Objective: To provide a levodopa dose equivalency (LED) for opicapone and safinamide.

Background: Tomlinson at al., provided a schedule to calculate LED of the different Parkinson’s disease (PD) therapies. This approach has facilitated a practical comparison of the generally complex treatment of PD patients both in real-life and in clinical trials. Opicapone, a COMT inhibitor, and safinamide, a MAO-B and glutamatergic inhibitor, were commercialized later, and, to our knowledge, their LED have not been calculated.

Method: Systematic search of the published literature to identify studies that reported conversion formulae for LED for safinamide and opicapone. Search terms:[ [(‘‘L-dopa,’’ or “levodopa”) and (‘‘equivalent,’’ or ‘‘equivalency’’)] and opicapone] or the same for safinamide. We searched electronic databases including Medline, Embase, and PubMed. We also analyzed the results of randomized clinical trials (RCT) of both drugs. We determined the reduction in OFF time or the increased on time without troublesome dyskinesia (primary end points of the RCT) as the main parameters to assign a therapeutic power to allow a comparison with the drugs of their pharmacologic group.

Results: The systematic search yielded three results for safinamide and none for opicapone. None of the three safinamide papers provide any conversion to LED for this drug. Both, opicapone and safinamide,  have two relevant RCT. In the two RCT of opicapone 50 mg the combine reduction in OFF time was 0,96 h, placebo time discounted. After comparison with other COMTi, tolcapone and entacapone, the conversion factor for opicapone 50 mg should be “levodopa dose x 0,4 LED”.In the two RCT of safinamide the combine improvement in ON time without troublesome dyskinesias was 0,63 h, placebo time discounted. There were no differences between safinamide 50 or 100 mg. After comparison with other MAOBi, selegiline and rasagiline, the conversion factor for safinamide, either 50 or 100 mg,  should be “100 mg LED”

Conclusion: The LED proposed for opicapone 50 mg is “total levodopa dose x 0,4 mg LED” and for safinamide 50 or 100 mg is “100 mg LED”.

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MDS Abstracts - https://www.mdsabstracts.org/abstract/levodopa-dose-equivalency-for-opicapone-and-safinamide/