FRANKFURT, Germany & RALEIGH, N.C. — May 28, 2026
Merz Therapeutics presented new research at the World Parkinson Congress (WPC) 2026 revealing the significant and often overlooked burden of OFF episodes in Parkinson’s disease (PD), while also showcasing additional clinical data supporting the use of INBRIJA® (levodopa inhalation powder) as a rapid and reliable on-demand treatment option.
New Research Reveals Complex Impact of OFF Episodes
The newly presented qualitative literature review created one of the most comprehensive models to date describing the patient experience during Parkinson’s disease OFF episodes. Researchers identified 132 distinct symptom and quality-of-life concepts, highlighting that OFF episodes extend far beyond visible motor impairments such as tremors and movement difficulties.
The analysis emphasized the major impact of “invisible” non-motor symptoms including fatigue, anxiety, cognitive difficulties, memory problems, emotional distress, and reduced daily functioning. According to the findings, these symptoms can significantly disrupt quality of life and may be equally or more debilitating than physical symptoms for many patients living with Parkinson’s disease.
Merz Therapeutics stated that the research provides clinicians and caregivers with a broader understanding of how OFF episodes affect patients physically, mentally, and socially. The company noted that recognizing these hidden burdens is critical for improving disease management and supporting more effective treatment strategies.
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Dr. Stefan Albrecht, Chief Scientific Officer of Merz Therapeutics, said the findings reinforce what many patients have reported for years — that OFF episodes represent a far more complex and disruptive experience than traditionally recognized within clinical practice.
INBRIJA Data Supports Rapid and Consistent Symptom Control
Alongside the patient burden research, Merz Therapeutics presented additional analyses supporting the efficacy and tolerability profile of INBRIJA®, an inhaled levodopa therapy used as an on-demand treatment for OFF episodes..
A pooled analysis involving 437 Parkinson’s disease patients across three Phase III clinical trials demonstrated that INBRIJA delivered rapid and consistent motor symptom improvement regardless of how long patients had experienced OFF episodes before treatment initiation. Patients with both shorter-duration OFF episodes and long-standing OFF episodes showed clinically meaningful improvements in motor function based on UPDRS-III score reductions.
Additional safety analyses showed that INBRIJA maintained a favorable tolerability profile over long-term treatment. The most commonly reported adverse events included mild cough and throat irritation, with no evidence of dose-related increases in severity. Researchers also reported that after 60 weeks of treatment, the majority of patients remained free from treatment-related cough events.
Parkinson’s Community Focuses on Unmet Needs
The findings presented at WPC 2026 underscore growing industry focus on improving management of Parkinson’s disease OFF episodes, which continue to represent a major unmet medical challenge. OFF episodes occur when the effects of routine Parkinson’s medications wear off, leading to the sudden return of motor and non-motor symptoms that can severely disrupt daily life.
Merz Therapeutics said the combination of new patient experience insights and additional INBRIJA clinical analyses strengthens the importance of rapid on-demand therapies capable of helping patients regain symptom control during unpredictable OFF periods.
The research presentations took place during the World Parkinson Congress 2026 held in Phoenix, Arizona, from May 24–27.
Source: Merz Therapeutics press release
