Prognosis for patients with amyotrophic lateral sclerosis: development and validation of a personalised prediction model

Early Axonal Dysfunction of the Peripheral Nervous System Influences Disease Progression of ALS: Evidence From Clinical Neuroelectrophysiology

Objective: To assess the prognostic value of the decrement in compound muscle action potential amplitude within 12 months of symptom onset (CMAP-12 amplitude) for the survival of patients with amyotrophic lateral sclerosis (ALS).

Methods: Patients were stratified into 4 groups according to the decrement of the CMAP-12 amplitudes: normal (≥the lower limit of normal, LLN), mild (<LLN but ≥50% of LLN), moderate (<50% but ≥30% of LLN) and severe (<30% of LLN). All patients were followed up every 3 months. Survival was analyzed using the Kaplan-Meier method and Cox proportional hazards regression.

Results: A total of 149 patients were included in the analysis [90 males (60.4%); mean age at onset, 50.7 years]. The decrement of CMAP-12 amplitudes was normal in 24.2% of patients, mild in 22.1%, moderate in 15.4% and severe in 38.3%. Kaplan–Meier analysis showed there was a significant difference in the overall survival across the 4 groups (p < 0.05). Further pairwise comparisons identified significant differences in survival between the normal vs. the moderate group (p < 0.05) and the normal vs. the severe group (p < 0.01). There was a significant inverse correlation between the CMAP-12 amplitude and overall survival. Compared to that in the normal group, survival in the moderately and severely decreased groups was significantly shorter (HR 3.394, 95% CI 1.292–8.917, p = 0.013; and HR 4.732, 95% CI 2.032–11.017; p = 0.000, respectively).

Conclusions: Our results suggest that CMAP-12 amplitude could be a prognostic indicator of disease progression in ALS. More importantly, our findings provide clinical evidence for the viewpoint that early axonal dysfunction of the peripheral nervous system accelerates disease progression of ALS.

Improving clinical trial outcomes in amyotrophic lateral sclerosis

Individuals who are diagnosed with amyotrophic lateral sclerosis (ALS) today face the same historically intransigent problem that has existed since the initial description of the disease in the 1860s - a lack of effective therapies. In part, the development of new treatments has been hampered by an imperfect understanding of the biological processes that trigger ALS and promote disease progression. Advances in our understanding of these biological processes, including the causative genetic mutations, and of the influence of environmental factors have deepened our appreciation of disease pathophysiology. The consequent identification of pathogenic targets means that the introduction of effective therapies is becoming a realistic prospect. Progress in precision medicine, including genetically targeted therapies, will undoubtedly change the natural history of ALS. The evolution of clinical trial designs combined with improved methods for patient stratification will facilitate the translation of novel therapies into the clinic. In addition, the refinement of emerging biomarkers of therapeutic benefits is critical to the streamlining of care for individuals. In this Review, we synthesize these developments in ALS and discuss the further developments and refinements needed to accelerate the introduction of effective therapeutic approaches.

Motor cortical excitability predicts cognitive phenotypes in amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) are well-recognised as an extended disease spectrum. This study hypothesised that cortical hyperexcitability, an early pathophysiological abnormality in ALS, would distinguish cognitive phenotypes, as a surrogate marker of pathological disease burden. 61 patients with ALS, matched for disease duration (pure motor ALS, n = 39; ALS with coexistent FTD, ALS-FTD, n = 12; ALS with cognitive/behavioural abnormalities not meeting FTD criteria, ALS-Cog, n = 10) and 30 age-matched healthy controls. Cognitive function on the Addenbrooke's cognitive examination (ACE) scale, behavioural function on the motor neuron disease behavior scale (MiND-B) and cortical excitability using transcranial magnetic stimulation (TMS) were documented. Cortical resting motor threshold (RMT), lower threshold indicating hyperexcitability, was lower in ALS-FTD (50.2 ± 6.9) compared to controls (64.3 ± 12.6, p < 0.005), while ALS-Cog (63.3 ± 12.7) and ALS (60.8 ± 13.9, not significant) were similar to controls. Short interval intracortical inhibition (SICI) was reduced across all ALS groups compared to controls, indicating hyperexcitability. On receiver operating characteristic curve analysis, RMT differentiated ALS-FTD from ALS (area under the curve AUC = 0.745, p = 0.011). The present study has identified a distinct pattern of cortical excitability across cognitive phenotypes in ALS. As such, assessment of cortical physiology may provide more precise clinical prognostication in ALS.

Multidisciplinary care in Amyotrophic Lateral Sclerosis: a systematic review and meta-analysis

Multidisciplinary care (MDC) has been the most recommended approach for symptom management in amyotrophic lateral sclerosis (ALS) but there is conflicting evidence about its effectiveness on survival and quality of life (QoL) of ALS patients. We conducted a systematic review to determine the effects of multidisciplinary care compared to general neurological care in survival and quality of life of ALS patients. A comprehensive literature search using Scopus, MEDLINE-PubMed, Cochrane, Web of Science, PEDro, and Science Direct was undertaken. Studies related to multidisciplinary care or general neurological care in ALS patients that assessed survival and quality of life and were published in the period up to and including January 2020 were included. A total of 1192 studies were initially identified, but only 6 were included. All studies that investigated survival showed and advantage of MDC over NC, and this benefit was even greater for bulbar onset patients. A meta-analysis was performed and showed a mean difference of 141.67 (CI 95%, 61.48 to 221.86), indicating that patients who received MDC had longer survival than those who underwent NC (p = 0.0005). Concerning QoL, only one study found better mental health scores related to QoL for patients under MDC. Multidisciplinary care is more effective than general neurology care at improving survival of patients with ALS, but only improves mental health outcomes related to quality of life of these patients.

Nomograms for Predicting Non-remission in Patients Who Underwent Bariatric Surgery: A Multicenter Retrospective Study in China

BACKGROUND

As a reflection of the increasing global incidence of obesity, there is a corresponding increase in the proportion of obese patients undergoing bariatric surgery. This study reviewed the factors and outcomes of patients who underwent bariatric surgical procedures and determined the relationships and developed a nomogram to calculate individualized patient risk.

