AuthorisedTherapeutic confirmatory (Phase III)Interventional

Montelukast as disease modifying treatment in mild-moderate Parkinson’s disease, an open-label, phase II extension trial (MONTPARK_OLE)

This study, called MONTPARK_OLE, is investigating whether a medication called montelukast could be a helpful treatment for people with mild to moderate Parkinson's disease. Montelukast is usually used to treat asthma, but scientists are now exploring its potential for Parkinson's. This is an extension of a previous study, meaning it follows up on earlier findings. The main goal is to carefully check how safe montelukast is and to identify any side effects that might occur. Researchers will compare these findings to earlier results where some people received montelukast and others received a dummy pill (placebo). We also want to see if it has a positive impact on Parkinson's symptoms.

At a glance

Status

Authorised

Phase

Therapeutic confirmatory (Phase III)

Sponsor

Karolinska University Hospital

Enrolment target

Start

03 Jun 2026

Parkinson's Disease

What is this study about?

This research study, known as MONTPARK_OLE, is looking at a medication called montelukast for people who have Parkinson's disease. Currently, montelukast is primarily used to treat conditions like asthma and allergies. However, there's growing interest in whether it might also have a role in helping people with Parkinson's.

This study is a continuation of earlier research (called MONTPARK). In the initial study, some people with Parkinson's received montelukast, while others received a dummy pill (a placebo). This new phase aims to gather more information, especially about the safety of montelukast when used over a longer period. We want to understand if there are any side effects, how often they occur, and how severe they might be, including any changes in blood test results.

Beyond safety, the study will also look at whether montelukast helps with various aspects of Parkinson's disease. This includes tracking motor symptoms (like movement and tremors), non-motor symptoms (such as sleep problems or mood changes), thinking abilities, and overall quality of life. The information collected from this study will help doctors and researchers decide if montelukast could be a new and effective treatment option for Parkinson's disease in the future.

Key takeaways

This study is testing montelukast, an existing asthma drug, for Parkinson's disease.
It's an extension of a previous trial, focusing on long-term safety and effects.
Researchers will closely monitor side effects and changes in Parkinson's symptoms.
Participation involves regular clinic visits for assessments and blood tests.
The goal is to see if montelukast could become a new treatment option for Parkinson's.

Who may be eligible?

This study is open to adults aged 18 and over who have Parkinson's disease. Both men and women can take part.

To be considered for this study, you would typically have been a participant in the earlier MONTPARK trial. This follow-up study is designed to continue collecting information from those who previously took part.

Your study doctor will discuss all the specific requirements with you to make sure this study is a safe and suitable option. These requirements help ensure that the research is conducted safely and that the results will be meaningful.

Could this study suit you?

Answer these quick questions to see if you may be eligible. This is a guide only — the research team makes the final call.

Are you 18 years old or older?
Do you have Parkinson's disease?
Did you take part in the earlier MONTPARK study?
Are you comfortable attending regular clinic visits?

Answer every question to see your result.

What does participation involve?

Taking part in this study would involve a series of visits to the research clinic. During these visits, the study team would carefully record any side effects you might experience, along with the results of blood tests. These checks will happen at each scheduled visit, and you'll also have a way to report any issues that come up between visits.

You would continue to receive the montelukast medication, as this is an extension of the previous trial. Alongside checking for side effects, the team would also carry out various assessments. These include questionnaires and tests to look at your movement symptoms, daily activities, thinking skills, mood, and overall well-being. The total duration of your participation in this extension study would be explained by the research team.

Potential risks and benefits

Participating in research always carries potential benefits and risks. A potential benefit of this study is early access to a treatment that might help manage Parkinson's disease. It also helps contribute valuable information to medical science, which could benefit many others in the future. As montelukast is already used for other conditions, its general side effects are known, but we are looking specifically at its use in Parkinson's. Potential risks could include known or unknown side effects of montelukast, as well as the time and effort required for clinic visits. Remember, your participation is voluntary, and you are free to withdraw from the study at any time without giving a reason, and it will not affect your usual medical care.

Locations (1)

Some site locations are approximate. We're improving this — please verify with the trial team before travelling.

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Unverified
Sweden

Common questions

What is montelukast?

Montelukast is a medicine that is commonly prescribed for conditions like asthma and allergies. This study is exploring if it could also help people with Parkinson's disease.

Who can join this study?

Generally, this study is for adults (18 years or older) with Parkinson's disease who previously took part in the original MONTPARK trial. Both men and women can participate.

What is the main goal of this study?

The main goal is to carefully check the safety of montelukast for people with Parkinson's and to monitor any side effects. We also want to see how it affects Parkinson's symptoms over time.

Will I receive the actual drug or a dummy pill?

As this is an extension study, participants who previously received montelukast will continue to receive it. The main focus is on long-term safety and effects.

How long will I be in the study?

The study team will explain the exact duration of your participation. It involves a series of visits and ongoing monitoring.