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Kondo Y, Zhao Y, Petkau J. Identification of treatment responders based on multiple longitudinal outcomes with applications to multiple sclerosis patients. Stat Med 2017; 36:1862-1883. [PMID: 28147439 DOI: 10.1002/sim.7230] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2015] [Revised: 12/03/2016] [Accepted: 01/03/2017] [Indexed: 11/10/2022]
Abstract
Identification of treatment responders is a challenge in comparative studies where treatment efficacy is measured by multiple longitudinally collected continuous and count outcomes. Existing procedures often identify responders on the basis of only a single outcome. We propose a novel multiple longitudinal outcome mixture model that assumes that, conditionally on a cluster label, each longitudinal outcome is from a generalized linear mixed effect model. We utilize a Monte Carlo expectation-maximization algorithm to obtain the maximum likelihood estimates of our high-dimensional model and classify patients according to their estimated posterior probability of being a responder. We demonstrate the flexibility of our novel procedure on two multiple sclerosis clinical trial datasets with distinct data structures. Our simulation study shows that incorporating multiple outcomes improves the responder identification performance; this can occur even if some of the outcomes are ineffective. Our general procedure facilitates the identification of responders who are comprehensively defined by multiple outcomes from various distributions. Copyright © 2017 John Wiley & Sons, Ltd.
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Affiliation(s)
- Yumi Kondo
- Robert Bosch LLC Research and Technology Center North America, Data Mining Services and Solutions, Palo Alto, California, U.S.A
| | - Yinshan Zhao
- BC Centre for Improved Cardiovascular Health, Division of Cardiology, Department of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - John Petkau
- Department of Statistics, University of British Columbia, Vancouver, BC, Canada
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Lorscheider J, Buzzard K, Jokubaitis V, Spelman T, Havrdova E, Horakova D, Trojano M, Izquierdo G, Girard M, Duquette P, Prat A, Lugaresi A, Grand'Maison F, Grammond P, Hupperts R, Alroughani R, Sola P, Boz C, Pucci E, Lechner-Scott J, Bergamaschi R, Oreja-Guevara C, Iuliano G, Van Pesch V, Granella F, Ramo-Tello C, Spitaleri D, Petersen T, Slee M, Verheul F, Ampapa R, Amato MP, McCombe P, Vucic S, Sánchez Menoyo JL, Cristiano E, Barnett MH, Hodgkinson S, Olascoaga J, Saladino ML, Gray O, Shaw C, Moore F, Butzkueven H, Kalincik T. Defining secondary progressive multiple sclerosis. Brain 2016; 139:2395-405. [PMID: 27401521 DOI: 10.1093/brain/aww173] [Citation(s) in RCA: 239] [Impact Index Per Article: 29.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2016] [Accepted: 06/02/2016] [Indexed: 11/12/2022] Open
Abstract
A number of studies have been conducted with the onset of secondary progressive multiple sclerosis as an inclusion criterion or an outcome of interest. However, a standardized objective definition of secondary progressive multiple sclerosis has been lacking. The aim of this work was to evaluate the accuracy and feasibility of an objective definition for secondary progressive multiple sclerosis, to enable comparability of future research studies. Using MSBase, a large, prospectively acquired, global cohort study, we analysed the accuracy of 576 data-derived onset definitions for secondary progressive multiple sclerosis and first compared these to a consensus opinion of three neurologists. All definitions were then evaluated against 5-year disease outcomes post-assignment of secondary progressive multiple sclerosis: sustained disability, subsequent sustained progression, positive disability trajectory, and accumulation of severe disability. The five best performing definitions were further investigated for their timeliness and overall disability burden. A total of 17 356 patients were analysed. The best definition included a 3-strata progression magnitude in the absence of a relapse, confirmed after 3 months within the leading Functional System and required an Expanded Disability Status Scale step ≥4 and pyramidal score ≥2. It reached an accuracy of 87% compared to the consensus diagnosis. Seventy-eight per cent of the identified patients showed a positive disability trajectory and 70% reached significant disability after 5 years. The time until half of all patients were diagnosed was 32.6 years (95% confidence interval 32-33.6) after disease onset compared with the physicians' diagnosis at 36 (35-39) years. The identified patients experienced a greater disease burden [median annualized area under the disability-time curve 4.7 (quartiles 3.6, 6.0)] versus non-progressive patients [1.8 (1.2, 1.9)]. This objective definition of secondary progressive multiple sclerosis based on the Expanded Disability Status Scale and information about preceding relapses provides a tool for a reproducible, accurate and timely diagnosis that requires a very short confirmation period. If applied broadly, the definition has the potential to strengthen the design and improve comparability of clinical trials and observational studies in secondary progressive multiple sclerosis.
