Combining two experimental Bristol-Myers Squibb Co. pills cleared the hepatitis C virus in 36 percent of patients not helped by a standard treatment, in a small study testing a new approach against the liver disease.
The study is the first to suggest that difficult hepatitis C cases may be cured without using the injected drug interferon, said Anna Lok, the lead study author and director of hepatology at the University of Michigan in Ann Arbor. Interferon, a mainstay of existing treatment, causes unpleasant side effects including fatigue and flu-like symptoms.
Drug companies including Bristol-Myers, Merck & Co., Gilead Sciences Inc., and Vertex Pharmaceuticals Inc. are racing to come up with interferon-free treatment. The new results in 21 patients show that such a therapy will be possible, Lok said.
Bristol-Myers, based in New York, plans to take the drug into a final stage trial in Japan, the company said yesterday in a statement.
Oral treatments with fewer side effects would vastly increase the number of patients treated, according to an editorial in the New England Journal of Medicine, where the study was published yesterday.
“We are on the threshold of a treatment revolution that will greatly improve the effectiveness of HCV therapy,” wrote Raymond Chung, a gastroenterologist at Massachusetts General Hospital in Boston. He called it “a watershed moment in the annals of HCV therapy.”
The study compared Bristol-Myers’s two pills in combination with interferon to the pills alone in 21 hepatitis C patients who weren’t helped by existing therapy. It found that 4 of 11 patients had undetectable virus 24 weeks after treatment with Bristol’s experimental oral drugs daclatasvir and asunaprevir.
Adding injectable drugs, however, boosted the response rate. Results showed that 9 of 10 patients who got the two oral drugs plus interferon and a fourth drug, ribavirin, for 24 weeks had no detectable virus 24 weeks after stopping therapy.
“The combination of drugs we picked may not be the best, and we need to tweak it and find the best combination,” Lok said in a telephone interview from Ann Arbor.
Interferon and ribavirin combination treatments clear the virus from only about half of patients with the most common strain of hepatitis C in the U.S., according to the Centers for Disease Control and Prevention in Atlanta. The new therapies aim for an all-oral treatment with fewer side effects, improved clearance rates and shorter time-frames.
Interferon is “really an awful drug. It has awful side effects and patients hate it,” Lok said. “If you’re a patient with hepatitis C and you have early stage liver disease and can’t tolerate interferon, there’s hope for those patients.”
The virus infects the liver and is transmitted through the blood. The CDC estimates that 3.2 million Americans have hepatitis C, which can cause liver disease and kills from 8,000 to 10,000 people a year in the U.S.
Bristol-Myers sponsored the clinical trial. Part of the data was presented at the October 2010 meeting of the American Association for the Study of Liver Diseases in Boston.
It isn’t yet known which combination of pills will produce optimal results, leading to a flurry of recent deals as drugmakers bolster their portfolios. Bristol-Myers recently agreed to spend $2.5 billion to buy Inhibitex Inc., which is developing an oral drug called INX-189 for treating hepatitis C. Gilead, based in Foster City, California, and the world’s largest maker of AIDS drugs, also recently paid $10.8 billion for Pharmasset Inc.
Inhibitex and Pharmasset have “nukes,” or nucleotide polymerase inhibitors, which are meant to stop the hepatitis C virus from replicating. These drugs may be used in an all-oral combination treatment.
Lok said the proof-of-concept trial would trigger other studies to find out what oral medications best cleared the virus from the body.