Accurate estimation of the accrual period is critical for the efficient completion of clinical trials, according to a recent study analyzing data from the Japan Clinical Oncology Group (JCOG). The study, published in Trials Journal, found that only 23.6% of the examined JCOG trials were completed within the initially planned accrual period, highlighting a significant challenge in clinical trial management.
Factors Affecting Trial Accrual
The research identified several factors that significantly impact trial accrual. Shorter planned accrual periods and the stratification of trial designs by phase and randomization were found to be significant risk factors for trial extensions. Stratified trial designs, particularly randomized phase III trials, face challenges due to the inability of patients to choose their treatment, making it difficult to obtain informed consent. In contrast, nonrandomized phase III trials often involve rare cancers, which inherently pose accrual challenges.
The Impact of Accrual Pace
The study emphasized the importance of considering the accrual pace of past trials when calculating the required accrual period for new trials. Trials that considered past accrual rates showed significantly smaller discrepancies between planned and actual accrual periods (0.6 years) compared to those that did not (2.1 years). This trend was particularly noticeable in phase III trials, suggesting that leveraging historical data can lead to more accurate accrual estimates.
Comparison with Other Studies
The findings align with trends reported by the National Cancer Institute-Cancer Therapy Evaluation Program (NCI-CTEP), where a significant percentage of trials fail to complete their target accrual within the planned period. While approximately 5% of JCOG trials were terminated early due to poor accrual—lower than the 27–31% reported by NCI-sponsored groups—the enforcement of early termination rules for trials with poor accrual by JCOG in 2019 indicates a growing emphasis on efficient trial management.
Recommendations for Future Trials
Based on the study's findings, several recommendations were made for future clinical trials. Proactive interventions are necessary for monitoring enrollment progress, especially in randomized phase III trials. This includes investigating reasons for poor accrual, monitoring enrollment progress at participating institutions, and conducting meetings with researchers and research groups. Additionally, employing electronic methods and offering incentives may boost patient accrual.
Limitations
The study acknowledges several limitations, including its focus on a single clinical trial group, which may limit the generalizability of the findings. The study also could not examine the methods used for determining the planned accrual period for trials that did not report this information. Furthermore, the study did not consider the impact of modifying eligibility criteria on accrual rates.
Conclusion
Accurate estimation of the planned accrual period, informed by historical data and proactive monitoring, is essential for improving the efficiency and success of clinical trials. By addressing the identified risk factors and implementing the recommended strategies, researchers can minimize delays, reduce costs, and accelerate the development of new treatments.
