced mild to moderate adverse reactions to the candidate, but nothing Bavarian Nordic sees as being atypical for vaccines in general. All the reactions cleared up within 5 days without intervention. The reactions were comparable across the two ages groups--18 to 49 and 50 to 65--that were enrolled in the study.

The clean safety profile was expected as Bavarian Nordic already has a wealth of clinical data from other vaccines that use the same MVA-BN technology. MVA-BN, an abbreviation of modified vaccinia Ankara and Bavarian Nordic, underpins the company’s smallpox and Ebola vaccines, both of which have advanced at least as far as late-phase trials. In advancing these programs, Bavarian Nordic has administered vaccines to more than 7,600 people, giving it a safety data set that suggested the RSV shot would emerge from Phase I with a clean bill of health.

A bigger, as-yet-unanswered question is the extent to which the vaccine can protect against RSV. The Phase I study gathered some immunogenicity data that showed an increase in antibodies and T cell responses following vaccination, but the bigger tests of MVA-BN are still to come. The first of those tests is scheduled to start later this year, when Bavarian Nordic will enroll 480 people and administer them with one of three doses of MVA-BN RSV or a placebo. By the time top-line data are ready in the middle of 2017, Bavarian Nordic hopes to have a better idea of the optimal dose and schedule.

As it stands, some fundamental questions have yet to be resolved. “Many people are speculating that RSV is a seasonal vaccination, and that may well be the case. We’re keeping that question very much open,” Bavarian Nordic CEO Paul Chaplin said on a conference call with investors. “It could well be that if you are stimulating a broad and balanced immune response that stimulates a strong memory, … you get a more durable response. In the proof-of-efficacy study we will certainly follow the subjects for multiple seasons.”

Before Bavarian Nordic gets to the proof-of-efficacy trial, it intends to start testing the vaccine in a pediatric population. And, having generated the Phase I RSV data in adults and given MVA-BN-based vaccines to children aged 6 months and up, Bavarian Nordic thinks it will be possible to expand the trial into the youngest, most vulnerable children after it starts the study in the back half of next year. “The FDA is actually quite comfortable with a stepwise approach in the first Phase I where we would be going into adolescents, children, toddlers and then … 6-month-old children,” Chaplin said.

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