ObjectiveTo identify preferred neurofilament assays and clinically validate serum neurofilament l... more ObjectiveTo identify preferred neurofilament assays and clinically validate serum neurofilament light (NfL) and phosphorylated neurofilament heavy (pNfH) as prognostic and potential pharmacodynamic biomarkers relevant to amyotrophic lateral sclerosis (ALS) therapy development.MethodsIn this prospective, multicenter, longitudinal observational study of patients with ALS (n = 229), primary lateral sclerosis (n = 20), and progressive muscular atrophy (n = 11), biological specimens were collected, processed, and stored according to strict standard operating procedures (SOPs). Neurofilament assays were performed in a blinded manner by independent contract research organizations.ResultsFor serum NfL and pNfH measured using the Simoa assay, there were no missing data (i.e., technical replicates below the lower limit of detection were not encountered). For the Iron Horse and Euroimmun pNfH assays, such missingness was encountered in ∼4% and ∼10% of serum samples, respectively. Mean coeffici...
Background The efficacy and tolerability of eculizumab were assessed in REGAIN, a 26-week, phase ... more Background The efficacy and tolerability of eculizumab were assessed in REGAIN, a 26-week, phase 3, randomized, double-blind, placebo-controlled study in anti-acetylcholine receptor antibody-positive (AChR+) refractory generalized myasthenia gravis (gMG), and its open-label extension. Methods Attainment of ‘minimal symptom expression’ was evaluated using patient-reported outcome measures of gMG symptoms [MG activities of daily living scale (MG-ADL), 15-item MG quality of life questionnaire (MG-QOL15)] at the completion of REGAIN and during the open-label extension. ‘Minimal symptom expression’ was defined as MG-ADL total score of 0–1 or MG-QOL15 total score of 0–3. Results At REGAIN week 26, more eculizumab-treated patients achieved ‘minimal symptom expression’ versus placebo [MG-ADL: 21.4% vs 1.7%; difference 19.8%; 95% confidence interval (CI) 8.5, 31.0; p = 0.0007; MG-QOL15: 16.1% vs 1.7%; difference 14.4%; 95% CI 4.3, 24.6; p = 0.0069]. During the open-label extension, the propo...
Our research aim was to develop a novel clinimetric scale sensitive enough to detect disease prog... more Our research aim was to develop a novel clinimetric scale sensitive enough to detect disease progression in primary lateral sclerosis (PLS).
Annals of the New York Academy of Sciences, Jan 24, 2017
Recently competed clinical trials of therapeutics for myasthenia gravis have varied widely in des... more Recently competed clinical trials of therapeutics for myasthenia gravis have varied widely in design, but also perhaps in less explicit ways. We explore ways in which these design characteristics may have influenced recruitment and results, as well as the implications for forthcoming studies. Trial eligibility criteria may inadvertently select for incident versus prevalent cases or patients with relatively mild versus more severe disease. Trial enrichment with patients who have relatively mild disease may limit the sensitivity of the trial to detect a therapeutic effect. Enrichment for patients with more severe disease may introduce confounds caused by regression toward the mean. Overly narrow eligibility may limit the generalizability of results. An exclusive focus on incident cases may hamper recruitment, as may many other factors, such as access to the experimental therapeutic treatment outside of the trial or following completion of the double-blind treatment period. We illustra...
ObjectivesTo develop and validate an international set of classification criteria for primary Sjö... more ObjectivesTo develop and validate an international set of classification criteria for primary Sjögren's syndrome (SS) using guidelines from the American College of Rheumatology (ACR) and the European League Against Rheumatism (EULAR). These criteria were developed for use in individuals with signs and/or symptoms suggestive of SS.MethodsWe assigned preliminary importance weights to a consensus list of candidate criteria items, using multi-criteria decision analysis. We tested and adapted the resulting draft criteria using existing cohort data on primary SS cases and non-SS controls, with case/non-case status derived from expert clinical judgement. We then validated the performance of the classification criteria in a separate cohort of patients.ResultsThe final classification criteria are based on the weighted sum of five items: anti-SSA/Ro antibody positivity and focal lymphocytic sialadenitis with a focus score of ≥1 foci/4 mm2, each scoring 3; an abnormal Ocular Staining Score...
