2 results
Evaluation of the Safety of Deutetrabenazine at Higher Doses to Treat Chorea in Huntington’s Disease
- Samuel Frank, Christina Vaughan, David Stamler, David Oakes, Mat D. Davis, Nicholas Gross, Mark Forrest Gordon, Juha-Matti Savola, Maria Wieman, Shirley Eberly, Elise Kayson, Jacquelyn Whaley, Jody Goldstein, Claudia M. Testa, on behalf of the Huntington Study Group ARC-HD Investigators
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- Journal:
- CNS Spectrums / Volume 26 / Issue 2 / April 2021
- Published online by Cambridge University Press:
- 10 May 2021, pp. 162-163
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Background
In the First-HD pivotal trial, the maximum deutetrabenazine dose evaluated to treat chorea associated with Huntington’s disease (HD chorea) was 48 mg/d, which is the approved maximum dose for this population. In ARC-HD, an open-label extension study evaluating the long-term efficacy and safety of deutetrabenazine to treat HD chorea, dosage ranged from 6 mg/d to 72 mg/d, with doses ≥12 mg/d administered twice daily. Doses in ARC-HD were increased by 6 mg/d per week in a response-driven manner based on efficacy and tolerability until 48 mg/d (Week 8). At the investigator’s discretion, further increases were permitted by 12 mg/d per week to a maximum of 72 mg/d. This post-hoc analysis evaluates the safety and tolerability of deutetrabenazine >48 mg/d compared to ≤48 mg/d to treat HD chorea in ARC-HD.
MethodsPatient counts and safety assessments were attributed to patients when they received a dose of either ≤48 mg/d or >48 mg/d. For 9 selected adverse events (AEs), we compared AE rates adjusted for duration of drug exposure (as number of AEs/year) at ≤48 mg/d or >48 mg/d. The AE rates were determined after titration when participants were on stable doses of deutetrabenazine.
ResultsAll 113 patients were exposed to doses ≤48 mg/d (177.1 patient-years) and 49 patients were ever exposed to doses >48 mg/d (74.1 patient-years). In patients taking deutetrabenazine >48 mg/d compared to ≤48 mg/d after the titration period, there were no apparent differences in exposure-adjusted AE rates.
ConclusionsBased on clinical experience, some patients with HD may benefit from doses higher than 48 mg/d to adequately control chorea. These doses were tolerated without apparent increase in the exposure-adjusted rates of selected AEs after titration. This analysis does not address the occurrence of other AEs or whether adequate efficacy was achieved at lower doses, factors that may have influenced dose increases.
FundingTeva Pharmaceutical Industries Ltd., Petach Tikva, Israel
Long-Term Efficacy and Safety of Deutetrabenazine for Chorea in Huntington’s Disease: Results From the ARC-HD Open-label Study
- Samuel Frank, Claudia M. Testa, David Stamler, Elise Kayson, David Oakes, Christina Vaughan, Jody Goldstein, Jacquelyn Whaley, Mat D. Davis, Mark Forrest Gordon, Juha-Matti Savola, on behalf of the Huntington Study Group ARC-HD Investigators
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- Journal:
- CNS Spectrums / Volume 26 / Issue 2 / April 2021
- Published online by Cambridge University Press:
- 10 May 2021, pp. 164-165
-
- Article
-
- You have access Access
- Export citation
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Background
Chorea is a prominent motor dysfunction in Huntington’s disease (HD). Deutetrabenazine, a vesicular monoamine transporter 2 (VMAT2) inhibitor, is FDA-approved for the treatment of chorea in HD. In the pivotal, 12-week First-HD trial, deutetrabenazine treatment reduced the Unified Huntington’s Disease Rating Scale (UHDRS) total maximal chorea (TMC) score versus placebo. ARC-HD, an open-label extension study, evaluated long-term safety and efficacy of deutetrabenazine dosed in a response-driven manner for treatment of HD chorea.
MethodsPatients who completed First-HD (Rollover) and patients who converted overnight from a stable dose of tetrabenazine (Switch) were included. Safety was assessed over the entire treatment period; exposure-adjusted incidence rates (EAIRs; adverse events [AEs] per person-year) were calculated. A stable, post-titration time point of 8 weeks was chosen for efficacy analyses.
ResultsOf 119 patients enrolled (Rollover, n=82; Switch, n=37), 100 (84%) completed ≥1 year of treatment (mean [SD] follow-up, 119 [48] weeks). End of study EAIRs for patients in the Rollover and Switch cohorts, respectively, were: any AE, 2.6 and 4.3; serious AEs, 0.13 and 0.14; AEs leading to dose suspension, 0.05 and 0.04. Overall, 68% and 73% of patients in Rollover and Switch, respectively, experienced a study drug–related AE. Most common AEs possibly related to study drug were somnolence (17% Rollover; 27% Switch), depression (23%; 19%), anxiety (9%; 11%), insomnia (10%; 8%), and akathisia (9%; 14%). Rates of AEs of interest include suicidality (9%; 3%) and parkinsonism (6%; 11%). In both cohorts, mean UHDRS TMC score and total motor score (TMS) decreased from baseline to Week 8; mean (SD) change in TMC score (units) was –4.4 (3.1) and –2.1 (3.3) and change in TMS was –7.1 (7.3) and –2.4 (8.7) in Rollover and Switch, respectively. While receiving stable dosing from Week 8 to 132 (or end of treatment), patients showed minimal change in TMC score (0.9 [5.0]), but TMS increased compared to Week 8 (9.0 [11.3]). Upon drug withdrawal, there were no remarkable AEs and TMC scores increased 4.4 (3.7) units compared to end of treatment.
ConclusionsThe type and severity of AEs observed in long-term deutetrabenazine exposure are consistent with the previous study. Efficacy in reducing chorea persisted over time. There was no unexpected worsening of HD or chorea associated with HD upon deutetrabenazine withdrawal.
FundingTeva Pharmaceutical Industries Ltd., Petach Tikva, Israel