Clinical-genetic associations in the Prospective Huntington at Risk Observational Study (PHAROS) implications for clinical trials

The Huntington Study Group PHAROS Investigators

Research output: Contribution to journalArticle

21 Citations (Scopus)

Abstract

IMPORTANCE Identifying measures that are associated with the cytosine-adenine-guanine (CAG) expansion in individuals before diagnosis of Huntington disease (HD) has implications for designing clinical trials. OBJECTIVE To identify the earliest features associated with the motor diagnosis of HD in the Prospective Huntington at Risk Observational Study (PHAROS). DESIGN, SETTING, AND PARTICIPANTS A prospective, multicenter, longitudinal cohort study was conducted at 43 US and Canadian Huntington Study Group research sites from July 9, 1999, through December 17, 2009. Participants included 983 unaffected adults at risk for HD who had chosen to remain unaware of their mutation status. Baseline comparability between CAG expansion (≥37 repeats) and nonexpansion (<37 repeats) groups was assessed. All participants and investigators were blinded to individual CAG analysis. A repeated-measures analysis adjusting for age and sex was used to assess the divergence of the linear trend between the expanded and nonexpanded groups. Data were analyzed from April 27, 2010, to September 3, 2013. EXPOSURE Huntington disease mutation status in individuals with CAG expansion vs without CAG expansion. MAIN OUTCOMES AND MEASURES Unified Huntington's Disease Rating Scale motor (score range, 0-124; higher scores indicate greater impairment), cognitive (symbol digits modality is the total number of correct responses in 90 seconds; lower scores indicate greater impairment), behavioral (score range, 0-176; higher scores indicate greater behavioral symptoms), and functional (Total Functional Capacity score range, 0-13; lower scores indicate reduced functional ability) domains were assessed at baseline and every 9 months up to a maximum of 10 years. RESULTS Among the 983 research participants at risk for HD in the longitudinal cohort, 345 (35.1%) carried the CAG expansion and 638 (64.9%) did not. The mean (SD) duration of follow-up was 5.8 (3.0) years. At baseline, participants with expansions had more impaired motor (3.0 [4.2] vs 1.9 [2.8]; P < .001), cognitive (P < .05 for all measures except Verbal Fluency, P = .52), and behavioral domain scores (9.4 [11.4] vs 6.5 [8.5]; P < .001) but not significantly different measures of functional capacity (12.9 [0.3] vs 13.0 [0.2]; P = .23). With findings reported as mean slope (95%CI), in the longitudinal analyses, participants with CAG expansions showed significant worsening in motor (0.84 [0.73 to 0.95] vs 0.03 [-0.05 to 0.11]), cognitive (-0.54 [-0.67 to -0.40] vs 0.22 [0.12 to 0.32]), and functional (-0.08 [-0.09 to -0.06] vs -0.01 [-0.02 to 0]) measures compared with those without expansion (P < .001 for all); behavioral domain scores did not diverge significantly between groups. CONCLUSIONS AND RELEVANCE Using these prospectively accrued clinical data, relatively large treatment effects would be required to mount a randomized, placebo-controlled clinical trial involving premanifest HD individuals who carry the CAG expansion.

Original languageEnglish (US)
Pages (from-to)102-110
Number of pages9
JournalJAMA Neurology
Volume73
Issue number1
DOIs
StatePublished - Jan 1 2016

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Cytosine
Guanine
Adenine
Huntington Disease
Observational Studies
Clinical Trials
Pyridinolcarbamate
Behavioral Symptoms
Mutation
Aptitude
Research
Longitudinal Studies
Cohort Studies
Randomized Controlled Trials
Placebos
Research Personnel

ASJC Scopus subject areas

  • Clinical Neurology

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Clinical-genetic associations in the Prospective Huntington at Risk Observational Study (PHAROS) implications for clinical trials. / The Huntington Study Group PHAROS Investigators.

In: JAMA Neurology, Vol. 73, No. 1, 01.01.2016, p. 102-110.

