(Reuters) - A combination of experimental oral hepatitis C treatments being developed by Abbott Laboratories led to cure rates higher than 90 percent in previously untreated patients, according to data from a small mid-stage study.
The data, to be presented at a major European liver meeting later this month, puts Abbott firmly in the crowded race to produce a short duration, interferon-free treatment regimen for the serious liver disease.
Abbott shares rose nearly 2 percent on a down day for the broader market. Shares of some companies developing rival drugs, such as Gilead Sciences Inc and Idenix Pharmaceuticals Inc fell.
“This demonstrates unprecedented cure rates for the most common form of hepatitis C infection. And we were able to achieve those rates with only a 12-week duration of therapy,” said Scott Brun, Abbott’s divisional vice president for infectious disease development.
Abstracts, or brief summaries, of studies to be presented at the European Association for the Study of the Liver (EASL) meeting in Barcelona were made available on Wednesday.
“At EASL it’s going to be very clear that we’ve reached a really transformational moment for patients with HCV (hepatitis C virus),” Brun said.
The Phase II trial of previously untreated patients, known as Co-Pilot, combined Abbot’s protease inhibitor ABT-450 boosted by the antiviral drug ritonavir with its polymerase inhibitor ABT-333 and ribavirin, a drug that is part of all current hepatitis C regimens.
Patients received the combination therapy for 12 weeks and were checked 24 weeks later for signs of the virus in the blood to determine if there was a sustained virologic response, or SVR. Any patients that achieved an SVR 24 weeks after completing treatment are deemed to be cured.
Eighteen of the 19 patients who received a 250 milligram dose of ABT-450 as part of their combination achieved SVR, or 95 percent, while 13 of 14 patients who got a 150 mg dose of ABT-450 were deemed to be cured, or 93 percent.
“We would acknowledge that the 4-drug combination from Abbott sets a high bar for competitors,” BMO Capital Markets analyst Jim Birchenough said in a research note.
He noted that Gilead shares were down in response to the Abbott data, but expressed confidence that a Gilead combination therapy will ultimately be able to match Abbott’s efficacy.
In a third arm of the study that involved patients who had failed to be helped by the former standard treatment of interferon and ribavirin, eight of 17 patients achieved SVR for a cure rate of 47 percent.
“In our view, the response rate in previous non-responders may not be competitive,” said Wells Fargo analyst Larry Biegelsen, who called the treatment naive data “very strong.”
Abbott is also testing a drug from a promising class known as NS5A inhibitors in various all-oral combinations that it believes may improve cure rates for prior non-responders.
“For a first step it’s very encouraging,” Brun said of the new data in non-responders. “If you’re able to add the potent NS5A inhibitor into the mix we think there’s the potential to do even better and that’s currently under study.”
There were no serious side effects seen in the study, with the most common side effects fatigue, nausea and headache.
The treatment of hepatitis C took a major leap forward last year with the approval of new drugs from Vertex Pharmaceuticals Inc and Merck & Co that led to far-higher cure rates with the potential for shorter treatment durations than interferon and ribavirin, which had to be taken for 48 weeks and cured about 40 percent of patients.
Vertex’s Incivek led to cure rates as high as 80 percent in previously untreated patients. But both new drugs must be taken with interferon and ribavirin, and the shortest treatment regimen is currently 24 weeks, with many patients still requiring 48 weeks.
Interferon, an injected drug, causes miserable flu-like symptoms that lead many patients to discontinue treatment and many more to put off treatment altogether. If left untreated, hepatitis C can lead to cirrhosis, liver cancer, and death. It is also the most common reason for liver transplants.
Analysts believe an interferon-free therapy with a high cure rate and shorter treatment duration is likely to be a multibillion-dollar seller. That has led to fierce competition among drugmakers.
Gilead and Bristol-Myers Squibb Co recently spent billions to buy companies developing such drugs. Vertex, Merck and several other smaller companies are also working on various interferon-free combinations.
Gilead shares were down 2.5 percent at $46.88, while shares of Idenix were off more than 11 percent at $9.09. Abbott shares were up 0.4 percent at $61.40 after climbing to a multi-year high of $62.55 earlier on Wednesday.
Far larger trials will be needed to confirm the efficacy and safety of the Abbott drugs, and the company said it is on track to begin pivotal Phase III testing in early 2013.
But the data Abbott will present at EASL this month clearly signals that it intends to be a major player in the field.
Reporting By Bill Berkrot, editing by M.D. Golan and Gunna Dickson