The National Institutes of Health (NIH) has reported final data from a clinical trial where Covid-19 convalescent plasma did not hinder disease progression in infected outpatients who are at increased risk.
Covid-19 convalescent plasma or survivor’s plasma is the blood plasma obtained from recovered patients.
Named ‘Clinical Trial of COVID-19 Convalescent Plasma in Outpatients (C3PO)’, the study analysed the effectiveness of convalescent plasma in Covid-19 patients when given within the first week of symptom onset.
The randomised, controlled clinical trial, which began in August 2020, enrolled 511 subjects in the US to receive either high-titre Covid-19 convalescent plasma with anti-Covid-19 antibodies or placebo.
The study was mainly funded by the NIH unit National Heart, Lung, and Blood Institute (NHLBI) and the US Biomedical Advanced Research and Development Authority.
These subjects had at least one risk factor for disease progression such as obesity, hypertension, diabetes, heart disease or chronic lung disease.
Prevention of disease progression to severe Covid-19 was the goal of the C3PO trial.
Due to a lack of efficacy in a planned interim analysis, the trial was suspended in February this year.
The trial findings showed that no substantial difference in disease progression was reported between both arms.
Nearly 30% of subjects in the Covid-19 plasma arm had disease progression versus 31.9% in the placebo arm, NIH noted.
The researchers said that no harm was caused by the plasma treatment in the study subjects.
Several studies of Covid-19 convalescent plasma are currently underway or planned in various populations.
The US-wide NIH-funded randomised ‘Pass It On’ trial is analysing if convalescent plasma can aid in faster recovery in hospitalised adult patients with Covid-19.
NHLBI Blood Epidemiology and Clinical Therapeutics medical officer Nahed El Kassar said: “The results show that convalescent plasma does not appear to benefit this particular group.
“But the findings answer an important clinical question and may help bring researchers a step closer to finding more effective treatments against this devastating disease.”
The US Food and Drug Administration granted emergency use authorization for use of convalescent plasma in hospitalised Covid-19 patients last year.