Kyowa Kirin to Present a Safety Meta-Analysis of NOURIANZ® (istradefylline) and Other Parkinson's Disease Add-On Therapies

Findings to be presented at 2024 American Academy of Neurology annual conference between April 13-18 in Denver, CO

PRINCETON, N.J., April 12, 2024 /PRNewswire/ -- Kyowa Kirin, Inc., an affiliate of Kyowa Kirin Co., Ltd. (Kyowa Kirin, TSE: 4151), a global specialty pharmaceutical company based in Japan, will announce findings from an updated systematic literature review (SLR) and meta-analysis comparing the safety of NOURIANZ(®) (istradefylline) in relation to other levodopa adjunctive therapies for patients with Parkinson's Disease (PD).(1,2) NOURIANZ is an adenosine receptor antagonist used with levodopa/carbidopa to treat adults with PD experiencing "off" episodes, the return of Parkinson's symptoms between medication doses. The findings will be presented at the American Academy of Neurology (AAN) 2024 Annual Meeting, during a poster presentation on Monday, April 15, from 5:30 - 6:30 PM MDT.

Parkinson's disease is a progressive, neurodegenerative disease characterized by motor symptoms such as tremors, rigidity, slow movement, and postural instability. Within 5 years of starting levodopa/carbidopa treatment, half of people living with PD begin to experience "off" time, including problems with movement.(3 )Adjunctive therapies may be used to treat these episodes but are often hampered by safety and tolerability issues that limit their clinical utility.(1)

"With the growing landscape of adjunctive therapies for Parkinson's disease, it is important for physicians to have data that demonstrates the relative risk profiles of these treatment options," said lead author Yasar Torres-Yaghi, MD, MedStar Georgetown University Hospital. "These data provide useful information on safety and tolerability of these therapies, an important factor for physicians when choosing an appropriate adjunctive therapy for patients experiencing "off" episodes."

About the Study

Researchers updated a previously published SLR with an additional 20 randomized controlled trials from Jan 1, 2010, to April 15, 2019, evaluating adjunctive therapies in patients with PD. The study analyzed data from a total of 57 randomized clinical trials involving 11,517 patients. Interventions included COMT inhibitors, monoamine oxidase type B (MAO-B) inhibitors, dopamine agonists (DAs), istradefylline, and amantadine ER. A pair-wise meta-analysis was conducted to calculate summary odds ratios (OR) and 95% confidence intervals (CI). Bucher indirect comparisons were used to generate estimates of relative safety, and information on study design, eligibility criteria, and baseline characteristics were extracted for heterogeneity assessment.


NOURIANZ is an adenosine receptor antagonist indicated as an 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.(4)

Important Safety Information

Warnings and Precautions
: NOURIANZ in combination with levodopa may cause dyskinesia or exacerbate pre-existing dyskinesia. In clinical trials, 1% of patients treated with either NOURIANZ 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 NOURIANZ. Consider dosage reduction or discontinuation if a patient develops hallucinations or psychotic behaviors while taking NOURIANZ.

Impulse Control / Compulsive Behaviors: Patients treated with NOURIANZ 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 NOURIANZ 40 mg was reported to have impulse control disorder, compared to no patient on NOURIANZ 20 mg or placebo.

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

Based on animal data, may cause fetal harm.

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 NOURIANZ 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 aims to discover and deliver novel treatments with life-changing value. As a Japan-based Global Specialty Pharmaceutical Company, we have invested in drug discovery and biotechnology innovation for more than 70 years and are currently working to engineer the next generation of antibodies and cell and gene therapies with the potential to help patients with high unmet medical needs, focusing on bone/mineral, intractable hematological diseases/hemato oncology, and rare diseases. A shared commitment to our values, to sustainable growth, and to making people smile unites us across the globe.

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    1. Torres-Yaghi Y., Qian, J. et al. (2024). Comparative Safety of
       Istradefylline Among Parkinson's Disease Adjunctive Therapies: A
       Systematic Review and Meta-Analysis of Randomized Controlled Studies.
       Data presented at the 2024 American Academy of Neurology Annual Meeting,
       April 13-18, 2024, Denver, CO.
    2. Stowe R et al. Movement disorders. 2011;26(4):587-98
    3. 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
    4. NOURIANZ. Prescribing Information. Kyowa Kirin Inc. Princeton, NJ.

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