Replies to post #1006 on Idenix Pharmaceuticals (IDIX)

[gofishmarko]

Re : handicapping drug interaction study


Let's hope it's not " handicapping " to future prospects for NM283. :)

The thing that frustrates me when reviewing the paper on the 283/riba interaction is the experiment they didn't do -- an interaction study comparing ifn/riba to nm283/ifn/riba.

The real 'magic' of riba in HCV is only revealed in combo with ifn. As monotherapy , riba is almost useless vs. HCV , in vitro or in vivo. Combine with ifn and you get a synergy in direct antiviral effect in vitro or in humans , and also the reduction in relapse rates in human studies. So , I agree with you that the riba/283 interaction paper points more toward a negative interaction on 283 antiviral activity , as opposed to one on riba direct antiviral activity , and it tells us nothing about how 283 might effect the 'magic' of the ifn/riba combo. It might have a positive , negative , or no effect , and human studies are the only way to get the full contribution of the immune effects , as you said. ( though innate immune effects , like ifn pathway effectors , can influence replicon antiviral results )

I think the upside on IDIX share price if the interaction study looks good is much greater than the downside if it looks bad. I'd place a bet here based on that imbalance , except for the gut feeling that tells me that the results will be problematic. I disagree with Dew that the decision to delay looking at combos with riba was just a gamble that didn't pay off. The 'magic' of the ifn/riba combo was well known when they started trials on 283. I think the decision was more likely based on replicon and maybe other studies that suggested it was not likely to be a fruitful exercise. It may have been NVS folks or others besides JP at IDIX who influenced that decision , but as CEO of IDIX , JP is the one who will bear the brunt of the blame if it turns out to have been a bad decision. In the recent webcast , he was careful to point out that riba combos will be studied immediately with the 2nd-gen candidate. " I ain't gonna go thru this mess again ! " **



** Not a direct quote. :)