Research output: Contribution to journalArticle

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abstract = "IMPORTANCE Identifying measures that are associated with the cytosine-adenine-guanine (CAG) expansion in individuals before diagnosis of Huntington disease (HD) has implications for designing clinical trials. OBJECTIVE To identify the earliest features associated with the motor diagnosis of HD in the Prospective Huntington at Risk Observational Study (PHAROS). DESIGN, SETTING, AND PARTICIPANTS A prospective, multicenter, longitudinal cohort study was conducted at 43 US and Canadian Huntington Study Group research sites from July 9, 1999, through December 17, 2009. Participants included 983 unaffected adults at risk for HD who had chosen to remain unaware of their mutation status. Baseline comparability between CAG expansion (≥37 repeats) and nonexpansion (<37 repeats) groups was assessed. All participants and investigators were blinded to individual CAG analysis. A repeated-measures analysis adjusting for age and sex was used to assess the divergence of the linear trend between the expanded and nonexpanded groups. Data were analyzed from April 27, 2010, to September 3, 2013. EXPOSURE Huntington disease mutation status in individuals with CAG expansion vs without CAG expansion. MAIN OUTCOMES AND MEASURES Unified Huntington's Disease Rating Scale motor (score range, 0-124; higher scores indicate greater impairment), cognitive (symbol digits modality is the total number of correct responses in 90 seconds; lower scores indicate greater impairment), behavioral (score range, 0-176; higher scores indicate greater behavioral symptoms), and functional (Total Functional Capacity score range, 0-13; lower scores indicate reduced functional ability) domains were assessed at baseline and every 9 months up to a maximum of 10 years. RESULTS Among the 983 research participants at risk for HD in the longitudinal cohort, 345 (35.1{\%}) carried the CAG expansion and 638 (64.9{\%}) did not. The mean (SD) duration of follow-up was 5.8 (3.0) years. At baseline, participants with expansions had more impaired motor (3.0 [4.2] vs 1.9 [2.8]; P < .001), cognitive (P < .05 for all measures except Verbal Fluency, P = .52), and behavioral domain scores (9.4 [11.4] vs 6.5 [8.5]; P < .001) but not significantly different measures of functional capacity (12.9 [0.3] vs 13.0 [0.2]; P = .23). With findings reported as mean slope (95{\%}CI), in the longitudinal analyses, participants with CAG expansions showed significant worsening in motor (0.84 [0.73 to 0.95] vs 0.03 [-0.05 to 0.11]), cognitive (-0.54 [-0.67 to -0.40] vs 0.22 [0.12 to 0.32]), and functional (-0.08 [-0.09 to -0.06] vs -0.01 [-0.02 to 0]) measures compared with those without expansion (P < .001 for all); behavioral domain scores did not diverge significantly between groups. CONCLUSIONS AND RELEVANCE Using these prospectively accrued clinical data, relatively large treatment effects would be required to mount a randomized, placebo-controlled clinical trial involving premanifest HD individuals who carry the CAG expansion.",
author = "{The Huntington Study Group PHAROS Investigators} and Biglan, {Kevin Michael} and Ira Shoulson and Karl Kieburtz and David Oakes and Elise Kayson and {Aileen Shinaman}, M. and Hongwei Zhao and Megan Romer and Anne Young and Steven Hersch and Jack Penney and Karen Marder and Jane Paulsen and Kimberly Quaid and Eric Siemers and Caroline Tanner and William Mallonee and Greg Suter and Richard Dubinsky and Carolyn Gray and Martha Nance and Scott Bundlie and Dawn Radtke and Sandra Kostyk and Corrine Baic and James Caress and Francis Walker and Victoria Hunt and Christine O’neill and Sylvain Chouinard and Stewart Factor and Timothy Greenamyre and Cathy Wood-Siverio and Jody Corey-Bloom and David Song and Guerry Peavy and Carol Moskowitz and Melissa Wesson and Ali Samii and Thomas Bird and Hillary Lipe and Karen Blindauer and Frederick Marshall and Carol Zimmerman and Jody Goldstein and Diana Rosas and Peter Novak and John Caviness and Charles Adler and Tatiana Foroud",
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T1 - Clinical-genetic associations in the Prospective Huntington at Risk Observational Study (PHAROS) implications for clinical trials

