Dataset Information

Tetrabenazine Versus Deutetrabenazine for Huntington's Disease: Twins or Distant Cousins?

ABSTRACT:

Background

Tetrabenazine is the only US Food and Drug Administration-approved drug for Huntington's disease, and deutetrabenazine was recently tested against placebo. A switching-trial from tetrabenazine to deutetrabenazine is underway, but no head-to-head, blinded, randomized controlled trial is planned. Using meta-analytical methodology, the authors compared these molecules.

Methods

RCTs comparing tetrabenazine or deutetrabenazine with placebo in Huntington's disease were searched. The authors assessed the Cochrane risk-of-bias tool, calculated indirect treatment comparisons, and applied the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) framework.

Results

The evidence network for this report comprised 1 tetrabenazine trial and 1 deutetrabenazine trial, both against placebo. Risk of bias was moderate in both. Participants in the tetrabenazine and deutetrabenazine trials did not differ significantly on motor scores or adverse events. Depression and somnolence scales significantly favored deutetrabenazine.

Conclusion

There is low-quality evidence that tetrabenazine and deutetrabenazine do not differ in efficacy or safety. It is important to note that these results are likely to remain the only head-to-head comparison between these 2 compounds in Huntington's disease.

SUBMITTER: Rodrigues FB

PROVIDER: S-EPMC5573977 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:BackgroundVesicular monoamine transporter 2 (VMAT2) inhibitors can improve hyperkinetic movements, and are effective treatment options for chorea of Huntington disease (HD). Tetrabenazine was assessed for treating chorea in the TETRA-HD trial, and while efficacious, there are tolerability concerns possibly due to its pharmacokinetic properties. Deutetrabenazine is a novel VMAT2 inhibitor that contains deuterium, which extends active metabolite half-lives and minimizes drug concentration fluctuations. In the First-HD trial, deutetrabenazine was efficacious in treating chorea and was generally well tolerated. In the absence of a head-to-head trial, we performed an indirect treatment comparison (ITC) of the tolerability of deutetrabenazine and tetrabenazine for the treatment of HD-associated chorea, as observed in the First-HD and TETRA-HD trials, using well-established comparison methods.MethodsData from the Phase III, 12-week, parallel-group, clinical trials First-HD (N = 90) and TETRA-HD (N = 84) were used to conduct an ITC of the tolerability of deutetrabenazine versus tetrabenazine using two anchor-based methods: Bucher comparison for unadjusted ITCs, and matching indirect comparison for adjusted ITCs. Overall adverse events (AEs; mild, moderate, and severe), serious AEs, specific AEs occurring in ≥10% of patients, and discontinuations (all-cause and AE-related) were included in the analysis. The risk differences of these outcomes for deutetrabenazine and tetrabenazine were estimated by subtracting the applicable placebo-adjusted risk in First-HD from that of TETRA-HD. Sensitivity analyses were performed to address differences between trials, and p-values were obtained from z-tests.ResultsCompared with tetrabenazine, deutetrabenazine was associated with a significantly lower risk of moderate to severe AEs and neuropsychiatric AEs including agitation, akathisia, depression, depression/agitated depression, drowsiness/somnolence, insomnia, and parkinsonism in both adjusted and unadjusted analyses (p < 0.05 for each). Deutetrabenazine had a significantly lower rate of dose reduction or dose reduction/suspension in the unadjusted and adjusted analyses (p < 0.001 for each). Deutetrabenazine resulted in numerically more mild AEs, such as diarrhea and coughing; however, these results were not statistically significant.ConclusionsThis indirect treatment comparison demonstrates that for the treatment of HD chorea, deutetrabenazine has a favorable tolerability profile compared to tetrabenazine.Trial registrationClinicalTrials.gov NCT01795859 and NCT00219804.

Project description:ImportanceTetrabenazine is efficacious for chorea control; however, tolerability concerns exist. Deutetrabenazine, a novel molecule that reduces chorea, was well tolerated in a double-blind, placebo-controlled study.ObjectivesTo evaluate the safety and explore the efficacy of conversion from tetrabenazine to deutetrabenazine in patients with chorea associated with Huntington disease (HD).Design, setting, and participantsIn this ongoing, open-label, single-arm study that started on December 21, 2013, 37 patients at 13 Huntington Study Group sites in the United States and Australia who were taking stable doses of tetrabenazine that provided a therapeutic benefit were switched overnight to deutetrabenazine therapy. After week 1, the deutetrabenazine dose was titrated on a weekly basis for optimal chorea control.InterventionsDeutetrabenazine administration at a dosage thought to provide comparable systemic exposure to the active metabolites of the prior, stable tetrabenazine regimen.Main outcomes and measuresSafety measures included adverse events (AEs), clinical laboratory tests, vital signs, electrocardiograms, and validated scales. Changes in the Unified Huntington's Disease Rating Scale total maximal chorea score and total motor score were efficacy end points.ResultsOf the 53 patients with HD screened for the study, 37 ambulatory patients with manifest HD (mean [SD] age, 52.4 [11.5] years; 22 [59%] male and 15 [41%] female; 36 white [97.3%]) were enrolled. Deutetrabenazine was generally well tolerated, with low rates of neuropsychiatric AEs. Safety scales did not reveal subclinical toxicity with deutetrabenazine treatment. Rates of dose reduction or suspension attributable to AEs were also low. Chorea control, as measured by the total maximal chorea score, was maintained at week 1 and significantly improved at week 8 (mean [SD] change from baseline, 2.1 [3.2]; P < .001).Conclusions and relevanceIn patients with chorea, overnight conversion to deutetrabenazine therapy provided a favorable safety profile and effectively maintained chorea control.