Merz Therapeutics Presents New Research at World Parkinson Congress 2026, Revealing the Hidden Burden of “OFF” Episodes in Parkinson’s Disease

May 28, 2026

  • A new qualitative literature review provides a comprehensive model of the patient experience of OFF episodes, identifying 132 distinct motor, non-motor and quality-of-life impacts1
  • The research highlights OFF episode as a complex, multifaceted experience, highlighting the profound and often invisible struggles faced by people with Parkinson’s disease1
  • Additional analyses of INBRIJA® (levodopa inhalation powder) confirm its clinical profile as a rapid, reliable and well-tolerated on-demand treatment for OFF episodes2,3

Frankfurt, Germany | Raleigh, N.C. – May 28, 2026 – Merz Therapeutics, a leading player in neurology-focused specialty pharma, today announced the presentation of new research at the World Parkinson Congress (WPC) 2026 that uncovers the multifaceted burden of “OFF” episodes in Parkinson’s disease (PD). The qualitative literature review demonstrates that these episodes are not only a re-emergence of motor symptoms, but also a complex mix of debilitating motor and non-motor symptoms that impact the lives of people with Parkinson’s disease.1 Additional data presented at the congress also confirm the clinical profile of INBRIJA® (levodopa inhalation powder) as a reliable and well-tolerated treatment for these debilitating events.

The new research moves beyond well-recognized physical signs to create a more comprehensive model for understanding the true patient experience of an OFF episode.1 The systematic review identified 132 distinct concepts, detailing the profound impact of “invisible” non-motor symptoms such as fatigue, memory problems and anxiety, which can be just as, if not more, debilitating.1 This work provides a new framework for clinicians and the wider community to appreciate the complex, multi-faceted burden of OFF episodes and underscores the critical need for effective on-demand solutions.1

“For too long, the conversation around ‘OFF’ episodes has focused primarily on visible motor symptoms. Our research highlights what we’ve been hearing from people with Parkinson’s: the burden of an ‘OFF’ episode is far broader and more disruptive than what can be seen,” said Dr. Stefan Albrecht, CSO, Merz Therapeutics. “It is a call to action for the entire Parkinson’s community to recognize and address the significant impact of ‘OFF’ episodes. At Merz Therapeutics, we’re committed to delivering effective and reliable therapeutic options to help address the needs of people with Parkinson’s disease.”

Supporting its commitment to delivering on-demand treatments, Merz Therapeutics also presented key data on the efficacy and safety of INBRIJA®:

  • A pooled analysis of 437 people with Parkinson’s disease from three Phase III trials demonstrated that INBRIJA® provides consistent and rapid motor improvement for people who had been experiencing OFF episodes for a shorter time (<2 years) as well as a longer time (≥2 years) before initiation of therapy, with mean UPDRS-III score reductions of -14.3 and -14.8, respectively.2
  • A dedicated safety analysis confirmed a favorable tolerability profile, showing that treatment-emergent adverse events, primarily cough and throat irritation, were mostly mild with no dose-dependent increase in severity. Furthermore, after 60 weeks of treatment, the probability of a patient remaining free of treatment-related cough was 84.7%.3

The research was presented at the WPC in Phoenix, Arizona, from May 24–27, 2026.

About OFF Episodes in Parkinson’s Disease

“OFF episodes” are the re-emergence of Parkinson’s disease symptoms, both motor (such as tremor and slowness) and non-motor (like anxiety and fatigue), that occur despite a patient’s regular medication schedule. These episodes can be unpredictable and severely disrupt a person’s ability to perform daily activities, creating significant challenges for people with Parkinson’s disease, their families and caregivers.

Important Safety Information

What is INBRIJA® (levodopa inhalation powder)?

INBRIJA is an inhaled levodopa prescription medicine used to treat the return of Parkinson’s symptoms (known as OFF episodes) in people with Parkinson’s disease who are treated with carbidopa/levodopa medicines. INBRIJA does not replace regular carbidopa/levodopa medicine. It is not known if INBRIJA is safe or effective in children.

Do not use INBRIJA if you: take or have taken a nonselective monoamine oxidase inhibitor such as phenelzine or tranylcypromine within the last 2 weeks.

Before using INBRIJA, tell your healthcare provider about your medical conditions, including if you:

  • have asthma, chronic obstructive pulmonary disease (COPD), or any chronic lung disease
  • have daytime sleepiness, sleep disorders, sleepiness/drowsiness without warning, or use medicine that increases sleepiness, including antidepressants or antipsychotics
  • have dizziness, nausea, sweating, or fainting when standing up
  • have abnormal movement (dyskinesia)
  • have mental health problems such as hallucinations or psychosis
  • have uncontrollable urges like gambling, sexual urges, spending money, or binge eating
  • have glaucoma
  • are pregnant or plan to become pregnant. It is unknown if INBRIJA can harm your unborn baby.
  • are breastfeeding or plan to breastfeed. Levodopa can pass into breastmilk and it is unknown if it can harm the baby.

Tell your healthcare provider about all of the medicines you take, including prescription and over-the-counter medicines, vitamins and herbal supplements.

