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Safety, CNS penetration and target engagement of Mirivadelgat in participants with Parkinson’s disease

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What is this study about?

The study focuses on Parkinson’s Disease and evaluates an oral medication called Mirivadelgat, given as a 300 mg capsule each day. Participants will be randomly assigned to receive either the study medication or a placebo that looks identical but does not contain the active drug.

The main goal of the study is to see if the medication is safe and how well it reaches the CNS and influences a brain chemical known as 4-hydroxy-2-nonenal. Over a period of about 12 weeks, participants will take the assigned pill daily and attend regular check‑ups. At the beginning and end of the study, a small amount of fluid surrounding the brain and spinal cord, called CSF, may be collected through a thin needle to measure the level of the drug’s breakdown product AD-835 and the amount of the brain chemical. Simple brain scans using 31P-MRS may be performed to assess the brain’s energy use, and blood samples will be analyzed with LC‑MS. Laboratory tests such as ELISA, TBARS, and measurement of MDA will be used to evaluate the brain chemical levels.

1 randomization and start of medication

after enrollment, the study assigns you to receive either mirivadelgat or a matching placebo without knowing which one you receive.

the first dose is taken on the first day of the treatment period.

2 daily medication intake

take one oral capsule containing mirivadelgat 300 mg (or the identical placebo) once each day.

the capsule is swallowed with water and should be taken at the same time each day for a total of 12 weeks.

3 clinic visits for safety and adherence monitoring

visit the study clinic regularly (for example, weekly or as scheduled) to report any side effects and to confirm that the medication is being taken as directed.

study staff will check vital signs, ask about symptoms, and record any adverse events.

4 sample collections

at the start of the study (baseline) and again at week 12, blood samples are drawn to measure drug levels and safety parameters.

a cerebrospinal fluid (csf) sample is collected by a lumbar puncture at the same time points to assess drug penetration into the brain and to measure specific proteins using tests such as elisa (a laboratory method that detects proteins).

5 brain imaging assessments

magnetic resonance imaging (mri) of the brain is performed at baseline and at week 12 to evaluate brain structure.

a specialized scan called phosphorus magnetic resonance spectroscopy (31p-mrs) is also done to measure energy‑related compounds in the brain, such as the inorganic phosphate to atp ratio.

6 end of treatment evaluation and study completion

at week 12, the final dose is taken and the last set of safety checks, sample collections, and imaging are completed.

after the week‑12 visit, no further study medication is given, and the study concludes for the participant.

Who Can Join the Study?

  • Be between 40 and 85 years old when you sign the consent form.
  • Have a diagnosis of Parkinson’s Disease that was made no more than 10 years ago, a Hoehn and Yahr score of 3 or lower while your medication is working, and be on a stable Parkinson’s medication routine (no new medicines or dose changes for at least 2 weeks before the study starts).
  • Weigh between 45 and 120 kilograms (about 99–265 pounds).
  • Identify as any gender; you must use birth‑control methods during the study and for at least 8 weeks after the last dose.
  • Sign the informed consent form that explains the study and its requirements.
  • Show evidence of loss of dopamine‑producing brain cells (dopaminergic nigrostriatal denervation) on a special brain scan called a dopamine transporter (DAT) SPECT or PET scan, or a [18F]DOPA‑PET scan.
  • Not have another brain‑degeneration disease or any serious physical or mental illness that could affect the study.
  • Be able to undergo an MRI scan (a detailed picture of the brain), have blood drawn, and have a lumbar puncture (a spinal tap to collect fluid from the spine).

Who Cannot Join the Study?

