True... EOT does not translate to SVR4... and SVR4 is still too early but starts to be a good indicator. SVR12, however... that you may want to hang your hat on these days. Here is a bit of info on drug pharmacokinetics. Peg has a pretty long half-life (not to mention ribavirin...why do you think the ribavirin label tells you to practice safe you-know-what for a long time AFTER you finish taking the drug?)... anyway you need to get to SVR12 with Peg/Riba just to see if there will be a lot of relapse due to this half-life (I didn't make this up... there is good data in the public domain from companies and the FDA to show this). If you are giving oral therapies with a short half-life, the drug pressure is gone rapidly. HCV also grows very fast (just ask a liver transplant patient) once the drug pressure is removed. I would have strong doubts you will see much relapse if any after SVR12. Probably you will see some patients in the study lost to follow-up between 12 and 24 (that is a long time to expect someone to come back for a blood draw) that may be counted conservatively as a "failure"... but that is really just a failure to obtain a blood draw!
I always find it so funny when people try to say things on these boards to get folks all crazy. I don't even have holding in these companies... I just know the science and it annoys me when people start shouting that the earth is flat and herbs and berries will cure you of all your woes.