Speed of Accrual Into Phase III Oncology Trials

Abstract

We sought to determine the speed at which patients were accrued into published phase III oncology trials across geographic locations and to identify the factors that may influence this process. We searched OVID-Medline and identified all phase III oncology therapeutic trials published in 2006 to 2010. The speed of accrual for each trial was calculated by dividing the number of patients enrolled by the number of months the trial was open (patients/mo). Five hundred forty-six trials were included in our study. Most of the trials were for adults (96%), late-stage cancers (78%), sponsored by either cooperative groups or academic centers (66%), and had negative results (58%). The most common trial locations were multinational (45%), United States (16%), Italy (7%), Germany (6%), Japan (6%), and France (5%). Compared with trials conducted in a single country, multinational trials accrued significantly more patients per trial, completed enrollment faster, and were published sooner (all P≤0.01). Multivariate analyses showed that multinational (P=0.001), breast cancer (P=0.001), industry sponsored (P=0.001), and equivalency trials (P=0.039) accrued significantly faster than other types of trials. Placebo-controlled and non-placebo-controlled trials accrued at similar speeds. We found no difference in speed of accrual between the United States and Europe. Speed of accrual for phase III oncology trials is fastest among multinational trials and independently influenced by the type of trial sponsor, cancer investigated, and study outcome, but not by placebo use. Trials conducted in single countries seem to accrue at similar speeds.