Hepatitis C Drug Rocks Virus in Early Test
Dramatic Impact in 2 Weeks; Long-Term Effect, Safety Unknown
May 17, 2005 -- In early tests on humans, a new hepatitis C drug had the
most powerful punch yet seen against this major cause of liver cancer.
The drug, from Vertex Pharmaceuticals, is code-named VX-950. Liver
specialist Henk W. Reesink, MD, of academic Medical Center in Amsterdam,
Netherlands, presented the findings at Digestive Disease Week 2005, the annual
meeting of several major medical specialty societies.
"This is really a breakthrough in the treatment of hepatitis C
virus," Reesink tells WebMD. "This first human study was very
successful. In the first two or three days of treatment there is a very rapid
[1,000-fold] decline in hepatitis C virus levels. Then, over two weeks, there
are further declines -- in some dosage groups, about a 25,000-fold reduction in
viral levels. That has never been shown with any other drug."
Reesink warns that VX-950 is in the very earliest stage of human studies.
Nobody knows if it will prove safe over time. Nobody knows whether its effects
will continue long enough to cure hepatitis C virus infection.
And while the drug appears exquisitely effective against genotype 1 -- the
most difficult-to-treat strain of hepatitis C virus and the one most common in
the U.S. and Europe -- it's not clear whether it will work against other
Despite being highly preliminary, Reesink's report excited the assembly of
specialists, says Eugene R. Schiff, MD, chief of hepatology and director of the
Center for Liver Diseases at the University of Miami School of Medicine.
"I was impressed, and everybody in the audience was impressed,"
Schiff tells WebMD. "Yes, this is preliminary, but this is an important
advance. It is the most important paper presented at this meeting. They showed
-- with an oral agent -- that they could drop hepatitis C viral levels, some to
undetectable levels, in a relatively short period of time."
Most of the patients in the Reesink study already had failed
state-of-the-art treatment for hepatitis C. That treatment is a combination of
a highly active form of interferon plus an antiviral drug called ribavirin.
This treatment offers long-term viral suppression -- what many experts call a
cure -- in about half of patients. But this treatment takes nearly a year, and
the side effects often are very difficult to endure.
VX-950: Protease Inhibitor Targets Hepatitis C Virus
VX-950 is a designer drug discovered only after huge effort. It targets a
key hepatitis C protein. That protein is called protease, an enzyme the virus
needs to reproduce.
It's not the first time a hepatitis C protease inhibitor has been tested in
humans. Recently, an experimental hepatitis C protease inhibitor called BILN
2061 showed promising results in short-term human trials. But that drug had to
be put on hold when monkey studies suggested it was toxic to the heart.