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Affiliation(s)
- Johannes Lorscheider
- 1 Department of Medicine, University of Melbourne, Melbourne, Australia 2 Department of Neurology, Royal Melbourne Hospital, Melbourne, Australia
| | - Katherine Buzzard
- 1 Department of Medicine, University of Melbourne, Melbourne, Australia 2 Department of Neurology, Royal Melbourne Hospital, Melbourne, Australia 3 Department of Neurology, Box Hill Hospital, Monash University, Melbourne, Australia
| | - Vilija Jokubaitis
- 1 Department of Medicine, University of Melbourne, Melbourne, Australia 2 Department of Neurology, Royal Melbourne Hospital, Melbourne, Australia
| | - Tim Spelman
- 1 Department of Medicine, University of Melbourne, Melbourne, Australia
| | - Eva Havrdova
- 4 Department of Neurology and Center of Clinical Neuroscience, Charles University in Prague, 1st Faculty of Medicine and General University Hospital in Prague, Prague, Czech Republic
| | - Dana Horakova
- 4 Department of Neurology and Center of Clinical Neuroscience, Charles University in Prague, 1st Faculty of Medicine and General University Hospital in Prague, Prague, Czech Republic
| | - Maria Trojano
- 5 Department of Basic Medical Sciences, Neuroscience and Sense Organs, University of Bari, Bari, Italy
| | | | | | | | | | - Alessandra Lugaresi
- 8 Department of Biomedical and NeuroMotor Sciences (DIBINEM), Alma Mater Studiorum - Università di Bologna, Bologna, Italy 9 IRCCS Istituto delle Scienze Neurologiche - "UOSI Riabilitazione Sclerosi Multipla" Bologna, Italy
| | | | | | | | | | - Patrizia Sola
- 14 Nuovo Ospedale Civile S.Agostino/Estense, Modena, Italy
| | - Cavit Boz
- 15 Karadeniz Technical University, Trabzon, Turkey
| | - Eugenio Pucci
- 16 Neurology Unit, ASUR Marche, AV3, Macerata, Italy
| | - Jeanette Lechner-Scott
- 17 Department of Neurology, John Hunter Hospital, Newcastle, Australia 18 School of Medicine and Public Health, University of Newcastle, Newcastle, Australia
| | | | | | | | | | | | | | | | | | - Mark Slee
- 27 Flinders University and Flinders Medical Centre, Adelaide, Australia
| | | | | | | | | | | | | | | | | | | | | | | | - Orla Gray
- 39 South Eastern Trust, Belfast, Northern Ireland
| | | | | | - Helmut Butzkueven
- 1 Department of Medicine, University of Melbourne, Melbourne, Australia 2 Department of Neurology, Royal Melbourne Hospital, Melbourne, Australia 3 Department of Neurology, Box Hill Hospital, Monash University, Melbourne, Australia
| | - Tomas Kalincik
- 1 Department of Medicine, University of Melbourne, Melbourne, Australia 2 Department of Neurology, Royal Melbourne Hospital, Melbourne, Australia
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Larochelle C, Uphaus T, Prat A, Zipp F. Secondary Progression in Multiple Sclerosis: Neuronal Exhaustion or Distinct Pathology? Trends Neurosci 2016; 39:325-339. [PMID: 26987259 DOI: 10.1016/j.tins.2016.02.001] [Citation(s) in RCA: 70] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Revised: 02/03/2016] [Accepted: 02/09/2016] [Indexed: 01/08/2023]
Abstract
Prevention of progression in neurological diseases, particularly in multiple sclerosis (MS) but also in neurodegenerative diseases, remains a significant challenge. MS patients switch from a relapsing-remitting to a progressive disease course, but it is not understood why and how this conversion occurs and why some patients never experience disease progression. Do aging and accumulation of neuronal damage induce progression, or do cognitive symptoms and accelerated grey matter (GM) atrophy point to distinct processes affecting networks? This review weighs accepted dogma against real data on the secondary progressive phase of the disease, highlighting current challenges in this important field and directions towards development of treatment strategies to slow or prevent progression of disability.
