The effect of variation in donor platelet function on transfusion outcome: a semirandomized controlled trial.

The effect of variation in platelet function in platelet donors on patient outcome following platelet transfusion is unknown. This trial assessed the hypothesis that platelets collected from donors with highly responsive platelets to agonists in vitro assessed by flow cytometry (high-responder donors) are cleared more quickly from the circulation than those from low-responder donors, resulting in lower platelet count increments following transfusion. This parallel group, semirandomized double-blinded trial was conducted in a single center in the United Kingdom. Eligible patients were those 16 or older with thrombocytopenia secondary to bone marrow failure, requiring prophylactic platelet transfusion. Patients were randomly assigned to receive a platelet donation from a high- or low-responder donor when both were available, or when only 1 type of platelet was available, patients received that. Participants, investigators, and those assessing outcomes were masked to group assignment. The primary end point was the platelet count increment 10 to 90 minutes following transfusion. Analysis was by intention to treat. Fifty-one patients were assigned to receive platelets from low-responder donors, and 49 from high-responder donors (47 of which were randomized and 53 nonrandomized). There was no significant difference in platelet count increment 10 to 90 minutes following transfusion in patients receiving platelets from high-responder (mean, 21.0 × 109/L; 95% confidence interval [CI], 4.9-37.2) or low-responder (mean, 23.3 × 109/L; 95% CI, 7.8-38.9) donors (mean difference, 2.3; 95% CI, -1.1 to 5.7; P = .18). These results support the current policy of not selecting platelet donors on the basis of platelet function for prophylactic platelet transfusion.

A no-prophylaxis platelet-transfusion strategy for hematologic cancers.

BACKGROUND: The effectiveness of platelet transfusions to prevent bleeding in patients with hematologic cancers remains unclear. This trial assessed whether a policy of not giving prophylactic platelet transfusions was as effective and safe as a policy of providing prophylaxis. METHODS: We conducted this randomized, open-label, noninferiority trial at 14 centers in the United Kingdom and Australia. Patients were randomly assigned to receive, or not to receive, prophylactic platelet transfusions when morning platelet counts were less than 10×10(9) per liter. Eligible patients were persons 16 years of age or older who were receiving chemotherapy or undergoing stem-cell transplantation and who had or were expected to have thrombocytopenia. The primary end point was bleeding of World Health Organization (WHO) grade 2, 3, or 4 up to 30 days after randomization. RESULTS: A total of 600 patients (301 in the no-prophylaxis group and 299 in the prophylaxis group) underwent randomization between 2006 and 2011. Bleeding of WHO grade 2, 3, or 4 occurred in 151 of 300 patients (50%) in the no-prophylaxis group, as compared with 128 of 298 (43%) in the prophylaxis group (adjusted difference in proportions, 8.4 percentage points; 90% confidence interval, 1.7 to 15.2; P=0.06 for noninferiority). Patients in the no-prophylaxis group had more days with bleeding and a shorter time to the first bleeding episode than did patients in the prophylaxis group. Platelet use was markedly reduced in the no-prophylaxis group. A prespecified subgroup analysis identified similar rates of bleeding in the two study groups among patients undergoing autologous stem-cell transplantation. CONCLUSIONS: The results of our study support the need for the continued use of prophylaxis with platelet transfusion and show the benefit of such prophylaxis for reducing bleeding, as compared with no prophylaxis. A significant number of patients had bleeding despite prophylaxis. (Funded by the National Health Service Blood and Transplant Research and Development Committee and the Australian Red Cross Blood Service; TOPPS Controlled-Trials.com number, ISRCTN08758735.).

A randomized noninferiority crossover trial of corrected count increments and bleeding in thrombocytopenic hematology patients receiving 2- to 5- versus 6- or 7-day-stored platelets.

BACKGROUND: Bacterial screening offers the possibility of extending platelet (PLT) storage to Day 7. We conducted a noninferiority, crossover trial comparing PLTs stored for 6 or 7 days versus 2 to 5 days. STUDY DESIGN AND METHODS: Stable hematology patients were allocated to receive blocks of 2- to 5- and 6- or 7-day PLTs in random order. The primary outcome was the proportion of successful transfusions during the first block, defined as a corrected count increment (CCI) of more than 4.5 at 8 to 24 hours posttransfusion. RESULTS: Of 122 patients with an evaluable first block, 87 (71%) and 84 (69%) had successful transfusions after 2- to 5- and 6- or 7-day PLTs of mean (SD) ages of 3.8 (1.0) and 6.4 (0.5) days, respectively. Six- or 7-day PLTs were declared noninferior to 2- to 5-day PLTs since the upper confidence interval (CI) limit was less than the predefined noninferiority margin of 10% (95% CI, -14.0% to 9.1%; p = 0.766). Logistic regression analysis gave an adjusted odds ratio of 0.86 (95% CI, 0.47-1.58; p = 0.625). Mean (SD) 8- to 24-hour CCIs were 9.4 (7.9) and 7.7 (7.1) after transfusion with 2- to 5- or 6- or 7-day PLTs (95% CI, -3.31 to 0.03; p = 0.054). The proportions of days with bleeding scores of WHO Grade 2 or higher were 13% (38/297 days) and 11% (32/296 days; 95% CI, -3.2 to 7.2; p = 0.454). Median interval to next PLT transfusion (2 days) was unaffected (95% CI, -10.5 to 5.4; p = 0.531). CONCLUSION: In hematology patients, there was no evidence that 6- or 7-day PLTs were inferior to 2- to 5-day PLTs, as measured by proportion of patients with successful transfusions, bleeding events, or interval to next transfusion.

Do all patients with hematologic malignancies and severe thrombocytopenia need prophylactic platelet transfusions? Background, rationale, and design of a clinical trial (trial of platelet prophylaxis) to assess the effectiveness of prophylactic platelet transfusions.

Although considerable advances have been made in many aspects of platelet transfusion therapy in the last 30 years, some areas continue to provoke debate, including the use of prophylactic platelet transfusions for the prevention of thrombocytopenic bleeding in patients with bone marrow failure. We have designed a randomized controlled trial to compare prophylactic platelet use with a threshold of a platelet count of 10 x 10(9)/L with no prophylaxis in adult thrombocytopenic patients with hematologic malignancies. The trial question is whether a no-prophylactic policy for the use of platelet transfusions in patients with hematologic malignancies is not inferior to a threshold prophylactic policy at 10 x 10(9)/L, for bleeding at World Health Organization (WHO) grade 2, 3, or 4, up to 30 days from randomization. The primary outcome measure is the proportion of patients who have a significant clinical bleed, defined as WHO grade 2 or higher up to 30 days from randomization. Subsidiary clinical outcome measures include time to first bleed and a descriptive analysis of all severe bleeds. A bleeding assessment form is completed daily for all study subjects until day 30 from randomization. Minor modifications were made to the definitions at WHO grades 1 and 2 for petechiae and duration of nose bleeds, after piloting of the bleeding assessment forms. This study has been designed as a 2-stage randomized trial with an interim analysis planned after a minimum of 100 patients had been randomized and had completed their period of observation. Patients have initially been enrolled through 3 United Kingdom hematology centers. The interim analysis has been completed, and the results have confirmed a final sample size of 600 patients. Recruitment is now being extended to other centers in United Kingdom and Australia. Local research nurses are not blinded to treatment allocation, but a number of measures to reduce risk of assessment bias include repeated education around standard operating procedures, common definitions, and duplication of assessments. The expected completion date for the 5-year study is December 2011.