Bavarian Nordic, touting phase 3 smallpox win, says it plans FDA filing for Imvamune

Bavarian Nordic plans to file for U.S. approval for its smallpox vaccine later this year. (Bavarian Nordic)

With a second set of phase 3 data in hand for smallpox vaccine Imvamune, Bavarian Nordic is gearing up for a U.S. filing later this year. On Tuesday, the biotech announced that its shot met primary endpoints in a late-stage noninferiority trial against Emergent BioSolutions' ACAM2000, the only smallpox vaccine currently approved by the FDA. 

In the study, investigators recorded peak neutralizing antibodies induced by Imvamune that were twice as high as those elicited by ACAM2000, a "statistically superior immune response," according to the biotech. 

The trial evaluated liquid-frozen Imvamune and ACAM2000 in 440 people at a U.S. military base in South Korea. The U.S. Army Medical Research Institute of Infectious Diseases led the work, helped by the U.S. Defense Health Agency. Together with earlier Imvamune clinical trial results, the data support "a favorable safety profile and efficacy in comparison to replicating smallpox vaccines" such as Emergent's option, the Danish vaccine developer said in a statement.

Emergent BioSolutions purchased ACAM2000 and a manufacturing facility in Massachusetts from Sanofi last year in a deal worth up to $125 million. But ACAM2000 is contraindicated in 66 million people in the U.S., according to a representative for Bavarian Nordic, including elderly individuals, pregnant women and those who are immunocompromised. 

The U.S. government already stockpiles Bavarian Nordic's Imvamune for emergency use for those who can't receive ACAM2000. The BN vaccine is approved in Canada as Imvamune and in the European Union as Imvanex. 

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According to BN's website, the U.S. government wants to stockpile enough nonreplicating vaccine to protect all 66 million people who can't receive ACAM2000. The biotech has already supplied 28 million liquid-frozen doses to the U.S. stockpile but has newer contracts to replenish the stockpile with a freeze-dried formulation. Both vaccines have received development assistance from the government.

FDA approval for Imvamune would grant Bavarian Nordic access to a priority review voucher, which could be used to accelerate a future review or sold to another drugmaker. The biotech plans to file for Imvamune approval in the second half of 2018.