Using INBRIJA and certain other medicines may affect each other and cause serious side effects. Especially tell your healthcare provider if you take:

  • MAO-B inhibitors
  • dopamine (D2) antagonists (including phenothiazines, butyrophenones, risperidone, metoclopramide)
  • isoniazid
  • iron salts or multivitamins that contain iron salts

How should I use INBRIJA?

INBRIJA is for oral inhalation use only. Do not swallow or open INBRIJA capsules. Only use INBRIJA capsules with the INBRIJA inhaler. Do not use the INBRIJA inhaler to take any other medicine.

Do not orally inhale more than 1 dose (2 capsules) for any OFF period. Do not take more than 5 doses (10 capsules) in a day.

What should I avoid while taking INBRIJA?

Do not drive, operate machinery, or do other activities until you know how INBRIJA affects you. Sleepiness and falling asleep suddenly can happen as late as a year after treatment is started.

What are the possible Side Effects of INBRIJA?

INBRIJA can cause serious side effects including:

  • falling asleep during normal daily activities with or without warning. If you become drowsy, do not drive or do activities where you need to be alert for your safety or the safety of others. Chances of falling asleep during normal activities increases if you take medicine that cause drowsiness.
  • withdrawal-emergent hyperpyrexia and confusion (fever, stiff muscles, or changes in breathing and heartbeat) if you suddenly stop using INBRIJA or carbidopa/levodopa, or suddenly lower your dose of carbidopa/levodopa.
  • low blood pressure when standing up (that may or may not happen with dizziness, fainting, nausea, and sweating). Get up slowly after sitting/lying down.
  • hallucinations and other psychosis – INBRIJA may cause or worsen seeing/hearing/believing things that are not real; confusion, disorientation, or disorganized thinking; trouble sleeping; dreaming a lot; being overly suspicious or feeling people want to harm you; acting aggressive; and feeling agitated/restless.
  • unusual uncontrollable urges such as gambling, binge eating, shopping, and sexual urges has occurred in some people using medicine like INBRIJA.
  • uncontrolled, sudden body movements (dyskinesia) may be caused or worsened by INBRIJA. INBRIJA may need to be stopped or other Parkinson’s medicines may need to be changed.
  • bronchospasm – people with asthma, COPD, or other lung diseases may wheeze or have difficulty breathing after inhaling INBRIJA. If this occurs, stop taking INBRIJA and seek immediate medical attention.
  • increased eye pressure in patients with glaucoma. Your healthcare provider should monitor this.
  • changes in certain lab values including liver tests.

The most common side effects of INBRIJA are cough, upper respiratory tract infection, nausea, and change in the color of saliva or spit. Another side effect of INBRIJA is sensation of choking right after use.

These are not all the possible side effects of INBRIJA

  • Call your doctor for medical advice about side effects.
  • You are encouraged to report negative side effects of prescription drugs to the FDA. Visit fda.gov/medwatch or call 1-800-FDA-1088.

The risk information provided here is not comprehensive. To learn more:

About Merz Therapeutics

Merz Therapeutics GmbH is dedicated to delivering better outcomes for more patients. With science as its foundation and the patient experience as its focus, the company relentlessly pursues innovative treatments and partnerships to address unmet needs in movement disorders, neurodegenerative conditions and other health conditions that severely impact patients’ quality of life.

Merz Therapeutics is headquartered in Frankfurt am Main, Germany, and is active in over 80 countries, with a North America affiliate in Raleigh, North Carolina. Merz Therapeutics GmbH is part of the Merz Group, a privately held, family-owned company with a 117-year legacy. With passion and purpose, Merz Therapeutics continues to advance care in specialty neurology in ways that benefit both patients and society. Please visit www.merztherapeutics.com.

This press release is not intended to offer recommendations, advice, endorsement, guidance or suggestions for administering or otherwise using INBRIJA® in any manner inconsistent with its current prescribing information approved by the U.S. Food and Drug Administration.

 

Media Contact:
Merz Therapeutics
Nicole Lovern
Corporate Communications
6601 Six Forks Road, Suite 400, Raleigh, NC 27615
(571) 442-9665
Nicole.Lovern@merz.com

 

References

  1. Scheschonka A et al., Episodes of motor and non-motor response fluctuations (OFF episodes) in people with Parkinson disease: a targeted qualitative literature review and preliminary patient-centric conceptual model. Presented at: World Parkinson Congress (WPC); May 24-27, 2026; Phoenix, AZ.
  2. Scheschonka A et al., Efficacy and safety of inhaled levodopa comparing early and late treatment initiation in patients with Parkinson disease: post hoc analysis of pooled data from three phase III trials. Presented at: World Parkinson Congress (WPC); May 24-27, 2026; Phoenix, AZ.
  3. Scheschonka A et al., Safety of inhaled levodopa by incidence and severity of treatment-related cough and throat irritation in people with Parkinson disease: post hoc analysis of pooled data from three phase III trials. Presented at: World Parkinson Congress (WPC); May 24-27, 2026; Phoenix, AZ.

 

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