ORIGINAL RESEARCH article
Front. Pharmacol.
Sec. Pharmacoepidemiology
Volume 16 - 2025 | doi: 10.3389/fphar.2025.1548631
Adherence and Persistence with Istradefylline Treatment in Patients with Parkinson's Disease in the United States
Provisionally accepted
- 1Chalmers P. Wylie Ambulatory Care Center, Columbus, United States
- 2Kyowa Kirin, Inc., Princeton, United States
- 3KMK Consulting Inc., Morristown, United States
- 4Texas Movement Disorder Specialists, PLLC., Georgetown, United States
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Background: Medication adherence and persistence are associated with better outcomes for patients with Parkinson's disease.Objectives: To evaluate 12-month adherence and persistence with istradefylline and identify factors associated with persistence among patients.Methods: A retrospective cohort study was conducted using IQVIA longitudinal prescription (LRx) and medical (Dx) claims data. Adult patients initiating istradefylline between 2019 and 2022 with ≥1 LRx and ≥1 Dx claim every 6 months over 12-month baseline and follow-up periods were included. Adherence was measured by the proportion of days covered (PDC) and medication possession ratio (MPR). Persistence was measured by the duration of prescription fills, allowing for a ≤60-day gap. Multivariate logistic regression was used to evaluate factors associated with 12-month persistence.Results: Among 2,045 patients, 76.0% were covered by Medicare Advantage and 23.9% were commercially insured. Over 12 months of follow-up, median adherence (both PDC and MPR) was 74.0% and median persistence was 276 days. In a subgroup analysis, median adherence and persistence were significantly greater in patients with Medicare Advantage versus commercial insurance (PDC and MPR: 82.2% vs 49.3%; persistence: 365 days vs 180 days; all P<0.001). Treatment initiated at 40 mg versus 20 mg (odds ratio [OR]: 1.33 [95% confidence interval [CI]: 1.10, 1.62]) and Medicare Advantage versus commercial insurance (OR: 1.79 [95% CI: 1.42, 2.26]) were independently associated with longer persistence.Conclusions: Patients initiating istradefylline at 40 mg versus 20 mg and those with Medicare Advantage versus commercial insurance were more likely to have higher adherence and longer persistence with istradefylline.
Keywords: Parkinson's disease, adherence, Persistence, Istradefylline, Treatment patterns
Received: 07 Jan 2025; Accepted: 18 Apr 2025.
Copyright: © 2025 Joseph, Qian, Cummings, Chen, Tewari and Soileau. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Joyce Qian, Kyowa Kirin, Inc., Princeton, United States
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