Low-dose prophylactic platelet transfusions in recipients of an autologous peripheral blood progenitor cell transplant and patients with acute leukemia: a randomized controlled trial with a sequential Bayesian design.

BACKGROUND: Prophylactic platelet (PLT) transfusions are standard treatment for patients receiving high-dose chemotherapy, but the optimal dose is not known. A randomized controlled trial was undertaken to examine the effectiveness of low-dose PLT transfusions and to determine the need for further studies.

STUDY DESIGN AND METHODS: Patients (n = 111) with acute leukemia or undergoing autologous peripheral blood progenitor cell (PBPC) transplantation were randomly assigned to receive low-dose (3 PLT units) or standard-dose (5 PLT units) prophylactic PLT transfusions and were monitored daily for bleeding. Using a sequential Bayesian design, the difference in major bleeding events was determined.

RESULTS: The percentage of patients with major bleeding events was 10.7 percent (95% credible region, 5.1%-21.2%) in the low-dose PLT group and 7.3 percent (95% credible region, 2.9%-17.2%) in the standard-dose PLT group. The two additional events in the low-dose group occurred when the PLT count exceeded 100 x 10(9) per L. There is an 89 percent probability that the absolute increase in major bleeds is less than 10 percent with low-dose PLT transfusions. The number of minor bleeding events was higher in the standard-dose group. Patients receiving low-dose PLT transfusions received 25 percent fewer PLT units. There was an 89 percent probability that low-dose transfusions reduced PLT utilization in patients with acute leukemia and a 60 percent probability in patients undergoing PBPC transplantation.

CONCLUSION: Low-dose PLT transfusions appear to be safe and effective and reduce PLT utilization. They should be further evaluated in clinical trials designed to evaluate equivalency.