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Merck & Co., Gilead Sciences
Inc, Abbott Laboratories, and other companies are working to come up with
all-oral hepatitis C treatments. So far, standard treatments for hepatitis C
include interferon, but interferon can be difficult for patients to tolerate.
Merck reports that during a midstage clinical trial of an experimental Merck
treatment, the drug, MK-5172, suppressed hepatitis C virus in most patients.
The drug study also included the use of injected interferon. MK-5172 appears to
be more potent than another Merck drug, Victrelis. Merck plans new studies of
MK-5172 as an all-oral hepatitis C treatment without interferon.
According to Eliav Bar, vice
president of infectious diseases at Merck’s research group, MK-5172, a protease
inhibitor, is more potent and carries a higher barrier to treatment resistance
than Victrelis. In a phase 2 clinical trial of about 330 hepatitis C patients,
who received different doses of MK-5172 in combination with ribavirin and
interferon for 12 weeks, 96 percent of patients who received the 100 mg dose of
MK-5172 had sustained virologic responses 12 weeks after treatment. This was
the highest response rate of all of the groups. In the Victrelis group, only 54
percent of patients achieved sustained virologic responses at 12 weeks.
However, higher doses of MK-5172 were associated with liver toxicities. Merck
plans to conduct phase 2 studies in combination with another experimental oral
drug, MK-8742, plus ribavirin, which is also oral. Barr stated that if the
experiments go well, the company may consider a combination of MK-5172 with
MK-8472.
Abbott Labs reported results of its
hepatitis C drugs in October. The results show a combination of three
experimental drugs—ABT-450 combined with a boosting agent ritonavir, ABT-267,
and ABT-333—plus ribavirin resulted in 12-week sustained virologic response
rates of 97 percent in treatment of naïve patients and 93 percent in patients
who had received prior treatment. A further trial without ribavirin resulted in
a sustained virologic response rate of 87 percent at 12 weeks in
treatment-naïve patients. About 1 percent of patients discontinued the study
because of adverse events. Abbot has begun phase 3, or late-stage testing of
the hepatitis C regimen, with and without ribavirin.
Bristol-Myers Squibb had a recent
setback when one of its hepatitis C compounds failed for safety issues, but the
company is working on others.
The Friends of AIDS Foundation is
dedicated to enhancing the quality of life for HIV positive individuals and
empowering people to make healthy choices to prevent the spread of the HIV
virus. To learn more about The Friends of AIDS Foundation, please visit: http://www.friendsofaids.org.
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