METHODS

The nomogram was based on a retrospective study on 259 patients who underwent bariatric surgery at the Chengdu Third People's Hospital from June 2017 to June 2019. The predictive accuracy and discriminative ability of the nomogram were determined by the ROC curve and C-index, respectively. The results were validated using bootstrap resampling and a retrospective study on 121 patients operated on from May 2015 to May 2019 at the Tenth People's Hospital of Shanghai.

RESULTS

The predictors contained in the prediction nomogram included age, sex, surgical approach, hyperlipidemia, blood pressure (BP), hyperuricemia, body mass index (BMI), and waist circumference (WC). The 6-month model displayed good discrimination with a C-index of 0.765 (95% CI: 0.756 to 0.774) and good calibration. The 1-year model reached a C-index of 0.768 (95% CI, 0.759 to 0.777) in the training cohort.

CONCLUSIONS

The proposed nomogram resulted in more accurate non-remission prediction for patients with obesity after bariatric surgery and may provide a reference for the preoperative choice of surgical methods.

Association of Single Nucleotide Polymorphism at rs2275294 in the ZNF512B Gene with Prognosis in Amyotrophic Lateral Sclerosis

The aim of this study is to explore whether the single nucleotide polymorphism rs2275294 in the ZNF512B gene is related to the length of survival of patients with amyotrophic lateral sclerosis (ALS). This prospective study examined 212 patients with ALS, who were genotyped at the rs2275294 locus in ZNF512B using the ligase method. Genotype was compared with clinical data and survival. Kaplan-Meier survival analysis and Cox hazard regression were used to identify risk factors of shorter survival. Our results were meta-analyzed together with previous work in order to examine the potential association between the rs2275294-C allele and survival. Of the 212 patients, 166 carried the CC + CT genotype at the rs2275294 locus, while 46 carried the TT genotype. Patients with the C allele showed significantly shorter survival than those without it (34.13 ± 1.9 vs. 45.32 ± 5.7 months, p = 0.036). Cox analysis identified the C allele and time from symptom onset to diagnosis as risk factors for shorter survival. Meta-analysis of 447 patients in China and Japan confirmed the rs2275294-C allele to be an independent risk factor of shorter survival in ALS patients. The C allele at the rs2275294 locus in ZNF512B is a risk factor for shorter survival in patients with ALS.

Amyotrophic lateral sclerosis (ALS) and the endocrine system: Are there any further ties to be explored?

Amyotrophic Lateral Sclerosis (ALS) belongs to the family of neurodegenerative disorders and is classified as fronto-temporal dementia (FTD), progressive muscular atrophy, primary lateral sclerosis, and pseudobulbar palsy. Even though endocrine dysfunction independently impacts the ALS-related survival rate, the complex connection between ALS and the endocrine system has not been studied in depth. Here we review earlier and recent findings on how ALS interacts with hormones a) of the hypothalamus and pituitary gland, b) the thyroid gland, c) the pancreas, d) the adipose tissue, e) the parathyroid glands, f) the bones, g) the adrenal glands, and h) the gonads (ovaries and testes). Of note, endocrine issues should always be explored in patients with ALS, especially those with low skeletal muscle and bone mass, vitamin D deficiency, and decreased insulin sensitivity (diabetes mellitus). Because ALS is a progressively deteriorating disease, addressing any potential endocrine co-morbidities in patients with this malady is quite important for decreasing the overall ALS-associated disease burden. Importantly, as this burden is estimated to increase globally in the decades to follow, in part because of an increasingly aging population, it is high time for future multi-center, multi-ethnic studies to assess the link between ALS and the endocrine system in significantly larger patient populations. Last, the psychosocial stress experienced by patients with ALS and its psycho-neuro-endocrinological sequelae, including hypothalamic-pituitaryadrenal dysregulation, should become an area of intensive study in the future.

Current application of neurofilaments in amyotrophic lateral sclerosis and future perspectives

Motor neuron disease includes a heterogeneous group of relentless progressive neurological disorders defined and characterized by the degeneration of motor neurons. Amyotrophic lateral sclerosis is the most common and aggressive form of motor neuron disease with no effective treatment so far. Unfortunately, diagnostic and prognostic biomarkers are lacking in clinical practice. Neurofilaments are fundamental structural components of the axons and neurofilament light chain and phosphorylated neurofilament heavy chain can be measured in both cerebrospinal fluid and serum. Neurofilament light chain and phosphorylated neurofilament heavy chain levels are elevated in amyotrophic lateral sclerosis, reflecting the extensive damage of motor neurons and axons. Hence, neurofilaments are now increasingly recognized as the most promising candidate biomarker in amyotrophic lateral sclerosis. The potential usefulness of neurofilaments regards various aspects, including diagnosis, prognosis, patient stratification in clinical trials and evaluation of treatment response. In this review paper, we review the body of literature about neurofilaments measurement in amyotrophic lateral sclerosis. We also discuss the open issues concerning the use of neurofilaments clinical practice, as no overall guideline exists to date; finally, we address the most recent evidence and future perspectives.

Beyond the Traditional Clinical Trials for Amyotrophic Lateral Sclerosis and The Future Impact of Gene Therapy

Amyotrophic lateral sclerosis (ALS) is a devastating and incurable motor neuron (MN) disorder affecting both upper and lower MNs. Despite impressive advances in the understanding of the disease’s pathological mechanism, classical pharmacological clinical trials failed to provide an efficient cure for ALS over the past twenty years. Two different gene therapy approaches were recently approved for the monogenic disease Spinal muscular atrophy, characterized by degeneration of lower MNs. This milestone suggests that gene therapy-based therapeutic solutions could be effective for the treatment of ALS. This review summarizes the possible reasons for the failure of traditional clinical trials for ALS. It provides then a focus on the advent of gene therapy approaches for hereditary forms of ALS. Specifically, it describes clinical use of antisense oligonucleotides in three familial forms of ALS, caused by mutations in SOD1, C9orf72 and FUS genes, respectively.. Clinical and pre-clinical studies based on AAV-mediated gene therapy approaches for both familial and sporadic ALS cases are presented as well. Overall, this overview highlights the potential of gene therapy as a transforming technology that will have a huge impact on treatment perspective for ALS patients and on the design of future clinical trials.

