Time to event variable

From: Wenhui Zhang wenhui.zhang@abbott.com Subject: [NMusers] Time to event variable Date: Thu, 24 Aug 2006 11:30:57 -0500 Dear All I am trying to model one of the adverse events we observed in animal studies as the time-to-event variable. All studies were multiple dose study. The difference is that in some of studies animals were moved away from study after adverse event was observed, i.e animals were not rechallenged with compound any more. In other studies, the animals were rechallenged with compound after adverse event was observed. Could anybody shed a light on how to model the multiple hazards , i.e multiple doses, and different data structure (with and with rechallenge)? Thanks a lot.