Evaluating Contribution of Treatment Regimen and Treatment Phases in Oncology Studies: Statistical Challenges, Innovative Designs, and Regulatory Considerations

Music City Center 

The design and interpretation of oncology clinical trials increasingly recognize the importance of evaluating the contribution of different treatment phases, such as induction, consolidation, and maintenance to overall clinical benefit. Each phase may differentially impact key efficacy endpoints, including response rate, progression-free survival, and overall survival. However, traditional trial designs often aggregate outcomes across all phases, obscuring the individual effects of each treatment period.

In parallel, the rapid rise of combination therapies reflects the complexity of cancer biology and the ongoing challenge of potential overtreatment. Whether pairing two approved agents, adding a novel drug to an established backbone, or co-developing dual novel therapies, these regimens have become central to modern cancer treatment. Regulatory agencies such as the FDA and EMA increasingly require clear evidence of each phase and each individual component's contribution, demonstrating how each drug or phase affects the disease, how interactions occur, and whether every component provides meaningful clinical benefit without disproportionate risk or potential overtreatment.

Isolating these effects has become difficult and, in some cases, requires large sample sizes that may not be feasible. This presentation will examine statistical and design considerations across a range of trial settings, addressing the contribution of effect in combination therapies and different treatment phases, outlining strategies for generating confirmatory evidence, and highlighting practical challenges and emerging solutions through examples from recent oncology trials.