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(Reuters) - An all oral regimen of experimental hepatitis C medicines developed by Abbott Laboratories led to high cure rates in both new patients and those for whom prior treatment failed, according to initial results from a midstage study.
Shares of Abbott rose more than 3 percent after the unveiling of the data, which will be presented next month at a major liver disease meeting. The findings should help cement Abbott as a major player in the race to develop an interferon-free treatment regimen for the serious liver disease.
After 12 weeks of treatment with three Abbott direct-acting antiviral medicines plus the older drug ribavirin, 99 percent of previously untreated patients and 93 percent of those who did not respond to older drugs achieved a sustained virologic response (SVR), which is considered cured, according to available data from a brief summary, or abstract, of the study.
Abbott will present much more detail on the Phase II study involving data from more patients at the American Association for the Study of Liver Diseases (AASLD) meeting in Boston.
"The data looks very good on efficacy and I didn't see anything that really caught my eye as far as side effects," Morningstar analyst Damien Conover said.
Based on the results, Abbott said it would test its three drugs, each of which attacks the virus using a different approach, both with and without ribavirin in a large Phase III program aimed at gaining approval for the treatment.
"The ability to show a sustained virological response in these patient populations without the use of interferon is extremely encouraging," Scott Brun, Abbott's head of infectious disease development, said in a statement.
A pair of new hepatitis C drugs approved last year significantly boosted cure rates and cut treatment duration to as low as 24 weeks for some patients. But those must still be taken with interferon, an injected drug that often causes severe flu-like symptoms that lead many hepatitis patients to delay or discontinue treatment.
Several companies, including Gilead Sciences Inc, Bristol-Myers Squibb Co and Vertex Pharmaceuticals Inc, are racing to develop interferon-free treatment regimens expected to bring in billions of dollars in revenue once approved.
Most analysts view Gilead as current leader both on timing and perceived advantages of its experimental hepatitis C program.
"One of the questions lingering here is whether these (Abbott) drugs can be used without ribavirin," Conover said. "Gilead's drug works pretty well without it, so it's going to be a pretty big competitive hurdle if they have to use ribavirin."
While not as onerous as interferon, ribavirin also has side effects that doctors and patients would like to avoid if possible.
The Abbott drugs, a protease inhibitor called ABT-450, a polymerase inhibitor ABT-333 and ABT-267 from a class known as NS5A inhibitors, were given along with ribavirin for just 12 weeks. Patients in whom the virus was undetectable 12 weeks after stopping treatment were considered cured.
Based on available data at the time the abstract was submitted for the liver meeting, 76 of 77 previously untreated patients and 38 of 41 prior null responders had achieved SVR.
Null responders, while a much smaller market than new patients, have been notoriously difficult to treat.
"The data presented so far appear to be very favorable in these early trials and we'll look for more extensive data at AASLD," JP Morgan analyst Michael Weinstein said in a research note, adding that he expects Abbott's hepatitis C program to reach the market by 2015.
One subject in the new patient group had a disease relapse after treatment and three of the prior null responders experienced viral breakthrough, meaning the virus levels rose during treatment after an initial response.
The most common side effects were fatigue and headache in both groups. Of five reported serious adverse events, one - joint pain - was deemed to be possibly caused by study drugs, the company said.
Abbott shares were up $2.29, or 3.3 percent, at $71.57 at midday on the New York Stock Exchange after rising to a new high of $71.99 earlier.
Reporting by Bill Berkrot; Editing by Andrew Hay, Steve Orlofsky and M.D. Golan