Hyderabad-based pharma company Bharat Biotech, on Wednesday, released the results of the first analysis of Covaxin phase 3 clinical trial. The COVID-19 vaccine demonstrated an interim vaccine efficacy of 81% in its phase 3 clinical trial. Covaxin is currently in its phase three clinical trial and is one of the two COVID-19 vaccines (apart from Serum Institute of India’s Covishield) currently being administered to the health care workers, frontline workers, citizens above 60 years and those above 45 years with comorbidities as part of the COVID-19 vaccination drive.
The interim analysis comes two months after several experts questioned the Indian drug regulator for approving Covaxin despite not having phase-three efficacy data. In January, when the Drug Controller General of India (DCGI) permitted Covaxin “for restricted use in clinical trial mode”, health experts questioned the urgency to push a vaccine that is still in its phase three clinical trial, especially in the absence of sufficient data to support its efficacy.
Bharat Biotech’s trial involved 25,800 subjects, one of the largesin India and was done in partnership with the Indian Council of Medical Research (ICMR). Bharat Biotech’s first interim analysis is based on 43 COVID-19 cases. While Pfizer analysed 170 cases of infection as part its interim analysis, Moderna announced its results based on 95 cases. AstraZeneca-Oxford vaccine (which is being manufactured in India as Covishield) analysed 131 cases in its interim analysis. Russia's Sputnik V published its interim results based on 26 cases. Pfizer, Moderna and Sputnik V reported an interim vaccine efficacy of over 92%. The AstraZeneca vaccine tested at Pune's Serum Institute of India reported an efficacy range of 62-90%, depending on the vaccine dose deployed.
The Phase 3 study enrolled 25,800 participants between 18-98 years of age, including 2,433 over the age of 60 and 4,500 with comorbidities. The first interim analysis is based on 43 cases, of which 36 cases of COVID-19 were observed in the placebo group versus seven cases observed in the Covaxin group, resulting in a point estimate of vaccine efficacy of 80.6%.
The data from 25,800 participants who received a vaccine or placebo in a 1:1 ratio showed that the vaccine candidate or Covaxin was well tolerated. “It was found that Covaxin demonstrated 81% efficacy in preventing COVID-19 in those without prior infection after the second dose,” said Bharat Biotech in a statement. An additional interim analysis is planned for 87 cases, and the final analysis is planned for 130 cases. The Bharat Biotech trial will continue.
Speaking about the result, Dr Krishna Ella, Chairman and Managing Director, Bharat Biotech, said, “With today’s results from our Phase 3 clinical trials, we have now reported data on our COVID-19 vaccine from Phase 1, 2, and 3 trials involving around 27,000 participants. Covaxin not only demonstrates high clinical efficacy trend against COVID-19 but also significant immunogenicity against the rapidly emerging variants”.
According to Bharat Biotech, “Analysis from the National Institute of Virology (NIV) indicates that vaccine-induced antibodies can neutralise the variant strains reported in the United Kingdom and other heterologous strains, which has been published in bioRxiv.”
Covaxin or BBV152 is an inactivated virus-based vaccine against coronavirus. It is stable at 2 to 8°C (refrigerated). It is shipped in a ready-to-use liquid formulation that permits distribution using existing vaccine supply chain channels. “The vaccine has a 28-day open vial policy as a unique product characteristic, thus reducing vaccine wastage by approximately 10-30%,” the company said.
India is currently in its second phase of the COVID-19 vaccination drive. Persons above 60 years and those between 45 and 59 with comorbidities are eligible to take the vaccine. Prime Minister Narendra Modi was among the leaders to take the Covaxin to quell vaccine hesitancy and encourage others to take the shot.