News Feature | December 15, 2014

PaxVax's Single-Dose Cholera Vaccine Succeeds In Final Phase 3 Study

By C. Rajan, contributing writer

California based vaccine maker, PaxVax, has announced positive results from the final Phase 3 trial of its single-dose oral cholera vaccine candidate, PXVX0200.

Based on the positive results of this last clinical milestone, PaxVax intends to submit a Biologics License Application (BLA) for the vaccine under the brand name Vaxchora, to the U.S. FDA in mid-2015. The company also plans to submit market applications in the EU, Canada, and Australia.

This Phase 3 trial was designed to test the safety, immunogenicity, and lot-to-lot consistency of the vaccine and enrolled about 3,000 participants at trial sites in Australia and the U.S. Three consecutive production lots of the PXVX0200 vaccine candidate were evaluated and found to induce satisfactory immunological responses across the clinical trial subjects.

Earlier this year in July, the company reported that the vaccine also met the goals in 10-day and 90-day cholera challenge, safety, and immunogenicity trials. The study showed that the vaccine was effective in 90 percent of patients “challenged” with the cholera causing agent 10 days after vaccination, and in 80 percent of patients 90 days after vaccination.

Last December, PaxVax secured $22 million in Series B financing and converted $35 million in debt to fund these final stage clinical trials.

There is no cholera vaccine currently available in the U.S., and if approved, PXVX0200 would be the first single-dose oral cholera vaccine available for U.S. travelers. PXVX0200 is prepared from a live but weakened cholera strain (CVD 103-HgR) that was previously approved and marketed in Europe in the 1990s under the brand name Orochol.

Only one cholera vaccine, Dukaro (Janssen), is available in Canada, Europe, and Australia, which is prepared from a killed cholera strain and requires a two dose regimen. PaxVax says that its single-dose vaccine will be advantageous to people who need to travel internationally at short notice.

“U.S. travelers currently have limited options to protect themselves against cholera, and we are pleased with the progress we are making in bringing an effective single-dose cholera vaccine to travelers and potentially those suffering endemic disease in developing countries in the future,” said Kenneth Kelley, CEO of PaxVax. “These favorable lot-to-lot consistency results validate our manufacturing capabilities and provide us with the last critical data required to support our BLA submission for Vaxchora.”

Cholera is a severe infectious disease caused by the bacterium, Vibrio cholerae, which is found in contaminated food and water. The toxigenic bacteria releases toxins in the intestines and causes severe watery diarrhea, which can lead to dehydration and death within a few hours if untreated. While it is relatively rare in the U.S., cholera is quite prevalent in other parts of the world and poses a major risk to travelers. The WHO estimates that there are 3 to 5 million cases of cholera every year with nearly 120,000 deaths.