--Gilead/Bristol combination had 100% viral suppression in most common type of hepatitis C
--Gilead reports positive results for GS-7977 in separate study
--Results bolster prospects for interferon-free, all-oral regimens
(Adds stock price activity for other companies developing hepatitis C drugs; updates stock prices.)
By Peter Loftus
A regimen combining experimental drugs from Gilead Sciences Inc. (>> Gilead Sciences, Inc.) and Bristol-Myers Squibb Co. (>> Bristol Myers Squibb Co.) suppressed the hepatitis C virus in most patients four weeks after completing treatment, according to a new study.
In a separate study, Gilead said a combination of its drug, GS-7977, with an older drug, ribavirin, suppressed the liver-disease-causing virus in most patients four weeks after treatment.
The results bolster the prospects for an all-oral regimen for hepatitis C that eliminates an injectable drug used in the current standard treatment, interferon, which can be difficult for patients to tolerate.
Bristol-Myers, Gilead and others including Abbott Laboratories (>> Abbott Laboratories) are racing to bring an all-oral hepatitis C regimen to market, hoping to tap what is expected to be a multibillion-dollar market for such a therapy.
Gilead shares jumped 12% to $52.24 in recent trading Thursday. The company appears to be leading the race of new oral hepatitis C treatments, as it hopes to bring a GS-7977-based therapy to market late next year or in 2014. Bristol was up 0.9% at $33.86.
UBS analyst Matthew Roden said the data released Thursday put Gilead "squarely in the driver's seat" in developing the next-generation hepatitis C regimen. He noted that Gilead was developing another drug that could be substituted for the Bristol-Myers drug in further development.
Hepatitis C is a viral disease that attacks the liver, and is believed to afflict about 180 million world-wide, with more than 4 million in the U.S., according to the National Institute of Allergy and Infectious Diseases. One research firm has estimated that the world-wide hepatitis C market could reach $16 billion in 2015, up from $1.7 billion in 2010.
The Gilead and Bristol data were among several new studies of hepatitis C therapies released Thursday at the annual scientific meeting of the European Association for the Study of the Liver, or EASL, in Barcelona.
The study tested Gilead's GS-7977, which it acquired in its $11 billion purchase of Pharmasset earlier this year, and Bristol-Myers' daclatasvir. Each works by a different mechanism to attack hepatitis C, which can cause inflammation of the liver.
The Gilead compound, GS-7977, is a so-called nucleotide inhibitor, or "nuke," which Gilead believes could be the cornerstone of the first all-oral regimen for hepatitis C. Bristol's daclatasvir is known as an NS5A replication complex inhibitor.
The companies studied three regimens in 88 hepatitis C patients who hadn't received prior therapy. In one arm, patients were assigned to take GS-7977 for seven days, then a combination of GS-7977 and daclatasvir for 23 weeks. The second group was assigned to take both drugs for 24 weeks, and the third group took both drugs plus an older drug, ribavirin, for 24 weeks.
Each of three regimens had patients divided into two groups: those with genotype 1 hepatitis C--the most common form of the disease in the U.S. and one that is difficult to treat--and a group combining genotypes 2 and 3.
At four weeks following completion of treatment, 100% of the genotype 1 patients across all three treatment regimens had achieved a sustained virologic response, or SVR 4, according to Bristol-Myers. A sustained virologic response that holds up over time is considered by many doctors to be a cure.
Among the genotype 2/3 patients, 91% achieved SVR 4. The breakdown was 100% in the group that received GS-7977 and daclatasvir for 24 weeks; 88% in the group receiving the seven-day lead-in with GS-7977; and 86% for the group that received ribavirin in addition to the experimental drugs.
Adverse events included fatigue, headache and nausea, and were generally mild to moderate.
Bristol and Gilead are awaiting additional data on whether the liver-disease-causing virus remains suppressed over a longer follow-up period. They are also studying whether halving the course of treatment to 12 weeks will achieve the same results.
The results "clearly put this combination into a leading position," said Douglas J. Manion, a senior vice president in Bristol's research-and-development division.
However, Manion said Gilead hasn't agreed to move the combination regimen into a late-stage, or Phase 3, study that could generate data to support a filing for regulatory approval. It's possible Gilead would seek to further develop GS-7977 with its own NS5A inhibitor, rather than Bristol's.
"There are a lot of encouraging data sets here at EASL, including for our own NS5A and non-nucleoside, to consider," said John McHutchison, Gilead's senior vice president of liver disease therapeutics. "We're going to look at everything presented here and be scientific in our approach as we consider the best option for proceeding as quickly and efficiently toward a safe, simple, all-oral regimen."
Bristol-Myers recently obtained another so-called "nuke" drug with its $2.5 billion acquisition of Inhibitex.
In a separate study, Gilead tested GS-7977 plus ribavirin in treatment-naive patients with genotype 1 hepatitis C. Of the 25 patients who completed 12 weeks of treatment, 88% achieved SVR 4, Gilead said.
Adverse events included fatigue, dizziness and headache.
In a press release, the lead investigator of the Gilead study said 12 weeks of GS-7977 and ribavirin may be enough to cure hepatitis C in many genotype 1 patients.
The EASL data triggered some volatility in shares of other companies developing hepatitis C drugs. Achillion Pharmaceuticals Inc. (>> Achillion Pharmaceuticals, Inc.) was off $1.26, or 13%, at $8.24.
Abbott shares dropped $1.16, or 1.9%, to $59.30, though the company reported updated positive data for a potential all-oral regimen it is developing.
Shares of Vertex Pharmaceuticals Inc. (>> Vertex Pharmaceuticals Incorporated) rose 3% to $36.61 after the company said it would start a new study of an all-oral regimen, and Idenix Pharmaceuticals Inc. (>> Idenix Pharmaceuticals, Inc.) rose 2.2% to $8.02.
-By Peter Loftus, Dow Jones Newswires; +1-215-982-5581; firstname.lastname@example.org