Effect of First-line S-1 Plus Oxaliplatin With or Without Ramucirumab Followed by Paclitaxel Plus Ramucirumab on Advanced Gastric Cancer in East Asia
Authors: Takaki Yoshikawa, Kei Muro, Kohei Shitara, Do-Youn Oh, Yoon-Koo Kang, Hyun Cheol Chung, Toshihiro Kudo, Keisho Chin, Shigenori Kadowaki, Yasuo Hamamoto, Shuichi Hironaka, Kazuhiro Yoshida, Chia-Jui Yen, Yasushi Omuro, Li-Yuan Bai, Kaijiro Maeda, Akichika Ozeki, Reigetsu Yoshikawa, Yuko Kitagawa
Journal: JAMA Network Open (2019)

<h3>Importance</h3> Ramucirumab, a human IgG 1 antibody against vascular endothelial growth factor receptor 2, has been shown to improve progression-free survival and overall survival in patients with advanced gastric cancer in the second-line setting. <h3>Objective</h3> To compare progression-free survival for S-1 and oxaliplatin plus ramucirumab with that for S-1 and oxaliplatin plus placebo in patients with advanced gastric cancer. <h3>Design, Setting, and Participants</h3> This phase 2, double-blind randomized clinical trial (RAINSTORM [First-line S-1 Plus Oxaliplatin With or Without Ramucirumab Followed by Paclitaxel Plus Ramucirumab in Patients With Advanced Gastric Cancer]) was conducted from October 12, 2015, to April 11, 2018, at 36 sites in Japan, South Korea, and Taiwan. Participants were chemotherapy-naive patients (n = 189) with metastatic gastric or gastroesophageal adenocarcinoma. Analyses of the full analysis set and safety population were conducted between November 27, 2017, and June 4, 2018. <h3>Interventions</h3> Patients randomized to the ramucirumab plus S-1 and oxaliplatin arm received S-1, 80 to 120 mg/d twice daily, on days 1 to 14 and oxaliplatin, 100 mg/m<sup>2</sup>, on day 1 with ramucirumab, 8 mg/kg, on days 1 and 8 in part A (21-day cycle). Patients randomized to the placebo plus S-1 and oxaliplatin arm received the same S-1 and oxaliplatin dosage as well as placebo on days 1 and 8 in part A. Eligible patients received second-line paclitaxel, 80 mg/m<sup>2</sup>, on days 1, 8, and 15 and ramucirumab, 8 mg/kg, on days 1 and 15 in part B (28-day cycle). <h3>Main Outcomes and Measures</h3> The primary end point was progression-free survival, analyzed using the stratified log-rank test; the hazard ratio (HR) was estimated using the stratified Cox proportional hazards regression model. Secondary end points included overall survival and adverse events. <h3>Results</h3> In total, 189 patients were randomized and received treatment: 96 to the ramucirumab plus S-1 and oxaliplatin arm and 93 to the placebo plus S-1 and oxaliplatin arm. Among the 189 patients, 121 (64.0%) were male, and the median (range) age was 62.0 (26-84) years. Median progression-free survival was not prolonged in the ramucirumab plus S-1 and oxaliplatin arm compared with the placebo plus S-1 and oxaliplatin arm (6.34 [80% CI, 5.65-6.93] vs 6.74 [80% CI, 5.75-7.13] months; HR, 1.07; 80% CI, 0.86-1.33;<i>P</i> = .70). Median overall survival was 14.65 (80% CI, 12.39-15.67) months in the ramucirumab plus S-1 and oxaliplatin arm and 14.26 (80% CI, 13.83-17.31) months in the placebo plus S-1 and oxaliplatin arm (HR, 1.11; 80% CI, 0.89-1.40;<i>P</i> = .55). The most commonly reported grade 3 or higher treatment-emergent adverse events in the ramucirumab plus S-1 and oxaliplatin arm in part A were decreased neutrophil count (14 patients [14.6%]), hypertension (10 patients [10.4%]), and anemia (10 patients [10.4%]). <h3>Conclusions and Relevance</h3> In this randomized clinical trial, the addition of ramucirumab to first-line S-1 and oxaliplatin treatment did not prolong progression-free survival or overall survival compared with S-1 and oxaliplatin alone among East Asian patients with advanced gastric cancer; no new safety signals for ramucirumab were identified. <h3>Trial Registration</h3> ClinicalTrials.gov identifier:NCT02539225