Discussion on "LEAP: the latent exchangeability prior for borrowing information from historical data" by Ethan M. Alt, Xiuya Chang, Xun Jiang, Qing Liu, May Mo, H. Amy Xia, and Joseph G. Ibrahim.

We commend Alt et al.'s innovative approach for analysis with a hybrid control arm while offering insights into two key considerations: the necessity for extrapolation and the potential benefits of curating historical control data before analysis.