Phase 1 trial of intraperitoneal paclitaxel in combination with intravenous cisplatin and oral capecitabine in patients with advanced gastric cancer and peritoneal metastases (IPGP study)

Aims: Gastric cancer with peritoneal involvement has a poor prognosis. Intraperitoneal (IP) paclitaxel has shown promising results in these patients. However, this approach has only been studied in the Asian population, and in combination with S-1. We investigated the maximum tolerated dose of IP paclitaxel, with a standard chemotherapy combination, in the Australian population. Methods: The study of the population included metastatic human epidermal growth factor receptor 2 (HER2) negative gastric adenocarcinoma with peritoneal involvement. Treatment included six 21-day cycles of cisplatin (80 mg/m² IV, day 1) plus capecitabine (1000 mg/m² PO BD, days 1–14) plus IP paclitaxel (days 1 and 8). IP paclitaxel doses for cohort 1–3 were 10, 20, and 30 mg/m², respectively, in a 3 + 3 standard dose-escalation design. Results: Fifteen patients were enrolled of which 6 were female and the median age was 63. Two patients developed dose-limiting toxicities. No grade 4/5 toxicities were recorded. The maximum tolerated dose was not reached. Therefore, as defined by the study protocol, the recommended phase-2 dose for IP paclitaxel was determined to be 30 mg/m². The 12-month survival rate was 46.7%, and the median survival was 11.5 months (interquartile range [IQR]: 15.3–6.9). Conclusions: IP paclitaxel is safe in combination with cisplatin and capecitabine and the recommended phase-2 dose is 30 mg/m².