Dystrophinopathy is a rare, severe muscle disorder, and nonsense mutations are found in 13% of ca... more Dystrophinopathy is a rare, severe muscle disorder, and nonsense mutations are found in 13% of cases. Ataluren was developed to enable ribosomal readthrough of premature stop codons in nonsense mutation (nm) genetic disorders. Randomized, double-blind, placebo-controlled study; males ≥ 5 years with nm-dystrophinopathy received study drug orally 3 times daily, ataluren 10, 10, 20 mg/kg (N=57); ataluren 20, 20, 40 mg/kg (N=60); or placebo (N=57) for 48 weeks. The primary endpoint was change in 6-Minute Walk Distance (6MWD) at Week 48. Ataluren was generally well tolerated. The primary endpoint favored ataluren 10, 10, 20 mg/kg versus placebo; the week 48 6MWD Δ=31.3 meters, post hoc P=0.056. Secondary endpoints (timed function tests) showed meaningful differences between ataluren 10, 10, 20 mg/kg, and placebo. As the first investigational new drug targeting the underlying cause of nm-dystrophinopathy, ataluren offers promise as a treatment for this orphan genetic disorder with high un...
Neuropathic disorders encompass those that affect the neuron's cell body or neuropathies,... more Neuropathic disorders encompass those that affect the neuron's cell body or neuropathies, those affecting the peripheral process, or peripheral neuropathies. The peripheral neuropathies can be broadly subdivided into the myelinopathies and axonopathies. These conditions can be hereditary or acquired. Each of these disorders has distinct clinical features that enable neurologists to recognize the various patterns of presentation. Once a particular pattern is established, further laboratory studies including electrophysiologic testing, nerve biopsy, and blood and cerebrospinal fluid examination can be performed to confirm the clinical impression. Therapy is available in some to correct the underlying disease state or at least to improve symptoms.
Although its overall prevalence is decreasing, leprosy continues to be a major cause of neuropath... more Although its overall prevalence is decreasing, leprosy continues to be a major cause of neuropathy worldwide. In the United States, it is a relatively rare condition. As a result, physicians may lack familiarity with the disease, which can delay diagnosis and treatment. Leprous neuropathy is characterized by involvement of dermal nerves and superficial peripheral nerve trunks in cooler body regions. A continuing pattern of immigration from endemic areas may allow practicing neurologists in any region of the country to become involved in the care of patients with leprosy. The diagnosis should be considered in patients from endemic regions presenting with peripheral neuropathy with or without skin lesions. Readily available diagnostic testing, access to subspecialists, and modern transportation and information systems through the satellite clinics of the Hansen's Disease center serve as major advantages for the management of leprosy patients in the United States.
ObjectiveTo identify preferred neurofilament assays and clinically validate serum neurofilament l... more ObjectiveTo identify preferred neurofilament assays and clinically validate serum neurofilament light (NfL) and phosphorylated neurofilament heavy (pNfH) as prognostic and potential pharmacodynamic biomarkers relevant to amyotrophic lateral sclerosis (ALS) therapy development.MethodsIn this prospective, multicenter, longitudinal observational study of patients with ALS (n = 229), primary lateral sclerosis (n = 20), and progressive muscular atrophy (n = 11), biological specimens were collected, processed, and stored according to strict standard operating procedures (SOPs). Neurofilament assays were performed in a blinded manner by independent contract research organizations.ResultsFor serum NfL and pNfH measured using the Simoa assay, there were no missing data (i.e., technical replicates below the lower limit of detection were not encountered). For the Iron Horse and Euroimmun pNfH assays, such missingness was encountered in ∼4% and ∼10% of serum samples, respectively. Mean coeffici...
Background The efficacy and tolerability of eculizumab were assessed in REGAIN, a 26-week, phase ... more Background The efficacy and tolerability of eculizumab were assessed in REGAIN, a 26-week, phase 3, randomized, double-blind, placebo-controlled study in anti-acetylcholine receptor antibody-positive (AChR+) refractory generalized myasthenia gravis (gMG), and its open-label extension. Methods Attainment of ‘minimal symptom expression’ was evaluated using patient-reported outcome measures of gMG symptoms [MG activities of daily living scale (MG-ADL), 15-item MG quality of life questionnaire (MG-QOL15)] at the completion of REGAIN and during the open-label extension. ‘Minimal symptom expression’ was defined as MG-ADL total score of 0–1 or MG-QOL15 total score of 0–3. Results At REGAIN week 26, more eculizumab-treated patients achieved ‘minimal symptom expression’ versus placebo [MG-ADL: 21.4% vs 1.7%; difference 19.8%; 95% confidence interval (CI) 8.5, 31.0; p = 0.0007; MG-QOL15: 16.1% vs 1.7%; difference 14.4%; 95% CI 4.3, 24.6; p = 0.0069]. During the open-label extension, the propo...
Our research aim was to develop a novel clinimetric scale sensitive enough to detect disease prog... more Our research aim was to develop a novel clinimetric scale sensitive enough to detect disease progression in primary lateral sclerosis (PLS).
