India’s first COVID-19 vaccine candidate, Covaxin, developed by Bharat Biotech is about to begin its Phase 3 trials amid a positive outlook shared by the drugmaker that it will be at least 60% successful.
The company was authorized by the Drug Controller General of India (DCGI) late last day to conduct a Phase 3 clinical trial and assess the efficacy of its vaccine candidate. It is likely that the interim results of the Phase 3 trial will be released by April or May next year.
“The benchmark for the efficacy of our anti-COVID-19 vaccine is 60%. We will be conducting the largest Phase 3 trial for Covaxin, and the efficacy results should be available by early April-May, 2021,” Sai Prasad, president of quality operations, Bharat Biotech International Ltd, said.
Mr. Prasad is a part of the product development team in Bharat Biotech.
Guidelines from WHO sets a standard for the quality, safety and effectiveness of respiratory syncytial virus vaccines and says that it should have at least 50% efficacy to be approved.
As per the current plan, the Phase 3 trial to assess vaccine efficacy will commence between early to mid-November. 26,000 study subjects at 25 to 30 sites across 13-14 states of India will participate in it. The organization recruited 375 subjects for the Phase 1 trial while in Phase 2, 400 subjects participated.
“The WHO, US FDA (Food and Drug Administration) and even India’s Central Drugs Standard Control Organization (CDSCO) approve a respiratory vaccine if it achieves 50% efficacy; for Covaxin, we aim to achieve at least 60%, but it could also be more. Chances of the vaccine being less than 50% effective are remote, as suggested by our trial results so far, which include results from animal studies.”
“We have begun site preparatory exercises for Phase 3; recruitment and dosage will begin in November. The trial will provide two doses each for the vaccine and placebo recipients. Site selection and recruitment depend on several factors such as attack rate, how the disease spreads locally, etc. About 2,000 subjects could be enrolled per hospital,” added Mr. Prasad.
Earlier the Phase 1 trial was completed by Bharat Biotech, who submitted the findings to DCGI. The findings did not identify any significant safety issues. The safety test has been completed for Phase 2, and the immunogenicity test (used to verify the immune response of the body to the vaccine) is currently ongoing.
“The follow-up for determining the immunogenicity of a vaccine candidate takes longer which is up to about a month or two. The interim data for Phase 2 will come out in November,” said Prasad.
Covaxin was developed using inactivated Sars-Cov-2, the virus that causes COVID-19, in collaboration with the Indian Council of Medical Research (ICMR)-National Institute of Virology (NIV).
According to experts, a lot would depend on the Phase 3 trial results. “Because of the large sample size for the Phase 3 clinical trial, its results will be crucial to determine whether the vaccine would work. Phase 1 and 2 trials show promise, while Phase 3 is all about performance,” said Dr K Srinath Reddy, founder, Public Health Foundation of India.
Recently, DCGI had given the go ahead to conduct the Phase 3 trials of Russian vaccine Sputnik V in India.
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