Phase I study of irinotecan and cisplatin with granulocyte colony-stimulating factor support for advanced non-small-cell lung cancer

PURPOSE Since leukopenia was one of the dose-limiting toxicities of the combination of irinotecan (CPT-11) and cisplatin in a previous trial, we conducted a phase I trial to investigate whether support with recombinant human granulocyte colony-stimulating factor (rhG-CSF) would permit further intensification of the CPT-11 dose in combination with a fixed cisplatin dose. PATIENTS AND METHODS Twenty previously untreated patients with stage IIIB or IV non-small-cell lung cancer (NSCLC) were treated with CPT-11 on days 1, 8, and 15 in combination with cisplatin 80 mg/m2 intravenously on day 1. In addition, rhG-CSF (2 micrograms/kg/d) was administered on days 4 to 21, except on the days of CPT-11 treatment. The starting dose of CPT-11 was 70 mg/m2, and the CPT-11 dose was escalated in 10-mg/m2 increments until the maximum-tolerated dose was reached. RESULTS Diarrhea was the dose-limiting toxicity at 90 mg/m2. Two of six patients experienced either grade 3 or 4 diarrhea or grade 3 leukopenia during the first course of therapy at this dose level. Modest escalation of the CPT-11 dose from 80 to 90 mg/m2 resulted in a marked increase in the plasma concentration of 7-ethyl-10-hydroxycamptothecin (SN-38). Occurrence of diarrhea was well correlated with the peak plasma concentration (Cmax) of SN-38 (P = .035). There were 10 partial responses (50%) among 20 patients. CONCLUSION The recommended dose for phase II studies is 80 mg/m2 of CPT-11, and 80 mg/m2 of cisplatin plus rhG-CSF. With the use of rhG-CSF, the CPT-11 dose can be increased 33% above that in the original regimen (60 mg/m2 of CPT-11 and 80 mg/m2 of cisplatin).