ADHD Drug Fails to Boost Cognition in Parkinson's

By Kristina Fiore 
June 24, 2016

But patients reported improvements in impulsivity, inattention

BERLIN.

A drug used to treat attention deficit-hyperactivity disorder didn't improve cognition in Parkinson's patients with mild cognitive impairment (MCI), researchers reported here.

In a single-center randomized controlled trial, patients on atomoxetine didn't have any benefits on neuropsychological testing for attention, working memory, information processing speed, and set-shifting, according to Vanessa Hinson, MD, PhD, of the Medical University of South Carolina in Charleston, and colleagues.

 But they did have improvements in self-reported measures of inattention and impulsivity compared with those on placebo, they reported at the Movement Disorders Society meeting here.

"Our patients were on the advanced spectrum of Parkinson's MCI, which is why the objective measures failed to show benefit," Hinson told MedPage Today. "We are excited and encouraged about the positive subjective measures [on the CAARS instrument] despite the advanced MCI stage in this group. The next step is to study ATM in patients who are less cognitively impaired."

Mild cognitive impairment is common in Parkinson's disease and may be a precursor of dementia, which occurs in about 80% of Parkinson's patients over the course of their disease.

There is currently no treatment for the cognitive problems that arise in Parkinson's, but it's an area that's garnering more research interest, Hinson said.

"Cognitive impairment in Parkinson's is a huge problem for patients and there is only one FDA-approved medication for Parkinson's dementia and none for Parkinson's MCI," she added

So she and colleagues conducted a 12-week, single-center, double-blind, placebo-controlled, parallel-group study of the norepinephrine reuptake inhibitor atomoxetine in 30 patients who had a mean age of 68.

They were randomized to 80 mg of the drug – starting at 40 mg and then uptitrated – or to a matching placebo.

All patients had neuropsychological testing at 10 weeks, after which the drug was discontinued and all were assessed again at 12 weeks for safety.

The primary endpoint was an effect on a composite of attention, working memory, information processing speed, and set-shifting.

Five patients withdrew because of side effects: four in the atomoxetine group, and one in the placebo group.

Overall, the researchers saw no significant differences in scores on neuropsychological testing between the drug and placebo groups (99.5 and 117.5, P=0.25).

Nor did they see any differences between groups on any of the individual measures in the primary endpoint.

They did, however, see statistically and clinically significant subjective improvements for those on the drug on subscales for inattention (CAARS A) and impulsivity (CAARS C), with a mean improvement of -5.7 points for impulsivity and -5.4 points for inattention. No changes occurred on these measures among those in the placebo group.

"Treatment with atomoxetine produced subjective, but not objective, improvements in executive function in Parkinson's patients with mild cognitive impairment," they reported, adding that the drug was generally well tolerated and didn't worsen Parkinson's severity.

Hinson said it's possible that patients in the study were too severely impaired to show change in the selected outcome measures and that a less severely impaired population might improve with atomoxetine in objective measures of cognition.

Claudia Trenkwalder, MD, of the University of Gottingen, who was not involved in the study, noted that this was the "first study ever to look at MCI in Parkinson's."

"No one is sure if this would really develop into dementia or not," Trenkwalder said, "so this is a real pilot trial."

http://www.medpagetoday.com/MeetingCoverage/MDS/58746?