Safety and Efficacy of Ecopipam in Patients with Tourette Syndrome: A Systematic Review and Meta-analysis

Background and Objectives Ecopipam is a selective antagonist of the dopamine D1 receptor, and its efficacy and safety have recently been explored in several clinical trials involving patients with Tourette syndrome (TS). The objectives of this systematic review were to determine the pooled estimate for efficacy [in terms of reduction in tic Yale Global Tic Severity Scale (YGTSS) scores] and safety of oral ecopipam in subjects with TS. Methods All clinical trials that explored the efficacy and/or safety of ecopipam in patients with TS were included to determine the pooled estimate for change in YGTSS, Clinical Global Impression (CGI)-TS, and the severity of comorbid attention-deficit hyperactive disorder (ADHD), obsessive compulsion disorder (OCD), and depressive symptoms, as well as the nature and frequency of adverse effects. Case-series, retrospective studies, and case reports were excluded. Databases, such as PUBMED, EMBASE, Cochrane Central Register of Controlled Trials, and SCOPUS were searched to identify these trials using suitable combination of MESH terms/keywords on 15 June 2024. ROB 2.0 and ROBINS-I tool were used to assess the risk of bias in included randomized-controlled trials (RCTs) and non-randomized intervention studies, respectively, and the GRADE system to determine the certainty of the collated evidence. Results A total of 96 records were identified in the database search and 31 records were screened after removing duplicates. After excluding 23 irrelevant records, the full-text review included 8 records. Finally, six publications from three completed clinical trials (two RCTs, with one having an open-label extension) and one ongoing clinical trial were included. A total of 251 participants were included. The pooled estimate for mean change in YGTSS-TTS from baseline to the completion of the randomization period was statistically better in the ecopipam group compared with the placebo group [mean difference: - 3.0, 95% (confidence interval (CI) - 4.2 to - 1.9, I-2 = 55%, p < 0.0001]. The ecopipam group also fared statistically better in terms of YGTSS-motor tic score, phonic tic score, as well as CGI-TS-S (p < 0.0001). Changes in depressive and obsessive-compulsive symptoms were comparable in both groups, as well as the incidence of adverse effects. Conclusions Ecopipam is effective in reducing the severity of tics in subjects with TS and has a good safety profile. However, only a limited number of studies were included in the review, with some having small sample sizes and short duration of follow-up.