Development and validation of a machine-learning ALS survival model lacking vital capacity (VC-Free) for use in clinical trials during the COVID-19 pandemic

Introduction: Vital capacity (VC) is routinely used for ALS clinical trial eligibility determinations, often to exclude patients unlikely to survive trial duration. However, spirometry has been limited by the COVID-19 pandemic. We developed a machine-learning survival model without the use of baseline VC and asked whether it could stratify clinical trial participants and a wider ALS clinic population. Methods. A gradient boosting machine survival model lacking baseline VC (VC-Free) was trained using the PRO-ACT ALS database and compared to a multivariable model that included VC (VCI) and a univariable baseline %VC model (UNI). Discrimination, calibration-in-the-large and calibration slope were quantified. Models were validated using 10-fold internal cross validation, the VITALITY-ALS clinical trial placebo arm and data from the Emory University tertiary care clinic. Simulations were performed using each model to estimate survival of patients predicted to have a > 50% one year survival probability. Results. The VC-Free model suffered a minor performance decline compared to the VCI model yet retained strong discrimination for stratifying ALS patients. Both models outperformed the UNI model. The proportion of excluded vs. included patients who died through one year was on average 27% vs. 6% (VCI), 31% vs. 7% (VC-Free), and 13% vs. 10% (UNI). Conclusions. The VC-Free model offers an alternative to the use of VC for eligibility determinations during the COVID-19 pandemic. The observation that the VC-Free model outperforms the use of VC in a broad ALS patient population suggests the use of prognostic strata in future, post-pandemic ALS clinical trial eligibility screening determinations.

Neck flexor weakness at diagnosis predicts respiratory impairment in amyotrophic lateral sclerosis

BACKGROUND AND PURPOSE

The purpose was to assess the prognostic role of neck muscle weakness at diagnosis in amyotrophic lateral sclerosis (ALS) patients with respect to survival and respiratory impairment.

METHODS

A retrospective cohort study was conducted. All ALS patients seen in the Turin ALS Centre from 2007 to 2014 were included. Muscle strength at diagnosis was evaluated using the Medical Research Council (MRC) scale. Survival was considered as the time from diagnosis to death or tracheostomy; time to respiratory impairment was considered as the interval from diagnosis to the first event amongst an ALS Functional Rating Scale revised item 10 <4, forced vital capacity <70%, start of non-invasive ventilation or tracheostomy. Time from diagnosis to dysarthria, dysphagia and walking impairment were considered as secondary outcomes. Cox proportional hazard regression models adjusted for sex, age at diagnosis, diagnostic delay, onset site, genetics status and the MRC scores of other muscle groups were used to assess the prognostic role of neck muscles.

RESULTS

A total of 370 patients were included in the study. Fifty-nine (15.9%) patients showed neck flexor weakness at diagnosis; MRC values were mostly in agreement for neck extensors. Neck flexors were the only muscles able to predict survival (hazard ratio 0.49, 95% confidence interval 0.28-0.86; p = 0.01). Furthermore, neck flexor normal strength decreased the risk of respiratory impairment (hazard ratio 0.46, 95% confidence interval 0.22-0.96; p = 0.04) but did not influence any secondary outcomes.

DISCUSSION

Neck flexor weakness at diagnosis predicts survival and respiratory impairment in ALS. This result could be valuable for both planning of patients' interventions and clinical trials' design.

Portable fixed dynamometry: towards remote muscle strength measurements in patients with motor neuron disease

Background

We aimed to determine (1) the test–retest reliability of a newly developed portable fixed dynamometer (PFD) as compared to the hand-held dynamometer (HHD) in patients with motor neuron disease (MND) and (2) the PFD’s ability to reduce possible examiner-induced ceiling effects.

Methods

Test–retest reliability of isometric muscle strength of the quadriceps was measured in patients with MND and non-neurological controls using the HHD and PFD. Reliability was estimated by the intraclass correlation coefficient (ICC) and standard error of measurement (SEM) using linear mixed effects models, and the Bland–Altman method of agreement.

Results

In total, 45 patients with MND and 43 healthy controls were enrolled in this study. The ICC of the PFD was excellent and similar in both patients and controls (ICC _Patients 99.5% vs. ICC _Controls 98.6%) with a SEM of 6.2%. A strong examiner-induced ceiling effect in HHD was found when the participant’s strength exceeded that of examiner. Employing the PFD increased the range of muscle strength measurements across individuals nearly twofold from 414 to 783 N.

Conclusions

Portable fixed dynamometry may significantly reduce examiner-induced ceiling effects, optimize the standardization of muscle strength testing, and maximize reliability. Ultimately, PFD may improve the delivery of care due to its potential for unsupervised, home-based assessments and reduce the burden to the patient of participating in clinical trials for MND or other neuromuscular diseases.

Discussing personalized prognosis in amyotrophic lateral sclerosis: development of a communication guide

BACKGROUND

Personalized ENCALS survival prediction model reliably estimates the personalized prognosis of patients with amyotrophic lateral sclerosis. Concerns were raised on discussing personalized prognosis without causing anxiety and destroying hope. Tailoring communication to patient readiness and patient needs mediates the impact of prognostic disclosure. We developed a communication guide to support physicians in discussing personalized prognosis tailored to individual needs and preferences of people with ALS and their families.

METHODS

A multidisciplinary working group of neurologists, rehabilitation physicians, and healthcare researchers A) identified relevant topics for guidance, B) conducted a systematic review on needs of patients regarding prognostic discussion in life-limiting disease, C) drafted recommendations based on evidence and expert opinion, and refined and finalized these recommendations in consensus rounds, based on feedback of an expert advisory panel (patients, family member, ethicist, and spiritual counsellor).

RESULTS

A) Topics identified for guidance were 1) filling in the ENCALS survival model, and interpreting outcomes and uncertainty, and 2) tailoring discussion to individual needs and preferences of patients (information needs, role and needs of family, severe cognitive impairment or frontotemporal dementia, and non-western patients). B) 17 studies were included in the systematic review. C) Consensus procedures on drafted recommendations focused on selection of outcomes, uncertainty about estimated survival, culturally sensitive communication, and lack of decisional capacity. Recommendations for discussing the prognosis include the following: discuss prognosis based on the prognostic groups and their median survival, or, if more precise information is desired, on the interquartile range of the survival probability. Investigate needs and preferences of the patients and their families for prognostic disclosure, regardless of cultural background. If the patient does not want to know their prognosis, with patient permission discuss the prognosis with their family. If the patient is judged to lack decisional capacity, ask the family if they want to discuss the prognosis. Tailor prognostic disclosure step by step, discuss it in terms of time range, and emphasize uncertainty of individual survival time.

