hepatitis drug receives approval
TRANSCRIPT
Following its approval in November by Health
Canada’s Therapeutic Products Program, lamivu-
dine (Fig. 1) has become the first orally available
antiviral drug for the treatment of hepatitis B.
Both Glaxo Wellcome (Stevenage, UK), the drug’s
manufacturer, and BioChem Pharma (Quebec,
Canada), the company that discovered the drug,
have said that a single, daily dose of lamivudine,
or Heptovir, retards the progression of liver disease
and, in some patients, can even stop it in its tracks.
According to Sam Lee, president of the
Canadian Association for the Study of the Liver
and associate professor of medicine at the
University of Calgary (Alberta, Canada),
Heptovir is a very potent inhibitor of hepatitis B
viral replication, and it has been shown to de-
crease the amount of virus to undetectable lev-
els in up to 98% of patients when placed on the
treatment. He adds that the potential longer-
term benefits of Heptovir might be to stave off
the development of cirrhosis or liver cancer in
hepatitis B patients.
Hepatitis BThere are an estimated 250,000 Canadians with
chronic hepatitis B infection. The World Health
Organization (WHO) conservatively estimates
that there are 350 million chronic carriers
worldwide. According to the WHO, hepatitis B is
one of the most common infectious diseases
and the ninth most common cause of death. It
also estimates that there are between one and
two million deaths each year from compli-
cations associated with the disease. Sexual
transmission is the most common transmission
route of the virus in Europe and North America,
with those aged between 15 and 24 at the
greatest risk. In addition however, other risk fac-
tors include contact with infected blood or dur-
ing the first year of life from mother to child.
As yet there is no cure and vaccination
through interferon therapy, which is aimed at
boosting cytokine activity, leads to side-effects
in some patients and does not protect those
already infected. Therefore, an effective oral drug
to control the disease is clearly very desirable.
Hepatitis B can cause serious liver disease
(cirrhosis) and can lead to liver failure, liver can-
cer and death. Infection in early childhood can
lead to premature death in adulthood from
hepatitis B complications. A drug such as
lamivudine controls the disease by slowing the
rate of viral replication and thus allows patients
to seroconvert and develop an immunity.
Irrespective of whether immunity is produced,
however, the drug retains benefits in terms of
slowing the rate of progress of the disease.
Lamivudine, also known as 3TC, is a nucleo-
side analogue reverse transcriptase-inhibitor
and has become an active combatant in the
fight against AIDS. Further trials performed by
Glaxo Wellcome on the drug showed that over
the course of a year more than half the patients
given the drug for hepatitis B showed improved
liver function and histology, compared with
36% of patients given interferon therapy and
only 25% taking a placebo.
Lamivudine is not without problems, how-
ever. According to a report in the BritishMedical Journal1, some patients who demon-
strated signs of improvement actually had in-
creased viral load, whereas in some patients re-
lapses were seen following cessation of the
treatment. Although the US Food and Drug
Administration granted approval last October, it
has recommended the continuation of further
studies into the drug’s efficacy.
According to A.J. Zuckerman, director of the
WHO Centre at the Royal Free and University
College Medical School, UCL (London, UK),
‘there is a need to extend antiviral therapy in
HBV carriers in order to prevent transmission of
the infection and progression to chronic liver
disease.’ Lamivudine represents ‘a very signifi-
cant advance’ in antiviral therapy against
chronic hepatitis B, but he points out that uni-
versal immunization would lead to the eradi-
cation of the virus.
Reference01 British Medical Journal (1998) 317, 1034
update news PSTT Vol. 2, No. 2 February 1999
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Hepatitis drug receives approvalDavid Bradley, tel/fax: 144 1954 202218, Web: http://www.camsoft.com/elemental/
Figure 1. Lamivudine, the first orallyavailable antiviral drug for the treatment ofhepatitis B. The drug is claimed to retardthe progression of liver disease and, in somecases, halt its advancement.
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