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Studies find no evidence of convalescent plasma benefit for hospitalised COVID-19 patients

Two flagship, NIHR-supported studies - REMAP-CAP and RECOVERY - have found no evidence of benefit from convalescent plasma as a treatment for hospitalised patients with COVID-19.

After contracting a virus, blood plasma contains antibodies that can help fight infection. It was hoped that a transfusion of plasma from someone who has recovered from coronavirus may improve outcomes for COVID-19 patients.

RECOVERY

However as part of a preliminary analysis of data from 10,406 patients randomised in the convalescent plasma arm of the RECOVERY study, no significant difference was found in the primary endpoint of 28-day mortality (18% convalescent plasma vs. 18% usual care alone).

The study has therefore now closed recruitment to its convalescent plasma treatment arm for all patients hospitalised with COVID-19. The Data Monitoring Committee found no convincing evidence that further recruitment would provide conclusive proof of worthwhile mortality benefit - either overall or in any subgroup of patients. Follow-up of existing patients is ongoing and analysis is continuing - with the final results to be published in due course.

REMAP-CAP

Early findings from the REMAP-CAP trial also found that treating critically ill COVID-19 patients in intensive care with blood plasma has limited impact on patient outcomes. The analysis found a low probability (2.2%) that convalescent plasma decreased the number of days that patients require intensive care support or death by more than 20%. The researchers found no evidence of harm as a result of convalescent plasma treatment, but based on the initial analysis of 912 patients - investigators have now paused recruitment of severely ill COVID-19 patients in intensive care to this arm of the study.

The trial is continuing to analyse data in case there is evidence of benefit in a subgroup, and to see whether patients who haven’t already started making their own antibodies may still benefit from being given convalescent plasma.

Prof Anthony Gordon, Chief Investigator of REMAP-CAP said: “Although it is disappointing that all critically ill patients don’t appear to gain any benefit, this is still vitally important to know. Convalescent plasma is a precious resource, and we can now continue to focus on identifying exactly which patients might benefit the most from treatment – maybe people earlier in their illness or those with weak immune systems.”

Importance of this research

Professor Nick Lemoine, Medical Director of the NIHR Clinical Research Network said: “Despite the negative convalescent plasma results from RECOVERY and REMAP-CAP, both studies demonstrate the huge importance of randomised clinical trials. Convalescent plasma was once widely considered a therapeutic option with a high potential for treating Covid-19 - yet NIHR-supported research has shown plasma transfusion to be ineffective overall. While disappointing, data from these vital studies will allow clinicians the world over to focus treatment decisions on proven therapeutic options.

“We want to say an enormous thank you to everyone who has taken part in these urgent public health studies - as well as to all those who have so kindly donated their blood plasma through NHS Blood and Transplant, having had this dreadful disease.”

Plasma donations

Following the results from RECOVERY and REMAP-CAP, NHS Blood and Transplant (NHSBT) has now temporarily stopped collecting plasma from people who have had COVID-19. Find out more on the NHSBT website.

Find out more

REMAP-CAP: Blood plasma treatment has limited effect for sickest COVID-19 patients

RECOVERY trial closes recruitment to convalescent plasma treatment for patients hospitalised with COVID-19