Summary Background Amyotrophic lateral sclerosis shares characteristics with some cancers, such as onset being more common in later life, progression usually being rapid, the disease affecting a ...particular cell type, and showing complex inheritance. We used a model originally applied to cancer epidemiology to investigate the hypothesis that amyotrophic lateral sclerosis is a multistep process. Methods We generated incidence data by age and sex from amyotrophic lateral sclerosis population registers in Ireland (registration dates 1995–2012), the Netherlands (2006–12), Italy (1995–2004), Scotland (1989–98), and England (2002–09), and calculated age and sex-adjusted incidences for each register. We regressed the log of age-specific incidence against the log of age with least squares regression. We did the analyses within each register, and also did a combined analysis, adjusting for register. Findings We identified 6274 cases of amyotrophic lateral sclerosis from a catchment population of about 34 million people. We noted a linear relationship between log incidence and log age in all five registers: England r2 =0·95, Ireland r2 =0·99, Italy r2 =0·95, the Netherlands r2 =0·99, and Scotland r2 =0·97; overall r2 =0·99. All five registers gave similar estimates of the linear slope ranging from 4·5 to 5·1, with overlapping confidence intervals. The combination of all five registers gave an overall slope of 4·8 (95% CI 4·5–5·0), with similar estimates for men (4·6, 4·3–4·9) and women (5·0, 4·5–5·5). Interpretation A linear relationship between the log incidence and log age of onset of amyotrophic lateral sclerosis is consistent with a multistage model of disease. The slope estimate suggests that amyotrophic lateral sclerosis is a six-step process. Identification of these steps could lead to preventive and therapeutic avenues. Funding UK Medical Research Council; UK Economic and Social Research Council; Ireland Health Research Board; The Netherlands Organisation for Health Research and Development (ZonMw); the Ministry of Health and Ministry of Education, University, and Research in Italy; the Motor Neurone Disease Association of England, Wales, and Northern Ireland; and the European Commission (Seventh Framework Programme).
Summary Two decades after the discovery that 20% of familial amyotrophic lateral sclerosis (ALS) cases were linked to mutations in the superoxide dismutase-1 ( SOD1 ) gene, a substantial proportion ...of the remainder of cases of familial ALS have now been traced to an expansion of the intronic hexanucleotide repeat sequence in C9orf72 . This breakthrough provides an opportunity to re-evaluate longstanding concepts regarding the cause and natural history of ALS, coming soon after the pathological unification of ALS with frontotemporal dementia through a shared pathological signature of cytoplasmic inclusions of the ubiquitinated protein TDP-43. However, with profound clinical, prognostic, neuropathological, and now genetic heterogeneity, the concept of ALS as one disease appears increasingly untenable. This background calls for the development of a more sophisticated taxonomy, and an appreciation of ALS as the breakdown of a wider network rather than a discrete vulnerable population of specialised motor neurons. Identification of C9orf72 repeat expansions in patients without a family history of ALS challenges the traditional division between familial and sporadic disease. By contrast, the 90% of apparently sporadic cases and incomplete penetrance of several genes linked to familial cases suggest that at least some forms of ALS arise from the interplay of multiple genes, poorly understood developmental, environmental, and age-related factors, as well as stochastic events.
Summary Amyotrophic lateral sclerosis is a progressive adult-onset neurodegenerative disease that primarily affects upper and lower motor neurons, but also frontotemporal and other regions of the ...brain. The extent to which each neuronal population is affected varies between individuals. The subsequent patterns of disease progression form the basis of diagnostic criteria and phenotypic classification systems, with considerable overlap in the clinical terms used. This overlap can lead to confusion between diagnosis and phenotype. Formal classification systems such as the El Escorial criteria and the International Classification of Diseases are systematic approaches but they omit features that are important in clinical management, such as rate of progression, genetic basis, or functional effect. Therefore, many neurologists use informal classification approaches that might not be systematic, and could include, for example, anatomical descriptions such as flail-arm syndrome. A new strategy is needed to combine the benefits of a systematic approach to classification with the rich and varied phenotypic descriptions used in clinical practice.
Summary Background Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease of motor neurons that results in progressive weakness and death from respiratory failure, commonly within about 3 ...years. Previous studies have shown association of a locus on chromosome 9p with ALS and linkage with ALS–frontotemporal dementia. We aimed to test whether this genomic region is also associated with ALS in an independent set of UK samples, and to identify risk factors associated with ALS in a further genome-wide association study that combined data from the independent analysis with those from other countries. Methods We collected samples from patients with sporadic ALS from 20 UK hospitals and obtained UK control samples from the control groups of the Depression Case Control study, the Bipolar Affective Case Control Study, and the British 1958 birth cohort DNA collection. Genotyping of DNA in this independent analysis was done with Illumina HumanHap550 BeadChips. We then undertook a joint genome-wide analysis that combined data from the independent set with published data from the UK, USA, Netherlands, Ireland, Italy, France, Sweden, and Belgium. The threshold for significance was p=0·05 in the independent analysis, because we were interested in replicating a small number of previously reported associations, whereas the Bonferroni-corrected threshold for significance in the joint analysis was p=2·20×10−7 Findings After quality control, samples were available from 599 patients and 4144 control individuals in the independent set. In this analysis, two single nucleotide polymorphisms in a locus on chromosome 9p21.2 were associated with ALS: rs3849942 (p=2·22×10−6 ; odds ratio OR 1·39, 95% CI 1·21–1·59) and rs2814707 (p=3·32×10−6 ; 1·38, 1·20–1·58). In the joint analysis, which included samples from 4312 patients with ALS and 8425 control individuals, rs3849942 (p=4·64×10−10 ; OR 1·22, 95% CI 1·15–1·30) and rs2814707 (p=4·72×10−10 ; 1·22, 1·15–1·30) were associated with ALS. Interpretation We have found strong evidence of a genetic association of two single nucleotide polymorphisms on chromosome 9 with sporadic ALS, in line with findings from previous independent GWAS of ALS and linkage studies of ALS–frontotemporal dementia. Our findings together with these earlier findings suggest that genetic variation at this locus on chromosome 9 causes sporadic ALS and familial ALS–frontotemporal dementia. Resequencing studies and then functional analysis should be done to identify the defective gene. Funding ALS Therapy Alliance, the Angel Fund, the Medical Research Council, the Motor Neurone Disease Association of Great Britain and Northern Ireland, the Wellcome Trust, and the National Institute for Health Research Dementias and Neurodegenerative Diseases Research Network (DeNDRoN).
