This why biotech is fun. Beginning yesterday and continuing through the weekend, many investors’ eyes will be focused on The Liver Meeting, being held in San Francisco, with the latest advances in liver disease being shared and discussed. The first salvo was released yesterday morning, when Inhibitex ($INHX) announced positive interim data on their lead asset INX-189 (briefly discussed here).  Investors who read their 3Q11 press release quickly unleashed a buying binge, which pushed the stock up to $8.54/share, a $650 MM market cap, at the close.  A 116% gain! Just think, my last post on $INHX was just two months ago, when it was trading with a $275 MM market cap. Today, the company’s fortune has changed significantly.

When we left the story, the company was testing a higher dose of INX-189 in HCV GT1 patients. The existing data had suggested that the 100 mg QD was safe and efficacious, but that there was room for improvement. This expectation for improved efficacy, or as a potential competitor to Pharmasset ($VRUS), is likely why some investors continued to hold and/or place their bets.

Generally speaking, during dose escalation studies, as the dose increases, efficacy typically increases as well, until it hits a wall. Makes sense, right?

While we should not compare data expressed as median with mean, and I don’t have the median numbers readily available for IDX-184 and VRUS-7977, the median HCV RNA reduction observed with INX-189 was robust (see table below) and can be viewed as a worthy competitor to $VRUS. The other looming issue would have been safety and at the 200 mg there did not appear to be any serious adverse events (SAEs).

* Press release, 11/4/11; sorry, need to work on table formatting

No doubt, $INHX stil has a long road ahead, but the race for the first all-oral HCV regimen is on.

I stand by my comments on rushing into GT2/3 patients, as I would rather take the 200 mg dose into patients. However, given that drug is development is a race, calculated risks are part of the game. We know that 1) GT2/3 patient are easier to treat, 2) direct acting anti-viral agents (DAAs) should work across multiple genotypes, and 3) $VRUS is laying a path forward for the rest to follow.

Is it too soon to wonder if the recent success of $VRUS, and now $INHX, could create another warehousing effect, whereby patients who can, will wait a few years for a new, better therapy before starting treatment.

Perhaps, we should simply just enjoy this data for now (and not forget about $MDVN’s recent success with MDV-3100).