The safety and effectiveness of α-synuclein immunotherapy vs. placebo for the treatment of Parkinson’s disease: a systematic review and meta-analysis

Abstract

Background: There is no consensus on the efficacy of using α-synuclein as the primary immunotherapy site for Parkinson's disease (PD). The present study sought to investigate the safety and effectiveness of α-synuclein immunotherapy for treating PD. Methods:The databases of CNKI, CBM, Cochrane Library, PubMed, Web of Science, and Embase were searched for randomized controlled trials (RCTs). Cochrane Collaboration's bias assessment tool was used to assess the risk of bias in the included articles, and the included PD patients older than 18 years adopted immunotherapy. Stata 15.0 was employed for statistical analysis.Results: A total of 6 RCTs were eligible for the present study, involving 606 immunotherapy recipients (using alpha-synuclein immunotherapy) and 254 control individuals (placebo). Our meta-analysis found no statistical difference in the Movement Disorder Society-sponsored revision of the Unified Parkinson's Disease Rating Scale (MDS-UPDRS) total score [weighted mean difference (WMD): −0.72, 95% confidence interval (CI): −1.56 to 0.13, P=0.099], adverse event incidence [relative risk (RR): 1.06, 95% CI: 0.98 to 1.15, P=0.150], headache incidence (RR: 0.95, 95% CI: 0.67 to 1.34, P=0.773), and constipation incidence (RR: 1.47, 95% CI: 0.77 to 2.78, P=0.242). However, the infection rate in the immunotherapy group was higher than in the control group (RR: 2.29, 95% CI: 1.40 to 3.74, P=0.003). The above results indicate that immunotherapy is significantly different from placebo in MDS-UPDRS and adverse event incidence, but it can reduce the incidence of infection rate.Conclusions: Existing results showed that α-synuclein immunotherapy had no significant effect on PD. high-quality, multi-center, and large-scale clinical studies are desired to corroborate our findings.