After Prostvac flop, Bavarian Nordic showcases 6-month RSV data

Bavarian Nordic
After a major cancer vaccine misstep, Bavarian Nordic reports positive six-week data from an ongoing phase 2 study on its RSV vaccine candidate.

Bavarian Nordic is ready to turn the page after its key cancer vaccine candidate Prostvac failed a phase 3 study, wiping off half its share price. The vaccine specialist is touting six-month data on its its candidate against RSV, simultaneously rolling out a new plan for an RSV challenge study.

At six months of follow-up, investigators are still finding persistent antibody response against multiple RSV targets in participants vaccinated with the MVA-BN vaccine. The findings are in line with investigators’ observations at the three-month mark.

MVA-BN RSV uses a vectored technology different from that used in Prostvac. Earlier results from the 421-subject study in the U.S. showed that most participants experienced 5- to 10-fold T-cell responses over placebo one week after vaccination, and two- to fourfold antibody responses after two weeks.

Free Daily Newsletter

Like this story? Subscribe to FiercePharma!

Biopharma is a fast-growing world where big ideas come along daily. Our subscribers rely on FiercePharma as their must-read source for the latest news, analysis and data on drugs and the companies that make them. Sign up today to get pharma news and updates delivered to your inbox and read on the go.

RELATED: Bavarian Nordic tanks after Bristol-Myers-partnered vaccine flunks phase 3 prostate cancer trial

Apart from the original plan to follow these healthy adults aged 55 and older for another six months to evaluate the vaccine’s long-term immunogenicity, Bavarian Nordic is now also planning a human challenge study. The study, slated to start in the second half of 2018, will give researchers an idea of the vaccine’s efficacy prior to a phase 3 trials, assisting them in the planning and design of late-phase trials, the company said.

The Danish company has partnered with a global CRO to develop the challenge model. It said in a release that the company has developed a primary isolate of RSV, which has a level of virulence on par with viruses circulating naturally outside of the lab. Bavarian Nordic didn’t reveal the identity of the CRO, and CEO Paul Chaplin only said in a statement that the CRO “is an ideal partner and a leader in the field having previously been successful in developing a virulent influenza challenge model.”

Also working to nab a share out of a potential $6 billion RSV vaccine market is Novavax, which in July posted positive topline data from a new 300-subject phase 2 study, tentatively confirming a way forward to pair the vaccine with an adjuvant to secure better efficacy. Novavax’s vaccine previously failed a large-scale phase 3 because of what the company called a weak RSV season. Because of that lesson, Bavarian Nordic said it will not limit its phase 3 to just one RSV season.

The new six-week RSV data came just days after Bavarian Nordic pulled the plug on its Bristol-Myers Squibb-partnered cancer vaccine Prostvac as a standalone therapy, as it decided that continuing a phase 3 would be futile. Shares in Bavarian Nordic fell more than 50% following the news at the time. Now, Prostvac's future lies only in its possibility of being paired up and enhancing the effect of other immuno-oncology agents.