AU - The Huntington Study Group PHAROS Investigators

AU - Biglan, Kevin Michael

AU - Shoulson, Ira

AU - Kieburtz, Karl

AU - Oakes, David

AU - Kayson, Elise

AU - Aileen Shinaman, M.

AU - Zhao, Hongwei

AU - Romer, Megan

AU - Young, Anne

AU - Hersch, Steven

AU - Penney, Jack

AU - Marder, Karen

AU - Paulsen, Jane

AU - Quaid, Kimberly

AU - Siemers, Eric

AU - Tanner, Caroline

AU - Mallonee, William

AU - Suter, Greg

AU - Dubinsky, Richard

AU - Gray, Carolyn

AU - Nance, Martha

AU - Bundlie, Scott

AU - Radtke, Dawn

AU - Kostyk, Sandra

AU - Baic, Corrine

AU - Caress, James

AU - Walker, Francis

AU - Hunt, Victoria

AU - O’neill, Christine

AU - Chouinard, Sylvain

AU - Factor, Stewart

AU - Greenamyre, Timothy

AU - Wood-Siverio, Cathy

AU - Corey-Bloom, Jody

AU - Song, David

AU - Peavy, Guerry

AU - Moskowitz, Carol

AU - Wesson, Melissa

AU - Samii, Ali

AU - Bird, Thomas

AU - Lipe, Hillary

AU - Blindauer, Karen

AU - Marshall, Frederick

AU - Zimmerman, Carol

AU - Goldstein, Jody

AU - Rosas, Diana

AU - Novak, Peter

AU - Caviness, John

AU - Adler, Charles

AU - Foroud, Tatiana

PY - 2016/1/1

Y1 - 2016/1/1

N2 - IMPORTANCE Identifying measures that are associated with the cytosine-adenine-guanine (CAG) expansion in individuals before diagnosis of Huntington disease (HD) has implications for designing clinical trials. OBJECTIVE To identify the earliest features associated with the motor diagnosis of HD in the Prospective Huntington at Risk Observational Study (PHAROS). DESIGN, SETTING, AND PARTICIPANTS A prospective, multicenter, longitudinal cohort study was conducted at 43 US and Canadian Huntington Study Group research sites from July 9, 1999, through December 17, 2009. Participants included 983 unaffected adults at risk for HD who had chosen to remain unaware of their mutation status. Baseline comparability between CAG expansion (≥37 repeats) and nonexpansion (<37 repeats) groups was assessed. All participants and investigators were blinded to individual CAG analysis. A repeated-measures analysis adjusting for age and sex was used to assess the divergence of the linear trend between the expanded and nonexpanded groups. Data were analyzed from April 27, 2010, to September 3, 2013. EXPOSURE Huntington disease mutation status in individuals with CAG expansion vs without CAG expansion. MAIN OUTCOMES AND MEASURES Unified Huntington's Disease Rating Scale motor (score range, 0-124; higher scores indicate greater impairment), cognitive (symbol digits modality is the total number of correct responses in 90 seconds; lower scores indicate greater impairment), behavioral (score range, 0-176; higher scores indicate greater behavioral symptoms), and functional (Total Functional Capacity score range, 0-13; lower scores indicate reduced functional ability) domains were assessed at baseline and every 9 months up to a maximum of 10 years. RESULTS Among the 983 research participants at risk for HD in the longitudinal cohort, 345 (35.1%) carried the CAG expansion and 638 (64.9%) did not. The mean (SD) duration of follow-up was 5.8 (3.0) years. At baseline, participants with expansions had more impaired motor (3.0 [4.2] vs 1.9 [2.8]; P < .001), cognitive (P < .05 for all measures except Verbal Fluency, P = .52), and behavioral domain scores (9.4 [11.4] vs 6.5 [8.5]; P < .001) but not significantly different measures of functional capacity (12.9 [0.3] vs 13.0 [0.2]; P = .23). With findings reported as mean slope (95%CI), in the longitudinal analyses, participants with CAG expansions showed significant worsening in motor (0.84 [0.73 to 0.95] vs 0.03 [-0.05 to 0.11]), cognitive (-0.54 [-0.67 to -0.40] vs 0.22 [0.12 to 0.32]), and functional (-0.08 [-0.09 to -0.06] vs -0.01 [-0.02 to 0]) measures compared with those without expansion (P < .001 for all); behavioral domain scores did not diverge significantly between groups. CONCLUSIONS AND RELEVANCE Using these prospectively accrued clinical data, relatively large treatment effects would be required to mount a randomized, placebo-controlled clinical trial involving premanifest HD individuals who carry the CAG expansion.

