Pharmacoeconomics of Combination Therapy for HCV
Wix58
Pharmacoeconomics of Combination Therapy for HCV
John Wong, MD
Chief
Division of Clinical Decision Making
New England Medical Center
Tufts University School of Medicine
Boston, Massachusetts
Abstract
Chronic hepatitis C affects 170 million people worldwide and more than
2.7 million in the US where it is the leading cause of death from
chronic liver disease and accounts for 20% to 30% of all liver
transplantation. It had led to a rising incidence of hepatocellular
carcinoma in Japan and the United States. On an individual level, it
results in impaired quality of life and indirect costs involving
decreased productivity and lost days from work. The Centers for Disease
Control and Prevention conservatively estimates US expenditures in
excess of $600 million annually.
Sir William Osler once wrote that "Medicine is a science of uncertainty
and an art of probability." This saying certainly holds true for the
treatment of hepatitis C. Some opponents to treatment suggest that
hepatitis C is only slowly progressive, that treatment is only effective
in a proportion of treated patients, that treatment is relatively
expensive and that treatment has potential side-effects.
Based on the prospective studies of transfusion associated non-A non-B
hepatitis and extrapolating findings to 20 years following acute
disease, 14% to 45% of patients should develop cirrhosis. Moreover,
aside from excessive alcohol intake and male gender as risk factors, it
is not possible to determine which patients will develop cirrhosis.
Although not all patients develop cirrhosis, the implications of
developing cirrhosis on length of life are substantial. Compared to
normal individuals from the general population, 40 to 60 year olds with
compensated cirrhosis would have their life expectancy shortened by 7 to
19 years.
Combination therapy for 48 weeks (combining the US and international
studies, n=1744) has an overall sustained viral negative response rate
of 41% compared to 33% with 24 weeks of combination therapy and 16% with
48 weeks of interferon.4-5 Sustained response rates for 48 weeks of
combination therapy reach as high as 67% in subgroups with favorable
characteristics but exceed 20% even for traditionally difficult to treat
subgroups (cirrhosis by liver biopsy or genotype 1).
One approach to trying to select out those patients likely to progress
to cirrhosis would be to perform repeated liver biopsies, but sustained
response rates appear to decline with worsening Metavir fibrosis score
and with advancing age, suggesting that delaying therapy may decrease
the chance for a response.
When compared to other common medical interventions, the projected life
expectancy gains from 48 weeks of combination therapy for hepatitis C
compare favorably. Based on stopping treatment for 24 week viral
non-responders and on clinical trial data (actual drug usage with
discontinuation or dose reduction for adverse events and estimates of
health care resource utilization including office visits, laboratory
tests and contraception), 48 weeks of combination therapy should cost
~$12,000 (US) which is comparable to the cost of one year of therapy for
HIV infection. For comparison, lifetime treatment of 40 to 60 year-old
patients with compensated cirrhosis should cost $34,000 to $53,000 (US).
Increasing data suggest the sustained viral negativity is associated
with transaminase normalization, histologic improvement, decreased risk
for developing cirrhosis or decompensation and perhaps improved
survival. Thus, the prevention of future expensive complications of
hepatitis C should offset the cost of combination therapy, making it a
cost-effective therapy when compared to other routinely accepted medical
interventions.
For example, when compared to coronary artery bypass surgery,
combination therapy costs less and provides a higher gain in life
expectancy.
Conclusion
Cirrhosis is likely to occur in ~28% of hepatitis C patients after 20
years, substantially decreasing life expectancy and increasing
healthcare costs. Combination therapy for 48 weeks results in sustained
response rates as high as 67% and should prevent the development of
cirrhosis. Because the response rate worsens with increasing Metavir
fibrosis score and advancing age, delaying treatment may not be an
optimal strategy. Although combination therapy may be considered
expensive, the cost of treatment should be substantially offset by
future savings through the prevention of liver related complications.
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