Replies to post #96498 on Biotech Values

[DewDiligence]

Re: Precedence list of HCV drug-class combinations

Going from strongest to weakest synergy is as follows [according to IDIX]:

a) PI + NS5A inhibitor + purine nuke
b) PI + non-nuke + purine nuke
c) PI + pyrimidine nuke + purine nuke
d) PI + NS5A
e) PI + non-nuke
f) PI + pyrimidine nuke

Are purine nukes ipso facto better than pyrimidine nukes as an addend to protease inhibitors? Or do the HCV purine nukes in development (e.g. IDX184) simply happen to be better than the pyrimidine nukes in development (e.g. RG7128)? If we had some medicinal chemists here, we could get a good debate going on this question.

My initial reaction to the precedence list above is that IDIX is guilty of “talking book.” I.e., it’s not clear to me that purine nukes are ipso facto more synergistic with PI’s than pyrimidine nukes are.

The other salient point regarding IDIX’s precedence list is how low the non-nuke class has slipped. On this point, IDIX is not simply talking book insofar as IDIX does have a non-nuke in the clinic (IDX375); rather, I think it’s fair to say that non-nukes, with the notable exception of VRTX’s VX-222, have to date been the least impressive of the main HCV drug classes.

[hptaxis]

For Slide 13, go to following link, Slide 5: http://www.idenix.com/hepc/drug/FDA_HCV_Public_Hearing_Final_4.30.10.pdf

Thanks for the info (just warming up on HCV)

[DewDiligence]

At the end of IDIX’s Citi webcast, CFO Ron Renaud mentioned in passing that the phase-2b trials of IDX899 vs Sustiva (first-line setting) and IDX899 vs Intelence (second-line setting) are expected to start in late 2010 rather than the current quarte, as previously guided (#msg-47558107). Renaud also said the IDX899 + GSK1349572 phase-2b “nuke-sparing” trial is expected to start in early 2011 rather than late 2010, as previously guided.

Inasmuch as GSK is running these trials and is in charge of all information dissemination about IDX899, IDIX presumably can’t reveal the reason for the delays. Renaud may have slipped up by even mentioning the timeline on the webcast.