Mitomycin C plus S-1 as second-line therapy in patients with advanced gastric cancer: A noncomparative phase II study

S-1 is an oral fluoropyrimidine consisting of the 5-fluorouracil prodrug tegafur combined with two modulating substances, gimeracil and potassium oxonate. On the basis of the potential additive effect between mitomycin C (MMC) and 5-fluorouracil as a continuous infusion, we conducted a phase II study to assess the efficacy and tolerability of the combination of S-1 and MMC as second-line chemotherapy for advanced gastric cancer (AGC). Patients with measurable AGC, progressive after one prior chemotherapy for metastatic disease, received MMC (7mg/m²) on day 1 and S-1 (40mg/m²) twice daily as an intermittent regimen of 4 weeks of treatment followed by a 2-week rest. Treatment was repeated every 6 weeks. The primary objective was the response rate. For 43 patients registered, 42 patients were treated with MMC plus S-1. A total of 121 chemotherapy cycles were delivered (median: 2; range: 1-6). The patients' median age was 53 years (range: 31-75) and nine (21%) had an Eastern Cooperative Oncology Group performance status of 2. In an intent-to-treat analysis, nine patients (21%) achieved an objective response, which was maintained for 4.1 months. The median progression-free and overall survivals were 3.4 months (95% confidence interval: 2.3-4.5) and 8.0 months (95% confidence interval: 6.1-9.9), respectively. Although fatigue was the most frequently encountered toxicity safety profiles were generally predictable and manageable. One patient developed hemolytic anemia, which was resolved spontaneously. Grade ≥2 hand-foot syndrome was observed in only three patients. Second-line chemotherapy with MMC and S-1 is an active and tolerable regimen for AGC patients with good performance status.