CONCLUSION

This communication guide supports physicians in tailoring discussion of personalized prognosis to the individual needs and preferences of people with ALS and their families.

Multicentre, prospective registry study of amyotrophic lateral sclerosis in mainland China (CHALSR): study protocol

INTRODUCTION

Amyotrophic lateral sclerosis (ALS) is a representative rare disease characterised by progressive, fatal motor neuron degeneration. Due to the unknown aetiology and variability of the phenotypes, there are no accurate reports concerning the epidemiology or clinical characteristics of the disease. The low prevalence, as previously reported, makes it difficult to carry out studies with large samples. The aim of this study was to explore the natural history and clinical features of ALS in mainland China through a multicentre, prospective cohort study. The findings will both offer a better understanding of ALS and also support the development of a model to study other rare diseases.

METHODS AND ANALYSIS

Patients from 88 representative hospitals in different parts of mainland China will be recruited through a specially designed online data system (http://www.chalsr.net/). We aim to recruit 4752 ALS patients over a 3-year period. Baseline data will be recorded, and follow-up data will be collected every 3 months. The primary outcome is effective survival. Overall survival and indices of disease progression will be measured as the secondary outcomes.

ETHICS AND DISSEMINATION

Ethical approval has been obtained from the ethics committee of Peking University Third Hospital (M2019388). Informed written consent will be obtained from each participant. Dissemination of the study protocol and data will take place primarily through a specially designed online data system (http://www.chalsr.net/). The collective results of the study will be published in peer-reviewed journals and shared in scientific presentations.

TRIAL REGISTRATION NUMBER

NCT04328675.

Discovery and validation of a personalized risk predictor for incident tuberculosis in low transmission settings

The risk of tuberculosis (TB) is variable among individuals with latent Mycobacterium tuberculosis infection (LTBI), but validated estimates of personalized risk are lacking. In pooled data from 18 systematically identified cohort studies from 20 countries, including 80,468 individuals tested for LTBI, 5-year cumulative incident TB risk among people with untreated LTBI was 15.6% (95% confidence interval (CI), 8.0-29.2%) among child contacts, 4.8% (95% CI, 3.0-7.7%) among adult contacts, 5.0% (95% CI, 1.6-14.5%) among migrants and 4.8% (95% CI, 1.5-14.3%) among immunocompromised groups. We confirmed highly variable estimates within risk groups, necessitating an individualized approach to risk stratification. Therefore, we developed a personalized risk predictor for incident TB (PERISKOPE-TB) that combines a quantitative measure of T cell sensitization and clinical covariates. Internal-external cross-validation of the model demonstrated a random effects meta-analysis C-statistic of 0.88 (95% CI, 0.82-0.93) for incident TB. In decision curve analysis, the model demonstrated clinical utility for targeting preventative treatment, compared to treating all, or no, people with LTBI. We challenge the current crude approach to TB risk estimation among people with LTBI in favor of our evidence-based and patient-centered method, in settings aiming for pre-elimination worldwide.

Amyotrophic lateral sclerosis and intestinal microbiota-toward establishing cause and effect

The intestinal microbiota may be involved, through metabolic gut-brain interactions, in a variety of neurological conditions. In this addendum, we summarize the findings of our recent study investigating the potentially modulatory influence of the microbiome in a transgenic ALS mouse model, and the possible application to human disease. We found that transgenic mice show evidence of dysbiosis, even at the pre-symptomatic stage, and have a more severe disease course under germ-free conditions or after receiving broad-spectrum antibiotics. We demonstrated that Akkermansia muciniphila ameliorated the disease in mice and that this may be due to the production of nicotinamide. We then conducted a preliminary study in human ALS and identified functionally similar alterations within the metagenome. Furthermore, we found that patients with ALS had lower systemic and CSF levels of nicotinamide, suggesting that the changes observed in the mouse model may be relevant to human disease.

The presymptomatic phase of amyotrophic lateral sclerosis: are we merely scratching the surface?

Presymptomatic studies in ALS have consistently captured considerable disease burden long before symptom manifestation and contributed important academic insights. With the emergence of genotype-specific therapies, however, there is a pressing need to address practical objectives such as the estimation of age of symptom onset, phenotypic prediction, informing the optimal timing of pharmacological intervention, and identifying a core panel of biomarkers which may detect response to therapy. Existing presymptomatic studies in ALS have adopted striking different study designs, relied on a variety of control groups, used divergent imaging and electrophysiology methods, and focused on different genotypes and demographic groups. We have performed a systematic review of existing presymptomatic studies in ALS to identify common themes, stereotyped shortcomings, and key learning points for future studies. Existing presymptomatic studies in ALS often suffer from sample size limitations, lack of disease controls and rarely follow their cohort until symptom manifestation. As the characterisation of presymptomatic processes in ALS serves a multitude of academic and clinical purposes, the careful review of existing studies offers important lessons for future initiatives.

Palliative Care Consults in an Inpatient Setting for Patients With Amyotrophic Lateral Sclerosis

Background:

Limited data about the frequency and outcomes of palliative care (PC) specialty consultations for patients with amyotrophic lateral sclerosis (ALS) are available.

Methods:

This study was a retrospective chart review. Patients with ALS admitted to 2 academic hospitals from 2013-2018 were included. We compared patients who were seen by an inpatient specialty PC service (PC group) with those who were not (NonPC group).

Results:

Twenty-four patients met inclusion criteria (9 PC group, 15 NonPC group). Patients in both groups were similar in age and had been diagnosed for a similar amount of time before admission. In the PC group, 6 patients were seen by more than 1 PC multidisciplinary team member (physician, social worker, spiritual care provider, clinical nurse specialist). PC consultations were requested for goals of care (GOC) (n = 7), pain (n = 4), hospice information/referral (n = 2), dyspnea (n = 1), and excessive oral secretions (n = 1). GOC topics addressed for both groups were code status, treatment preferences (tracheostomy placement, percutaneous endoscopic gastrostomy placement, change to comfort care), prognostication, and hospice information/referral. Patients in the PC group were significantly more likely to be discharged with GOC (89%, p = 0.02) and completed advance care planning (ACP) documents (89%, p = 0.04) than patients in the NonPC group (32%; 47%). Despite reason for consultation, at least 1 symptom was addressed for every patient seen by PC specialists.

