Background: Deutetrabenazine, an inhibitor of vesicular monoamine transporter type 2 (VMAT2) depletes presynaptic dopamine and is useful in the treatment of hyperkinetic movement disorders. This study explored the safety, tolerability, and preliminary efficacy of deutetrabenazine in adolescents with moderate-to-severe tics associated with Tourette syndrome (TS).
Methods: In this open-label study of 12-18-year-old patients with TS-related tics, deutetrabenazine was titrated up to 36 mg/day over 6 weeks to adequately suppress tics without bothersome adverse effects (AEs), followed by maintenance at optimal dose for 2 weeks. An independent blinded rater assessed tic severity using the Yale Global Tic Severity Scale (YGTSS), which was the primary outcome measure. Secondary outcome measures included the TS Clinical Global Impression (TS-CGI) and TS Patient Global Impression of Change (TS-PGIC).
Results: Twenty-three enrolled patients received deutetrabenazine and had at least 1 post-baseline YGTSS assessment. The mean (SD [standard deviation]) baseline YGTSS Total Tic Severity Score (TTS) was 31.6 (7.9) and had decreased by 11.6 (8.2) points at week 8, a 37.6% reduction in tic severity (p<0.0001). The TS-CGI score improved by 1.2 (0.81) points (p<0.0001) and the TS-PGIC results at week 8 indicated that 76% of patients were much improved or very much improved compared with baseline. The mean (SD) daily deutetrabenazine dose at week 8 was 32.1 (6.6) mg (range 18-36 mg). One week after withdrawal of deutetrabenazine, the TTS scores increased by 5.6 (8.4) points, providing confirmation of the drug effect. No serious or severe adverse events were reported.
Discussion: The results of this open-label 8-week study suggest that deutetrabenazine is safe and associated with improvement in tic severity in adolescents with TS and troublesome tics.
Keywords: SD-809; Tics; Tourette syndrome; VMAT2; deutetrabenazine.