"Combination of VX-950 and Pegylated Interferon Shows Benefits in Difficult-to-Treat Hepatitis C Patients: Presented at EASL"
By Jill Stein
VIENNA, AUSTRIA -- May 2, 2006 -- The investigational agent VX-950 in combination with pegylated interferon alfa-2a (Pegasys[R; peg-IFN) is potent and well tolerated in patients with chronic genotype 1 hepatitis C virus (HCV) infection, researchers said here at the 41st Annual Meeting of the European Association for the Study of the Liver (EASL).
VX-950 is an oral, highly selective peptidomimetic inhibitor of the NS3-4A enzyme, which plays a critical role in the viral replication process.
"We're excited about these early results because only about 50% of patients with the chronic genotype 1 hepatitis C virus strain benefit from the current standard of care," said Henk W. Reesink, MD, associate professor of medicine, Academic Medical Center, Amsterdam, the Netherlands, during a presentation on April 29th.
The current treatment standard involves a combination of weekly peg-IFN and twice daily oral ribavirin.
Dr. Reesink and colleagues randomized 20 treatment-naïve patients to receive a VX-950 tablet at a dose of 750 mg every 8 hours in combination with a standard dose of peg-IFN, the same dose of VX-950 administered alone, or a standard dose of peg-IFN alone.
Demographic and clinical characteristics were the same for the 3 treatment groups.
The median baseline viral load for the entire cohort was 6.65 log10 IU/mL HCV RNA, or about 4.4 million IU/mL.
Dr. Reesink reported that the combination treatment yielded an initial median reduction in plasma HCV RNA that exceeded 3 log10 in the first 2 days.
Antiviral results after 14 days of dosing showed a median 5.5 log10 reduction in HCV RNA in patients receiving VX-950 and peg-IFN; 6 of 8 patients had viral levels below the limit of quantitation (30 IU/mL) at 14 days, and 4 of 8 also achieved viral levels below the limit of detection (10 IU/mL).
A median 4.0 log10 reduction in HCV RNA was observed in patients receiving VX-950 alone; 1 of 8 patients had viral levels below the limit of detection (10 IU/mL).
A median 1.0 log10 reduction in HCV RNA was documented in patients receiving peg-IFN alone; no patient had viral levels below the limit of quantitation (30 IU/mL) at 14 days.
There were no serious adverse reactions nor were dose reductions or treatment discontinuations required.
Following the completion of this study, patients were offered a full course of treatment with peg-IFN and ribavirin.
All 8 patients in the combination group opted to receive treatment with peg-IFN and ribavirin. After 3 months, all patients were shown to have undetectable levels of HCV RNA.
"The continued viral suppression during follow-on therapy points to the robustness of the viral response to VX-950 and peg-IFN and is encouraging for the design of future VX-950 studies that assess the potential for short-course, curative therapy," Dr. Reesink said in a news release.
"Unlike peg-IFN and ribavirin, VX-950 was designed to specifically target the hepatitis C virus," he added. "The specificity and potency of this approach should provide greater and more rapid viral suppression and a better side effect profile, which will hopefully mean that more patients will be treated and that treatment duration will be shorter."
Of the approximately 3 million Americans with hepatitis C, roughly 70% to 75% have the chronic genotype 1 strain, making it the most common strain of hepatitis C in the U.S., Dr. Reesink said.
The study was funded by Vertex Pharmaceuticals Incorporated in Cambridge, Massachusetts.
[Presentation title: Initial Results of a 14-Day Study of the Hepatitis C Virus Inhibitor Protease VX-950, in Combination With Peginterferon-Alpha-2A." Abstract 737]
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