Science Editor

It is, of course, no great feat to predict that hepatitis C will be an important topic at the Annual Meeting of the American Association for the Study of Liver Diseases (AASLD), which will take place in San Francisco in early November. The Centers for Disease Control and Prevention estimated that nearly 3 million Americans are infected with hepatitis C, meaning that the virus is rivaled only by alcoholic liver disease as a cause of liver problems.

But the FDA has approved two drugs for hepatitis C within the last year, and the association updated its practice guidelines for hepatitis C last week. Between those developments and the abstracts, which were published last week, it looks like there will be lots to talk about.

Both new drugs, Merck & Co. Inc.'s Victrelis (boceprevir) and Vertex Pharmaceutical Inc.'s Incivek (telaprevir) were approved within two weeks of each other last May. (See BioWorld Today, May 17, 2011, and May 24, 2011.)

And the AASLD stated that "both drugs are in the forefront of a wave of new drugs that will reach the market in the near future," in its press release announcing the new guidelines.

So far, Victrelis and Incivek are used in addition to the current treatment regimen of pegylated interferon and ribavirin, a fact which the AASLD stressed in its announcement of updated clinical guidelines.

"The drugs [Victrelis and Incivek] are intended for use only in combination with pegylated interferon and ribavirin," according to the AASLD, "and if not used in combination with those drugs, treatment will be ineffective and will cause emergence of antiviral-resistant mutants that could be difficult to treat subsequently."

But given that the current pegylated interferon/ribavirin standard comes with often-grueling side effects, it is unsurprising that some researchers are eyeing the possibility of giving them the boot.

Howard Liang and Jonathan Eckard, of Leerink Swann, wrote in a research note that they "expect data on interferon-free regimens to generate the greatest interest at this AASLD," though they noted that so far the number of patients who have undergone such regimens is still small. One Japanese trial went even further, testing telaprevir as 24-week monotherapy.

Investors seemed to get quite excited about one drug that might be able to do without interferon: Princeton, N.J.-based Pharmasset's PSI-7977.

The company had a jump in its share price when abstracts were released on Friday. Pharmasset is presenting several abstracts on its PSI-7977, including an abstract reporting data from its ELECTRON study that, at least so far, showed pegylated interferon may not add much to a combination of PDI-7977 and ribavirin.

The study compared treatment-naïve non-cirrhotic patients with genotype 2 or 3 who receive PSI-7977 and ribavirin to those who additionally receive pegylated interferon for varying amounts of time. According to the abstract, "week 4 antiviral response rates were similar in the PEG-free and PEG-containing arms;" notably, all 10 subjects who received no pegylated interferon nevertheless achieved a rapid viral response.

As Liang and Eckard noted, the title pretty much gave it all away: "Once Daily PSI-7977 plus RBV: Pegylated interferon-ALFA not required for Complete Rapid viral response in Treatment-naïve Patients with HCV GT2 or GT3."

Pharmasset's shares closed at $87.63 on Friday, up from $77.25 the day before.

Other companies presenting data at the AASLD include:

• Boehringer Ingelheim GmbH, of Ingelheim, Germany, will disclose data testing an interferon-free regimen. The company will publish results from a planned interim analysis of SOUND-C2, a Phase IIb study evaluating an interferon-free oral combination therapy of BI's investigational compounds, BI 201335 and BI 207127, with and without ribavirin.

• Achillion Pharmaceuticals Inc., of New Haven, Conn., will present clinical trial results for ACH-1625, a once-daily protease inhibitor, and preclinical data on ACH-2684 and second-generation NS5A inhibitor compounds.

• Medivir AB, of Huddinge, Sweden, will present data on its TMC435, which it is developing jointly with Tibotec Pharmaceuticals, a subsidiary of New Brunswick, N.J.-based Johnson & Johnson. Data presented include those from the Phase IIb PILLAR trial. In the TMC435 arms of that trial, 79 percent to 86 percent of patients were eligible to complete treatment at week 24.

• Santaris Pharma A/S, of Hoersholm, Denmark, will report results from the miravirsen Phase IIa proof-of-concept study to treat patients infected with HCV. Miravirsen targets microRNA 122 and is the first microRNA-targeted drug to enter clinical trials. In the trial, which is ongoing, miravirsen was associated with dose-dependent, prolonged reductions in HCV RNA that continued to fall after the completion of miravirsen therapy.