Imvamune smallpox vaccine is effective in comparison to ACAM2000.

The study achieved both of its primary endpoints, demonstrating Imvamune's efficacy in comparison to ACAM2000, the current U.S. licensed replicating smallpox vaccine. In this randomized, open-label study of 440 volunteers, the peak neutralizing antibodies induced by Imvamune were shown to be 2-fold higher than those stimulated by ACAM2000. This met the co-primary endpoint of non-inferiority and was even shown to be a statistically superior immune response.

A historical measure of efficacy against smallpox in people vaccinated for the first time was the induction of a vaccine take (pustule, scab and scar) following the skin vaccination (scarification) with replicating smallpox vaccines like ACAM2000. However, the prevention or attenuation of a take in subjects that are re-vaccinated was a historical measure that a subject had a protective immune response against smallpox. Importantly, this co-primary endpoint was also successful. Primary vaccination with Imvamune resulted in a highly attenuated take (reduction in lesion size), and in fact prevented the vaccine take in the majority of subjects re-vaccinated with ACAM2000.

Imvamune has been given to more than 7,800 subjects in 21 clinical studies, including two Phase III studies that have supported a favorable safety profile and efficacy in comparison to replicating smallpox vaccines.

Comment: The company plans to file a Biological License Application in the second half of 2018. If approved, the Company would also be eligible to receive a Priority Review Voucher, which could be used to accelerate the review of a future BLA, and is also transferrable. The vaccine is approved in the EU and Canada.