Randomized phase II study of second-line chemotherapy with the best available 5-fluorouracil regimen versus weekly administration of paclitaxel in far advanced gastric cancer with severe peritoneal metastases refractory to 5-fluorouracil-containing regimens (JCOG0407)

Background: This randomized phase II study compared weekly administration of paclitaxel (wPTX) with the best available 5-fluorouracil (5-FU) regimen as second-line treatment for advanced gastric cancer patients with severe peritoneal metastasis refractory to fluoropyrimidine. Methods: In the best available 5-FU arm, continuous infusion of 5-FU (800 mg/m²/day, days 1–5, every 4 weeks) was given to patients with prior chemotherapy including bolus 5-FU, and methotrexate and 5-FU sequential bolus injection (methotrexate at 100 mg/m² followed by bolus 5-FU at 600 mg/m² with leucovorin, weekly) was given to those who had previously received continuous infusion of 5-FU or oral administration of fluoropyrimidine. In the wPTX arm, paclitaxel (80 mg/m²) was administered on days 1, 8, and 15, every 4 weeks. This study adopted a screening design (one-sided α = 30 %) with the primary end point of overall survival. Results: One hundred patients were randomized to the 5-FU arm (n = 49) or the wPTX arm (n = 51). Although the median survival time was 7.7 months in both arms, the 2-year survival rates were 2.9 % in the 5-FU arm and 9.1 % in the wPTX arm [hazard ratio 0.89 (95 % confidence interval 0.57–1.38), one-sided p = 0.298}. The median progression-free survival was longer with wPTX than with 5-FU [3.7 months vs 2.4 months; hazard ratio 0.58 (95 % confidence interval 0.38–0.88), one-sided p = 0.005]. The incidences of grade 4 neutropenia, grade 3/4 febrile neutropenia, diarrhea, and treatment-related death were 6 %, 4 %, 10 %, and 2 %, respectively, in the 5-FU arm and 2 %, 0 %, 0 %, and 0 %, respectively, in the wPTX arm. Conclusions: As second-line chemotherapy, wPTX appears feasible and promising. This regimen can be included in a test arm in future phase III trials for treatment of advanced gastric cancer with severe peritoneal metastasis.