A multicenter phase II trial of ramucirumab plus irinotecan for early recurrence of gastric cancer during or after adjuvant chemotherapy with docetaxel plus S-1 therapy: the RAMIEL trial (OGSG1901)

Abstract Background There is currently no established chemotherapy regimen for early recurrence of pathological stage III gastric cancer (GC) following adjuvant chemotherapy with docetaxel plus S-1 (DS) after D2 gastrectomy. We aimed to evaluate the efficacy and safety of ramucirumab plus irinotecan in patients with GC who experienced early recurrence during or within 6 months after DS adjuvant chemotherapy. Methods This prospective, open-label, multicenter phase II trial enrolled eligible patients treated at 25 centers of the Osaka Gastrointestinal Cancer Chemotherapy Study Group in Japan. Patients received ramucirumab (8 mg/kg) and irinotecan (150 mg/m 2 ) every 2 weeks. The primary endpoint was overall survival (OS), and secondary endpoints included progression-free survival (PFS), objective response rate (ORR), and safety. The sample size was set at 40 based on a threshold median OS of 7 months and an expected median OS of 11 months, with a one-sided alpha error of 0.05 and a power of 0.80. Results Between November 2019 and July 2023, 43 patients were enrolled, and 39 were included in the analysis after excluding three ineligible patients and one who did not initiate protocol treatment. The median OS was 15.9 months (95% CI: 8.8–42.0; p = 0.003). The median PFS was 5.5 months (95% CI: 3.9–8.1), and the ORR was 38.5%. Grade ≥ 3 adverse events, including neutropenia (25.6%) and hypertension (25.6%), were observed in more than 20% of patients. Conclusion Ramucirumab plus irinotecan demonstrated promising efficacy and manageable toxicity in patients with early recurrence of GC following adjuvant DS therapy. Trial registration This study was prospectively registered in the Japan Registry of Clinical Trials (jRCTs05119071, October 6, 2019, https://jrct.niph.go.jp/latest-detail/jRCTs051190071 ).