S-1 as monotherapy or in combination with leucovorin as second-line treatment in gemcitabine-refractory advanced pancreatic cancer: a randomized, open-label, multicenter, phase II study

In this study, we compared the efficacy and safety of the oral fluoropyrimidine S-1 as monotherapy or in combination with leucovorin as the second-line treatment for patients with metastatic pancreatic cancer whose disease had progressed on gemcitabine treatment.

The study was a randomized, open-label, controlled study. Patients randomly received S-1 or S-1 in combination with leucovorin (SL arm) in 21-day cycles. The primary endpoint was the 6-month survival rate.

A total of 92 patients were randomized to S-1 (n = 47) and SL (n = 45). No statistically significant differences were observed between the two arms with regard to 6-month survival rates (40% vs. 49%), median overall survival (5.5 vs. 6.3 months), median progression-free survival (1.9 vs. 3.0 months), and overall response rate (4.7% vs. 8.3%). The rate of major grade 3-4 adverse events of digestive toxicity was significantly higher in the SL arm than in the S-1 arm.

Compared with S-1, SL did not improve the survival of patients with metastatic pancreatic cancer who had failed to benefit from prior gemcitabine treatment, but SL had a higher adverse event rate.