Objective: This study examined real-world utilization of istradefylline and other PD-related medications before and after istradefylline initiation.
Background: Istradefylline is indicated as adjunctive therapy to carbidopa/levodopa in patients with Parkinson’s disease (PD) experiencing “OFF” episodes. Research regarding the real-world use of istradefylline in the US is limited since its 2019 approval.
Method: In this retrospective cohort study, patients who initiated istradefylline (1st filled prescription = index) 9/1/2019-6/30/2020 were identified from the 2019-2020 US Medicare Fee-for-Service 100% sample. They were required to have ≥1 PD diagnosis in the 6-month pre-index period and continuous enrollment during the 6-month pre- and post-index periods. Patient demographics, comorbid medical conditions, istradefylline prescriptions filled, starting dosage, dose change, and concomitant PD-related medications were examined. Levodopa equivalent daily dose (LEDD) and PD-related medications were compared in the 6-month pre- and post-index periods.
Results: This study included 734 patients (mean age: 74.0 years; female: 41.0%; White: 86.4%). PD-related comorbid medical conditions were prevalent, including pain (65.1%), gait abnormalities (34.5%), sleep disorders (33.7%), fatigue (31.2%), falls (12.5%), fractures (9.5%), and tremor (8.2%). Overall, 78.8% of the istradefylline patients initiated with a 20mg dose. Among patients with a second istradefylline prescription filled, 89.8% had no dose change. The most common concomitant treatment was carbidopa-levodopa (28.9%) alone. The LEDD significantly decreased statistically in the 6-month post-index period vs. the 6-month pre-index period (median [interquartile range]: 430.4 [298.3-637.4] vs. 285.7 [172.5-416.7] mg/day; p <0.001). Fewer prescriptions filled per patient were also observed in the post-index period across several PD-related drug classes: dopamine precursors (4.7 vs. 4.5, p=0.036), dopamine agonists (1.5 vs. 1.3, p<0.001), catechol-o-methyl transferase (COMT) inhibitors (0.4 vs. 0.3, p=0.039), and monoamine oxidase-B (MAO-B) inhibitors (1.0 vs. 0.9, p=0.041).
Conclusion: In this real-world study, patients treated with istradefylline demonstrated reduced utilization of dopamine precursors, dopamine agonists, COMT inhibitors, and MAO-B inhibitors.
To cite this abstract in AMA style:
M. Rezak, J. Qian, Y. Zhao, A. Silverstein, J. Chamber, J. Swindle, N. Kronfeld, P. Lewitt. Real-World Utilization of Istradefylline Among Patients with Parkinson’s Disease [abstract]. Mov Disord. 2023; 38 (suppl 1). https://www.mdsabstracts.org/abstract/real-world-utilization-of-istradefylline-among-patients-with-parkinsons-disease/. Accessed June 15, 2025.« Back to 2023 International Congress
MDS Abstracts - https://www.mdsabstracts.org/abstract/real-world-utilization-of-istradefylline-among-patients-with-parkinsons-disease/