Replies to post #211724 on Innovation Pharmaceuticals Inc (IPIX)

[PlentyParanoid]

Some clarification,

This is my take on consensus practise:
SOM developing during radiation therapy is considered to be caused by radiation therapy as is SOM developing during the 4 weeks following the radiation therapy. In trials for SOM the limit for 'eligible' SOM is therefore set to be 11 to 12 weeks. IPIX used 11 weeks. For study purposes SOM developing after 11 weeks is considered not originated by radiation and is excluded from the study. Hence, what's the point of following subjects that have not developed SOM by the end of week 11. No point. These kind of subjects are usually censored at the next scheduled visit. This is common practise in trials with time limits. And usully called admistrative censoring.

Proper administrative censoring does not have any affect on Kaplan Meier estimate, because it is executed after the last event/failure, and censor has an effect to Kaplan Meier proportion only if it has an event/failure follwing it. As for possibel effects on other proportional measures - those are done against intent to treat or per protocol population and censoring does not remove subjects from those populations, so - no effect.