Popular Alzheimer’s drug proven ineffective
Authors of a UK study
in The Lancet, a British medical journal, concluded that the most
widely used drugs to treat Alzheimer's disease have only minimal efficacy,
and that an alternative approach for treatment is needed. Alzheimer’s
disease currently strikes an estimated 4.2 million to 5.8 million Americans.
It is estimated that by 2020, 30 million people will be affected by this
devastating disorder worldwide and by 2050, the number could increase to 45
million.
A class of drugs called
cholinesterase inhibitors has been found to cause small increases in tests
of mental ability among AD patients, although questions remain over their
long-term efficacy and cost-effectiveness.
Richard Gray from the
University of Birmingham, UK, and colleagues investigated whether donepezil
(a cholinesterase inhibitor licensed in the UK in 1997) produced worthwhile
improvements in disability, dependency, behavioral and psychological
symptoms, wellbeing of care-givers, or delay in institutionalization. In the
study (called AD2000), 565 AD patients were randomly allocated either
donepezil (5 mg or 10 mg) or a placebo.
Donepezil did improve
tests of mental and functional ability over the first two years of
treatment, although at low levels. However, there was no significant delay
in institutionalization (42% donepezil, 44% placebo at three years), or
progression of disability (58% for patients given donepezil, 59% for
patients given placebo). There were also no differences between donepezil
and placebo in behavioral and psychological symptoms, formal care costs,
unpaid caregiver time, adverse events or deaths, or between the two doses of
donepezil used in the study.
Professor Gray
commented: “Based on our results, clinicians and health-care funders can
validly question whether other uses of the scarce resources allocated to
dementia care would provide better value than routine prescription of
cholinesterase inhibitors.”
In an accompanying
Commentary, Lon S. Schneider from the University of
Southern California,
pointed out that the research findings do not validate the claims made by
drug companies. “Results [of the study] are incompatible with many
drug-company-sponsored observational studies and advertisements claiming
remarkable effects for cholinesterase inhibitors. For example, claims that
donepezil stabilizes cognitive decline, or delays nursing-home placement by
2-5 years now can be seen as implausible in the light of AD2000.”
SOURCE:
“Long-term donepezil treatment in 565 patients with Alzheimer's disease
(AD2000): randomised double-blind trial.” The Lancet, June 2004.