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Affiliation(s)
- Catherine Larochelle
- Department of Neurology, Focus Program Translational Neuroscience (FTN) and Immunotherapy (FZI), Rhine-Main Neuroscience Network (rmn(2)), University Medical Centre of the Johannes Gutenberg University Mainz, Germany; Neuroimmunology Unit, Department of Neuroscience, Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Université de Montréal, Montréal, Canada
| | - Timo Uphaus
- Department of Neurology, Focus Program Translational Neuroscience (FTN) and Immunotherapy (FZI), Rhine-Main Neuroscience Network (rmn(2)), University Medical Centre of the Johannes Gutenberg University Mainz, Germany
| | - Alexandre Prat
- Neuroimmunology Unit, Department of Neuroscience, Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Université de Montréal, Montréal, Canada
| | - Frauke Zipp
- Department of Neurology, Focus Program Translational Neuroscience (FTN) and Immunotherapy (FZI), Rhine-Main Neuroscience Network (rmn(2)), University Medical Centre of the Johannes Gutenberg University Mainz, Germany.
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Riddell CA, Zhao Y, Petkau J. An adaptive clinical trials procedure for a sensitive subgroup examined in the multiple sclerosis context. Stat Methods Med Res 2013; 25:1330-45. [PMID: 23592713 DOI: 10.1177/0962280213480576] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The biomarker-adaptive threshold design (BATD) allows researchers to simultaneously study the efficacy of treatment in the overall group and to investigate the relationship between a hypothesized predictive biomarker and the treatment effect on the primary outcome. It was originally developed for survival outcomes for Phase III clinical trials where the biomarker of interest is measured on a continuous scale. In this paper, generalizations of the BATD to accommodate count biomarkers and outcomes are developed and then studied in the multiple sclerosis (MS) context where the number of relapses is a commonly used outcome. Through simulation studies, we find that the BATD has increased power compared with a traditional fixed procedure under varying scenarios for which there exists a sensitive patient subgroup. As an illustration, we apply the procedure for two hypothesized markers, baseline enhancing lesion count and disease duration at baseline, using data from a previously completed trial. MS duration appears to be a predictive marker relationship for this dataset, and the procedure indicates that the treatment effect is strongest for patients who have had MS for less than 7.8 years. The procedure holds promise of enhanced statistical power when the treatment effect is greatest in a sensitive patient subgroup.
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Affiliation(s)
- Corinne A Riddell
- Department of Epidemiology, Biostatistics, and Occupational Health, McGill University, Montreal, Quebec, Canada
| | - Yinshan Zhao
- MS/MRI Research Group, University of British Columbia, Vancouver, British Columbia, Canada
| | - John Petkau
- Department of Statistics, University of British Columbia, Vancouver, British Columbia, Canada
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Abstract
Owing to its ability to depict the pathologic features of multiple sclerosis (MS) in exquisite detail, conventional magnetic resonance (MR) imaging has become an established tool in the diagnosis of this disease and in monitoring its evolution. MR imaging has been formally included in the diagnostic work-up of patients who present with a clinically isolated syndrome suggestive of MS, and ad hoc diagnostic criteria have been proposed and are updated on a regular basis. In patients with established MS and in those participating in treatment trials, examinations performed with conventional MR pulse sequences provide objective measures to monitor disease activity and progression; however, they have a limited prognostic role. This has driven the application of newer MR imaging technologies, including higher-field-strength MR units, to estimate overall MS burden and mechanisms of recovery in patients at different stages of the disease. These techniques have allowed in vivo assessment of the heterogeneity of MS pathologic features in focal lesions and in normal-appearing tissues. More recently, some of the finer details of MS, including macrophage infiltration and abnormal iron deposition, have become quantifiable with MR imaging. The utility of these modern MR techniques in clinical trial monitoring and in the assessment of the individual patient's response to treatment still need to be evaluated.
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Affiliation(s)
- Massimo Filippi
- Neuroimaging Research Unit, Division of Neuroscience, Scientific Institute and University Hospital San Raffaele, Via Olgettina 60, 20132 Milan, Italy.
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