India may approve covid-19 vaccines that show 50% efficacy in clinical trials2 min read . Updated: 22 Sep 2020, 02:28 PM IST
- The Indian regulator has also clarified that people who have been infected with the novel coronavirus, SARS-CoV-2, earlier should be allowed to participate in trials as long as they did not have acute Covid-19 or other acute infectious illnesses
NEW DELHI: Taking a leaf from the benchmarks set by World Health Organization and US Food and Drug Administration, the Indian drug regulator has said it plans to approve covid-19 vaccines that can provide immunity to at least 50% of the participants in phase 3 clinical trials.
“To ensure that a widely deployed COVID-19 vaccine is effective, the primary efficacy endpoint point estimate for a placebo-controlled efficacy trial should be at least 50%," the Central Drugs Standard Control Organization (CDSCO) said in its draft regulatory guidelines for vaccine development, with special consideration for covid-19 vaccine issued on Monday.
The CDSCO’s draft benchmarks are same as those set by the WHO and US FDA in April and June respectively.
“Ideally 70% efficacy and above, but certainly 50% would be the point estimate that we would classify as an effective vaccine. It is also important how these endpoints are studied in clinical trials, because as you know around the point estimate you have confidence interval. So it is also important that the confidence intervals are not too wide," WHO chief scientist Soumya Swaminathan said on Monday at a virtual press conference, adding that the low boundary of efficacy adjusted for confidence interval is 30%.
The CDSCO has also cited the same benchmark of 30% as the lower boundary of efficacy after accounting for confidence interval. Confidence intervals look at the probability of error in efficacy rate. It is also dependent on the size of the clinical trial.
The regulator has cited various potential primary and secondary endpoints for the vaccine to target, which are goals for measuring success of the study.
"SARS-CoV-2 infection (whether or not symptomatic) should be evaluated as a secondary or exploratory endpoint, if not evaluated as a primary endpoint," the regulator said.
The Indian regulator has also clarified that people who have been infected with the novel coronavirus, SARS-CoV-2, earlier should be allowed to participate in trials as long as they did not have acute Covid-19 or other acute infectious illnesses.
“Vaccine safety and COVID-19 outcomes in individuals with prior SARS-CoV-2 infection, which might have been asymptomatic, is also important to examine because pre-vaccination screening for prior infection may not be feasible in practice when the COVID-19 vaccine is approved and introduced in the market," the regulator said in the draft.
The draft regulations come after several calls by vaccine manufacturers that India needs to have its own benchmarks for approving vaccines, something that had not been made clear so far.
Currently, there are three vaccines undergoing human trials, with another half a dozen vaccines in pre-clinical trials. The furthest of these vaccines in human trials are Serum Institute of India’s vaccines, which was jointly developed by AstraZeneca plc and University of Oxford and is currently undergoing phase 2 and 3 trials in India. The other two vaccines in human trials are Zydus Cadila’s and Bharat Biotech International’s.