Thoracic radiation therapy and concomitant low-dose daily paclitaxel in non-small cell lung cancer: a phase I study

The primary objective of the current study was to determine the maximum tolerated dose of paclitaxel (PTX) that could be added daily to radiation therapy (RT) in patients with non-small cell lung cancer (NSCLC). The secondary objective was to achieve a plasma concentration of PTX estimated to exert a radiosensitizing effect. Eighteen patients with locally advanced NSCLC were treated. 60 Gy of RT were given in 2 Gy fractions, 5 days per week. A daily dose of PTX was delivered by 4-h i.v. infusion before RT. The initial dose level of PTX was 9 mg/m2/day, escalated by 1 mg at each additional patient triplet. Two out of 6 patients experienced acute dose limiting toxicity (DLT) at the 12 mg/m2/day PTX dose level. PTX continuously greater than 10 nM, the estimated radiosensitizing condition, was achieved at the PTX dose level of 12 mg/m2/day. PTX at doses up to 11 mg/m2/day may be safely added to a conventional conformal RT course. Both DLT and the estimated radiosensitizing plasma exposure to PTX were encountered at the 12 mg/m(2)/day dose level.