Bayesian models to estimate causal effects of biological treatments on time-to-event endpoints in clinical trials with principal strata defined by the occurrence of antidrug antibodies. The methodology is based on Frangakis and Rubin (2002) doi:10.1111/j.0006-341x.2002.00021.x and Imbens and Rubin (1997) doi:10.1214/aos/1034276631, and intended to be applied to a specific time-to-event setting.#'