Trial of Prion-filtered vs Standard Red cells in Surgical and Multi-transfused Patients

Do patients given prion-filtered red cells experience any unusual adverse reactions or develop significant new antibodies?

What was this study about?

The appearance of variant Creutzfeld-Jacob disease (vCJD) has put the safety of the blood supply in the UK at risk as it is possible that vCJD could be transmitted through blood, and possible transmissions have been recorded. A new blood filter has been produced which removes prions, which are thought to be the infectious particles that cause vCJD.

This trial was part of a wider clinical evaluation to assess the safety of using these filters in patients being undertaken by the UK Blood Services, and was planned as a two stage trial. PRISM Study A was a safety study being conducted in patients given prion-filtered blood.  The objective of the study was to evaluate the clinical safety of blood red cells that had been filtered through the European Union approved P-Capt Prion Filter which removes prions.

What difference did this study make?

The results demonstrated that transfusion of prion-filtered red cells to patients undergoing surgery did not increase the rate of adverse immune responses or other reactions.
This outcome has been accepted by the Department of Health Safety Committee (SaBTO) and together with other studies that ran in parallel to PRISM-A, incorporated into their final recommendations on the implementation of the P-Capt Prion Filter.

Although the P-Capt Prion Filter was considered safe, based on the results of the trial, SaBTO's final decision was not to implement this procedure for various reasons. 

The PRISM-A study was conducted for the UK Blood Transfusion Services (UKBTS) and coordinated by the former NHSBT/ MRC Clinical Studies Unit.

Type of study

Non-randomised trial

Contact details

Who funded the study?

The trial was funded by the UK Blood Services comprising: NHS Blood and Transplant (NHSBT), Scottish National Blood Transfusion Service (SNBTS), Welsh Blood Service (WBS) and Northern Ireland Blood Transfusion Service (NIBTS)

When did it take place?

Recruitment to PRISM-A started on 01/07/2007 and ended on 31/03/2011.

Where did it take place?

PRISM-A recruited in 9 centres; 7 in the UK and 2 in Scotland.

Who was included?

540 Patients who were likely to have a blood transfusion. 270 of these patients were in the control group and 270 were in the treatment group who received prion filtered blood.