A Phase 1b, Prospective, Randomized, Double-blind, Placebo-controlled Trial Evaluating the Safety and Tolerability of Multiple Oral Doses of IRL757 in Participants With Parkinson's Disease and Apathy
This clinical trial's goal is to evaluate if the IRL757 is safe and has a good tolerability in participants with Parkinson's disease and experiencing apathy (a lack of interest or motivation). In addition, the trial is aiming to learn if IRL757 has effects on the symptoms of Parkinson's disease. Researchers will compare the effects of IRL757 to a placebo (a look-alike substance that contains no drug). Participants who fit the study criteria will be treated with the study drug (either the active drug IRL757 or placebo) for 12 weeks and will visit the clinic at 5 defined timepoints for check-ups and tests. A follow-up call after the end of treatment will be done 4 weeks after the last study drug intake.
• Male and female participants between 50 and 90 years of age, inclusive, with diagnosed Parkinson's disease according to the Movement Disorders Society Clinical Diagnostic Criteria for Parkinson's disease.
• Hoehn and Yahr stage ≤ 4 at screening.
• MoCA score of 20 or greater at screening and baseline.
• Meets the ISCTM definition of apathy (criterion B), defined as exhibiting ≥ 1 symptom in ≥ 2 of the following 3 dimensions, that is persistent or frequently recurrent (ie, ≥ 3 days per week) for ≥ 4 weeks prior to screening:
‣ Diminished initiative (less spontaneous and/or active than usual self; less likely to initiate usual activities such as hobbies, chores, self-care, conversation, work-related or social activities),
⁃ Diminished interest (less enthusiastic about usual activities, less interested in, or less curious about, events in their environment, less interested in activities and plans made by others, less interested in friends and family, less persistence in maintaining or completing tasks or activities), or
⁃ Diminished emotional expression/responsiveness (less spontaneous emotions, less affectionate compared to their usual self, expresses less emotion in response to positive or negative events, less concerned about the impact of their actions on other people, less empathy).
• The symptoms must represent a significant change from the participant's usual behaviour and cause significant impairment in personal, social, or occupational functioning. Finally, the symptoms must not be due to psychiatric illness, intellectual disability, physical/motor disabilities, or changes in level of consciousness or the effects of substances.
• Participants with moderate to severe apathy based on a score of at least -16 on the LARS at screening and baseline.
• Availability of the primary caregiver, any adult who spends greater than 10 hours a week with the participant and supervises his or her care, to accompany the participant to trial visits and to participate in the trial.
• Treatment with anti-Parkinson drugs, antidepressants (except for those listed as prohibited medications in the protocol), and Choline esterase inhibitors is permitted if doses are stable for 1 month before randomization and remain stable during the trial.