Efficacy and safety of istradefylline for Parkinson's disease: A systematic review and meta-analysis.

As an adenosine receptor A2A antagonist, istradefylline is used as an adjunctive agent of levodopa to improve motor symptoms in advanced Parkinson's disease (PD) patients. In this study, we re-evaluated the effects of istradefylline on treating the motor symptoms of PD patients. We performed a literature search up to November 2021 from electronic databases. Eligible studies were synthesized for efficacy, tolerability, OFF time, Unified Parkinson's Disease Rating Scale part III score, ON state with dyskinesia, and the incidence of treatment-emergent adverse events. As a result, nine clinical studies with 2727 subjects on istradefylline treatment for PD patients were included. Our results showed that compared to placebo, istradefylline exhibited a statically significant difference in efficacy (1.39 [1.15 to 1.69]; p = 0.001), decreasing OFF time (-0.58 [-1.01 to - 0.16]; p = 0.007), and improving ON state with dyskinesia (0.69 [0.02 to 1.37]; p = 0.043). For tolerability, UPDRS III, and adverse effects, there was no significant difference between istradefylline and placebo. In conclusion, the results suggest that istradefylline exhibits an efficient and well-tolerated role in treating PD patients. Randomized controlled trials and long-term studies are still required to investigate the effects of istradefylline on motor and non-motor symptoms of PD in future research.