Efficacy of Sequential Ipilimumab Monotherapy versus Best Supportive Care for Unresectable Locally Advanced/Metastatic Gastric or Gastroesophageal Junction Cancer.

Ipilimumab, a monoclonal antibody that blocks cytotoxic T-lymphocyte-associated protein-4 interactions, enhances T-cell activation and promotes tumor immunity. This phase II study evaluated the safety and efficacy of ipilimumab monotherapy versus best supportive care (BSC) among patients with advanced/metastatic gastric or gastroesophageal junction cancer who achieved at least stable disease with first-line chemotherapy. Eligible patients were randomized to ipilimumab 10 mg/kg every 3 weeks for four doses, then 10 mg/kg every 12 weeks for up to 3 years, or BSC, which could include continuation of fluoropyrimidine until progression or toxicity. The primary endpoint was immune-related progression-free survival (irPFS); secondary endpoints included PFS by modified World Health Organization criteria and overall survival (OS). Of 143 patients screened, 57 were randomized to each arm. irPFS with ipilimumab versus BSC was not improved [2.92 months, 95% confidence interval (CI), 1.61-5.16 vs. 4.90 months, 95% CI, 3.45-6.54, HR = 1.44; 80% CI, 1.09-1.91; = 0.097], resulting in study cessation. At study closeout, which occurred 8 months after the interim analysis, the median OS durations were 12.7 months (95% CI, 10.5-18.9) and 12.1 months (95% CI, 9.3-not estimable), respectively. Grade 3/4 treatment-related adverse events occurred in 23% of ipilimumab-treated patients, in whom diarrhea (9%) and fatigue (5%) were most frequent, and in 9% of active BSC-treated patients. Although ipilimumab at 10 mg/kg was manageable, it did not improve irPFS versus BSC. However, comparable median OS of approximately 1 year and a favorable safety profile support the investigation of ipilimumab in combination with other therapies for advanced gastric cancer. .