Abstract
Background:
In recent times, the US-FDA approved istradefylline and opicapone as an adjunct to
levodopa/carbidopa for managing the "off" episodes in Parkinson’s disease.
Purpose:
Current meta-analysis was performed to determine the safety and efficacy of these drugs
in the management of “off” episodes and to recognize which among them would provide
therapeutic benefits clinically.
Methods:
A thorough literature search was performed through the Cochrane Library, PubMed, and
clinicaltrials.gov for a period from January 2003 to October 2020, with the following
keywords: Istradefylline, KW-6002, opicapone, BIA 9-1067, and Parkinson’s disease. Those
randomized, double-blind placebo/active comparator-controlled trials that analyzed the
efficacy and safety of istradefylline and opicapone and that were published in the
English language were included. In this analysis, the outcomes focused on the least
square mean change in “off” time and Unified Parkinson’s Disability Rating Scale (UPDRS)
III score from baseline to the end of the study, and the incidence of treatment-emergent
adverse events (TEAEs) and dyskinesia.
Results:
Both drugs have shown significant reduction in “off” time duration (mean difference
[MD] = –0.70; 95% CI [–1.11, –0.30]; P < 0.001 for istradefylline
and MD = –0.85; 95% CI [–1.09, –0.61]; P < .001 for opicapone).
Istradefylline showed significant improvement in UPDRS III (MD = –1.56; 95% CI [–2.71,
–0.40]; P < .008), but the same was not observed with opicapone (MD
= –0.63; 95% CI [–1.42, –0.15]; P < .12). The incidence of TEAEs and
dyskinesia reportedly were higher in the intervention group rather than with the
placebo, (risk ratio RR =1.11, 95% CI [1.02,1.20] for istradefylline and RR =1.12, 95%
CI [1.00,1.25] for opicapone, and for dyskinesia particularly, the incidence was higher
with opicapone as compared to istradefylline (RR = 3.47, 95% CI [2.17, 5.57], and RR =
1.77, 95% CI [1.29, 2.44], respectively).
Conclusions:
Both drugs were comparable in efficacy; however, istradefylline seemed to be better in
reducing the UPDRS III score. Although the incidence of TEAEs and dyskinesia were higher
with both the drugs, the incidence of dyskinesia was more in the opicapone group.
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