By Lucy Piper, Senior medwireNews Reporter
Once-daily opicapone is effective for the treatment of end-of-dose motor fluctuations in patients receiving levodopa for Parkinson’s disease, phase III study findings show.
The results indicate that at a dose of 50 mg/day the drug, a potent third-generation catechol-O-methyltransferase (COMT) inhibitor, was superior to placebo and non-inferior to entacapone (200 mg with each levodopa dose) in reducing the absolute time patients spent in the off state.
The magnitude of effect with opicapone was greater that than of entacapone, with a 26.2 minute greater reduction in the time spent in the off state after 14–15 weeks of treatment and a 60.8 minute greater reduction compared with placebo.
Opicapone 50 mg “is, therefore, the only once-daily COMT inhibitor to provide a mean reduction in time in the off state that is clinically relevant,” say Patrício Soares-da-Silva (BIAL, Coronado, Portugal) and team.
The average changes from baseline in time spent in the off state over a 24-hour period were 116.8 minutes in 115 patients taking opicapone 50 mg/day, 96.3 minutes in 120 patients taking entacapone and 56.0 minutes in the placebo group.
Opicapone 25 mg and 5 mg were also tested in 116 and 119 patients, respectively, but the effects of these doses on the time patients spent in the off state did not differ significantly from that of placebo.
The researchers note in The Lancet Neurology that, in addition to greater reductions in the time patients spent in the off state, opicapone 50 mg was associated with greater increases in the percentage of time patients spent in the on state without troublesome dyskinesia, with a 5.4% difference compared with placebo and a 1.2% difference compared with entacapone.
Improvements in global symptoms were seen in significantly more patients taking opicapone 50 mg than in those taking entacapone, and while numerical improvements in motor symptom scores were seen in all groups, differences between active treatment and placebo groups were not significant.
Dyskinesia was the most common treatment-emergent adverse event and, in line with its more potent inhibition of COMT, occurred most frequently in patients taking opicapone 50 mg.
Otherwise, the incidence of serious treatment-emergent adverse events did not differ significantly from that in the placebo or entacapone group.
Soares-da-Silva and colleagues believe that “[o]picapone once daily could enable a simplified drug regimen that allows the physician to individually tailor the existing levodopa daily regimen by potentially decreasing the total daily levodopa dose, increasing the dosing interval, and ultimately reducing the number of intakes, therefore maximising its benefit.”
Commentators David Devos and Caroline Moreau, from the University of Lille in France, agree that “[t]hese clinical trial results are likely to substantially affect clinical practice”.
And add that some key questions now need to be addressed, including whether administration of opicapone in the early stages of levodopa therapy could delay the onset of motor complications and whether a patient’s COMT genotype could influence the drug dose.
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