Objective: To evaluate the efficacy and safety of mesdopetam compared with placebo for levodopa‑induced dyskinesia (LID) in Parkinson’s disease (PD).
Background: Mesdopetam (IRL790) is a selective dopamine D3‑receptor antagonist developed to reduce LID without worsening parkinsonism. Multiple randomized trials have investigated its clinical effects across different dose ranges, but results have varied.
Method: A meta‑analysis of randomized, double‑blind, placebo‑controlled trials was conducted using studies registered on ClinicalTrials.gov to ensure methodological rigor and consistency. Outcomes extracted included the UDysRS total score, ON-time without troublesome dyskinesia (hours), OFF time (hours), MDS-UPDRS‑IV, activities of daily living (MDS-UPDRS‑II), and adverse events (AEs). Mean differences (MD), standardized mean differences (SMD), and risk ratios (RR) for dichotomous outcomes were pooled using inverse‑variance statistical models.
Results: Across 3 studies (n = 323), mesdopetam was non-significant for dyskinesia severity reduction (MD –1.77 points, 95% CI –4.07 to 0.54) [Figure 1]. ON-time without troublesome dyskinesia improvement was nonsignificant (MD –0.47 h, 95% CI –1.25 to 0.31) [Figure 2]. OFF time decreased significantly (MD –0.61 h, 95% CI –1.16 to –0.07) [Figure 3]. UPDRS-IV (MD –0.15 points, 95% CI –0.37 to 0.07) and activities of daily living (SMD –0.17, 95% CI –0.39 to 0.06) were not significant. Overall, any AEs (RR 1.12, 95% CI 0.94–1.34), serious AEs (RR 0.45, 95% CI 0.14–1.42), and falls (RR 1.09, 95% CI 0.45–2.59) were comparable between groups. Fatigue occurred less frequently with mesdopetam, showing a protective effect (RR 0.23, 95% CI 0.06–0.81).
Conclusion: Mesdopetam appears safe and modestly effective for LID, with small improvements in dyskinesia severity and OFF time and no worsening of motor disability. Larger trials are warranted to clarify optimal dosing and confirm clinical benefit.
Forest plot of pooled MD of UDysRS total score.
Pooled MD of ON-time wo troublesome dyskinesia.
Forest plot of pooled MD of OFF-time.
To cite this abstract in AMA style:
A. Achuthaprasad, J. Rissardo, J. Patino, A. Caprara, A. Mcgarry, I. Walker. Efficacy and Safety of Mesdopetam (IRL790) for Levodopa Induced Dyskinesia in Parkinson’s Disease: A Meta analysis of Randomized Controlled Trials [abstract]. Mov Disord. 2026; 41 (suppl 1). https://www.mdsabstracts.org/abstract/efficacy-and-safety-of-mesdopetam-irl790-for-levodopa-induced-dyskinesia-in-parkinsons-disease-a-meta-analysis-of-randomized-controlled-trials/. Accessed October 1, 2026.« Back to 2026 International Congress
MDS Abstracts - https://www.mdsabstracts.org/abstract/efficacy-and-safety-of-mesdopetam-irl790-for-levodopa-induced-dyskinesia-in-parkinsons-disease-a-meta-analysis-of-randomized-controlled-trials/