The government plans to disallow the use of placebo in clinical trials of upcoming Covid-19 vaccines and, instead, allow companies to use an existing vaccine (such as Covishield or Covaxin) to assess the immunogenicity and efficacy of the new vaccine, reports The Economic Times. Placebo is an inactive drug or treatment used in clinical trials.
One of the reasons officials cited for the proposed change is that participants placed in the placebo arm in such trials will lose out on vaccines. Some experts had called for such a change in trials.
“A placebo arm was justified when there was no vaccine available, but depriving a person of the currently available standard of care is unethical,” Amar Jesani, editor of Indian Journal of Medical Ethics says. “In a trial, 50% of the participants get vaccines while the rest who are in a placebo arm do not get any. Why should one join a trial when a vaccine is easily available?” he says.
In phase 3 trials of Covovax — Serum Institute of India’s version of Novavax’s Covid-19 vaccine — the Drugs Controller General of India (DCGI) has already approved conducting the clinical trials by doing away with placebo.
Some experts said making a comparison of various Covid-19 vaccines is difficult because they are developed on different technology platforms.
Ideally, vaccines from the same platform should be used as a comparator, they said, adding that the unavailability of mRNA vaccines like Pfizer and Moderna vaccines in India poses a challenge for Gennova’s vaccine candidate.
According to a recent article in New England Journal of Medicine (NEJM), a long-standing practice in research has called for either stopping the ongoing trials when a successful product is available outside such trials or at least informing trial participants so that they may leave the study in order to access the newly available product.