Why carry out this study?

Partitioned-survival modeling, via standard parametric survival functions, has been historically common in survival analyses of anticancer therapies; however, several advanced extrapolation techniques (e.g., mixture cure models, spline-based models) have been established and implemented to account for the potentially curative nature of novel treatments, including chimeric antigen receptor T cell (CAR-T) therapies.

Given the different statistical methods available to researchers, the goal of this research was to conduct a global systematic literature review to identify trends and rationale in survival extrapolation techniques used when projecting the survival benefits of CAR-T therapies over time.

What was learned from this study?

Our findings suggest that nearly two-thirds of cost-effectiveness (CE) models (65%) used advanced extrapolation techniques in base case analyses to account for the potentially curative nature of CAR-T therapies for a proportion of treated patients.

On the basis of this observation, it is our position that future survival analyses of CAR-T therapies should consider incorporating these advanced techniques in base case analyses when extrapolating short-term survival data from clinical trials to long-term horizons that extend well beyond the clinical trial duration.