Identification of the efficacy and safety of apomorphine in the treatment of Parkinson’s disease via meta-analysis

Background The majority of Parkinson’s disease (PD) patients experience motor fluctuations and dyskinesias as the disease progresses. Apomorphine has been used as an acute treatment for off episodes in PD in recent years. However, conclusions from clinical studies regarding the efficacy and safety of apomorphine have been inconsistent, particularly prior to the publication of larger pivotal trials. Objectives To systematically evaluate the efficacy and safety of apomorphine in PD patients, a meta-analysis of randomized controlled trials (RCTs) and single-armed studies were performed. Methods PubMed, Web of Science, Embase, and Cochrane databases were searched to identify all related studies. Outcomes of interest were changes in Parkinson’s Disease Rating Scale Part III (UPDRS-III) scores, ON and OFF time, and adverse events (AES). Results In this meta-analysis, 20 clinical studies were included ( n = 1262 patients): seventeen RCTs, and three single-armed studies. The pooled results from RCTs indicate that apomorphine treatment significantly improved patients’ motor function compared to placebo. Specifically, there was a mean difference (MD) of -12.28 (95% CI: [-17.98, -6.59]) in UPDRS-III scores. Patients treated with apomorphine experienced a reduced off time (MD = -10.70, 95% CI: [-20.33, -1.06]), indicating a shorter duration of the “off” state. Furthermore, the combined results indicated a conversion rate from off to on state in PD patients treated with apomorphine of 0.79 (95% CI 0.67–0.89). In terms of safety analyses from single-armed studies, apomorphine treatment was associated with several AES, including nausea, drowsiness, vomiting, dizziness, and excessive sweating. However, the findings suggest that the incidence of AES was relatively low during treatment with apomorphine. Conclusion The meta-analysis results indicate that apomorphine effectively improves dyskinesia and motor fluctuations in patients with PD. Furthermore, the incidence of AES was relatively low during treatment with apomorphine.