Purpose: To determine the maximum tolerated dose (MTD) and dose-limiting toxicity of twice-weekly gemcitabine and concurrent thoracic radiation in patients with Stage IIIa/IIIb non-small-cell lung cancer (NSCLC).
Methods and materials: Seventeen patients with histologically confirmed Stage IIIa and IIIb NSCLC were studied. Gemcitabine was administered via a 30-min i.v. infusion twice weekly for 6 weeks concurrent with 60 Gy of thoracic radiation. Gemcitabine, starting at a twice-weekly dose of 10 mg/m2 (20 mg/m2/week), was escalated in 10-15 mg/m2 increments in successive cohorts of 3 to 6 patients until dose-limiting toxicity was observed.
Results: Of the 17 patients entered, 16 were evaluable for toxicity. The dose-limiting toxicity at 50 mg/m2 given twice weekly (100 mg/m2/week) was Grade 3 pneumonitis observed in 1 patient, Grade 3 pulmonary fibrosis in a second patient, and Grade 4 esophagitis observed in two additional patients. Twice-weekly gemcitabine at a dose of 35 mg/m2 was determined to be the MTD. The overall response rate for the 16 evaluable patients was 88%. The median survival for the entire group is 16.0 months.
Conclusions: The MTD of twice-weekly gemcitabine is 35 mg/m2 (70 mg/m2/week) given with thoracic radiation. A Phase II study within the Cancer and Leukemia Group B to ascertain the potential efficacy of this treatment regimen is in development.