Interim Analysis of a Prospective Randomised Study Comparing a Therapeutic Platelet Transfusion Strategy with the Prophylactic Platelet Transfusion Standard in Patients after Autologous Peripheral Stem Cell Transplantation (ASCT).
Authors: Schaefer-Eckart Kerstin , Wendelin Knut , Wilhelm Martin , Mahlknecht U. , Conradi R. , Schaich M. , Leimer L. , Wandt Hannes 
Published: October 2019

Abstract
We have previously shown, that a therapeutic platelet transfusion strategy is safe in patients after autologous peripheral stem cell transplantation(ASCT) and can reduce the number of platelet transfusions to about 50% compared with the prophylactic strategy (Wandt et al, BMT2006, 37, 387–392). To confirm these results, we started a randomised multicenter study in 2005 and present the results of the first planned interim analysis.
In the prophylactic platelet transfusion arm (p) transfusions were given to patients if the morning platelet count was < 10/nl, while in the therapeutic transfusion arm (t) clinically stable patients (no sepsis or systemic inflammatory response syndrome II° or III° (SIRS), no invasive Aspergillosis or infection with Stenotrophomonas maltophilia) received platelet transfusions only in the case of clinically relevant bleeding. Apheresis platelets were recommended, but pooled platelet units were allowed as well. We now analysed the first 92 patients, 45 patients with a prophylactic and 47 patients with a therapeutic transfusion strategy. Both groups were well balanced according to age, gender, diagnosis and conditioning regimens.
Median days of thrombocytopenia < 20/nl were 4 (0–14) in the prophylactic and 4 (0–20) in the therapeutic arm. The corresponding days regarding platelets below 10/nl were 1(p) (0–5) and 2(t) (0–14), respectively. The total number of days with thrombocytopenia <20/nl was 185 in the prophylactic arm and 239 in the therapeutic arm, resp. The number of days with a platelet count below 10/nl was 63 (p) vs. 110 (t). The number of days in hospital was 15 (p) (6–29) and 14 (t) (9–29), resp. Minor hemorrhages were observed in only 13 patients: 4 out of 45 patients in the prophylactic arm (8,9%) and 9 out of 47 patients in the therapeutic arm (19,2%). This difference was due to the protocol strategy and not significant. We observed no major clinically relevant bleedings.
There was a significant difference in the number of transfused platelet units: 68 (p) vs 37 (t), (p=0,005). The median number of platelet units was 1(0–6) in the prophylactic arm and 0(0–5) in the therapeutic arm. More than 95% of the transfusions were single apheresis units. So the primary objective of the study, a reduction of platelet transfusions by 25% was reached, without significant difference in the number of major bleeding complications (secondary objective). 9 out of the 37 platelet transfusions (24%) in the therapeutic strategy arm were given because of sepsis or SIRS and in 4 out of the 37 (11%) transfusions there was no indication according to the protocol. There was a non-significant difference in the number of red blood cell transfusions: 59 (median 0, range 0–8) in the prophylactic arm versus 87 (median 2, range 0–12) in the therapeutic arm.
With these first results of the randomised study we could confirm that a therapeutic platelet transfusion strategy is safe and can reduce the number of platelet transfusions by about 50%. The study will continue until 200 patients are included.