Plasma therapy gets thumbs down from expert panel

Convalescent plasma (plasmaderived therapy) from Covid-19 patients and products derived from it have failed to get a thumbs up from the expert panel advising the Indian drug regulator on Covid vaccines and drugs.

The subject expert committee (SEC) noted recently that clinical trials on convalescent plasma in Mumbai’s Wockhardt Hospitals and on hyperimmune globulins by Intas Pharmaceuticals (Intas) have not shown any remarkable difference in efficacy between the treatment and control arms. The panel has rejected Intas’ application for restricted emergency-use authorisation for the blood product.

The absence of drugs to target the Sars-cov-2 virus had triggered research on repurposed drugs, as well as biologics. Immunity modulating products derived from convalescent plasma (part of blood) were put to test to see if it worked to treat Covid-19 patients.

Ahmedabad-based Intas had initiated work on what they call Covid-19 hyperimmune globulins. A patient who has recovered from Covid has antibodies that are targeted against the virus. In convalescent plasma therapy, these Sars-cov-2-neutralising antibodies containing plasma are administered to a patient. The Covid-19 hyperimmune globulin product is also prepared from convalescent plasma.

It is processed, purified, and concentrated; blood-borne pathogens, too, are removed and made into standard doses. Intas, for example, is manufacturing 10-ml vials. A patient typically needs 30-60-ml dosage, compared to 200-400 ml of plasma.

Since its storage requires 28 degrees Celsius, the handling and administration are easier. It did Phase 2 clinical trials and presented the data before the SEC. The SEC has noted, “The firm presented Phase 2 clinical study results on Covid-19 hyperimmune globulin before the committee. After detailed deliberation, the committee opined that the Phase 2 trial data presented did not show any statistical significant difference in efficacy with respect to primary and secondary endpoints between treatment and control arms. Therefore, the committee did not consider the request of the firm for approval for restricted emergency-use of the product.”

At the same time, not too many benefits were noted from the Phase 2 clinical study using convalescent plasma in patients at Wockhardt Hospitals in Mumbai, which was one of the centres conducting convalescent plasma therapy trials in India.