This is an interesting and important question.
It is unclear whether the trial data set will include the subsequent therapies patients received – particularly if they received them more than a year after the initial randomization.  Should confirm the reliability of these data by asking the study sponsor.
When comparing different types of subsequent therapy (i.e. the investigators list 7 different categories), it is unclear how immortal time bias will be addressed.  That is, some patients would have to live long enough to receive the second line therapy.  Some investigators impose  minimal survival time in order to address this.