Summary Background In a phase 2 study, dexpramipexole (25–150 mg twice daily) was well tolerated for up to 9 months and showed a significant benefit at the high dose in a combined assessment of ...function and mortality in patients with amyotrophic lateral sclerosis. We aimed to assess efficacy and safety of dexpramipexole in a phase 3 trial of patients with familial or sporadic disease. Methods In our randomised, double-blind, placebo-controlled phase 3 trial (EMPOWER), we enrolled participants aged 18–80 years (with first amyotrophic lateral sclerosis symptom onset 24 months or less before baseline) at 81 academic medical centres in 11 countries. We randomly allocated eligible participants (1:1) with a centralised voice–interactive online system to twice-daily dexpramipexole 150 mg or matched placebo for 12–18 months, stratified by trial site, area of disease onset (bulbar vs other areas), and previous use of riluzole. The primary endpoint was the combined assessment of function and survival (CAFS) score, based on changes in amyotrophic lateral sclerosis functional rating scale–revised (ALSFRS-R) total scores and time to death up to 12 months. We assessed the primary endpoint in all participants who received at least one dose and had at least one post-dose ALSFRS-R measurement or died. We monitored adverse events in all participants. This study is registered with ClinicalTrials.gov , number NCT01281189. Findings Between March 28, 2011, and Sept 30, 2011, we enrolled 943 participants (474 randomly allocated dexpramipexole, 468 randomly allocated placebo, and one withdrew). Least-square mean CAFS scores at 12 months did not differ between participants in the dexpramipexole group (score 441·76, 95% CI 415·43–468·08) and those in the placebo group (438·84, 412·81–464·88; p=0·86). At 12 months, we noted no differences in mean change from baseline in ALSFRS-R total score (–13·34 in the dexpramipexole group vs −13·42 in the placebo group; p=0·90) or time to death (74 16% vs 79 17%; hazard ratio 1·03 0·75–1·43; p=0·84). 37 (8%) participants in the dexpramipexole group developed neutropenia compared with eight (2%) participants in the placebo group, and incidence of other adverse events was similar between groups. Interpretation Dexpramipexole was generally well tolerated but did not differ from placebo on any prespecified efficacy endpoint measurement. Our trial can inform the design of future clinical research strategies in amyotrophic lateral sclerosis. Funding Biogen Idec.
Summary Background Neurite outgrowth inhibitor A (Nogo-A) is thought to have a role in the pathophysiology of amyotrophic lateral sclerosis (ALS). A monoclonal antibody against Nogo-A showed a ...positive effect in the SOD1G93A mouse model of ALS, and a humanised form of this antibody (ozanezumab) was well tolerated in a first-in-human trial. Therefore, we aimed to assess the safety and efficacy of ozanezumab in patients with ALS. Methods This randomised, double-blind, placebo-controlled, phase 2 trial was done in 34 centres in 11 countries. Patients aged 18–80 years with a diagnosis of familial or sporadic ALS were randomly assigned (1:1), centrally according to a computer-generated allocation schedule, to receive ozanezumab (15 mg/kg) or placebo as intravenous infusions over 1 h every 2 weeks for 46 weeks, followed by assessments at week 48 and week 60. Patients and study personnel were masked to treatment assignment. The primary outcome was a joint-rank analysis of function (ALS Functional Rating Scale-Revised) and overall survival, analysed at 48 weeks in all patients who received at least one dose of study drug. This study is registered with ClinicalTrials.gov , number NCT01753076 , and with GSK-ClinicalStudyRegister.com , NOG112264, and is completed. Findings Between Dec 20, 2012, and Nov 1, 2013, we recruited 307 patients, of whom 303 were randomly assigned to receive placebo (n=151) or ozanezumab (n=152). The adjusted mean of the joint-rank score was −14·9 (SE 13·5) for the ozanezumab group and 15·0 (13·6) for the placebo group, with a least squares mean difference of −30·0 (95% CI −67·9 to 7·9; p=0·12). Overall, reported adverse events, serious adverse events, and adverse events leading to permanent discontinuation of study drug or withdrawal from study were similar between the treatment groups, except for dyspepsia (ten 7% in the ozanezumab group vs four 3% in the placebo group), depression (11 7% vs five 3%), and diarrhoea (25 16% vs 12 8%). Respiratory failure was the most common serious adverse event (12 8% vs seven 5%). At week 60, the number of deaths was higher in the ozanezumab group (20 13%) than in the placebo group (16 11%), mainly as a result of respiratory failure (ten 7% vs five 3%). Two deaths were considered related to the study drug (bladder transitional cell carcinoma in the ozanezumab group and cerebrovascular accident in the placebo group). Interpretation Ozanezumab did not show efficacy compared with placebo in patients with ALS. Therefore, Nogo-A does not seem to be an effective therapeutic target in ALS. Funding GlaxoSmithKline.
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