Phase I/II trial of a biweekly combination of S-1 plus docetaxel in patients with previously treated non-small cell lung cancer (KRSG-0601)

Background:

Combination of S-1, an oral fluorouracil derivative, plus docetaxel against non-small cell lung cancer (NSCLC) showed promising efficacy but clinically problematic emesis. A phase I/II study utilising a new schedule for this combination was conducted.

Methods:

A biweekly regimen of docetaxel on day 1 with oral S-1 on days 1–7 was administered to previously treated NSCLC patients. Doses of docetaxel/S-1 were escalated to 30/80, 35/80, and 40/80 mg m⁻², respectively, and its efficacy was investigated at the recommended dose below maximum tolerated dose (MTD).

Results:

In phase I study employing 13 patients, dose-limiting toxicities were febrile neutropenia and treatment delay, with the respective MTDs for docetaxel 40 mg m⁻²/S-1 80 mg m⁻². In the phase II study, 34 patients were treated with docetaxel 35 mg m⁻²/S-1 80 mg m⁻² for a median cycle of 6. The response and disease control rates were 34.3% (95% confidence interval (CI), 18.6–50.0%) and 62.9% (95% CI, 46.8–72.9%), respectively. Median progression-free survival was 150.5 days. Haematologic grade 4 toxicities were observed in neutropenia (11.8%) and thrombocytopenia (2.9%). Regarding non-haematologic toxicities, including emesis, there were no grade 3/4 side effects.

Conclusion:

Combination of 1-week administration of S-1 with biweekly docetaxel is safe and active for NSCLC.