Purpose: To assess the efficacy of vincristine-laden platelets in patients with refractory thrombocytopenia.
Patients and methods: Patients who received vincristine-laden platelets for refractory thrombocytopenia between 1991 and 2003 were included in this retrospective study. Vincristine (1 mg) was added to the platelets and the bag was incubated for 1 hour prior to transfusion. The following data were collected: age and gender of the patient, nature of the underlying disease causing thrombocytopenia, baseline renal and hepatic function, previous therapy for thrombocytopenia, platelet counts on days 0, 1, 3, 7, 15, 30 and 90 following vincristine-laden platelet transfusion, number of units of platelets transfused in the week prior to and the week after transfusion of vincristine-laden platelets. The rate of change in platelet count was calculated for each patient as a slope.
Results: 20 patients were included in the study. The underlying disease causing thrombocytopenia was lung cancer (n=4), breast cancer following autologous hematopoietic stem cell transplantation and acute myeloid leukemia (n=3 each), myelodysplastic syndrome (n=2), acute lymphoid leukemia, chronic lymphoid leukemia, chronic myeloid leukemia, multiple myeloma, ovarian cancer, aspergillosis, cytomegalovirus infection and systemic lupus erythematosus (n=1 each). The median rate of change of platelet count was 550/μL/day (range, −1000 to 12,800/μL/day) and was significantly greater than 0 (p=0.003, Wilcoxon rank sum test). There was a significant decrease in the number of units of platelets transfused in the week after vincristine-laden platelet transfusion (median, 6; range, 0–16) as compared to the week prior to the transfusion (median, 6.5; range, 0–17). The median change in the number of units of platelets transfused was −1.5 (p=0.031, Wilcoxon rank sum test). Patients were also compared based on their underlying diagnosis to evaluate if patients who did not have bone marrow involvement by their primary disorder did better than those who did have marrow involvement. Patients who had a hematological malignancy with bone marrow involvement had a median rate of change in platelet counts post-vincristine, of 15/μL/day (range, −32 to 2900/μL/day). Patients who had other disorders had a median rate of change of 1230/μL/day (range, −100 to 12,800/μL/day). These rates were not statistically significantly different (p=0.27, Wilcoxon rank sum test). There was no difference in the change in the number of units of platelets transfused between the two groups. The change in the number of units of platelets transfused in the hematological malignancy group was −1.0 (range, −7 to 6) as compared to −4 (range, −7 to 4) in the non-hematological malignancy group (p=0.18, Wilcoxon rank sum test).
Conclusions: Vincristine-laden platelet transfusion significantly increased the platelet counts and decreased the need for platelet transfusion. Thus transfusion of vincristine-laden platelets is an easy, inexpensive method to manage refractory thrombocytopenia.