Background
The rolling six design (RSD) is currently being used by the Children’s
Oncology Group (COG) as their standard design for Phase I trials. Because the COG has
large multi-center trials with fast accrual, the motivation for adopting the RSD is
to hasten accrual and shorten the duration of their trials. However, trial suspension
due to completion of follow-up still cannot be entirely avoided by the RSD.
Therefore, a design that allows continuous enrollment of patients throughout the
entire trial is needed.
Purpose
To demonstrate the superior performance of the Time-to-Event Continual
Reassessment Method (TITE-CRM) with continuous patient recruitment relative to the
RSD, in terms of identifying the maximum tolerated dose (MTD) and reducing exposure
of patients to toxic doses.
Methods
Using scenarios that were based on an actual pediatric Phase I trial at the
University of Michigan, Monte Carlo simulations were used to investigate the
operational characteristics of RSD and TITE-CRM.
Results
The TITE-CRM treated all available patients, identified the MTD more
accurately than the RSD and did not increase the probability of exposing patients to
toxic doses.
Limitations
Both the TITE-CRM and RSD assume that the probability of dose limiting
toxicity increases with higher dose level.
Conclusions
The TITE-CRM, which allows for continual enrollment of patients, provides a
safe design for pediatric oncology Phase I trials with better accuracy than the
RSD.