Effect of Plasmodium inactivation in whole blood on the incidence of blood transfusion transmitted malaria in endemic regions: the African Investigation of the Mirasol System (AIMS) randomised controlled trial
Venue: The Lancet

Transfusion transmitted malaria is a frequent but neglected adverse event in Ghana. We did a randomised controlled clinical trial to assess the efficacy and safety of a whole blood pathogen reduction technology at preventing transfusion transmission of Plasmodium spp parasites.  For this randomised, double blind, parallel group clinical trial, eligible adult patients (aged 18 years) with blood group O+ who required up to two whole blood unit transfusions within 3 days of randomisation and were anticipated to remain in hospital for at least 3 consecutive days after initial transfusion, were enrolled from Komfo Anokye Teaching Hospital in Kumasi, Ghana. The main exclusion criteria were symptoms of clinical malaria, antimalaria treatment within 7 days before randomisation, fever, and haemorrhage expected to require transfusion with up to two units of whole blood during the 3 days following study entry. Eligible patients were randomly assigned 1:1 by computer generated permuted block randomisation (block size four) list to receive transfusion with either pathogen reduced whole blood (treated) or whole blood prepared and transfused by standard local practice (untreated) Patients, health care providers, and data collectors were masked to treatment allocation. Patients in both groups received up to two whole blood unit transfusions that were retrospectively tested for parasitaemia. Pre transfusion and post transfusion blood samples (taken on days 0, 1, 3, 7, and 28) were tested for presence and amount of parasite genome, and assessed for haematological and biochemical parameters. The primary endpoint was the incidence of transfusion transmitted malaria in non parasitaemic recipients exposed to parasitaemic whole blood, defined as two consecutive parasitaemic post transfusion samples with parasite allelic matching, assessed at 1 7 days after transfusion. Secondary endpoints included haematological parameters and a safety analysis of adverse events in patients.  Between March 12, 2014, and Nov 7, 2014, 227 patients were enrolled into the study, one of whom was subsequently excluded because she did not meet the inclusion criteria. Of the 226 randomised patients, 113 were allocated to receive treated whole blood and 113 to receive standard untreated whole blood. 223 patients (111 treated and 112 untreated) received study related transfusions, whereas three patients (two treated and one untreated) did not. 214 patients (107 treated and 107 untreated) completed the protocol as planned and comprised the per protocol population. Overall, 65 non parasitaemic patients (28 treated and 37 untreated) were exposed to parasitaemic blood. The incidence of transfusion transmitted malaria was significantly lower for the pathogen reduced (treated) patients (1 [4% of 28 patients) than the untreated group (8 [22% of 37 patients) in this population (p=0.039) Overall, 92 (41% of 223 patients reported 145 treatment related emergent adverse events during the conduct of the study, with a similar incidence of adverse events between groups receiving untreated or treated whole blood. No transfusion related deaths occurred in the trial.  Treatment of whole blood with the Mirasol pathogen reduction system for whole blood reduced the incidence of transfusion transmitted malaria. The primary endpoint of the study was achieved in the population of non parasitaemic patients receiving parasitaemic whole blood. The safety profile and clinical outcomes were similar across the two treatment groups.