Covaxin showed 81% interim efficacy: Bharat Biotech on Phase 3 results

Covaxin demonstrates significant immunogenicity against the rapidly emerging variants, says Bharat Biotech CMD

Bharat Biotech's homegrown Covid-19 vaccineç Covaxin, has shown an interim vaccine efficacy of 81% in late-stage clinical trials, the Hyderabad-based company said on Wednesday. That’s better than Bharat Biotech’s guidance last year of around 60% and India’s benchmark of 50% for vaccines targeting the novel coronavirus.

The trials involved 25,800 participants and was conducted in partnership with Indian Council of Medical Research (ICMR), the Indian government's medical research body. This was the largest ever trial conducted in India. 

"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 company said in a statement. 

"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 1, 2, and 3 trials involving around 27,000 participants," Bharat Biotech Chairman and Managing Director Krishna Ella said.

Covaxin demonstrates high clinical efficacy trend against Covid-19 but also significant immunogenicity against the rapidly emerging variants, he added. 

Analysis from the National Institute of Virology indicates that vaccine-induced antibodies can neutralize the UK variant strains and other heterologous strains, said the company.

“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. “We could not have achieved this public-private partnership milestone without the relentless commitment of those involved.”

Participants received a vaccine or placebo in a 1:1 ratio, which showed that the vaccine candidate was well tolerated, said the company. Bharat Biotech expects to share further details of the trial results as additional data become available. An additional interim analysis is planned for 87 cases, and the final analysis is planned for 130 cases. All data from the second interim and final analyses will be shared via pre-publication servers as well as submitted to a peer-reviewed journal for publication.

"Clinical trial to 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," the company said. 

The interim analysis was based on 43 recorded cases of Covid-19 in the trial of 25,800 participants.

Thirty-six of the 43 cases were recorded in participants who received a placebo, compared with seven cases in people who were given the Bharat Biotech vaccine, pointing to an efficacy rate of 80.6%, the company said.

India had approved Covaxin in January without late-stage efficacy data, raising questions about its effectiveness.

Earlier this week, Indian Prime Minister Narendra Modi was inoculated with the first dose of Covaxin.

"More than 40 countries globally have expressed their interest in Covaxin. These countries are highly satisfied with the safe, inactivated vaccine technology and robust data package for safety and immunogenicity," said Bharat Biotech. 

The findings cement Bharat Biotech’s claims of the vaccine being safe and may help overcome vaccine hesitancy as India rolls out one of the world’s biggest inoculation programs to contain Covid-19 outbreak. The data is also a rebuttal for critics who had questioned the unprecedented haste with which the indigenously produced shot was approved in early January and deployed among India’s frontline health care workers even before providing any Phase 3 trial data.

In June last year, India’s drug regulator permitted the family-run and closely-held Bharat Biotech to develop a homegrown vaccine in record time. Soon after, work on Covaxin was bogged down by controversies ranging from unrealistic government schedules to sporadic reports of adverse reactions.

Despite the vaccine receiving the emergency use approval in January, many of those in the priority list for receiving the initial injections failed to turn up for their shots, concerned that they may be given the experimental vaccine. The sign ups among those willing to be vaccinated have improved in the past week.

Officials in New Delhi and the management of Bharat Biotech have vigorously defended the vaccine’s safety and effectiveness during the roll out. The new data may boost uptake in a nation that has registered the world’s second-largest outbreak and is reporting a further spurt of infections in some states such as Maharashtra, triggering fears of regional restrictions after a national lockdown in March last year that hobbled the economy.

India has also approved the shot from Astrazeneca Plc’s local partner, the Serum Institute of India Ltd., but the country’s inoculation campaign saw a tepid response in the initial weeks, endangering its target of reaching about a quarter of its population by August.

With a capacity to manufacture about 300 million doses on an annual basis, the promising efficacy data will likely aid Bharat Biotech find further export markets. The company shipped the vaccine to Brazil this month and has signed an agreement with Ocugen Inc. to co-develop the vaccine for the U.S.

The encouraging news comes at a time when India has seen a sudden spurt in new cases and has also entered the next phase of Covid-19 vaccination, whih commenced from March 1 for those who are over 60 years of age and for people aged 45 and above with specified co-morbid conditions.

More than 1.56 crore (1,56,20,749) vaccine doses have been administered through 3,12,188 sessions, according to provisional report till Wednesday 7 am.

These include 67,42,187 healthcare workers (1st dose), 27,13,144 HCWs (2nd dose), 55,70,230 frontline workers (1st dose) and 834 FLWs (2nd dose), 71,896 beneficiaries aged more than 45 years with specific co-morbidities (1st dose) and 5,22,458 beneficiaries aged more than 60 years.

Maharashtra, Kerala, Punjab, Tamil Nadu, Gujarat and Karnataka continue to report a surge in fresh COVID-19 cases and they account for 85.95 per cent of the cases reported in a span of 24 hours, the Union Health Ministry said on Wednesday.