Conclusions:

Inpatient specialty PC consultation for patients with ALS leads to greater documentation of GOC and ACP by discharge. PC consultants participate in symptom management in patients with ALS during hospitalization.

Median Nerve-Neurophysiological Index Correlates With the Survival of Patients With Amyotrophic Lateral Sclerosis

Objective: This study aims to explore the association between median nerve-neurophysiological index (NI) and survival of patients with amyotrophic lateral sclerosis (ALS).

Methods: A retrospective case series with a prospective follow-up study was performed in 238 patients with ALS. Their clinical profiles and NI were recorded. Kaplan-Meier curves and Cox regression were adopted to perform survival analysis.

Results: The median survival time of all ALS cases was 33.0 months. Multivariate analysis showed that older age of onset, shorter diagnostic delay, higher ΔALSFRS-R, and faster progression {NI ≤ 2.15; hazard ratio [HR] = 1.543 [95% confidence interval (CI), 1.136–2.094]} were associated with short survival. NI was correlated with ALSFRS-R at baseline (r_s = 0.3153; p < 0.0001) and ALSFRS-R at different time points of follow-up (r_s = 0.5127; p < 0.0001). The higher NI slope of decline (> 0.25) showed shorter survival compared with the lower group (≤ 0.25; 34.0 vs. 52.0 months; p = 0.0003). A predictive model was constructed based on the age of onset, diagnostic delay, median nerve NI, and ΔALSFRS-R. The higher predictive score (> 14) showed significantly shorter survival compared with the lower group (≤ 14; HR = 3.907, 95% CI, 2.857–5.342).

Conclusion: Median nerve NI and its slope of decline were predictive of survival of ALS.

Motor Neuron Disease Register for England, Wales and Northern Ireland-an analysis of incidence in England

INTRODUCTION

Amyotrophic lateral sclerosis (ALS) has a reported incidence of 1-2/100,000 person-years. It is estimated that there are 5000 people with ALS in the UK at any one time; however, the true figure and geographical distribution, are unknown. In this study, we describe the establishment of a population register for England, Wales, and Northern Ireland and report-estimated incidence. Methods: People with a diagnosis of ALS given by a consultant neurologist and whose postcode of residence is within England, Wales, or Northern Ireland were eligible. The catchment area was based on six data contributors that had been participating since 2016. All centres included in this analysis were in England, and therefore Wales and Northern Ireland are not included in this report. Crude age- and sex-specific incidence rates were estimated using population census records for the relevant postcodes from Office of National Statistics census data. These rates were standardized to the UK population structure using direct standardization. Results: There were 232 people in the database with a date of diagnosis between 2017 and 2018, when missing data were imputed there were an estimated 287-301 people. The denominator population of the catchment area is 7,251,845 according to 2011 UK census data. Age- and sex-adjusted incidence for complete cases was 1.61/100,000 person-years (95% confidence interval 1.58, 1.63), and for imputed datasets was 2.072/100,000 person-years (95% CI 2.072, 2.073). Discussion: We found incidence in this previously unreported area of the UK to be similar to other published estimates. As the MND Register for England, Wales, and Northern Ireland grows we will update incidence estimates and report on further analyses.

Amyotrophic lateral sclerosis and lead: A systematic update

Heavy metals are considered to be among the leading environmental factors that trigger amyotrophic lateral sclerosis (ALS). However, no convincing biopathological mechanism and therapeutic clinical implication of such metals in ALS pathogenesis have been established. This is partly attributable to the technical and scientific difficulties in demonstrating a direct and causative role of heavy metals in the onset of ALS in patients. However, a body of epidemiological, clinical and experimental evidences suggest that lead (Pb), more than other metals, could actually play a major role in the onset and progression of ALS. Here, to clarify the nature of the association and the causative role of Pb in ALS, we comprehensively reviewed the scientific literature of the last decade with objective database searches and the methods typically adopted in systematic reviews, critically analysing and summarising the various scientifically sound evidence on the relationship between ALS and Pb. From these tasks, we noted a number of multidisciplinary associations between ALS and Pb, and specifically the importance of occupational exposure to Pb in ALS development and/or progression. We also report the possible involvement of TAR DNA binding protein (TDP-43)-based molecular mechanism in Pb-mediated ALS, although these data rely on a single study, which included both in vitro experiments and an animal model, and are therefore still preliminary. Finally, we briefly examined whether this knowledge could inspire new targeted therapies and policies in the fight against ALS.

Triage of Amyotrophic Lateral Sclerosis Patients during the COVID-19 Pandemic: An Application of the D50 Model

Amyotrophic lateral sclerosis (ALS) is a progressive neuromuscular disease, the management of which requires the continuous provision of multidisciplinary therapies. Owing to the novel coronavirus disease (COVID-19) pandemic, regular contact with ALS patients at our center was severely restricted and patient care was at risk by delay of supportive therapies. We established a triage system based on the D50 disease progression model and were thus able to identify a prospective cohort with high disease aggressiveness (D50 < 30). Thirty-seven patients with highly aggressive disease were actively offered follow-up, either via telephone or on-site, depending on their disease-specific needs and abilities. We describe here the procedures, obstacles, and results of these prescient efforts during the restrictions caused by COVID-19 in the period between March and June 2020. In conclusion, four patients with highly aggressive disease were initiated with non-invasive ventilation and two received a gastrostomy. We could show that a comparable amount of advanced care was induced in a retrospective cohort within a similar time period one year prior to the COVID-19 outbreak. Our workflow to identify high-risk patients via D50 model metrics can be easily implemented and integrated within existing centers. It helped to maintain a high quality of advanced care planning for our ALS patients.

