Factors Influencing the Discontinuation of Glioma Clinical Trials: A Retrospective Cohort Analysis from the past Twenty Years

Introduction: Gliomas are among the most difficult types of brain tumors to treat, with high morbidity and mortality. Clinical trials are essential for finding new treatments, yet many are discontinued early, limiting the development of effective therapies, and wasting valuable resources. Since the underlying factors affecting trial discontinuation remain underexplored, this study aims to provide a comprehensive understanding of the challenges facing glioma research and identify potential interventions to improve trial continuity.

Methods: A retrospective cohort of glioma trials from January 1, 2003, through December 31, 2023, from Clinicaltrials.gov was reviewed, only including studies that had been either suspended, terminated, or withdrawn. Trial data collected included the funding source, reason for discontinuation, trial phase, allocation, total number of enrollments, posting of results, and manuscript publication. Data was abstracted using a structured tool and analyzed using IBM SPSS Statistics (version 27). All categorical variables were analyzed using a chi-squared test.

Results: A total of 417 clinical trials out of 2,672 glioma trials were included. While study termination was most often related to recruitment and enrollment, study withdrawal was usually tied to funding sources, and study suspension was normally linked to a sponsor or business decision, revealing a significant difference (p=0.002). When funding sources were considered, no statistical difference existed between suspended, terminated, or withdrawn studies (p=0.494). Similarly, no statistical difference was noted for allocation allotments between discontinuation groups (p=0.660). The most common phase to be either terminated or withdrawn were phase 2 trials, while suspended trials were generally phase 5.

Conclusion : The reason for halting a glioma study is different based upon if a study is suspended, terminated, or withdrawn. Although funding and resources may play a key role in halting a study, it does not appear that funding sources are the main driving factor in a study’s eventual discontinuation.