[en] Purpose: We report the toxicity profile and pharmacokinetic data of a schedule-dependent chemoradiation regimen using pulsed low-dose paclitaxel for radiosensitization in a Phase I study for inoperable non-small-cell lung cancer. Methods and Materials: Paclitaxel at escalating doses of 15 mg/m², 20 mg/m², and 25 mg/m² were infused on Monday, Wednesday, and Friday with daily chest radiation in cohorts of 6 patients. Daily radiation was delayed for maximal G2/M arrest and apoptotic effect, an observation from preclinical investigations. Plasma paclitaxel concentration was determined by high-performance liquid chromatography. Results: Dose-limiting toxicities included 3 of 18 patients with Grade 3 pneumonitis and 3 of 18 patients with Grade 3 esophagitis. There was no Grade 4 or 5 pneumonitis or esophagitis. There was also no Grade 3 or 4 neutropenia, thrombocytopenia, anemia or neuropathy. For Dose Levels I (15 mg/m²), II (20 mg/m²), and III (25 mg/m²), the mean peak plasma level was 0.23 ± 0.06 μmol/l, 0.32 ± 0.05 μmol/l, and 0.52 ± 0.14 μmol/l, respectively; AUC was 0.44 ± 0.09 μmol/l, 0.61 ± 0.1 μmol/l, and 0.96 ± 0.23 μmol/l, respectively; and duration of drug concentration >0.05 μmol/l (t > 0.05 μmol/l) was 1.6 ± 0.3 h, 1.9 ± 0.2 h, and 3.0 ± 0.9 h, respectively. Conclusion: Pulsed low-dose paclitaxel chemoradiation is associated with low toxicity. Pharmacokinetic data showed that plasma paclitaxel concentration >0.05 μmol/l for a minimum of 1.6 h was sufficient for effective radiosensitization