If the former arm outperforms on safety or effcacy, it won’t be clear whether to attribute the disparity to Lambda vs Pegasys or to Daclatasvir vs Incivek.
Agreed. My guess is that they intend to use a different trial as the disentangler - they already have an Incivek plus lambda trial running in the same population. On a disease as 'predictable' as HCV splitting of what would ordinarily be one trial into two trials should work fine - although it might result in some approval problems.
In any event, it may take a long time to enroll this trial.
Historically these trials have enrolled much faster than expected. And I would suggest that that is because ifn-alpha is the primary toxic agent in current SOC and lambda is both substantially less toxic and substantially better efficacy than alpha. Until the primary protocol of SOC moves to something less toxic I'd expect the trials to continue to enroll more quickly than expected as per clinical trials.
PS Note that the trial you pointed to is, in fact, like some missing arms of the lambda plus incivek trial I mentioned - and that trial had a predicted due date of Dec 2015, whereas this new trial is Dec 2014. I think there is some reasonable likelihood that the end date of the new trial is actually an updated prediction of old trial. I.e. the old trial is enrolling more rapidly than expected.