Table 2.
Summary of the included studies
| Study ID | Study design | Registration (NCT) | Follow‐up duration (w) | Country | N randomized | Type of Analysis | Diagnostic criteria | Intervention (s) | Comparator | Outcomes assessed | Findings |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Athauda 2017 [36] | Double-blind RCT | NCT01971242 | 60 | UK | 62 | ITT | Queen Square Brain Bank criteria | S.c. exenatide 2 mg once weekly + usual care | Placebo | MDS-UPDRS part III, NMSS, PDQ-39, LED, MADRS, MDRS, and Unified Dyskinesia Rating Scale | Exenatide had positive, sustained effects on motor and non-motor scores in PD patients |
| Aviles-Olmos 2013 [37] | Single-blind RCT | NCT01174810 | 52 | UK | 44 | PP | Queen Square Brain Bank criteria | S.c. exenatide 5 μg or 10 μg BID + usual care | Usual care | MDS-UPDRS part III, part IV, part II, part I, PDQ-39, LED, MADRS, MDRS, Dyskinesia Rating Scale, and safety | Exenatide had clinically relevant improvements in PD across motor and cognitive measures |
| Malatt 2022 [16] | Double-blind RCT | NCT02953665 | 54 | US | 63 | PP | UK Brain Bank Criteria | S.c. Liraglutide 0.6–1.8 mg daily + usual care | Placebo + usual care | MDS-UPDRS part III, part IV, part II, part I, NMSS, PDQ-39, LED, MDRS, and safety | Liraglutide showed no significant effect on motor symptoms but improved non-motor symptoms, unlike placebo, which worsened them |
| McGarry 2024 [30] | Double-blind RCT | NCT04154072 | 44 | US | 255 | ITT | UK Brain Bank Criteria | S.c. NLY01 2.5 mg, NLY01 5 mg once weekly | Placebo | MDS-UPDRS part III, part II, and part I, NMSS, PDQ-39, SE-ADL, MoCA, SCOPA-Cog, and safety | NLY01 at 2.5 and 5 mg was not associated with any improvement in PD motor or non-motor features compared with placebo |
| Meissner 2024 [31] | Double-blind RCT | NCT03439943 | 52 | France | 156 | ITT | UK Brain Bank Criteria | S.c. lixisenatide 10 μg or 20 μg daily + usual care | Placebo + usual care | MDS-UPDRS part III, part IV, part II, part I, LED, and safety | Lixisenatide therapy resulted in less progression of motor disability than placebo but was associated with gastrointestinal side effects |
ITT Intention to treat, PP Per protocol, RCT randomized clinical trial, S.c. subcutaneous, N Sample size, MDR-UPDRS Movement Disorder Society-Sponsored Revision of the Unified Parkinson’s Disease, MMSE Mini-Mental State Examination, MoCA Montreal Cognitive Assessment, PDQ-39 Parkinson’s Disease Questionnaire