The Safety of Deutetrabenazine for Chorea in Huntington Disease: An Open-Label Extension Study
Samuel Frank, Claudia Testa, Mary Edmondson, Jody Goldstein, Elise Kayson, Blair R. Leavitt, David Oakes, Christine J. O’Neill, Christina Vaughan, Jacquelyn Whaley, Nicholas J. Gross, Mark Forrest Gordon, Juha‐Matti Savola, The Huntington Study Group/ARC-HD Investigators and Coordinators, Samuel Frank, Claudia Testa, David Stamler, Elise Kayson, Mary Edmondson, Blair R. Leavitt, David Oakes, Christine J. O’Neill, Christina Vaughan, Jody Goldstein, Margaret Bockus, Stephanie Leyva, Victoria Snively, Jacquelyn Whaley, Cynthia Wong, William Mallonee, Gregory Suter, Joseph Jankovic, Joohi Jimenez‐Shahed, Christine Hunter, Daniel O. Claassen, Lauren West, O Román, Victor Sung, Jenna Smith, Ronda Clouse, Marie Saint‐Hilaire, Denyse Turpin, Raymond James, Ramon L. Rodriguez, Kyle Rizer, Karen E. Anderson, Hope Heller, Alexis Ahmad, Susan R. Criswell, Brad A. Racette, Frederick C. Nucifora, Gregory Churchill, MaryJane Ong, Tilak Mendis, Neila Mendis, Carlos Singer, Jane S. Paulsen, Jane Kerr, Richard Dubinsky, Carolyn Steele Gray, Stewart A. Factor, Elaine Sperin, Eric Molho, Sharon Evans, Breanna Nickels, Courtney Bergen, Jessica Jaynes, Christina Reeves, Vicki Segro, Ali Samii, Emily Christopher, Debra del Castillo, Sylvain Chouinard, Peggy Perry-Trice, Sherali Esmail, Wai Lun Alan Fung, Clare Gibbons, Amy Colcher, Cory Hackmyer, Andrew McGarry, Kevin J. Klos, Mark Gudesblatt, Daniel Schneider, Rohit Dhall, Edith Simpson, Joanne Wojcieszek, Andrea Hurt, Kathrin LaFaver, Annette Robinson, Fredy J. Revilla, Andrew P. Duker, Erin Neefus, Hilary Wilson, David Shprecher, Tyler Hohnholt, Paola Wall, James T. Boyd, Emily Houston, Eric S. Farbman, Shamine Poynor
Abstract
BACKGROUND: Deutetrabenazine is approved in the USA, China, Australia, Israel, Brazil, and South Korea for the treatment of chorea associated with Huntington disease. OBJECTIVE: We aimed to evaluate the long-term safety and tolerability of deutetrabenazine for the treatment of Huntington disease. METHODS: This open-label, single-arm, multi-center study included patients who completed a double-blind study (Rollover) and patients who converted overnight from a stable tetrabenazine dose (Switch). Exposure-adjusted incidence rates (adverse events per person-year) were calculated. Efficacy was analyzed using a stable post-titration timepoint (8 weeks). Changes in the Unified Huntington's Disease Rating Scale total motor score and total maximal chorea score from baseline to week 8, as well as those from week 8 to week 145 (or the last visit on the study drug if that occurred earlier), were evaluated as both efficacy and safety endpoints during the study. RESULTS: Of 119 patients (Rollover, n = 82; Switch, n = 37), 100 (84%) completed ≥ 1 year of treatment. End-of-study exposure-adjusted incidence rates for adverse events in Rollover and Switch, respectively, were: any, 2.57 and 4.02; serious, 0.11 and 0.14; leading to dose suspension, 0.05 and 0.04. Common adverse events (≥ 4% either cohort) included somnolence (Rollover, 20%; Switch, 30%), depression (32%; 22%), anxiety (27%; 35%), insomnia (23%; 16%), and akathisia (6%; 11%). Adverse events of interest included suicidality (9%; 5%) and parkinsonism (4%; 8%). Mean dose at week 8 was 38.1 mg (Rollover) and 36.5 mg (Switch). Mean dose across cohorts after titration was 37.6 mg; at the final visit, mean dose across cohorts was 45.7 mg. Patients showed minimal change in the Unified Huntington's Disease Rating Scale total maximal chorea scores with stable dosing from weeks 8-145 or at the end of treatment, but total motor score increased versus week 8 (mean change [standard deviation]: 8.2 [11.9]). There were no unexpected adverse events upon drug withdrawal, and mean (standard deviation) total maximal chorea scores increased 4.7 (4.6) units from week 8 to 1-week follow-up. CONCLUSIONS: Adverse events observed with long-term deutetrabenazine exposure were consistent with previous studies. Reductions in chorea persisted over time. Upon treatment cessation, there was no unexpected worsening of chorea. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT01897896.