Manifold learning for amyotrophic lateral sclerosis functional loss assessment : Development and validation of a prognosis model

Amyotrophic lateral sclerosis (ALS) is an inexorably progressive neurodegenerative condition with no effective disease-modifying therapy at present. Given the striking clinical heterogeneity of the condition, the development and validation of reliable prognostic models is a recognised research priority. We present a prognostic model for functional decline in ALS where outcome uncertainty is taken into account. Patient data were reduced and projected onto a 2D space using Uniform Manifold Approximation and Projection (UMAP), a novel non-linear dimension reduction technique. Information from 3756 patients was included. Development data were sourced from past clinical trials. Real-world population data were used as validation data. Predictors included age, gender, region of onset, symptom duration, weight at baseline, functional impairment, and estimated rate of functional loss. UMAP projection of patients showed an informative 2D data distribution. As limited data availability precluded complex model designs, the projection was divided into three zones defined by a functional impairment range probability. Zone membership allowed individual patient prediction. Patients belonging to the first zone had a probability of [Formula: see text] (± [Formula: see text]) to have an ALSFRS score over 20 at 1-year follow-up. Patients within the second zone had a probability of [Formula: see text] (± [Formula: see text]) to have an ALSFRS score between 10 and 30 at 1 year follow-up. Finally, patients within the third zone had a probability of [Formula: see text] (± [Formula: see text]) to have an ALSFRS score lower than 20 at 1 year follow-up. This approach requires a limited set of features, is easily updated, improves with additional patient data, and accounts for results uncertainty. This method could therefore be used in a clinical setting for patient stratification and outcome projection.

Does including machine learning predictions in ALS clinical trial analysis improve statistical power?

Objective

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease which leads to progressive muscle weakness and eventually death. The increasing availability of large ALS clinical trial datasets have generated much interest in developing predictive models for disease progression. However, the utility of predictive modeling on clinical trial analysis has not been thoroughly evaluated.

Methods

We evaluated a predictive modeling approach for ALS disease progression measured by ALSFRS‐R using the PRO‐ACT database and validated our findings in a novel test set from a former clinical trial. We examined clinical trial scenarios where model predictions could improve statistical power for detecting treatment effects with simulated clinical trials.

Results

Models constructed with imputed PRO‐ACT data have better external validation results than those fitted with complete observations. When fitted with imputed data, super learner (R² = 0.71, MSPE = 19.7) and random forest (R² = 0.70, MSPE = 19.6) have similar performance in the external validation and slightly outperform the linear mixed effects model (R² = 0.69, MSPE = 20.5). Simulation studies suggest including machine learning predictions as a covariate in the analysis model of a 12‐month clinical study can increase the trial's effective sample size by 16% when there is a hypothetical treatment effect of 25% reduction in ALSFRS‐R mean rate of change.

Interpretation

Predictive modeling approaches for ALSFRS‐R are able to explain a moderate amount of variability in longitudinal change, which is improved by robust missing data handling for baseline characteristics. Including ALSFRS‐R post‐baseline model prediction results as a covariate in the model for primary analysis may increase power under moderate treatment effects.

Altered serum protein levels in frontotemporal dementia and amyotrophic lateral sclerosis indicate calcium and immunity dysregulation

Frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS) are neurodegenerative diseases that are considered to be on the same disease spectrum because of overlapping genetic, pathological and clinical traits. Changes in serum proteins in FTD and ALS are poorly understood, and currently no definitive biomarkers exist for diagnosing or monitoring disease progression for either disease. Here we applied quantitative discovery proteomics to analyze protein changes in FTD (N = 72) and ALS (N = 28) patient serum compared to controls (N = 22). Twenty three proteins were significantly altered in FTD compared to controls (increased-APOL1, C3, CTSH, EIF5A, MYH2, S100A8, SUSD5, WDR1; decreased-C1S, C7, CILP2, COMP, CRTAC1, EFEMP1, FBLN1, GSN, HSPG2, IGHV1, ITIH2, PROS1, SHBG, UMOD, VASN) and 14 proteins were significantly altered in ALS compared to controls (increased-APOL1, CKM, CTSH, IGHG1, IGKC, MYH2; decreased-C7, COMP, CRTAC1, EFEMP1, FBLN1, GSN, HSPG2, SHBG). There was substantial overlap in the proteins that were altered in FTD and ALS. These results were validated using western blotting. Gene ontology tools were used to assess functional pathways potentially dysregulated in the two diseases, and calcium ion binding and innate immunity pathways were altered in both diseases. When put together, these results suggest significant overlap in pathophysiological peripheral changes in FTD and ALS. This study represents the first proteomics side-by-side comparison of serum changes in FTD and ALS, providing new insights into under-recognized perturbed pathways and an avenue for biomarker development for FTD and ALS.

Development and validation of a 1-year survival prognosis estimation model for Amyotrophic Lateral Sclerosis using manifold learning algorithm UMAP

Amyotrophic Lateral Sclerosis (ALS) is an inexorably progressive neurodegenerative condition with no effective disease modifying therapies. The development and validation of reliable prognostic models is a recognised research priority. We present a prognostic model for survival in ALS where result uncertainty is taken into account. Patient data were reduced and projected onto a 2D space using Uniform Manifold Approximation and Projection (UMAP), a novel non-linear dimension reduction technique. Information from 5,220 patients was included as development data originating from past clinical trials, and real-world population data as validation data. Predictors included age, gender, region of onset, symptom duration, weight at baseline, functional impairment, and estimated rate of functional loss. UMAP projection of patients shows an informative 2D data distribution. As limited data availability precluded complex model designs, the projection was divided into three zones with relevant survival rates. These rates were defined using confidence bounds: high, intermediate, and low 1-year survival rates at respectively [Formula: see text] ([Formula: see text]), [Formula: see text] ([Formula: see text]) and [Formula: see text] ([Formula: see text]). Predicted 1-year survival was estimated using zone membership. This approach requires a limited set of features, is easily updated, improves with additional patient data, and accounts for results uncertainty.

Prognostic value of weight loss in patients with amyotrophic lateral sclerosis: a population-based study

OBJECTIVE

To determine the prevalence and prognostic value of weight loss (WL) prior to diagnosis in patients with amyotrophic lateral sclerosis (ALS).

METHODS

We enrolled patients diagnosed with ALS between 2010 and 2018 in a population-based setting. At diagnosis, detailed information was obtained regarding the patient's disease characteristics, anthropological changes, ALS-related genotypes and cognitive functioning. Complete survival data were obtained. Cox proportional hazard models were used to assess the association between WL and the risk of death during follow-up.

RESULTS

The data set comprised 2420 patients of whom 67.5% reported WL at diagnosis. WL occurred in 71.8% of the bulbar-onset and in 64.2% of the spinal-onset patients; the mean loss of body weight was 6.9% (95% CI 6.8 to 6.9) and 5.5% (95% CI 5.5 to 5.6), respectively (p<0.001). WL occurred in 35.1% of the patients without any symptom of dysphagia. WL is a strong independent predictor of survival, with a dose response relationship between the amount of WL and the risk of death: the risk of death during follow-up increased by 23% for every 10% increase in WL relative to body weight (HR 1.23, 95% CI 1.13 to 1.51, p<0.001).

