Purpose: Recombinant human interleukin-6 (rhuIL-6) is a glycosylated cytokine with hematopoietic stimulatory effects. In particular, preclinical studies suggest the agent can stimulate thrombopoiesis, even in conjunction with chemotherapy. We attempted to determine whether higher dose chemotherapy for ovarian cancer was possible given the pharmacologic use of this important growth factor.
Methods: We conducted a randomized, double-blind phase II study of IL-6 plus granulocyte colony-stimulating factor (G-CSF) versus placebo plus G-CSF in combination with a standard chemotherapy regimen. Patients with epithelial ovarian cancer, stages Ic to IV, were eligible. All patients were previously untreated with chemotherapy and had Karnofsky performance status >/=60. rhuIL-6 (Escherichia coli, SDZ ILS 969) 1.0 micrograms/kg or placebo was given subcutaneously on days 2-8 every cycle together with G-CSF 5.0 micrograms/kg subcutaneously days 2-15, following administration of paclitaxel 175 mg/m2 as a 3-h infusion and carboplatin given to a desired AUC of 7.5 on day 1 every 21 days.
Results: Fifty patients were entered in this study, although the study was temporarily suspended by the FDA in midstudy over manufacturing concerns. Therefore, 37 patients were evaluable for efficacy of growth factor; 19 patients received placebo plus G-CSF and 18 rhIL-6 plus G-CSF. There was no difference in prognostic variables between these two groups. Platelet nadirs were lower in the first cycle for the placebo group (P = 0.004, Wilcoxon sum-rank test) but not in other cycles. There was no statistically significant difference in cycle treatment delays, carboplatin dose delivered, number of patients with grade 4 thrombocytopenia, or platelet transfusion. Nonetheless, the trend of the data favored IL-6 in all cases.
Conclusions: This study demonstrated a minimal effect (statistically significant in the first cycle only) on thrombopoiesis in women undergoing paclitaxel and carboplatin therapy of ovarian cancer. No clinically significant effect on actual chemotherapy delivery was demonstrated, however. Future studies, if warranted, to ameliorate thrombocytopenia should be carried out with regimens producing even greater thrombocytopenia than the current regimen in the control arm.
Copyright 1999 Academic Press.