Ishigami H, et al. - Researchers studied if intraperitoneal paclitaxel plus systemic chemotherapy is better than standard systemic chemotherapy with respect to overall survival in patients with gastric cancer with peritoneal metastasis. They found that intraperitoneal paclitaxel plus systemic chemotherapy was not statistically superior to standard systemic chemotherapy. However, possible clinical benefits of intraperitoneal paclitaxel for gastric cancer were indicated in exploratory analyses.

Methods

• In this randomized phase 3 trial, patients with gastric cancer with peritoneal metastasis who had been given no or short-term (< 2 months) chemotherapy were included.
• Stratified by center, previous chemotherapy, and extent of peritoneal metastasis, randomization (2:1) of patients to receive intraperitoneal and intravenous paclitaxel plus S-1 (IP; intraperitoneal paclitaxel 20 mg/m² and intravenous paclitaxel 50 mg/m² on days 1 and 8 plus S-1 80 mg/m² per day on days 1 to 14 for a 3-week cycle) or S-1 plus cisplatin (SP; S-1 80 mg/m²per day on days 1 to 21 plus cisplatin 60 mg/m²on day 8 for a 5-week cycle) was carried out.
• Overall survival was the primary end point, and secondary end points were response rate, 3-year overall survival rate, and safety.

Results

• In this study, a total of 183 patients were enrolled and efficacy analyses was performed on 164 eligible patients.
• Other than patients in the IP arm having significantly more ascites, the arms had balanced baseline characteristics.
• For the IP and SP arms, the observed median survival times were 17.7 and 15.2 months, respectively (hazard ratio, 0.72; 95% CI, 0.49 to 1.04; stratified log-rank P=.080).
• The hazard ratio was estimated to be 0.59 in the sensitivity analysis adjusted for baseline ascites (95% CI, 0.39 to 0.87; P=.008).
• In the IP arm and in the SP arm, the estimated 3-year overall survival rate was 21.9% (95% CI, 14.9% to 29.9%) and 6.0% (95% CI, 1.6% to 14.9%), respectively.
• Good tolerability of both regimens was demonstrated.