Compared with placebo, the proportion of patients with a reduction in off time of at least one hour was significantly higher in patient who received 25 mg or 50 mg of opicapone, and the proportion of patients with an increase in on time of at least one hour was significantly higher in patients who received 50 mg of opicapone. No significant differences were noted in off and on state rates for entacapone versus placebo. Results for the other secondary end points supported those of the primary analysis.
The percentage of patients who discontinued because of treatment-emergent adverse events was low and similar across the treatment groups. The most common treatment-emergent adverse events leading to discontinuation were diarrhea, visual hallucinations, and dyskinesia. Dyskinesia was the most frequently reported treatment-emergent adverse event possibly related to the study drug, and the highest incidence occurred in the opicapone groups. Approximately 80% of treatment-emergent dyskinesias occurred in patients in all groups who already had dyskinesia at baseline. The incidence of serious treatment-emergent adverse events was low (ie, 7% or less) in all groups, and 35% of these events were judged to be unrelated to the study drug.
“The beneficial effects of opicapone 50 mg at reducing the time in the off state were accompanied by a corresponding increase in time in the on state without troublesome dyskinesia, whereas the duration of time in the on state with troublesome dyskinesia did not change,” said Dr. Ferreira. The study results “suggest an overall positive risk-to-benefit ratio for the use of opicapone in patients with Parkinson’s disease with end-of-dose motor fluctuations,” he added. Results of the authors’ open-label extension study will be published in the future.
—Erik Greb