Session Information
Date: Thursday, June 23, 2016
Session Title: Parkinson's disease: Clinical trials, pharmacology and treatment
Session Time: 12:00pm-1:30pm
Location: Exhibit Hall located in Hall B, Level 2
Objective: To determine predictors of response and conversion ratios for a novel extended release levodopa preparation.
Background: A new extended release levodopa preparation, Rytary®, has demonstrated improved “on” time in fluctuating Parkinson’s disease patients, compared to optimally dosed immediate release levodopa. The milligram dosing, however, differs markedly and no ratio or formula for dose conversion currently exists.
Methods: We converted fluctuating patients with problematic “off” time to the new levodopa ER using a semi-structure dose titration schedule, and collected data regarding efficacy, tolerability, and dosing, in order to determine a rational dose conversion formula.
Results: Levodopa ER samples were offered to 62 fluctuating patients with meaningful “off” time. Two were lost to follow-up, 2 dosed incorrectly and were excluded, 5 never started levodopa ER, usually secondary to cost, and 1 died within a day of starting from an unrelated cause. Of 52 subjects (31 male, age 67±10 y, duration PD of 10±5 y), 24 (46%) eventually discontinued the new preparation (mean f/u 99±77 days), primarily due to adverse events (14), lack of superior efficacy (8), cost (2), and DBS implantation (1). All 6 subjects with prior DBS discontinued. Interestingly, only 15/52 total subjects reported any new onset adverse event. Number of daily L-dopa doses decreased from 4.5±1.2 to 3.7±0.6 and total daily calculated L-dopa dose increased from 805±437 (N=52) to 1,553±675 (N=43 subjects with any dose titration). New ER L-dopa: Old L-dopa ratio was 2.1±0.7 [range 1.2-3.5], N=43. This ratio was not significantly different in subjects without any baseline dyskinesia 2.2±0.8 vs. those with any baseline dyskinesia 1.9±0.7, P=0.23. Mean dyskinesia score (0-4) improved from 1.1±1.2 to 0.6±0.5 after conversion.
Conclusions: The total daily levodopa mg dose conversion is approximately 2 to 1. The fact that 14/15 subjects who reported any AE dropped the new medicine suggests contribution from other factors (cost, lack of clear improvement).
To cite this abstract in AMA style:
W. Ondo, P. Coss, M. Christie. Real world conversion of levodopa to a novel extended release levodopa preparation: Determining predictors and dose ratios [abstract]. Mov Disord. 2016; 31 (suppl 2). https://www.mdsabstracts.org/abstract/real-world-conversion-of-levodopa-to-a-novel-extended-release-levodopa-preparation-determining-predictors-and-dose-ratios/. Accessed June 14, 2025.« Back to 2016 International Congress
MDS Abstracts - https://www.mdsabstracts.org/abstract/real-world-conversion-of-levodopa-to-a-novel-extended-release-levodopa-preparation-determining-predictors-and-dose-ratios/