April 4, 2002
Research Programs Department
A new study showed that the oral medication Aricept® (donepezil hydrochloride, Pfizer, Inc.) modestly improved performance on a memory test in individuals with multiple sclerosis.
A new study showed that the oral medication Aricept® (donepezil hydrochloride, Pfizer, Inc.) modestly improved performance on a memory test in individuals with multiple sclerosis. Lauren B. Krupp, MD, and colleagues in the AIMS (Aricept in MS) study group at State University of New York, Stony Brook, reported results at the 55th Annual Meeting of the American Academy of Neurology in Honolulu, Hawaii.
Cognitive changes often occur in MS, most commonly problems with learning, memory and the speed of information processing. Although these problems are not equivalent to those seen in Alzheimer’s disease, researchers are investigating whether Aricept – a drug shown to improve memory in Alzheimer’s disease – can improve memory in MS. Aricept is an inhibitor of an enzyme (acetylcholinesterase) that normally breaks down messenger chemicals (neurotransmitters) through which brain cells communicate. It is thought to enhance memory by temporarily increasing the concentration of neurotransmitters that are involved in memory. There is no evidence that it alters the underlying course of Alzheimer’s disease or MS.
Two open-label studies have found that Aricept improved cognitive function in people with MS. (In the open-label studies, all participants were treated with Aricept, and no comparison with inactive placebo was undertaken.) A recent clinical trial of Aricept in people with MS who had cognitive dysfunction was discontinued because sufficient numbers of patients could not be enrolled in the study. Now, researchers are reporting results from a small study of Aricept in people with MS with mild to moderate cognitive impairment.
After screening to ascertain eligibility for the trial, individuals in the study were randomly assigned to once-daily oral treatment with Aricept (35 subjects) or inactive placebo (34 subjects). Treatment continued for 24 weeks, with safety, clinical and neurological assessments conducted at weeks 4, 14 and 24. Study participants and clinic personnel were “blinded” as to which treatment each individual was taking. The primary outcome measured was the participants’ ability to recall words that they learned on the Selective Reminding Test (SRT), a test widely used in MS and other conditions. The basic task involved in the SRT is learning and then recalling a list of 12 words presented six times in a single session. The maximum possible score is thus 72. Researchers also recorded, as secondary outcomes, the clinicians’ and patients’ impressions of how cognitive function changed during the study period.
Individuals taking Aricept showed significantly greater improvements on the SRT than people taking placebo. On average, those taking Aricept improved their SRT scores by approximately 5 compared to approximately1 for those taking placebo. This difference remained significant even if other factors that might have affected cognitive function, such as reading level or years of education, were taken into consideration. In addition, 65.7% of subjects in the Aricept group reported cognitive improvements, versus 32.4% in the placebo group. Clinicians noted cognitive improvements in 54.3% of the Aricept group, versus 29.4% in the placebo group. The study did not examine the extent to which improvement in memory might have had an impact on everyday activities.
The drug was well tolerated. Two persons in the Aricept group and two in the placebo group stopped treatment due to gastrointestinal symptoms.
This study, although small, suggests that Aricept may have the potential
to modestly improve memory function in individuals with MS who have mild
to moderate cognitive impairment. However, it is not clear to what
extent this improvement would have an impact on daily activities.
Larger studies are needed to confirm the safety and benefits of this medication
for improving memory in MS.
© 2003 The National Multiple Sclerosis Society