Purpose: We designed a phase I dose-escalation study of vinorelbine on a novel (daily-times-three) schedule with ifosfamide with granulocyte colony-stimulating factor (G-CSF) support to define the dose-limiting toxicity (DLT) and maximum-tolerated dose (MTD) of vinorelbine in this combination.
Patients and methods: Cohorts of patients with stage IIIB or IV non-small-cell lung cancer (NSCLC) and no prior chemotherapy received vinorelbine starting at 15 mg/m2 on days 1, 2, and 3, and ifosfamide starting at 2.0 g/m2 on days 1, 2, and 3 with G-CSF support for all patients. Cycles were repeated every 21 days. Plasma vinorelbine concentrations were also analyzed.
Results: Forty-two patients were treated. The median age was 58 years (range, 34 to 75) and 41 had a performance status of 0 or 1. The DLT was neutropenia and sepsis at a maximum-administered vinorelbine dose of 35 mg/m2 for 3 days. The recommended phase II dose was vinorelbine 30 mg/m2 with ifosfamide 1.6 g/m2 both given on 3 consecutive days. The overall response rate was 40% (17 of 42; all partial responders). The median survival duration was 50 weeks, with a 1-year survival rate of 48%. Pharmacokinetic analysis showed that vinorelbine in this combination and on this schedule is cleared 1.5 to two times faster than in single-agent once-weekly studies.
Conclusion: Myelosuppression is the DLT of this regimen with no major subjective toxicities. With tolerable toxicity and an encouraging 1-year survival rate of 48%, further investigation of this new vinorelbine schedule is warranted in this and other combination regimens.