CONCLUSIONS

This population-based study shows that two-thirds of the patients with ALS have WL at diagnosis, which also occurs independent of dysphagia, and is related to survival. Our results suggest that WL is a multifactorial process that may differ from patient to patient. Gaining further insight in its underlying factors could prove essential for future therapeutic measures.

Addressing heterogeneity in amyotrophic lateral sclerosis CLINICAL TRIALS

Amyotrophic lateral sclerosis (ALS) is a debilitating neurodegenerative disorder with complex biology and significant clinical heterogeneity. Many preclinical and early phase ALS clinical trials have yielded promising results that could not be replicated in larger phase 3 confirmatory trials. One reason for the lack of reproducibility may be ALS biological and clinical heterogeneity. Therefore, in this review, we explore sources of ALS heterogeneity that may reduce statistical power to evaluate efficacy in ALS trials. We also review efforts to manage clinical heterogeneity, including use of validated disease outcome measures, predictive biomarkers of disease progression, and individual clinical risk stratification. We propose that personalized prognostic models with use of predictive biomarkers may identify patients with ALS for whom a specific therapeutic strategy may be expected to be more successful. Finally, the rapid application of emerging clinical and biomarker strategies may reduce heterogeneity, increase trial efficiency, and, in turn, accelerate ALS drug development.

Cortical thinning trajectories across disease stages and cognitive impairment in amyotrophic lateral sclerosis

BACKGROUND

Cortical neuron degenerative process underlying upper motor neuron involvement in amyotrophic lateral sclerosis (ALS) spreads to extra-motor regions as disease progresses. This is associated with cognitive and behavioural worsening in more severe disease stages. However, the clinical variability of ALS patients might reflect different cortical involvement in extra-motor areas.

OBJECTIVES

To investigate cortical thinning across disease stages in ALS patients accounting for their cognitive/behavioural impairment.

METHODS

Thirty-six ALS patients (17 with cognitive/behavioural impairment, ALSimp) and 26 healthy controls underwent structural 3T magnetic resonance imaging. Cortical thickness was measured with a region-wise approach. The King's Clinical Staging System was used to determine disease stages. The Jonckheere-Terpstra test tested for trends in cortical thinning and cognitive involvement across disease stages.

RESULTS

Significant trends toward cortical atrophy across disease stages were found in bilateral frontal and cingular cortex, left temporal gyrus and right occipital gyrus of ALS patients, consistently with cognitive impairment in phonemic fluency, language, verbal episodic memory and social cognition. Sub-group analyses revealed that ALSimp had specific thinning in the right fronto-temporal insular cortex related to more pronounced cognitive involvement.

CONCLUSION

Looking at ALS patients irrespective of their cognitive phenotype, motor and extra-motor cortical involvement is consistent with neuropathological studies of disease dissemination. Segregating patients according to their cognitive status, a distinctive trajectory of cortical thinning emerged for ALSimp patients, suggesting a specific course distinct to that of the classic ALS phenotype.

Time to diagnosis and factors affecting diagnostic delay in amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a progressive, degenerative neuromuscular disease with limited treatment options. The diagnosis of ALS can be challenging for numerous reasons, resulting in delays that may compromise optimal management and enrollment into clinical trials. Several studies have examined the process and challenges regarding the clinical diagnosis of ALS. Twenty-one studies that were almost exclusively from the English literature published between 1990 and 2020 were identified via PubMed using relevant search terms and included patient populations from the United States, Canada, Japan, Egypt, and several countries in South America and Europe. Probable or definitive ALS patients were identified using El Escorial or revised El Escorial/Airlie House Criteria. Time to diagnosis or diagnostic delay was defined as mean or median time from patient-reported first symptom onset to formal diagnosis by a physician, as recorded in medical records. The typical time to diagnosis was 10-16 months from symptom onset. Several points of delay in the diagnosis course were identified, including specialist referrals and misdiagnoses, often resulting in unnecessary procedures and surgeries. Bulbar onset was noted to significantly reduce time to ALS diagnosis. Future interventions and potential research opportunities were reviewed.

Review: Microglia in motor neuron disease

Motor Neuron Disease (MND) is a fatal neurodegenerative condition, which is characterized by the selective loss of the upper and lower motor neurons. At the sites of motor neuron injury, accumulation of activated microglia, the primary immune cells of the central nervous system, is commonly observed in both human post mortem studies and animal models of MND. Microglial activation has been found to correlate with many clinical features and importantly, the speed of disease progression in humans. Both anti-inflammatory and pro-inflammatory microglial responses have been shown to influence disease progression in humans and models of MND. As such, microglia could both contribute to and protect against inflammatory mechanisms of pathogenesis in MND. While murine models have characterized the microglial response to MND, these studies have painted a complex and often contradictory picture, indicating a need for further characterization in humans. This review examines the potential role microglia play in MND in human and animal studies. Both the pro-inflammatory and anti-inflammatory responses will be addressed, throughout the course of disease, followed by the potential of microglia as a target in the development of disease-modifying treatments for MND.

The Distinct Traits of the UNC13A Polymorphism in Amyotrophic Lateral Sclerosis

Objective

The rs12608932 single nucleotide polymorphism in UNC13A is associated with amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) susceptibility, and may underlie differences in treatment response. We aimed to characterize the clinical, cognitive, behavioral, and neuroimaging phenotype of UNC13A in patients with ALS.

Methods

We included 2,216 patients with ALS without a C9orf72 mutation to identify clinical characteristics associated with the UNC13A polymorphism. A subcohort of 428 patients with ALS was used to study cognitive and behavioral profiles, and 375 patients to study neuroimaging characteristics. Associations were analyzed under an additive genetic model.

