Vaxart Challenges Takeda with Oral Norovirus Vaccine

Vaxart Challenges Takeda with Oral Norovirus Vaccine August 8, 2016
By Alex Keown, BioSpace.com Breaking News Staff

SOUTH SAN FRANCISCO – Nausea. Diarrhea. Extreme stomach discomfort. Exhaustion. Dehydration.

None of those sound pleasant and when coupled together, it’s a witch’s brew of bad health news. In other words, it’s the norovirus, a highly contagious virus that can wrack individuals young and old. The symptoms can be serious for some people, particularly the younger or older patient, due to the threat of dehydration. It’s a serious illness that sickens about 700 million people annually, causing 219,000 deaths and has an estimated $64 billion economic impact, mostly through productivity losses. Currently there are no approved vaccines for the virus.

However, San Francisco-based Vaxart is hoping to change that with the first oral vaccine for the norovirus. The company is initiating a Phase I clinical trial of Vaxart’s VP1 protein-based norovirus oral tablet vaccine, studying the safety and immunogenicity in 66 adult volunteers.

“It’s a memorable event if you run into this guy,” Wouter Latour, Vaxart’s chief executive officer, said of the norovirus during an exclusive interview with BioSpace.

The first patient was dosed on July 31 and Latour said so far things are going well. The 66 candidates were dosed with a single tablet during this study and will be followed by researchers for one year. Latour said researchers will be looking for a broad range of systemic and local immune responses, essentially antibodies. Vaxart researchers will learn if it’s effective in developing antibodies in patients and how long the protection could last against the norovirus.

He anticipates interim data from the trial being available in the first half of 2017.

“One of the advantages of the approach we’ve taken is we have a pretty good idea of what kind of responses should happen,” he said. “It gives us a good sense in a first trial of whether it’s safe and effective.”

Unlike the flu, the norovirus does not evolve yearly, but does change every five or so years, Latour said.

Since it is tablet-form vaccine, Latour said that could be advantageous in the fight against the norovirus, as it is easily transportable globally and does not require a qualified healthcare professional to administer the drug. The tablet also eliminates medical waste that injectable vaccines leave behind.

Vaxart is not the only company working on a vaccine for the norovirus. Japan-based Takeda Pharmaceuticals also has a vaccine in the clinic, although this one is an injectable. Latour said Takeda has blazed a trail in the field for norovirus vaccine development. In June, Takeda initiated the first field test of its norovirus vaccine—a Phase IIb study that will evaluate the efficacy of intramuscular administration of Takeda’s norovirus vaccine candidate against moderate or severe acute gastroenteritis (AGE) due to norovirus.

But because Vaxart’s drug is an oral, Latour said he believes that will give Vaxart an edge over a Takeda vaccine because it would have a greater impact in the gut.

“The norovirus is an infection of the intestine. Vaccinating the intestine itself will give a superior profile compared to an injectable,” he said.

This marks the third drug Vaxart has moved into the clinical trial phase. The South San Francisco-based company also has oral vaccines for respiratory syncytial virus and seasonal influenza. Last year, Vaxart was an almost $14 million grant by the Office of Biomedical Advanced Research and Development Authority (BARDA) to fund a Phase II challenge study. In this study, Vaxart’s vaccine will be tested against a traditional injectable and a placebo. Latour anticipates data from the Phase II trial in 2017.

Vaxart is also developing an oral vaccine for the Zika virus, although this is still in preclinical but Latour said he feels the company is headed in the right direction regarding the mosquito-borne illness.

“This (Zika virus) is bad news all around and doesn’t seem to show signs of stopping. This tablet-form vaccine could make a huge difference in the areas most impacted,” Latour said.

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