Bharat Biotech International Ltd in Hyderabad will start a Phase I clinical trial of Zika virus vaccine (MR 766) in two centres in India next month. The inactivated vaccine being tested in humans will be an African Zika virus strain. “We have already got the approval from DCGI [Drug Controller General of India] in March to carry out the Phase I clinical trial,” says Dr. Krishna Ella, Chairman and Managing Director of Bharat Biotech.
It will be a randomised, placebo-controlled, double-blind trial involving 48 adults, both men and women (who are not pregnant). Each volunteer will receive two doses of the vaccine on days 0 and 30 and followed-up for a year for both safety and immune responses. Three different dose ranges (2.5, 5 and 10 microgram) will be tested.
There will be three arms in the trial and each arm will get one of the three different dose ranges. There will be 16 subjects per arm.
The Phase I human clinical trial is being initiated based on the promising results seen in animals trials. In the animal trials, two doses of the vaccine made using an African Zika virus strain conferred 100% protection against mortality and disease in mice. The protection was the same when the mice were infected with an Asian and an African Zika virus strains.
While the viral load was “undetectable” in the case of vaccinated mice, the amount of virus in unvaccinated mice shot up four days after being infected. All the unvaccinated mice died eight days after infection by the African strain of the virus and 12 days after infection by the Asian strain.