Validation of overall survival extrapolations made by TLV in the assessment of cost-effectiveness of oncology drugs in Sweden - A pilot study comparing extrapolated and observed life-years gained.

We conclude that it is feasible to validate OS extrapolations by comparing extrapolated and observed life-years. Even if survival extrapolations are reasonably accurate for the treatment group, this may still imply that extrapolations of LYs gained deviates to a larger extent. Follow-up studies on OS should be carried out to an increased extent to be able to validate, update and improve OS extrapolations in cost-effectiveness analysis of oncology drugs.