Phase II study of recombinant human interleukin 3 administration following carboplatin and etoposide chemotherapy in small-cell lung cancer patients

Recombinant human interleukin 3 (rhIL-3) has been suggested to be a useful agent for the treatment of chemotherapy-induced thrombocytopenia. For evaluation of this possibility, rhIL-3 was given subcutaneously for 10 days to patients with small-cell lung cancer (SCLC). Chemotherapy consisted of carboplatin (CBDCA) given at 400 mg/m(2) to previously untreated patients or at 350 mg/m(2) to previously treated patients on day 1 and etoposide (VP-16) given at 100 mg/m(2) on days 1-3 every 4 weeks. If the platelet count nadir was <75,000/mu l in the control cycle of chemotherapy, patients were randomly assigned for the next cycle to rhIL-3 given at 5 or 10 mu g/kg per day on days 4-13. A total of 41 patients (32 previously untreated patients and 9 previously treated patients) were enrolled in the study, The platelet count nadir in the cycles including rhIL-3 was significantly higher at both dose levels (P<0.01) than in the control cycle. The duration of thrombocytopenia (<75,000/mu l) and the mean time from the Ist day of chemotherapy to thrombocyte recovery (>100,000/mu l) in the rhIL-3 cycle were significantly shorter than those in the control cycle (P<0.01). The neutrophil count nadir and the duration of neutropenia (<1,000/mu l) were also significantly improved in the rhIL-3 cycle (P<0.05). The major side effects were fever (80.5%), headache (24.3%), and fatigue (14.6%). All side effects were tolerable and of less than grade II. There was no difference in the efficacy of the two dose levels, but the 5-mu g/kg dose appeared to be better tolerated than the 10-mu g/kg dose. We conclude that rhIL-3 administration following chemotherapy consisting of CBDCA and VP-16 reduces the incidence and severity of chemotherapy-induced thrombocytopenia and neutropenia with an acceptable adverse events profile.