July 15 (UPI) -- The drug rotigotine might slow the progression of Alzheimer's disease enough to allow patients to continue normal day-to-day activities for a longer period of time, a study published Wednesday by JAMA Network Open found.
Researchers said, however, that the agent, which is used to treat Parkinson's disease and restless leg syndrome, does not appear to improve other aspects of cognitive dysfunction associated with the disease, such as memory loss.
"Standard therapy" for Alzheimer's disease focuses on the brain processes that "provide some improvement on memory" but not those that control emotions, problem solving, memory, language and judgment, study co-author Dr. Giacomo Koch told UPI.
Drugs like rotigotine, however, might strengthen communication between brain cells to maintain decision-making and other important functions, said Koch, a neurologist at the University of Rome Tor Vergata in Italy.
"The combination" of existing drugs with rotigotine likely can be used together to improve multiple aspects of cognitive function, Koch said.
The findings of the Phase 2 trial -- the second step in the drug evaluation and approval process -- are based on the performance of 78 patients on three commonly used assessments for Alzheimer's disease, the researchers said.
In all, 36 of the study participants received rotigotine, which is administered as a transdermal patch applied daily on the skin, while 42 were given a placebo, they said.
On the first assessment, the Alzheimer's Disease Assessment Scale-Cognitive Subscale, or ADAS, which evaluates memory and language comprehension, average scores among study participants increased in both groups -- to roughly 23 from 20 in those treated with rotigotine and to approximately 22 from 19 in those given the placebo, according to the researchers.
The ADAS scores Alzheimer's disease patients on a 0 to 150 scale, with higher scores indicating worse cognitive function, the researchers said.
However, participants on rotigotine saw their scores on the Alzheimer Disease Cooperative Study-Activities of Daily Living, or ADCS-ADL, assessment drop by more than three points to 58 while those on placebo had their scores drop by more than seven points to 56, they said.
The ADCS-ADL is a 0 to 78 scale that measures the ability of people with Alzheimer's to perform normal daily activities, with lower scores indicating worse performance, according to the researchers.
Participant performance on the Frontal Assessment Battery, or FAB, test also declined by an average of 0.5 points for those on rotigotine and 0.7 points for those on placebo, the researchers said.
The FAB is a 0 to 18 scale used in the diagnosis of Alzheimer's disease, with higher scores indicating better cognitive function, they said.
Phase 3 clinical trials, which are underway, are needed to confirm the findings but rotigotine "seems safe" in people with Alzheimer's, Koch told UPI.
The drug has been used for years in people with Parkinson's disease, with no significant issues, he added.