MO1-19-3 Final analysis of survival outcomes in the KSCC1501A trial of up-front therapy for HER2-negative advanced gastric cancer.

Background According to the results of the randomized phase III study, G-SOX, the combination of S-1 and oxaliplatin (SOX) is as effective as the combination of S-1 and cisplatin for the treatment of HER2-negative advanced gastric cancer (AGC), and also has a favorable safety profile. In this trial, the dose of oxaliplatin tested was 100 mg/m2; however, the dose of 130 mg/m2 is covered by insurance in Japan, based on the results of the pivotal global study. Therefore, the efficacy and safety of the SOX regimen with oxaliplatin 130 mg/m2 (SOX130) remains to be elucidated. In this study, we conducted the final analysis of the survival outcomes in a phase II trial to assess the efficacy and safety of SOX130 in HER2-negative AGC. Methods Patients with HER2-negative AGC or recurrent gastric cancer received 80 mg/m2 S-1 per day orally on days 1-14, and 130 mg/m2 oxaliplatin intravenously, on day 1 of each 21-day cycle, until criteria for treatment withdrawal were fulfilled. The primary endpoint was the response rate (RR), and the secondary endpoints were progression-free survival (PFS) and overall survival (OS). Adverse events (AE) were recorded according to CTCAE version 4.0. Results In this study, 71 patients were enrolled from June 2015 to November 2016, but 8 patients were excluded owing to ineligibility. Therefore, the efficacy and safety analyses were finally conducted among 63 patients. The confirmed RR, assessed by an independent review committee, was 46.0% (95% confidence interval [CI]: 34.3-58.2), and the disease control rate was 77.8% (95% CI: 66.1-86.3). The median PFS and OS were 4.9 months (95% CI: 4.2-7.1) and 14.8 months (95% CI: 11.1-18.9), respectively. The incidence rates of grade 3 or 4 AE were as follows: neutropenia, 9.5%; thrombocytopenia, 11.1%; anemia, 6.3%; sensory neuropathy, 12.7%; anorexia, 19.0%; and diarrhea, 6.3%. Conclusions SOX130 showed favorable survival outcomes and an acceptable safety profile in the treatment of HER2-negative AGC. [ABSTRACT FROM AUTHOR]