A Study Testing the Safety of IRL757 in Adults with Parkinson’s Disease Who Have Apathy

What is this study about?

This study is looking at Parkinson’s Disease in people who also experience apathy, which means a lack of interest or motivation to do things. Apathy can include having less energy to start activities, feeling less interested in daily life, or showing fewer emotions than usual. The study will test a medication called IRL757, which is given as a capsule taken by mouth. Some people in the study will receive IRL757 at different dose levels, while others will receive placebo capsules that do not contain active medication.

The purpose of this study is to find out if IRL757 is safe and well tolerated when taken daily for 12 weeks by people with Parkinson’s Disease who have moderate to severe apathy. The study will look at whether the medication causes any unwanted effects and how the body responds to it over time. Participants will need to have a caregiver who spends time with them regularly and can come to study visits.

During the study, participants will take the assigned capsules every day for 12 weeks. The doctors will check for any side effects by doing physical examinations, blood tests, heart tests, and asking questions about mood, behavior, and sleepiness. They will also measure changes in apathy symptoms using questionnaires that ask about motivation, interest in activities, and emotional responses. Participants must continue taking their regular medications for Parkinson’s Disease at the same doses throughout the study.

1 Initial assessment and baseline measurements

At the beginning of the trial, your current health status will be assessed. This includes a physical examination, laboratory tests, and measurements of vital signs such as blood pressure and heart rate.

An electrocardiogram (a test that records the electrical activity of your heart) will be performed.

Your cognitive function will be evaluated using the MoCA test, which assesses memory and thinking abilities.

The level of apathy (lack of interest or motivation) will be measured using specific questionnaires: the LARS (a scale that evaluates apathy) and the NPI-C apathy domain (which assesses behavioral symptoms).

Additional assessments will include the C-SSRS (a questionnaire about suicidal thoughts), the QUIP-RS (which evaluates impulse control), and the ESS (a scale measuring daytime sleepiness).

Your primary caregiver, who spends more than 10 hours per week with you, will need to accompany you to this visit and participate in the assessments.

2 Beginning of treatment period

After the baseline assessments, you will be assigned to receive either IRL757 or placebo capsules. The assignment will be random, and neither you nor the medical team will know which treatment you are receiving.

You will begin taking the assigned medication orally (by mouth) in capsule form.

The treatment will be taken daily for a period of 12 weeks.

The dosage will be determined according to the trial protocol, and you should take the medication as instructed.

If you are currently taking medications for Parkinson’s disease, antidepressants, or other approved medications, you should continue taking them at the same dose throughout the trial period.

3 Regular monitoring visits during treatment

Throughout the 12-week treatment period, you will attend scheduled visits for safety monitoring and assessments.

At each visit, the medical team will check for any adverse events (unwanted or harmful effects that may occur during the trial).

Physical examinations, laboratory tests, vital signs measurements, and electrocardiograms will be repeated at specific time points to monitor your health.

The questionnaires assessing apathy, suicidal thoughts, impulse control, and daytime sleepiness will be administered again to track any changes.

Your caregiver will continue to accompany you to these visits and provide information about your condition and behavior.

4 End of treatment assessment

After completing the 12-week treatment period, a final assessment will be conducted.

All the same measurements and tests performed at baseline will be repeated, including physical examination, laboratory tests, vital signs, electrocardiogram, and all questionnaires.

The changes in apathy symptoms will be evaluated by comparing the results from the beginning and end of the treatment period using the LARS and NPI-C apathy domain.

The safety and tolerability of the medication will be assessed by reviewing all adverse events, laboratory results, and other health measurements collected during the trial.

Who Can Join the Study?

You must be between 50 and 90 years old
You must have a diagnosis of Parkinson’s disease, which is a condition that affects movement and is caused by changes in the brain
Your Parkinson’s disease must be at a certain stage, measured by a scale called Hoehn and Yahr stage, and must be at stage 4 or lower
You must score 20 or higher on a test called MoCA, which checks memory and thinking abilities
You must have apathy, which means a lack of interest, motivation, or emotional response. This must include at least one symptom in at least two of these areas: reduced ability to start activities on your own, reduced interest in things around you, or reduced emotional reactions. These symptoms must occur at least 3 days per week for at least 4 weeks
Your apathy symptoms must be a clear change from how you normally behave and must affect your daily life, work, or relationships
Your apathy symptoms must not be caused by other mental health conditions, intellectual disabilities, physical limitations, or effects of medications or substances
You must score at least minus 16 on the LARS, which is a specific test that measures the severity of apathy, showing you have moderate to severe apathy
You must have a primary caregiver, someone who spends more than 10 hours per week with you and helps supervise your care, who can come with you to study visits
If you are taking medications for Parkinson’s disease, antidepressants, or certain memory medications called ChEIs, your doses must be stable for at least 1 month before joining the study and must stay the same during the study
Both men and women can participate in this study

Who Cannot Join the Study?

