Convalescent plasma therapy, which recently received emergency use authorisation in the US, has failed to save people dying from Covid-19, found a clinical trial carried out by the Indian Council of Medical Research (ICMR) at multiple centres involving 464 patients.

Mortality rates

The randomised controlled trials named PLACID Trials were conducted between April 22 and July 14 at 39 centres across the country, and it failed to exhibit any significant difference in the mortality rates between those who received convalescent plasma and those in the control group, said the results of the study posted on MedRxiv on Tuesday.

In India, too, convalescent plasma is authorised for off-label use, and many States already use it on compassionate grounds.

While 235 patients received convalescent plasma therapy, along with standard Covid-19 care, 229 patients in the control group received onlyCovid-19 care. As many as 47 people who received convalescent plasma therapy, and 41 people in the control group, died during the course of treatment.

“CP (convalescent plasma) was not associated with reduction in mortality or progression to severe Covid-19,” said the scientists led by Anup Agarwal and Aparna Mukherjee at ICMR’s Clinical Trial and Health Systems Research Unit. Apart from a few other ICMR colleagues, physicians and researchers from 39 hospitals and research labs were also authors of the study.

The scientists refused to discuss more on the findings, citing conflict of interest, as the study is expected to appear in a peer-reviewed journal soon.

Symptomatic relief

Even though plasma therapy did not reduce mortality when compared to other treatments, if offered some symptomatic relief to patients who received it. According to the study, most patients who received plasma therapy were found to exhibit improvement in shortness of breath and fatigue when compared to those in the control group.

Another interesting observation by the researchers was that as most of the donors who donated plasma were those with mild Covid-19 infection, the plasma contained fewer neutralising antibodies in their serum. Moderate-to-severe patients who recovered may have higher concentration of neutralising antibodies in their plasma, but they were reluctant to donate plasma. This, too, may probably have had an impact on the outcome.

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