Phase II Open-Label Extension Study of Oral Montelukast Sodium for Disease Modification in Mild-Moderate Parkinson’s Disease (MONTPARK_OLE)

The primary objective is to assess the long‑term safety and tolerability of oral montelukast in patients with Parkinson's disease during the extension phase, providing essential data on the risk profile of a potential disease‑modifying therapy. Secondary objectives include: • evaluation of clinical benefit over time with possible improvements in motor and non‑motor symptoms; • characterization of changes in inflammatory and neurodegenerative biomarkers to explore mechanistic effects.

The trial enrolled individuals diagnosed with Parkinson's disease who had previously completed the MONTPARK trial and provided written informed consent. Both male and female patients were eligible; female participants were required to be at least one year post‑menopausal or to use a highly effective method of contraception throughout treatment and for three months after the last dose. Selection was based on the investigator’s assessment that the Parkinson’s disease diagnosis remained valid and that the subject continued to meet eligibility criteria for extended therapy. The sponsor did not provide information on the total number of participants or the specific age range, and no details regarding diet, physical activity, or other lifestyle factors were supplied.

The study is an open-label, phase II extension trial evaluating the long‑term safety and tolerability of Montelukast in patients with mild‑moderate Parkinson’s disease. Eligible participants are those who successfully completed the preceding MONTPARK trial, have provided written consent, and meet all inclusion criteria. After a screening visit to confirm eligibility, subjects receive a baseline assessment and begin daily oral Montelukast 60 mg. Follow‑up visits are scheduled every three months to document adverse events, laboratory values, and secondary efficacy outcomes (e.g., MDS‑UPDRS Part 3, MoCA, PDQ‑8). The final visit occurs at the end of the treatment period, resulting in an overall participant involvement of approximately 30 months. Early termination is permitted in cases of participant withdrawal, serious adverse events, or investigator‑determined safety concerns. The trial recruitment period extends from August 2026 to December 2028.

The investigational product is montelukast sodium supplied in the pharmaceutical form identified as PHF00082MIG. It is administered via the oral route at a dose of 60 mg. The medication is classified under ATC code R03DC03 and is intended for evaluation as a disease‑modifying therapy in patients with mild‑to‑moderate Parkinson’s disease.

Efficacy will be evaluated using a set of secondary clinical endpoints. Motor and non‑motor aspects will be assessed with the MDS‑UPDRS (Parts 1, 2, 3, and 4). Cognitive performance will be measured by the Montreal Cognitive Assessment (MoCA). Overall disease severity will be quantified using the Clinical Impression of Severity Index for Parkinson's Disease (CISI‑PD). Health‑related quality of life will be evaluated with the Parkinson’s Disease Questionnaire (PDQ‑8). Emotional status will be screened using the Hospital Anxiety and Depression Scale (HAD), and non‑motor symptoms will be recorded via the Non‑Motor Symptoms Questionnaire (NMSQ).

All instruments are validated for use in Parkinson's Disease and will be administered at each scheduled study visit. Data will be collected according to the trial protocol and analyzed to compare changes from baseline across the extended treatment period.