Aviragen, Vaxart merge to develop oral vaccines for influenza, norovirus and RSV

merger and acquisition
Aviragen and Vaxart have merged into a single company that develops oral vaccines against seasonal flu, norovirus and RSV. (istocksdaily)

For some antigens like norovirus and RSV, there are no approved vaccines. For others, like the seasonal flu, immunization rates are often far from ideal. Now, a new company, the product of a merger between Aviragen Therapeutics and Vaxart, aims to develop oral vaccines against these diseases.

After the transaction, which executives believe will close early next year, the combined company will take Vaxart’s name. Vaxart CEO Walter Latour will lead the combined company and shares will trade on Nasdaq under the proposed ticker “VXRT.”

The new Vaxart will have about $30 million in cash, which it will use to advance several key candidates in the company’s pipeline, Wouter Latour, M.D., CEO of Vaxart, said during a conference call on Monday about the transaction. Recent positive clinical data have derisked Vaxart’s platform, Aviragen CEO Joseph Patti, Ph.D., said on the call, leading the Nasdaq-listed company to pursue the merger after an extensive review of about 60 strategic options.

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An H1N1 influenza vaccine is currently farthest in the company’s pipeline. In a head-to-head phase 2 challenge study funded by a $13.9 million contract from the HHS’ Biomedical Advanced Research and Development Authority (BARDA), the Vaxart tablet vaccine reduced disease by 39%, compared to a 27% reduction by Sanofi Pasteur’s market leader, Fluzone quadrivalent.

“These results provide clinical proof-of-concept for Vaxart’s groundbreaking oral tablet vaccine technology,” Latour said in an Oct. 26 statement (PDF) announcing the results. “A convenient and effective tablet vaccine could significantly increase current vaccination rates and generate important public health benefits for at-risk groups and the population as a whole,” he said.

Although the CDC recommends all eligible children and adults get a flu shot, the agency estimated that only 59% of adults and 43.3% of children got one during the 2016-17 flu season.

RELATED: Takeda's lead in norovirus boosted by first major field trial

Vaxart has also announced readouts from a 60-participant, phase 1b, dose-ranging study on its norovirus candidate. All of those in the high-dose group experienced significant increase in IgA and IgG antibody cells, and more than 90% had at least two-fold increase of norovirus-blocking antibody titers 28 days after dosing, according to the company.

According to CDC’s tally, norovirus causes about 19 to 21 million cases of acute gastroenteritis in the U.S. each year, but there’s no vaccine available to prevent norovirus infections. Takeda is currently leading research efforts in the field.

Now, Vaxart plans to start a phase 2 challenge study for its norovirus candidate in the second half of 2018. Besides that, it also has a preclinical RSV candidate and a preclinical therapeutic vaccine for HPV. Vaxart values all these clinical assets at $90 million.