Johansson 2013

Methods	Type of study: cross‐over, randomised controlled trial Type of publication: full Setting and country: Transfusion Services of Rigshospitalet in Copenhagen, Denmark Number of centres: 1 Dates of trial (start and end): September 2010 to April 2011 Treatment period + follow‐up: 24‐hour surveillance period after each study transfusion Power calculation performed: not reported
Participants	16 adults with a haemato‐oncological diagnosis (majority had acute myeloid leukaemia (N = 9) or B‐cell lymphoma (N = 3)), age range 25 to 75 years, with or expected to develop thrombocytopenia requiring at least 3 platelet transfusions. All participants had a prior history of receiving platelet transfusions with no transfusion reaction. Number analysed for primary outcome: 10 (per‐protocol analysis), 1 enrolled participant was later found to have splenomegaly and was withdrawn from the study before receiving study treatment; 3 participants were excluded from the per‐protocol analysis because they did not require a second platelet transfusion; 2 participants had technical problems in collecting pre‐ or 1‐hour post‐transfusion thromboelastography data. People who were actively bleeding excluded?: yes; "active bleeding requiring one or more transfusions of red blood cells" was an exclusion criterion People with platelet refractoriness or alloimmunisation excluded?: yes; "history of refractoriness to PLT transfusions (two successive corrected count increments at 1 hr [CCI1hr] < 5000, presence of HLA antibodies, positive lymphocytotoxicity, or previously documented alloimmunization" were exclusion criteria
Interventions	Each participant to receive 2 prophylactic study transfusions of 2‐ to 4‐day‐old pooled buffy coat‐derived platelets ‐ 1 Mirasol PCT platelet transfusion and 1 control platelet transfusion PCT: Mirasol PCT platelets prepared from an unreported number of pooled buffy coats, suspended in SSP+ platelet additive solution. Platelet components were gamma irradiated when directed by the treating physician. Control: standard platelets, prepared from an unreported number of pooled buffy coats, suspended in InterSol platelet additive solution. Platelet components were gamma irradiated when directed by the treating physician. Timing of platelet dose measurement: platelet counts were performed after pooling and again before product release on Days 2 to 4 of storage, unclear which count was used to assess platelet dose Storage duration of platelets: 2 to 4 days Transfusion trigger: Prophylactic platelet transfusions were given when platelet counts < 10 x 109/L in non‐febrile, clinically stable participants or < 20 x 109/L in participants with fever. The transfusion trigger could be raised to 50 x 109/L for participants that were at high risk of bleeding. % off‐protocol transfusions: not reported Red cell transfusion protocol specified: not reported
Outcomes	Primary outcome measure: haemostatic function 1 hour pre‐ and post‐study platelet transfusions using computerised thromboelastography. Secondary outcome measures: bleeding assessments 12 hours pre‐ and post‐transfusions platelet counts 1 hour pre‐ and post‐transfusions adverse transfusion reactions (within 24 hours) serious adverse events (within 24 hours).
Notes	Trial registration: trial is part of the Pathogen Reduction Extended Storage Study (PRESS) registered at ClinicalTrials.gov ID: NCT01368211 on 6 June 2011 Sources of funding: research funding for this study was provided by Terumo BCT to PIJ. Conflicts of interest: LD, PVH, and RPG are employees of Terumo BCT. SSY is a contract employee of Terumo BCT. Intervention exposure: single dose
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Randomisation was performed according to a computer‐generated randomisation scheme with a block size of 2.
Allocation concealment (selection bias)	Low risk	Allocation to interventions was performed randomly by computer.
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	No information on blinding of participants was reported.
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Clinical site personnel responsible for participant enrolment, physical examination, and safety monitoring were blinded.
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	16 participants were initially randomised to receive the interventions, and the number of participants lost to follow‐up or treatment withdrawals were reported with reasons after randomisation. 1 enrolled participant was later found to have splenomegaly (an exclusion criterion) and was withdrawn from the study before receiving study treatment. Only 15 participants were included in the ITT analysis. 10 participants were included in the PP analysis including the study's primary outcome. 3 participants were excluded from the PP analysis because they did not require a second platelet transfusion (included in analysis of safety data, including bleeding); 2 participants had technical problems in collecting pre‐ or 1‐hour post‐transfusion thromboelastography data.
Selective reporting (reporting bias)	Unclear risk	Protocol not available, and trial registration was after the trial had been completed.
Other bias	Unclear risk	The majority of participants were male (14 out of 15 in ITT analysis and 11 out of 12 in PP analysis). The study was retrospectively registered on a trial database (study completed April 2011 and registered June 2011).