By Ransdell Pierson and Bill Berkrot
(Reuters) - A combination of five oral drugs being tested by AbbVie Inc cured at least 88 percent of new patients with hepatitis C after only eight weeks of treatment, without raising significant safety issues, researchers said on Tuesday.
The latest findings from an ongoing trial sponsored by AbbVie, called Aviator, also showed that 96 percent of patients taking the five medicines for 12 weeks eliminated the virus, as assessed by blood tests 24 weeks after they stopped treatment.
If the virus is undetectable 24 weeks after completing treatment, known as SVR 24, a patient is considered cured.
The latest results were deemed little different than the 99 percent sustained virologic response (SVR) rate reported in October, for patients evaluated 12 weeks after completing 12 weeks of the five-drug treatment regimen.
"We are pleased that the data remain consistent and robust," said Dr. Kris Kowdley, who is presenting the data this week at a meeting of the European Association for the Study of the Liver (EASL) in Amsterdam.
"The data confirm that the 12-week treatment appears to be optimal, but certainly we are still very pleased with ... data for the eight-week treatment," Kowdley said in an interview.
AbbVie is deemed to be in a horse race with Gilead Sciences Inc to be first to market with an all-oral treatment for the serious liver disease, as companies work to eliminate difficult-to-tolerate intravenous interferon from the regimen, while raising cure rates and shortening treatment duration.
Current hepatitis C treatments take either 24 or 48 weeks.
Hepatitis C affects an estimated 170 million people worldwide, and if left untreated can lead to cirrhosis, liver cancer or the need for a new liver.
Gilead has been given an edge by many analysts because its experimental regimen involves fewer drugs. But Abbvie said it is also testing regimens with fewer drugs and ones that do not include the older oral drug ribavirin, which can also be difficult for some patients to tolerate.
Any oral regimen to treat hepatitis C is expected to garner billions of dollars in annual sales.
Patients in the Aviator study had the most common, but hardest to treat, genotype 1 variation of the infectious virus. The AbbVie drugs were the protease inhibitor ABT-450, whose effect was boosted by a widely used antiviral called ritonavir; the polymerase inhibitor ABT-333 and ABT-267 from a class known as NS5A inhibitors. Those were given along with the generic antiviral medicine, ribavirin.
Kowdley, director of the Liver Center of Excellence at Virginia Mason Medical Center in Seattle, said the trial also showed impressive results among patients who had failed to benefit from earlier therapy.
The cure rate after 12 weeks of treatment was 93 percent for those patients, called null responders, assessed both 12 weeks and 24 weeks after completion of their drug regimens. That compared with a cure rate of 95 percent for patients treated for 24 weeks, and then assessed 24 weeks after treatment stopped.
AbbVie said the safety of the tested drugs was similar to that seen in results presented last year. Of the 247 patients evaluated, serious side effects were seen in four patients (1.6 percent), while seven patients had elevated levels of liver enzymes that can be considered a potential sign of toxicity.
Less serious side effects seen in more than 10 percent of patients included headache, fatigue, nausea, insomnia and diarrhea.
(Editing by Jan Paschal)