Dynavax dips as its hep B drug faces another setback
- An approval decision for Dynavax Technologies Corp.'s hepatitis B medication may not come until November due to a Food and Drug Administration request for more information about a planned, post-marketing study of the drug.
- The FDA wants more specific details about the study's timeline — including when the drugmaker intends to submit a final protocol — as well as its enrollment, data review, bias control methods and statistical analysis plan, according to a statement issued Thursday afternoon.
- Dynavax's Heplisav-B had a target action date of Aug. 10. But providing those added details constitutes a major amendment to the drug's Biologics License Application (BLA), meaning the FDA gets an additional three months to make its approval decision. Dynavax expects the decision no later than Nov. 10.
Heplisav-B (hep B vaccine, recombinant (adjuvanted)) has experienced a journey to market laden with setbacks. The latest one, however, was a little more surprising.
That's because the drug received a thumbs up from the FDA's Vaccines and Related Biological Products Advisory Committee (VRBPAC) just last week. By a 12-1 vote with three members abstaining, the committee determined Heplisav-B was safe enough to send it to market. U.S. regulators had long recognized the drug's efficacy, but safety concerns, such as the potential for patients to experience cardiac or rare autoimmune adverse events, resulted in the FDA rejecting Heplisav-B's BLA twice before.
Though the FDA isn't required to follow advisory committee recommendations, it often does. And investors banked on that likelihood; Dynavax shares opened at $16.95 apiece on July 31, up more than 83% from the previous close on July 28.
Dynavax did note in a July 28 statement announcing the committee's positive opinion that conversations were ongoing with the FDA about Heplisav-B post-marketing initiatives. It's clear now that ironing out the details of those initiatives will be more time-consuming than investors may have guessed.
"Our conversation with the Agency was open and productive and confirmed our mutual understanding of the VRBPAC's suggested requirements for the post-marketing study," Dynavax CEO Eddie Gray said in the Aug. 3 statement. "We are working with our third-party providers to develop an appropriate study that addresses the advisory committee's feedback. We now have clarity on the path forward and next steps required to complete the regulatory review of Heplisav-B."
In spite of the target action date delay, Dynavax still expects to launch Heplisav-B in the U.S. in early 2018.
And yet — even with shareholder and advisory committee backings — the drug hasn't been able to break away from its history of setbacks. Following this latest one, Dynavax shares opened at $16.10 apiece on Friday morning, down more than 5% from the previous day's close.
- Dynavax Technologies Corp. Statement
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