Adult Neuro-Oncology Trials in the United States over Five Decades: Analysis of Trials Completion Rate to Guide the Path Forward

Abstract

Clinical trials are important to close the gap between therapeutic unmet needs and scientific advances in neuro-oncology. This study analyzes the landscape of neuro-oncology trials to identify completion rates and guide strategies for the path forward. US-registered adult neuro-oncology clinical trials were extracted from www .clinicaltrials.gov (1966-2019), including funding source, trial type, scope, phase, and subjects’ demographics. Completed trials, defined as those that had completed participants’ examinations or intervention administration for the purpose of the final collection of data for the primary outcome were dichotomized against those that failed to reach completion. Univariate and multivariate analysis were used to detect differences across factors and comparing the last two decades (2000-2009, 2010-2019). Our search yielded 4522 trials, 1257 eligible for this study. In 25 US states, neuro-oncology trial availability is <0.85/100,000 population. Comparing the past two decades, trial completion rate decreased from 88% to 64% (p<0.001) and NIH funding decreased from 47% to 24% (p<0.001). Inclusion of subjects >65-year-old and women increased while inclusion of Hispanic subjects decreased (p< 0.001). The top two reasons for lack of completion included accrual and operational difficulties. A larger proportion of women, non-Hispanic subjects, and older adults were enrolled in completed trials than in those that failed completion. Our study is the first report on the neuro-oncology clinical trial landscape in the US and supports the development of strategies to further improve access to these trials. Additionally, attention is needed to identify and modify other factors contributing to lack of completion.