PaxVax, a US-based developer of new vaccines against infectious diseases, has started its Phase III clinical trial programme for its single-dose oral cholera vaccine, PXVX0200 also called as CVD 103-HgR.
Some 3,000 participants will be enrolled in the trial programme, which includes cholera challenge, safety and immunogenicity studies.
Travellers in Europe and elsewhere currently have a cholera vaccine that needs a two-dose treatment, which takes longer to complete, while a single-dose, oral vaccine would be more convenient for all travellers to take, mainly those who travel on short notice.
Cincinnati Children’s Hospital Medical Center professor Mitch Cohen said cholera continues to infect areas around the world that suffer from poor sanitation, poverty, and poor access to safe drinking water, particularly parts of the world like Haiti and South Asia that are recovering from recent natural disasters.
"For travellers visiting endemic areas of the world, where significant risk of contracting cholera exists, we are eager to start these clinical trials, which will determine if an oral, single dose of PXVX0200 provides protection against cholera after vaccination," Cohen said.
Three top vaccine testing centres including the University of Maryland, the University of Vermont Vaccine Testing Center and Cincinnati Children’s Hospital Medical Center will be responsible for carrying out the main efficacy cholera challenge studies.
All these efficacy trials will be randomised, double-blind and placebo-controlled.
Initially, vaccination will be given to volunteers enrolled in the trials and then challenged, or exposed to the cholera-causing agent and at ten days after vaccination, as well as at three months post-vaccination, participants will be evaluated to determine the protective ability of PXVX0200.
Each clinical research centre will follow all standard clinical trial safety procedures and guidelines while carrying out the studies.
In order to confirm vaccine safety in a larger population, measure immunogenicity, and demonstrate lot-to-lot consistency of different vaccine manufacturing batches required by the FDA, additional trials will be carried out at sites in Canada, Australia, and the US.
In recognition of the lack of any available traveller’s vaccine against cholera, and the corresponding unmet medical need, PXVX0200 has been granted ‘fast track’ designation by FDA.
According to the results of the Phase I trial, a single oral dose of PXVX0200 was highly immunogenic; overall, seroconversion to vibriocidal antibody occurred in 89% of vaccines by day 14.
PaxVax CEO Ken Kelley said: "PXVX0200 is our lead vaccine candidate. Pending the successful outcome of these trials, we hope to file a Biologics license application (BLA) and begin to establish our traveller’s vaccine portfolio."
Cholera is an acute intestinal infection generally caused by consuming contaminated water or food, which contains toxigenic Vibrio cholerae bacteria.
Currently, there is no vaccine available for cholera in the US and for the residents who may travel abroad to areas where cholera is common.