  • You must not have any other known cause of parkinsonism besides typical Parkinson’s disease, such as rare brain disorders (e.g., progressive supranuclear palsy, multiple system atrophy, corticobasal syndrome, dementia with Lewy bodies) or drug‑induced parkinsonism from medicines like antipsychotics or metoclopramide.
  • You cannot take part if you have an active cancer. If the cancer was completely cured, the investigator may decide if you can join.
  • A history of solid organ transplantation (such as a kidney or liver transplant) excludes you.
  • Recent alcohol or drug abuse (within the past year) makes you ineligible.
  • Any psychiatric condition that could prevent you from following the study procedures will exclude you.
  • Any other serious physical illness that could interfere with study participation will exclude you.
  • If you are currently in another clinical trial, or have been in an experimental‑therapy trial within 12 weeks (or the time it takes for the previous drug to leave your body), you cannot join.
  • A prolonged heart‑beat interval called a QT interval greater than 480 ms (measured as QTcF) at screening excludes you.
  • Any abnormal heart rhythm on an ECG that the doctor thinks could cause dangerous heart beats (ventricular arrhythmia) excludes you.
  • Having a positive test for HIV (human immunodeficiency virus) at screening excludes you.
  • Having a positive test for hepatitis C virus at screening excludes you.
  • Current hepatitis B infection (positive hepatitis B surface antigen) excludes you, although past infection with immunity or vaccination is allowed.
  • A serious infection (such as pneumonia or bloodstream infection) within 8 weeks before the first dose excludes you.
  • Liver enzyme levels (ALAT, ASAT, bilirubin) that are 1.5 times higher than normal at screening exclude you, except for people with Gilbert’s syndrome who have a known mild bilirubin rise.
  • A urinary albumin/creatinine ratio of 20 mg/mmol or higher at enrollment excludes you.
  • An estimated kidney function (eGFR) lower than 60 mL/min/1.73 m² at screening excludes you.
  • Hemoglobin levels below 12 g/dL for men or 11 g/dL for women at screening exclude you.
  • Platelet counts below 145 × 10⁹/L for men or 165 × 10⁹/L for women at screening exclude you.
  • Use of the herbal supplement Mucuna pruriens within 90 days before baseline or during the study excludes you.
  • Use of any recreational (non‑medical) drugs within 7 days before baseline or during the study excludes you.
  • Use of strong CYP3A enzyme inhibitors (such as clarithromycin, itraconazole, ketoconazole, voriconazole, ritonavir, cobicistat, indinavir, telaprevir) within 14 days (or five drug half‑lives) before randomization, and during the study, excludes you.
  • A score below 23 on the MoCA cognitive test, dementia, or other significant memory problems that could affect study assessments exclude you.
  • Any reason that makes a brain MRI unsafe (such as having a pacemaker, MRI‑incompatible implants, or severe claustrophobia) excludes you.
  • Any reason that makes a lumbar puncture unsafe (such as increased pressure inside the skull, spinal infection, spinal cord compression, low platelet count, high INR, use of most blood thinners, or other bleeding risks) excludes you.
  • Known allergy or hypersensitivity to Mirivadelgat, the placebo, or any of their inactive ingredients excludes you.
  • Being prescribed a medication or supplement that is known to interact with Mirivadelgat excludes you.
  • Having previously taken part in the SLEIPNIR 2 study arm covered by this sub‑protocol excludes you.
  • Being unable to attend clinic visits while off Parkinson’s medication (the “OFF” state) excludes you.
  • Use of a dopaminergic therapy pump (such as continuous levodopa or apomorphine infusion) excludes you.
  • Any history of brain surgery for Parkinson’s disease (e.g., pallidotomy, deep brain stimulation, fetal tissue transplant) or focused ultrasound, or recent brain stimulation procedures (like TMS or tDCS/tACS within 90 days) excludes you.
  • A moderate or high risk of suicide on the Columbia Suicide Severity Rating Scale (C‑SSRS) at screening excludes you.
  • History of unstable angina, heart attack, severe heart failure (New York Heart Association Class 3 or 4), or serious heart rhythm problems (such as unstable atrial fibrillation) within the past year excludes you.
  • Poorly controlled diabetes, defined as needing a change in diabetes medication within 3 months before the first dose or having an HbA1c (glycosylated hemoglobin) of 8 % or higher at screening, excludes you.

Where you can join this trial?

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Other Sites

Site Name City Country Status
Hfvsa Bwcujk Hn Bergen Norway

Want to learn more about this study or check if you can participate? Contact us.

Trial status

Country Status Recruitment Start
Norway Norway
Not yet recruiting
30.09.2026

Trial locations

Mirivadelgat is an oral capsule being studied in people with Parkinson’s disease. The trial looks at how safe the medicine is, how well participants can tolerate it, and whether it reaches the brain. Researchers will measure the level of the drug’s active breakdown product, called AD‑835, in the blood and spinal fluid after participants take the medication for 12 weeks. The study also checks if the drug can lower a chemical marker (4‑hydroxy‑2‑nonenal protein adducts) that is linked to brain damage. By doing this, the trial aims to understand whether Mirivadelgat can affect the disease process in Parkinson’s disease.

Parkinson’s Disease – Parkinson’s disease is a progressive disorder of the nervous system that mainly affects movement. It develops slowly, often beginning with a subtle tremor or stiffness in one hand, and then may spread to other parts of the body. The condition results from a gradual loss of dopamine‑producing cells in the brain, leading to slower movements, reduced facial expression, and balance problems. As it advances, everyday tasks such as walking, writing, or buttoning clothes become increasingly difficult. Symptoms can also include a softer voice and a shuffling gait that becomes more pronounced over time.

Trial ID:
2025-523570-17-00
Protocol code:
SLEIPNIR-2
Trial Phase:
Therapeutic exploratory (Phase II)

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