December 31, 2010

What's Next for Achillion Pharma?

by: Jason Chew December 30, 2010

Achillion stock (ACHN) has been flat all year, underperforming the biotech indices as well as its peers in the Hepatitis C drug development community. The stock began to leap a couple days after the company announced that data from ongoing clinical studies of ACH-1625 has been accepted for presentation at the 21st Annual Conference of the Asian Pacific Association for the Study of the Liver (APASL 2011) to be held February 17-21, 2011. It has since climbed from $2.73 to close at $4.00 Wednesday, a 47% increase since the December 6th announcement.

So why all the excitement? Achillion had been making headlines all year; it promoted two new drugs into the clinic, began Phase II trials for lead candidate ACH-1625, presented at multiple industry conferences, and raised a total of $71.4 million in stock offerings.

The reason, I believe, is a key phrasing in the press release, “data from ongoing clinical studies of ACH-1625” was to be presented at the conference. There is only one ongoing study: A 144 patient Phase IIa randomized, double blinded trial of ACH-1625 in combination with ribavirin and peg-interferon alpha. The trial begins with a dose-ranging 28 day phase that will be evaluated to determine the optimal dose for the final 12 week treatment phase.

The company had initially targeted March 2011 for release of the first set of results. Having the ability to move the release date up to February speaks well for trial enrollment. This data will provide the first look at how Achillion’s lead candidate performs in a larger setting and importantly, in combination with current standard of care. ACH-1625 has already been shown to significantly reduce viral loads in patients by 3 to 4.25 log10 and maintain a sustained viral response even after therapy has stopped. It has also been shown to be safe up to 2000mg/day, a level far above the highest dose tested in this Phase IIa.

Pre-clinical studies show ACH-1625 to be additive-synergistic to ribavirin and peg-interferon alpha; this study will be a first look at how well those studies translate in the clinic. Although 28 days is still short, the multiple active drug doses as well as a placebo control will allow investigators to gauge in detail the effectiveness of ACH-1625 in this combination. In any case, a full profile of the compound and its potential as part of this three-drug regimen will be in known by the end of 2011. There’s a lot riding on this study.

Aside from its lead compound, Achillion also has a lineup of several other HCV antivirals in development. The once promising ACH-1095, an inhibitor of the NS4A protease is in Phase I. It was originally developed in collaboration with Gilead (GILD), but its rights have since been handed back to the company- though Gilead still retains the ability to opt in at a later stage in the compound’s development.

Early this year in January, a second NS3 protease inhibitor, ACH-2684, was nominated to enter clinical development. It's interesting that Achillion is developing additional NS3 inhibitors considering there are so many out there. This one is being positioned as more potent and effective against commonly seen viral mutants. It will enter Phase I trials in 2011.

The NS5A inhibitor, ACH-2928, was nominated in mid-year. It is also set to initiate Phase I testing in 2011. ACH-2928 is one of the few NS5A inhibitors currently in development. The most prominent competitor compound is BMS-790052 from Bristol Myers Squibb (BMY), currently in Phase II and looking pretty good. Both of these compounds have similarly high potencies in vitro.

Achillion also has some work in antibiotics and HBV, but they are not a major focus. The goal now is to push forward with its HCV pipeline. 2011 will be pivotal for the company as data comes in from its lead project. Funds raised during the year will allow it to complete both portions of the Phase II trial and at the same time initiate two separate Phase I studies. It will be interesting to see how the company chooses to proceed from there.


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