Tumor Dynamic Model-Based Decision Support for Phase Ib/II Combination Studies: A Retrospective Assessment Based on Resampling of the Phase III Study IMpower150

Early go/no-go decisions in oncology often rely on traditional endpoints such as objective response rate (ORR) and progression-free survival (PFS). This retrospective analysis evaluated whether model-based tumor growth inhibition (TGI) metrics could provide stronger decision support in early Phase Ib/II combination studies.

Using data resampled from the Phase III IMpower150 study in non-small cell lung cancer, the researchers compared TGI metrics with ORR and PFS across simulated early-study designs with varying sample sizes and follow-up periods. Model-based TGI metrics generally outperformed traditional RECIST endpoints, with tumor growth rate (KG) emerging as the most robust exploratory metric for supporting early go/no-go decisions.