Value of central review of RECIST v1.1 outcomes in the AGITG INTEGRATE randomised phase 2 international trial for advanced oesophago-gastric cancer.

PURPOSE: Activity estimates should be accurately evaluated in phase 2 clinical trials to ensure appropriate decisions about proceeding to phase 3 trials. RECIST v1.1. progression-free survival (PFS) is a common endpoint in oncology; however, it can be influenced by assessment criteria and trial design. We assessed the value of central adjudication of investigator-assessed PFS times of participants in a double-blind, randomised phase 2 trial evaluating regorafenib versus placebo in advanced gastro-oesophageal cancer (AGITG INTEGRATE) to inform plans for central review in future trials. METHODS: We calculated the proportion of participants with a disagreement between the site investigator assessment and blinded independent central review and in whom central review resulted in a change, then evaluated the effect of central review on study conclusions by comparing hazard ratios (HRs) for PFS based on site review versus central review. Post-progression unblinding was assessed with similar methods. Simulation studies explored the effect of differential and non-differential measurement error on treatment effect estimation and study power. RESULTS: Disagreements between site assessments versus central review occurred in 8/147 (5.4%) participants, 5 resulting in amended date of progression (3.4%). PFS HRs (sites vs central review progression dates) were similar (0.39 vs 0.40). RECIST progression occurred in 82/86 (95%) of cases where post-progression unblinding was requested by the site investigator. CONCLUSIONS: Blinded independent central review was feasible and supported the reliability of site assessments, trial results, and conclusions. Modelling showed that when treatment effects were large and outcome assessments blinded, central review was unlikely to affect conclusions.

Regorafenib for the Treatment of Advanced Gastric Cancer (INTEGRATE): A Multinational Placebo-Controlled Phase II Trial.

PURPOSE: We evaluated the activity of regorafenib, an oral multikinase inhibitor, in advanced gastric adenocarcinoma. PATIENTS AND METHODS: We conducted an international (Australia and New Zealand, South Korea, and Canada) randomized phase II trial in which patients were randomly assigned at a two-to-one ratio and stratified by lines of prior chemotherapy for advanced disease (one v two) and region. Eligible patients received best supportive care plus regorafenib 160 mg or matching placebo orally on days 1 to 21 of each 28-day cycle until disease progression or prohibitive adverse events occurred. The primary end point was progression-free survival (PFS). Final analysis included data to December 31, 2014. RESULTS: A total of 152 patients were randomly assigned from November 7, 2012, to February 25, 2014, yielding 147 evaluable patients (regorafenib, n = 97; placebo, n = 50). Baseline characteristics were balanced. Median PFS significantly differed between groups (regorafenib, 2.6 months; 95% CI, 1.8 to 3.1 and placebo, 0.9 months; 95% CI, 0.9 to 0.9; hazard ratio [HR], 0.40; 95% CI, 0.28 to 0.59; P < .001). The effect was greater in South Korea than in Australia, New Zealand, and Canada combined (HR, 0.12 v 0.61; interaction P < .001) but consistent across age, neutrophil-to-lymphocyte ratio, primary site, lines of chemotherapy, peritoneal metastasis presence, number of metastatic sites, and plasma vascular endothelial growth factor A. A survival trend in favor of regorafenib was seen (median, 5.8 months; 95% CI, 4.4 to 6.8 v 4.5 months; 95% CI, 3.4 to 5.2; HR, 0.74; P = .147). Twenty-nine patients assigned to placebo received open-label regorafenib after disease progression. Regorafenib toxicity was similar to that previously reported. CONCLUSION: In this phase II trial, regorafenib was effective in prolonging PFS in refractory advanced gastric adenocarcinoma. Regional differences were found, but regorafenib was effective in both regional groups. A phase III trial is planned.