Replies to post #155825 on Biotech Values

[DewDiligence]

GILD—the doubt I've raised is that TAF regimen (‘Quad Prime’) will [not] differ from Viread regimen (Stribild) in safety/efficacy terms… If TAF proves to be superior to Viread, it would be easier for GILD to switch patients to the TAF regimen even before Viread goes generic and keep them after generic competition.

‘Quad Prime’ doesn’t have to be superior to Stribild to be a successful product, IMO (although it would clearly help if it were); non-inferiority ought to be sufficient for the reason mentioned in #msg-81039562.

[DewDiligence]

GILD’s TAF-based regimen was roughly similar to Stribild at 24 weeks in a phase-2 study previously discussed on this board:

http://finance.yahoo.com/news/gilead-announces-full-24-week-171500194.html

At 24 weeks, 87 percent (n=97/112) of patients taking TAF and 90 percent (n=52/58) of patients taking Stribild achieved HIV RNA (viral load) less than 50 copies/mL, based on the FDA snapshot algorithm (95 percent CI for the difference: -15.7 percent to 5.9 percent for TAF vs. Stribild; p=0.36). There were no statistically significant differences in the frequency and nature of Grades 3-4 laboratory abnormalities, and the frequency and nature of adverse events were similar between the two arms.

Note: This wasn’t a non-inferior trial with a pre-specified NI margin, so there is no assertion of statistical significance on non-inferiority. (The p-value of 0.36 in the PR is for the direct comparison of the two trial arms without adjustment for a NI margin.)

As noted in #msg-81039562, the TAF-based regimen, which I’ve dubbed Quad Prime (Sribild was once called Quad) need not be superior to Stribild to be commercially useful to GILD.