Telaprevir phase 3 trial, question

[geterdone]

Jim/All

I’ve been looking over this chart of the latest Prove – phase3 trial in comparison to the prove 1 & 2 and the one thing that sticks out to me is that all are basically the same except for the T/P/R 8 week and the extended 16 weeks of P/R to bring it to 24 weeks in the phase 3 trial. I am wondering if the 8 week T/P/R is shorter than the other 12 week T/P/R’s in prove 1&2 because of the severe rash associated with the longer duration of the 12 week course? If so, it would make perfectly good sense if this is when the rash is at its peak, meaning that in the clinical trial data somewhere the 8 week marker is when it becomes severe to the patient and in the same respect the TVR hits the virus the hardest as with SOC in the beginning. Any thoughts on the 8 week arm?

I am trying to make some sense of the numbers of the prove 1&2 trials and its correlation to this 8 week treatment.

jasper


http://www.vpharm.com/current-projects/drug-candidates/telaprevir-VX-950.html

[lab-rat]

Thanks for the link to the study charts.  That's interesting that they're trying a shorter arm for the triple-therapy...plus the only arm that includes 48 weeks of treatment is the control arm.  That makes me feel a little better since I'm doing a 24 week rollover trial after relapsing w/48 weeks of SOC.

I don't know anything about the data from the studies (other than anecdotally what I've read here)...but I believe you're onto something with the 8-week rash theory.  Since I begin week 8 of triple-therapy tomorrow, I've been looking up a lot of the old "rash" posts and that's exactly the timeframe when it really hits the fan.  

[geterdone]

Yes, that is what I’m thinking that the telaprevir is faster acting than the riba but I have not found any other data to support that. The only data is from the trials posted at Vertex’s web site and if you can decipher that information let me know, lol but looking at the RVR from prove 1&2 combined 77% in the TPR groups and out of 573 people, 441 had RVR in the first 4 weeks and looks pretty impressive and a building block to the phase three 8 week trial. So, if the riba has a 8 week serum build up then the telaprevir is a faster acting agent if I did the math right.

http://investors.vrtx.com/releasedetail.cfm?ReleaseID=272873

jasper

[dointime]

Isn't 8 weeks the time it takes for riba to get to full blood serum concentration?  By that time all that's left of the virus should be telaprevir resistant variants which in theory the full-strength SOC should mop up.  

And yes I think the rash is a factor.  Many people didn't develop the rash until around week 8, so stopping telaprevir at week 8 should considerably improve the figures on discontinuations for reasons of rash.

dointime

[jmjm530]

Yes, the results of that 8-week ARM should be a very interesting comparision to the longer T/P/R ARMs in terms sfx profiles and perhaps more important, eventual SVR rates.It's also good to see that all ARMs are trialing with riba now. Still, your chances of being in SOC appears to be 33.3% which means 48 weeks of treatment, should you follow trial protocol. Curious if the different ARMs will be blinded again and for how long. Thanks for the link.

-- Jim