Dynavax's hep B vaccine outperforms Glaxo's jab in top-line PhIII results

The FDA has already rejected Dynavax's ($DVAX) hepatitis B vaccine once, but the Berkeley, CA-based biotech is planning to resubmit its licensing application for the jab as it serves up promising top-line data from the third Phase III trial of Heplisav-B.

The trial pitted the candidate against GlaxoSmithKline's ($GSK) already marketed Engerix-B, which has been the standard of care since its approval in 1989. Dubbed HBV-23, the trial took place at 40 sites in the U.S. and involved an estimated 8,250 adults aged 18 to 70 with Type 2 diabetes. Two-thirds of participants received two doses of Heplisav-B a month apart, and the remaining third received three doses of GSK's Engerix-B, at zero, one, and 6 months, the company said in a statement on Thursday.

The data indicated that Heplisav-B conferred a "statistically significant higher rate of seroprotection" against hep B in diabetic patients (90%) as compared to the rate of protection conferred by Engerix-B (65%). Heplisav also outperformed Engerix-B in every subgroup analyzed, by sex, body mass index, etc., as well as in the overall population (95.4% vs. Engerix-B's 81.3%).

"We are delighted to report these topline results from HBV-23 and confirm our intention to resubmit the HEPLISAV-B BLA by the end of March," said Dynavax CEO Eddie Gray in the statement. "These results support our belief that HEPLISAV-B, if approved, could offer benefits to adults at risk for hepatitis B." The company anticipates a 6-month review period by the FDA.

Dynavax launched HBV-23 in response to a 2013 Complete Response Letter, in which the FDA requested more safety data. The rejection followed an FDA panel vote, which deemed the safety data inadequate on the concern that the vaccine's adjuvant could cause autoimmune disorders.

While some autoimmune events were recorded in the trial, they were evenly distributed over the two arms, affecting 11 patients in the Heplisav group and 10 in the Engerix group. The number of patients experiencing "new-onset" autoimmune events was more skewed toward Heplisav: 8 patients in that arm versus just one in the Engerix arm. But given the balanced distribution in the total population of the trial, RBC Capital Markets' Simos Simeonidis wrote in an analyst note that the candidate "should still be OK in terms of approval."

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