Phase 3 clinical trials of Covaxin shows 81 per cent efficacy, says Bharat Biotech

Bharat Biotech on Wednesday released results of Phase 3 clinical trials of its coronavirus vaccine Covaxin, with the drug demonstrating 81 per cent interim efficacy against Covid-19.

"The whole virion inactivated COVID-19 vaccine candidate demonstrated an interim vaccine efficacy of 81 per cent in its phase III clinical trial. The trials involved 25,800 subjects, the largest ever conducted in India, in partnership with the Indian Council of Medical Research (ICMR), the biotech company said in a release.

The company said the phase III study enrolled 25,800 participants between 18-98 years of age, including 2,433 over the age of 60 and 4,500 with co-morbidities.

"The primary endpoint of phase III clinical trial is based on the first occurrence of PCR-confirmed symptomatic (mild, moderate, or severe) Covid-19 with onset at least 14 days after the second study vaccination in serologically negative (to SARS-CoV-2) adult participants at baseline," it stated.

Bharat Biotech further said 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 BBV152 (Covaxin) group, resulting in a point estimate of vaccine efficacy of 80.6 per cent.

"The interim analysis included a preliminary review of the safety database, which showed that severe, serious, and medically attended adverse events occurred at low levels and were balanced between vaccine and placebo groups. The trial's conduct and monitoring are as per Good Clinical Practice guidelines and have been outsourced to IQVIA," it added.

The company added that the analysis from the National Institute of Virology indicates that vaccine-induced antibodies can neutralize the UK variant strains and other heterologous strains, which has been published in bioRxiv.

Talking about the phase III result, Dr Krishna Ella, Chairman, and Managing Director, Bharat Biotech said Covaxin demonstrates a high clinical efficacy trend against Covid-19 but also significant immunogenicity against the rapidly emerging variants.

"Today is an important milestone in vaccine discovery, for science and our fight against coronavirus. With today's results from our Phase 3 clinical trials, we have now reported data on our Covid-19 vaccine from phase I, II, and III trials involving around 27,000 participants," he added.

"I want to thank every one of the participants, who volunteered to participate in this vital clinical trial, our partners, principal investigators across 25 study sites, and our team at Bharat Biotech who dedicated their time to this vaccine discovery," said Suchitra Ella, Joint Managing Director, Bharat Biotech.

According to Bharat Biotech, BBV152 contains a whole virion inactivated SARS-CoV-2 vaccine, which is produced in Vero cells. It is stable at 2 degrees Celsius to 8 degrees Celsius (refrigerated) and is shipped in a ready-to-use liquid formulation that permits distribution using existing vaccine supply chain channels.

"BBV152 has a 28-day open vial policy as a unique product characteristic, thus reducing vaccine wastage by approximately 10-30 per cent. BBV152 is based on an established manufacturing platform with a better safety profile when compared to other vaccine platforms. The inclusion of the Algel-IMDG adjuvant enhances T-cell immune responses to Covid-19, leading to long-term protection," it added.

The company has further stated that the clinical trial will continue through to final analysis at 130 confirmed cases in order to gather further data and to evaluate the efficacy of Covaxin in additional secondary study endpoints.

Covaxin is one of two Covid vaccines that was granted emergency use approval in the country early January.

Drugs Controller General of India (DCGI) in early January gave permission to Covaxin "for restricted use in an emergency situation." However, a huge backlash followed the announcement as the vaccine had yet not completed Phase III trails.

On Monday, Prime Minister Narendra Modi received the first dose of Covaxin at AIIMS in Delhi as the second phase of the vaccination drive in the country began.

( With inputs from ANI )