Replies to post #25 on Idenix Pharmaceuticals (IDIX)

[DewDiligence]

Summary of PROVE-1 over/under guesses
for initial 20-patients randomization:

 
                    Gofish  Dew  dewphl 
 PCR-neg* @10 wks     95%   95%   95% 
 SVR12**              90%   80%   70% 
 SVR**                88%   70%   60%

*TaqMan assay
**Based on original patient pool

[gofishmarko]

>> I'm banking on fact that svrs go way down for gen-1 with short (24 wks) vs long (48 wks)duration of therapy for those who are undetectable at end of tx, and that 10 weeks is just inadequate. <<

dew,

I believe that the current SOC for gen 1 patients who are hcv-neg at wk.4 and remain so is 24wks. of treatment , because additional tx. does not significantly raise the SVR rate. This is more comparable to the situation here rather than just looking at end-of-treatment hcv-negativity. I agree that the 12-wk. tx. length may well be too short to be effective , and my WAG is relying on the extended length of triple therapy , versus the 2 or 4 wks. in the earlier studies , to make up for the reduced overall tx. time. As I said , I won't be too surprised regardless because there are no precedents for 3-month treatments like this. Even if your guess of 60% SVR turns out to be correct , it will still be a dramatic result considering the shorter tx. , but it probably wouldn't impress the Street too much.

>> I'll also guess there is an appreciable spread between svr 12 and 24 with such a short duration of tx, although this difference may disappear with longer treatment duration. <<

I haven't seen much data on time-to-relapse after stopping treatment , but what I've seen suggests that the bulk of patients become hcv-pos. in the first month , and virtually all by 3 months. I'm making the assumption that high-sensitivity testing (10 IU/ml) will capture virtually all relapsers by 3 months off-treatment. Of course , when you start to get higher ranges of SVR , as VX-950 is almost certain to do , then by definition the differences between SVR12 and SVR24 will become smaller on an absolute basis. So whatever regimen VRTX settles on , if it results in high SVRs , will likely result in the replacement of SVR with SVR12 sooner or later. JMHO/WAG.

BTW , if this bet was for real money I'd bet on your numbers , not mine.

;-)