Alzheimer's Patch Could Replace Pills
Delivering Exelon via the skin easier on patients, caregivers, study finds
WEDNESDAY, July 19, 2006 (HealthDay News) -- The first patch designed to deliver a widely used Alzheimer's medication via the skin appears to minimize side effects while being easy to use, Swedish researchers say.
"We think we have a new treatment strategy, and it will be very, very much used," said study author Dr. Bengt Winblad, a chief physician in geriatrics medicine at the Karolinska Institutet in Huddinge.
Results of the study -- which compared the continuous, controlled delivery of the patch against traditional twice-daily capsules -- were announced Wednesday in Madrid at the International Conference on Alzheimer's Disease and Related Disorders, sponsored by the Alzheimer's Association.
Winblad teamed up with colleagues at the University of California at Los Angeles (UCLA) and the pharmaceutical company Novartis to explore the potential of once-a-day patch designed to deliver the Alzheimer's drug rivastigmine.
Sold under the trade name Exelon, the drug is manufactured by Novartis and comes from a class of medications called cholinesterase inhibitors. Other cholinesterase medications include Aricept (donepezil) and Reminyl (galantamine).
Such treatments aim to slow the progression of disease symptoms by preventing the breakdown of a critical chemical messenger in the brain called acetylcholine.
The researchers conducted a 24-week experiment in which they gave either a placebo or a small or large version of a rivastigmine patch to about 600 patients from 21 countries. All of the patients were between 50 and 85 years of age, and were diagnosed with moderate-stage Alzheimer's.
Approximately 600 other patients, matched for age and disease stage, were given either a placebo or a standard regimen of twice-daily rivastigmine in pill form.
The researchers report that, when compared against placebo, the patch induced "significant benefits" in terms of the patient's cognitive abilities and impression of change, as well as his or her ability to engage in active daily routines. Overall, outcomes of patients on the patch were equal to those achieved by the oral medication.
The patch also came out on top in terms of side effects. Three times fewer of the small-patch patients experienced nausea compared with those taking pills (7 percent vs. 23 percent, respectively), the study group found. Patch users experienced a similar improvement when it came to treatment-linked vomiting.
The researchers speculate that the patch's slow-and-steady drug delivery probably translates into more consistent medication-blood levels, while reducing the medication's effect on the liver, stomach and intestine.
The patch was very well-tolerated, the researchers said, with moderate or severely abnormal redness of the skin being observed in less than 8 percent of patients.
A follow-up survey of more than 1,000 caregivers for the patients in the study found that the patch was also their drug-delivery system of choice, since it made it much easier for patients to receive their medication as directed.
The research team pointed out that caregivers also benefit from the visual assurance offered by a patch as to whether or not a medication has been properly taken.
In this regard, they noted that Alzheimer's patients are typically burdened by memory, reasoning and decision-making problems, as well as difficulties swallowing. All these factors are mitigated, they suggested, by the use of a patch rather than a pill.
"This has large practical implications, because both the patients and the caregivers really appreciate the patches," said Winblad. "It's really very easy to use. You put it on dry skin once a day -- on the breast, or arm, or on the back, wherever you want -- and there really is no irritation."
"Caregivers were very satisfied," he added, "because they could really control for patients using the patches once a day. And it reduces side effects, which has been a problem in the past."
Winblad said he believed that the patch delivery system should become available to American patients sometime in 2007, after receiving approval from the U.S. Food and Drug Administration.
Dr. Gary W. Small is director of the Center on Aging at UCLA. He has no affiliation with the study, but expressed enthusiasm for the benefits the patch could offer to both patients and doctors.
"I think the patch is clearly an advance in offering patients and families an additional treatment option," he said. "The side-effect profile of the patch appears to be more favorable compared to the oral form of the same drug. And families will also avoid some of the challenges with medication compliance."
A second study, also presented Wednesday at the conference, found that a prostate cancer drug called leuprolide acetate may help stabilize cognitive function in patients with mild- to moderate Alzheimer's when taken along with a cholinesterase inhibitor drug, such as the one used in the patch study.
Researcher Christopher W. Gregory, of Voyager Pharmaceutical Corp. in Raleigh, N.C., presented the preliminary results of a 48-week study involving 119 male patients, all 65 years of age or over and diagnosed with mild to moderate Alzheimer's.
Those taking the dual-drug treatment, which appeared to be well-tolerated, gained the most benefit when compared with those taking a cholinesterase inhibitor plus placebo, Gregory reported.
For more on Alzheimer's, visit the Alzheimer's Association.