Droxidopa Demonstrates Significant Activity in Adult ADHD

Researchers have announced positive results from a phase II clinical study of droxidopa in combination with carbidopa in adults with ADHD.

Chelsea Therapeutics International Ltd. has announced positive results from a phase II clinical study of droxidopa in combination with carbidopa in adults with attention deficit hyperactivity disorder (ADHD).

“The single-center, 12-week study enrolled 20 patients diagnosed with adult ADHD. The top-line results showed that droxidopa dramatically improved the patients’ mean score on the adult ADHD Investigator Symptom Rating Scale (AISRS),” according to a company press release.

“Upon enrollment, patients in the study had a mean AISRS score of 34. After three weeks of open-label droxidopa monotherapy (titration from 200mg-600mg TID), the mean AISRS score decreased by approximately 47% to 19 (P<0.0001). The reduction in AISRS score was maintained with the addition of carbidopa (25 mg or 50 mg) for another three weeks,” according to the release.

“This exploratory study showed that droxidopa rapidly improved ADHD symptoms during open-label treatment,” said Lenard A. Adler, MD, professor of psychiatry at New York University Langone Medical Center, the study’s lead investigator. “The magnitude of the treatment effect combined with the marked safety and tolerability of the medication is of interest and clearly warrants future study of droxidopa in adult ADHD.”

Interpretation of the data in the following two-week double-blind, placebo-controlled withdrawal period of the study is limited due to the small number of patients who continued in the study, with five patients receiving placebo and six patients receiving the droxidopa/carbidopa combination.

“Furthermore, as seen in prior studies with a limited washout period, patients withdrawn to placebo after prolonged droxidopa treatment continued to experience therapeutic benefits and no statistically significant difference was observed between treatment and placebo arms at the end of the two-week randomized period. Droxidopa was well tolerated with no serious adverse events observed. The most common adverse events observed throughout both the open-label and double-blind portions of the study were headache (n=5; 25%) and drowsiness (n=5; 25%), both of which were mild.”


Preliminary Data From Exploratory Phase II Study Demonstrates Significant Activity of Droxidopa in Adult Attention Deficit Hyperactivity Disorder [Chelsea Therapeutics]