RAINFALL: A randomized, double-blind, placebo-controlled phase III study of cisplatin (Cis) plus capecitabine (Cape) or 5FU with or without ramucirumab (RAM) as first-line therapy in patients with metastatic gastric or gastroesophageal junction (G-GEJ) adenocarcinoma.

Abstract

5 Background: Ramucirumab, a VEGFR-2 IgG1 human monoclonal antibody, is the only biologic with proven efficacy as both a single-agent and in combination with paclitaxel in the second-line treatment of G-GEJ adenocarcinoma. RAINFALL (NCT02314117) is a global, double-blind, placebo-controlled randomized clinical trial addressing the hypothesis that adding ramucirumab to first-line Cis plus Cape or 5-fluorouracil (5FU) produces significant clinical benefit. Methods: Metastatic G-GEJ cancer patients eligible for first-line chemotherapy with ECOG performance status 0-1 were randomized 1:1 to receive either RAM (8 mg/kg iv D1, D8) or placebo (PL), every 21d. All patients received Cape (or 5FU)+Cis. Cis was given for up to 6 cycles. Cape+RAM/placebo was continued until progressive disease, toxicity or other discontinuation criteria. The primary endpoint was progression-free survival (PFS) for the first 508 patients; overall survival (OS) for ITT population was a powered secondary endpoint. Results: 645 patients were randomized to receive RAM+Cape/Cis (n=326) or PL+Cape/Cis (n=319). PFS was significantly prolonged in patients treated with RAM+Cape/Cis versus PL+Cape/Cis (HR, 0.75; 95% CI 0.61–0.94; p=0.011; median, 5.7 vs 5.4 mos), meeting the primary endpoint. There was no survival benefit for patients treated with RAM+Cape/Cis versus PL+Cape/Cis (HR, 0.96; 95% CI 0.80–1.16; p=0.68; median, 11.2 vs 10.7 mos). ORR in the ITT population was 41.1% in the RAM arm (95% CI 35.8–46.4) and 36.4% (95% CI 31.1–41.6) in the PL arm. Grade ≥3 adverse events in ≥10% of patients in the RAM arm were: neutropenia (26.3% RAM; 27.0% PL), anemia (12.1% RAM; 14.0% PL), and hypertension (9.9% RAM; 1.6% PL). No new safety signals were observed. Conclusions: In treatment-naïve patients with metastatic G-GEJ adenocarcinoma, the addition of ramucirumab to first-line chemotherapy conferred a significant 25% reduction in the risk of disease progression or death in the primary endpoint of PFS; however, ramucirumab was not associated with an improved OS. Clinical trial information: NCT02314117.