AB - IMPORTANCE Identifying measures that are associated with the cytosine-adenine-guanine (CAG) expansion in individuals before diagnosis of Huntington disease (HD) has implications for designing clinical trials. OBJECTIVE To identify the earliest features associated with the motor diagnosis of HD in the Prospective Huntington at Risk Observational Study (PHAROS). DESIGN, SETTING, AND PARTICIPANTS A prospective, multicenter, longitudinal cohort study was conducted at 43 US and Canadian Huntington Study Group research sites from July 9, 1999, through December 17, 2009. Participants included 983 unaffected adults at risk for HD who had chosen to remain unaware of their mutation status. Baseline comparability between CAG expansion (≥37 repeats) and nonexpansion (<37 repeats) groups was assessed. All participants and investigators were blinded to individual CAG analysis. A repeated-measures analysis adjusting for age and sex was used to assess the divergence of the linear trend between the expanded and nonexpanded groups. Data were analyzed from April 27, 2010, to September 3, 2013. EXPOSURE Huntington disease mutation status in individuals with CAG expansion vs without CAG expansion. MAIN OUTCOMES AND MEASURES Unified Huntington's Disease Rating Scale motor (score range, 0-124; higher scores indicate greater impairment), cognitive (symbol digits modality is the total number of correct responses in 90 seconds; lower scores indicate greater impairment), behavioral (score range, 0-176; higher scores indicate greater behavioral symptoms), and functional (Total Functional Capacity score range, 0-13; lower scores indicate reduced functional ability) domains were assessed at baseline and every 9 months up to a maximum of 10 years. RESULTS Among the 983 research participants at risk for HD in the longitudinal cohort, 345 (35.1%) carried the CAG expansion and 638 (64.9%) did not. The mean (SD) duration of follow-up was 5.8 (3.0) years. At baseline, participants with expansions had more impaired motor (3.0 [4.2] vs 1.9 [2.8]; P < .001), cognitive (P < .05 for all measures except Verbal Fluency, P = .52), and behavioral domain scores (9.4 [11.4] vs 6.5 [8.5]; P < .001) but not significantly different measures of functional capacity (12.9 [0.3] vs 13.0 [0.2]; P = .23). With findings reported as mean slope (95%CI), in the longitudinal analyses, participants with CAG expansions showed significant worsening in motor (0.84 [0.73 to 0.95] vs 0.03 [-0.05 to 0.11]), cognitive (-0.54 [-0.67 to -0.40] vs 0.22 [0.12 to 0.32]), and functional (-0.08 [-0.09 to -0.06] vs -0.01 [-0.02 to 0]) measures compared with those without expansion (P < .001 for all); behavioral domain scores did not diverge significantly between groups. CONCLUSIONS AND RELEVANCE Using these prospectively accrued clinical data, relatively large treatment effects would be required to mount a randomized, placebo-controlled clinical trial involving premanifest HD individuals who carry the CAG expansion.

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