Transfusion of 7-day-old amotosalen photochemically treated buffy-coat platelets to patients with thrombocytopenia: a pilot study

BACKGROUND: Photochemical treatment (PCT) of platelets (PLTs) with amotosalen and ultraviolet A light to inactivate bacteria may facilitate extension of storage from 5 to 7 days. STUDY DESIGN AND METHODS: A randomized, double‐blinded, crossover, noninferiority, single‐site pilot study utilizing pooled buffy‐coat PLTs was conducted. The primary endpoint was the 1‐hour corrected count increment (CCI) after one transfusion each of 7‐day‐old PCT and reference (R) PLT components. Secondary endpoints included 1‐hour count increment, time to next transfusion, hemostasis, transfusion reactions, and serious adverse events. RESULTS: Twenty patients with thrombocytopenia were randomly assigned: 9 to the PCT‐R sequence and 11 to the R‐PCT sequence. A significant treatment‐by‐period interaction was observed. Therefore, the first period only was also analyzed for the primary endpoint. Including both treatment periods, mean 1‐hour CCI was 6587 ± 4531 for PCT versus 8935 ± 5478 for R‐PLTs. For the first period only, mean 1‐hour CCI was 8739 ± 3785 for PCT versus 7433 ± 5408 for R‐PLTs. The upper bound of the one‐sided 95 percent confidence interval of 2400 for the mean difference was higher than the specified noninferiority margin of 2200 for both analyses. Overall median time to next transfusion was 22 hours for PCT versus 27 hours for R‐PLTs. Hemostasis was adequate and no transfusion reactions or serious adverse events were reported. CONCLUSIONS: Although this pilot study of a limited number of patients failed to show noninferiority within the specified noninferiority margin, 7‐day‐old PCT PLTs showed acceptable efficacy and safety for support of thrombocytopenia. The results, however, warrant evaluation in a larger trial of 7‐day‐old PCT PLTs.