Kyowa Kirin Presents New Findings from Real-World Study in Parkinson’s Disease at the 2023 IAPRD Conference

  • Findings to be presented at International Association of Parkinsonism and Related Disorders (IARPD) 2023 World Congress being held May 13-16, 2023.

Bedminster, N.J., May 12, 2023 - Kyowa Kirin, Inc., an affiliate of Kyowa Kirin Co., Ltd. (Kyowa Kirin, TSE: 4151), a global specialty pharmaceutical company, will share results from a retrospective study evaluating real-world utilization of istradefylline along with other Parkinson’s disease (PD) medications among patients with PD.1 These findings will be presented on Sunday, May 14 from 12:15 - 1:15 PM CDT at the International Association of Parkinsonism and Related Disorders (IAPRD) conference in Chicago, Illinois.

As PD progresses, approximately 50% of patients will experience off time, which is a return of Parkinson’s disease symptoms between doses of levodopa within 5 years of initiating levodopa treatment. 2,3,4 NOURIANZ® (istradefylline) is prescription medication indicated as adjunctive treatment to levodopa/carbidopa in adult patients with PD experiencing “off” episodes.

Patients with Parkinson’s disease are often on multiple medications to manage their PD symptoms or “off” episodes.5 This underscores the need to evaluate polypharmacy medication use in order to contribute to medical understanding of treatment regimens and appropriate patient management.

About Study Design

This retrospective cohort study investigated the real-world use of istradefylline and other PD-related medications in 734 patients with PD who initiated Nourianz between 9/1/2019-6/30/2020. Patients were identified from the 2019-2020 US Medicare Fee-for-Service (FFS) 100% sample and required to have continuous enrollment during the 6-month pre- and post-index periods, and at least one PD diagnosis in the pre-index period. The study examined the treatment patterns of PD patients six months before and after starting Nourianz, analyzing the usage of levodopa equivalent daily dose (LEDD) and other PD-related medications, such as dopamine (DA) precursors, DA agonists, catechol-o-methyl transferase (COMT) inhibitors, anticholinergic agents, and monoamine oxidase-B (MAO-B) inhibitors. Real-world findings from this retrospective study may not represent the treatment paradigm of all patients with PD.

About Parkinson’s Disease

Parkinson's disease is a progressive, neurodegenerative disease characterized by motor symptoms such as tremors, rigidity, slow movement, and postural instability. Parkinson's disease is caused by a reduction of dopamine levels in certain parts of the brain, such as the substantia nigra and striatum. The loss of dopaminergic neurons in these regions is responsible for the coordination of normal motor function.

About Nourianz® (istradefylline)

Nourianz® (istradefylline) is an adenosine receptor antagonist indicated as adjunctive treatment to levodopa/carbidopa in adult patients with Parkinson’s disease (PD) experiencing “off” episodes. It is not known if istradefylline is safe and effective in children.

Important Safety Information

Warnings and Precautions

Dyskinesia: istradefylline in combination with levodopa may cause dyskinesia or exacerbate pre-existing dyskinesia. In clinical trials, 1% of patients treated with either istradefylline 20 mg or 40 mg discontinued treatment because of dyskinesia, compared to 0% for placebo.

Hallucinations / Psychotic Behavior: Because of the potential risk of exacerbating psychosis, patients with a major psychotic disorder should not be treated with istradefylline. Consider dosage reduction or discontinuation if a patient develops hallucinations or psychotic behaviors while taking istradefylline.

Impulse Control / Compulsive Behaviors: Patients treated with istradefylline and one or more medication(s) for the treatment of Parkinson’s disease (including levodopa) may experience intense urges to gamble, increased sexual urges, intense urges to spend money, binge or compulsive eating, and/or other intense urges, and the inability to control these urges. In clinical trials, 1 patient treated with istradefylline 40 mg was reported to have impulse control disorder, compared to no patient on istradefylline 20 mg or placebo.

Drug Interactions

The maximum recommended dosage in patients taking strong CYP3A4 inhibitors is 20 mg once daily. Avoid use of istradefylline with strong CYP3A4 inducers.

Specific Populations

Pregnancy: Based on animal data, may cause fetal harm.

Hepatic impairment: The maximum recommended dosage of istradefylline in patients with moderate hepatic impairment is 20 mg once daily. Avoid use in patients with severe hepatic impairment.

Adverse Reactions

The most common adverse reactions with an incidence ≥5% and occurring more frequently than with placebo were dyskinesia (15%, 17%, and 8%), dizziness (3%, 6%, and 4%), constipation (5%, 6%, and 3%), nausea (4%, 6%, and 5%), hallucination (2%, 6%, and 3%), and insomnia (1%, 6%, and 4%) for istradefylline 20 mg, 40 mg, and placebo, respectively.

You are encouraged to report suspected adverse reactions to Kyowa Kirin, Inc. at 1-844-768-3544 or FDA at 1-800-FDA-1088 or

Please click to see full Prescribing Information for Nourianz.

About Kyowa Kirin

Kyowa Kirin strives to create and deliver novel medicines with life-changing value. As a Japan-based global specialty pharmaceutical company with a more than 70-year heritage, the company applies cutting-edge science, including expertise in antibody research and engineering, to address the needs of patients across multiple therapeutic areas such as nephrology, oncology, immunology/allergy, and neurology. Across its four regions – Japan, Asia Pacific, North America and EMEA/International – Kyowa Kirin focuses on its purpose, to make people smile, and is united by its shared values of commitment to life, teamwork, innovation, and integrity.

You can learn more about the Kyowa Kirin North America at:

# # #

Nourianz® is a trademark of Kyowa Kirin Co., Ltd.

Kyowa Kirin North America, Inc.
Susan Thiele
Director, Communication & Advocacy
Phone: +1 908-328-7117


  1. Rezak, M., Qian, J., Zhao, Y., et al. (2023). Real-World Utilization of Istradefylline Among Patients with Parkinson's Disease. Data presented at the 2023 World Congress on Parkinson’s Disease and Related Disorders, May 13-16, 2023, Chicago, IL.
  2. Hickey, P., & Stacy, M. (2011). Available and Emerging Treatments for Parkinson's Disease: A Review. Drug Design, Development and Therapy, 5, 241-254. doi:10.2147/DDDT.S11836
  3. Stacy, M., Bowron, A., Guttman, M., et al. (2005). Identification of Motor and Nonmotor Wearing-Off in Parkinson's Disease: Comparison of a Patient Questionnaire Versus a Clinician Assessment. Movement Disorders, 20(6), 726-733. doi:10.1002/mds.20383
  4. Chou, K. L., Stacy, M., Simuni, T., et al. (2018). The Spectrum of "Off" in Parkinson's Disease: What Have We Learned Over 40 Years? Parkinsonism & Related Disorders, 51, 9-16. doi:10.1016/j.parkreldis.2018.02.001
  5. Tan, Q. Y., Zhang, Z. C., Zhang, Y., et al. (2021). The Experiences of Treatment Burden in People with Parkinson's Disease and Their Caregivers: A Systematic Review of Qualitative Studies. Journal of Parkinson's Disease, 11(4), 1597-1617. doi:10.3233/JPD-202604.
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