Pregnancy or breastfeeding: Women who are pregnant, planning to become pregnant during the study, or currently breastfeeding cannot participate.
Severe heart problems: Patients with serious heart conditions or recent heart attacks cannot join the study.
Uncontrolled high blood pressure: Blood pressure that is not well managed with medication is a reason for exclusion.
Severe kidney or liver disease: Serious problems with kidney or liver function prevent participation. The kidneys filter waste from blood, and the liver helps process medications.
History of stroke: Patients who have had a stroke, which is when blood flow to the brain is blocked, cannot participate.
Seizure disorder: A condition causing repeated seizures, which are sudden electrical disturbances in the brain, is an exclusion reason.
Other major brain disorders: Conditions affecting the brain besides Parkinson’s disease may prevent participation.
Active cancer: Patients currently being treated for cancer or with recent cancer diagnosis cannot join.
Severe depression or suicidal thoughts: Serious mental health conditions or thoughts of self-harm are reasons for exclusion.
Substance abuse: Current problems with alcohol or drug abuse prevent participation in the study.
Allergies to study medication: Known allergic reactions to the study drug or its ingredients are an exclusion criterion.
Participation in other studies: Being in another clinical trial or having recently participated in one may prevent enrollment.
Unable to follow study requirements: Patients who cannot attend visits, take medication as directed, or complete study tasks cannot participate.

Where you can join this trial?

Verified and Recommended Sites

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Verified Sites

Site Name	City	Country
Technische Universitaet Dresden	Dresden	Germany
NeuroKlinika Gabinet Lekarski Prof. Andrzej Bogucki	Lodz	Poland
Neurology Institution	Berlin	Germany

Other Sites

Site Name	City	Country
Centrum Medyczne Neuromed Sp. z o.o.	Bydgoszcz	Poland
Hospital Victoria Eugenia De La Cruz Roja Espanola	Sevilla	Spain
Euromedis Sp. z o.o.	Szczecin	Poland
Hospital Universitario Ramon Y Cajal	Madrid	Spain
Hospital General Universitario De Elche	Elche	Spain
Diagnostic-consultative center “Aleksandrovska” EOOD	Sofia	Bulgaria
Samodzielny Publiczny Zaklad Opieki Zdrowotnej Szpital Uniwersytecki W Krakowie	Cracow	Poland
Neuroprotect Sp. z o.o.	Warsaw	Poland
University First multiprofile hospital for active treatment Sofia St. Joan Krastitel EAD	Sofia	Bulgaria
Mlmgzzz Cizqam Axggycihn 2xiu Eekh	Pleven	Bulgaria
Nubqbndttb Shw z orhc sfafp	Katowice	Poland
Ulnadousbylmiwwwwniib Meoqsgye Aov	Munster	Germany
Husryzfo Df Lx Sxzcf Cnci I Salg Plj	Barcelona	Spain
Mpulnvs Cbntpo Kcphps Ogj	Pleven	Bulgaria

Trial status

Country	Status	Recruitment Start
Bulgaria	Recruiting	17.11.2025
Germany	Recruiting	17.11.2025
Poland	Recruiting	17.11.2025
Spain	Recruiting	17.11.2025

Trial locations

IRL757 is an experimental medication being tested in this clinical trial. It is given by mouth (orally) and is being studied to see if it is safe and well-tolerated when taken daily for 12 weeks by people with Parkinson’s Disease who experience apathy. Apathy means having a lack of interest, motivation, or emotion. This medication is being compared to a placebo to understand its effects better.

Investigated diseases:

Parkinson's disease

Parkinson’s Disease – Parkinson’s disease is a brain disorder that affects movement and develops gradually over time. It occurs when nerve cells in the brain that produce dopamine, a chemical messenger important for controlling movement, become damaged or die. The main symptoms include trembling of the hands, arms, legs, or face, stiffness of the limbs and trunk, slowness of movement, and problems with balance and coordination. As the disease progresses, people may also experience non-movement symptoms such as apathy, which is a lack of interest, motivation, or emotional response to activities. The symptoms typically start mild and worsen slowly over months and years. This condition primarily affects older adults, though it can occur in younger people as well.

Apathy – Apathy is a condition characterized by a lack of motivation, interest, and emotional response to activities that would normally be engaging or important. It involves reduced goal-directed behavior, decreased initiative to start or complete tasks, and diminished emotional reactions to events. People with apathy may appear indifferent, show little concern about their personal affairs, and have difficulty engaging in social interactions. This condition can occur on its own or as a symptom of other brain disorders such as Parkinson’s disease, dementia, or stroke. The severity can range from mild disinterest to complete lack of motivation that significantly impacts daily functioning. Apathy differs from depression, though the two conditions can sometimes occur together.

Trial ID:

2025-523612-37-00

Protocol code:

IRL757C003

Trial Phase:

Human Pharmacology (Phase I) – Other

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A Study Testing the Safety of IRL757 in Adults with Parkinson’s Disease Who Have Apathy

What is this study about?

Who Can Join the Study?

Who Cannot Join the Study?