%0 Journal Article %T Enrollment Forecast for Clinical Trials at the Planning Phase with Study-Level Historical Data. %A Yu M %A Zhong S %A Xing Y %A Wang L %J Ther Innov Regul Sci %V 58 %N 1 %D 2024 01 15 %M 37713098 %F 1.337 %R 10.1007/s43441-023-00564-8 %X Given progressive developments and demands on clinical trials, accurate enrollment timeline forecasting is increasingly crucial for both strategic decision-making and trial execution excellence. Naïve approach assumes flat rates on enrollment using average of historical data, while traditional statistical approach applies simple Poisson-Gamma model using time-invariant rates for site activation and subject recruitment. Both of them are lack of non-trivial factors such as time and location. We propose a novel two-segment statistical approach based on Quasi-Poisson regression for subject accrual rate and Poisson process for subject enrollment and site activation. The input study-level data are publicly accessible and it can be integrated with historical study data from user's organization to prospectively predict enrollment timeline. The new framework is neat and accurate compared to preceding works. We validate the performance of our proposed enrollment model and compare the results with other frameworks on 7 curated studies.