Annals of the New York Academy of Sciences, Jan 24, 2017
Recently competed clinical trials of therapeutics for myasthenia gravis have varied widely in des... more Recently competed clinical trials of therapeutics for myasthenia gravis have varied widely in design, but also perhaps in less explicit ways. We explore ways in which these design characteristics may have influenced recruitment and results, as well as the implications for forthcoming studies. Trial eligibility criteria may inadvertently select for incident versus prevalent cases or patients with relatively mild versus more severe disease. Trial enrichment with patients who have relatively mild disease may limit the sensitivity of the trial to detect a therapeutic effect. Enrichment for patients with more severe disease may introduce confounds caused by regression toward the mean. Overly narrow eligibility may limit the generalizability of results. An exclusive focus on incident cases may hamper recruitment, as may many other factors, such as access to the experimental therapeutic treatment outside of the trial or following completion of the double-blind treatment period. We illustra...
ObjectivesTo develop and validate an international set of classification criteria for primary Sjö... more ObjectivesTo develop and validate an international set of classification criteria for primary Sjögren's syndrome (SS) using guidelines from the American College of Rheumatology (ACR) and the European League Against Rheumatism (EULAR). These criteria were developed for use in individuals with signs and/or symptoms suggestive of SS.MethodsWe assigned preliminary importance weights to a consensus list of candidate criteria items, using multi-criteria decision analysis. We tested and adapted the resulting draft criteria using existing cohort data on primary SS cases and non-SS controls, with case/non-case status derived from expert clinical judgement. We then validated the performance of the classification criteria in a separate cohort of patients.ResultsThe final classification criteria are based on the weighted sum of five items: anti-SSA/Ro antibody positivity and focal lymphocytic sialadenitis with a focus score of ≥1 foci/4 mm2, each scoring 3; an abnormal Ocular Staining Score...
Dystrophinopathy is a rare, severe muscle disorder, and nonsense mutations are found in 13% of ca... more Dystrophinopathy is a rare, severe muscle disorder, and nonsense mutations are found in 13% of cases. Ataluren was developed to enable ribosomal readthrough of premature stop codons in nonsense mutation (nm) genetic disorders. Randomized, double-blind, placebo-controlled study; males ≥ 5 years with nm-dystrophinopathy received study drug orally 3 times daily, ataluren 10, 10, 20 mg/kg (N=57); ataluren 20, 20, 40 mg/kg (N=60); or placebo (N=57) for 48 weeks. The primary endpoint was change in 6-Minute Walk Distance (6MWD) at Week 48. Ataluren was generally well tolerated. The primary endpoint favored ataluren 10, 10, 20 mg/kg versus placebo; the week 48 6MWD Δ=31.3 meters, post hoc P=0.056. Secondary endpoints (timed function tests) showed meaningful differences between ataluren 10, 10, 20 mg/kg, and placebo. As the first investigational new drug targeting the underlying cause of nm-dystrophinopathy, ataluren offers promise as a treatment for this orphan genetic disorder with high un...
Neuropathic disorders encompass those that affect the neuron's cell body or neuropathies,... more Neuropathic disorders encompass those that affect the neuron's cell body or neuropathies, those affecting the peripheral process, or peripheral neuropathies. The peripheral neuropathies can be broadly subdivided into the myelinopathies and axonopathies. These conditions can be hereditary or acquired. Each of these disorders has distinct clinical features that enable neurologists to recognize the various patterns of presentation. Once a particular pattern is established, further laboratory studies including electrophysiologic testing, nerve biopsy, and blood and cerebrospinal fluid examination can be performed to confirm the clinical impression. Therapy is available in some to correct the underlying disease state or at least to improve symptoms.
Although its overall prevalence is decreasing, leprosy continues to be a major cause of neuropath... more Although its overall prevalence is decreasing, leprosy continues to be a major cause of neuropathy worldwide. In the United States, it is a relatively rare condition. As a result, physicians may lack familiarity with the disease, which can delay diagnosis and treatment. Leprous neuropathy is characterized by involvement of dermal nerves and superficial peripheral nerve trunks in cooler body regions. A continuing pattern of immigration from endemic areas may allow practicing neurologists in any region of the country to become involved in the care of patients with leprosy. The diagnosis should be considered in patients from endemic regions presenting with peripheral neuropathy with or without skin lesions. Readily available diagnostic testing, access to subspecialists, and modern transportation and information systems through the satellite clinics of the Hansen's Disease center serve as major advantages for the management of leprosy patients in the United States.
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Papers by Richard Barohn