This study assessed the safety and efficacy of recombinant human
interleukin (rhIL)-11 in decreasing
platelet transfusion requirements in patients with
breast cancer who were undergoing autologous
bone marrow transplantation (ABMT) with peripheral blood progenitor cell (PBPC) support. After high-dose
therapy with
cyclophosphamide,
cisplatin, and
carmustine, 80 patients were randomized to one of three treatment groups: placebo (26), 25 microg/kg of
rhIL-11 (28), and 50 microg/kg of
rhIL-11 (26). Of those randomized, 75 (94%) received at least one dose of the masked study
drug and the remaining 5 (6%) withdrew consent before study
drug administration. In the placebo group, each patient received an average 12.4 (+/-10.2)
platelet transfusions vs. 9.2 (+/-5.0) in the 25-microg/kg
rhIL-11 group (p = 0.17) and 9.9 (+/-3.5) in the 50-microg/kg
rhIL-11 group (p = 0.34). There was no statistically significant difference between the
rhIL-11 groups and the placebo group in the median number of days to platelet recovery. Neutrophil and red blood cell recovery were similar for all treatment groups. The imbalance in the number of patients already alloimmunized at study entry in the
rhIL-11 groups (12) and in the placebo group (1) may have confounded the primary efficacy assessment. Most adverse events were related to the high-dose
chemotherapy. Generally mild
edema and minor conjunctival
bleeding (grades 1 or 2) were statistically associated with
rhIL-11 administration (p < 0.04). There was no association between
rhIL-11 and the occurrence of atrial arrhythmias, although there was a suggestion of an association with
rhIL-11, 5 of 50 cases vs. 1 of 25 in the placebo group. Two cardiovascular events,
tachycardia and
hypotension (grade 1 or 2), occurred in the 50-microg/kg
rhIL-11 group. The number of patients who discontinued study
drug dosing because of an adverse event was distributed across all treatment groups. In summary,
rhIL-11 was safe and well tolerated in this study. The results did not demonstrate that
rhIL-11 treatment significantly decreased
platelet transfusion requirements after high-dose
chemotherapy with ABMT and PBPC support.