Keywords: PFS2, estimand
PFS2, defined as the time from randomization to objective tumor progression on next-line treatment or death from any cause, is recommended by the EMA as an intermediate endpoint between PFS and OS to help understand treatment benefit beyond subsequent therapy when OS cannot be measured, i.e., in settings where one or more lines of therapy are anticipated after progression. A growing number of oncology clinical trials have included PFS2 as an endpoint. However, different definitions of PFS2 have been adopted across studies. This presentation will review commonly used PFS2 estimands per the ICH-E9 addendum, as well as corresponding requirements for data collection to facilitate common understanding and consistent implementation in oncology clinical trials. This presentation is given on behalf of the Treatment Switching Sub-team of Estimands in Oncology Working Group.