Results

Genotyping rs12608932 resulted in 854 A/A, 988 A/C, and 374 C/C genotypes. The C allele was associated with a higher age at symptom onset (median years A/A 63.5, A/C 65.6, and C/C 65.5; p < 0.001), more frequent bulbar onset (A/A 29.6%, A/C 31.8%, and C/C 43.1%; p < 0.001), higher incidences of ALS‐FTD (A/A 4.3%, A/C 5.2%, and C/C 9.5%; p = 0.003), lower forced vital capacity at diagnosis (median percentage A/A 92.0, A/C 90.0, and C/C 86.5; p < 0.001), and a shorter survival (median in months A/A 33.3, A.C 30.7, and C/C 26.6; p < 0.001). UNC13A was associated with lower scores on ALS‐specific cognition tests (means A/A 79.5, A/C 78.1, and C/C 76.6; p = 0.037), and more frequent behavioral disturbances (A/A 16.7%, A/C 24.4%, and C/C 27.7%; p = 0.045). Thinner left inferior temporal and right fusiform cortex were associated with the UNC13A single nucleotide polymorphism (SNP; p = 0.045 and p = 0.036).

Interpretation

Phenotypical distinctions associated with UNC13A make it an important factor to take into account in clinical trial design, studies on cognition and behavior, and prognostic counseling. ANN NEUROL 2020;88:796–806

Urinary neopterin, a new marker of the neuroinflammatory status in amyotrophic lateral sclerosis

OBJECTIVE

To comprehensively assess whether neopterin in urine could be a candidate biomarker for determining the neuroinflammatory status in ALS.

METHODS

We performed an observational, cross-sectional study in 81 pALS, 68 age- and sex-comparable healthy controls (HC), 14 patients affected by MS and 24 OND patients. ALS patients underwent a neurological evaluation to assess the global functional status evaluated by Amyotrophic Lateral Sclerosis Functional Rating Scale-Revised (ALSFRS-R) and the disease progression rate. Urinary neopterin concentrations were determined by high-performance liquid chromatography method and were recorded at the time of first examination to assess their effect on disease severity and survival.

RESULTS

Urinary neopterin was significantly higher in pALS (263.90 [198.71-474.90]) compared to MS (155.28 [131.74-190.38], p =  < .001), OND patients (205.60 [158.96-299.41], p = 0.04) and HC (169.55 [134.91-226.10], p < .001). Moreover, a significant negative correlation was found between neopterin level and the severity of symptoms evaluated by ALSFRS-R total score (r = - 0.46, p < .001) and its subscores (bulbar r = - 0.34, p = 0.002; motor r = - 0.33, p = 0.003; respiratory r = - 0.53, p < .001), also adjusting for the effect of sex, site of onset, age at evaluation and time from onset to evaluation.

CONCLUSIONS

Our finding indicates that urine neopterin is elevated in ALS, emphasizing the role of the cell-mediated inflammation in the disease. Moreover, whether confirmed in further studies, our results will underline the neopterin's potential use as non-invasive clinical biomarker of ALS, to discriminate patients possibly candidates to clinical interventions aimed to interfere the neuroinflammatory processes.

A placebo-controlled trial to investigate the safety and efficacy of Penicillin G/Hydrocortisone in patients with ALS (PHALS trial)

OBJECTIVE

A recent case-series described patients with ALS to improve and/or stabilize after treatment with intravenous high-dose Penicillin G/Hydrocortisone (PenGH). In this study, we determine the safety and efficacy of intravenous PenGH versus placebo in combination with riluzole in patients with ALS.

METHODS

Patients diagnosed with ALS according to the El Escorial criteria were randomized double-blind to four quarterly cycles of 21 d of intravenous PenGH or placebo in a 5:3 ratio. The primary outcome was change from baseline to week 48 in Amyotrophic Lateral Sclerosis Functional Rating Scale-Revised (ALSFRS-R). Secondary outcomes were lung function, muscle strength, plasma creatinine, clinical stage, gastrostomy placement, quality of life and occurrence of adverse of events.

RESULTS

In total, 16 patients were randomized (10 PenGH and 6 placebo), of which 6 (40%) completed the study. Patients treated with PenGH progressed with 2.2 (95% CI 1.1-3.3) ALSFRS-R points per month and PenGH treatment did not halt disease progression (p = 0.002). No significant differences were found between PenGH or placebo (mean difference 0.5, 95% CI -1.01 to ∞, p = 0.28). Although PenGH was well-tolerated, 6 patients (38%, 3 in each arm) had thrombotic complications due to the intravenous administration method.

CONCLUSIONS

Treatment with PenGH does not halt disease or reverse progression in patients with ALS and showed no statistical difference with those who received placebo. Prolonged intravenous administration therapies may inflate thrombosis risk.

Amyotrophic lateral sclerosis: a clinical review

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder affecting primarily the motor system, but in which extra-motor manifestations are increasingly recognized. The loss of upper and lower motor neurons in the motor cortex, the brain stem nuclei and the anterior horn of the spinal cord gives rise to progressive muscle weakness and wasting. ALS often has a focal onset but subsequently spreads to different body regions, where failure of respiratory muscles typically limits survival to 2-5 years after disease onset. In up to 50% of cases, there are extra-motor manifestations such as changes in behaviour, executive dysfunction and language problems. In 10%-15% of patients, these problems are severe enough to meet the clinical criteria of frontotemporal dementia (FTD). In 10% of ALS patients, the family history suggests an autosomal dominant inheritance pattern. The remaining 90% have no affected family members and are classified as sporadic ALS. The causes of ALS appear to be heterogeneous and are only partially understood. To date, more than 20 genes have been associated with ALS. The most common genetic cause is a hexanucleotide repeat expansion in the C9orf72 gene, responsible for 30%-50% of familial ALS and 7% of sporadic ALS. These expansions are also a frequent cause of frontotemporal dementia, emphasizing the molecular overlap between ALS and FTD. To this day there is no cure or effective treatment for ALS and the cornerstone of treatment remains multidisciplinary care, including nutritional and respiratory support and symptom management. In this review, different aspects of ALS are discussed, including epidemiology, aetiology, pathogenesis, clinical features, differential diagnosis, investigations, treatment and future prospects.

Focus on the heterogeneity of amyotrophic lateral sclerosis

The clinical manifestations of amyotrophic lateral sclerosis (ALS) are variable in terms of age at disease onset, site of onset, progression of symptoms, motor neuron involvement, and the occurrence of cognitive and behavioral changes. Genetic background is a key determinant of the ALS phenotype. The mortality of the disease also varies with the ancestral origin of the affected population and environmental factors are likely to be associated with ALS at least within some cohorts. Disease heterogeneity is likely underpinned by the presence of different pathogenic mechanisms. A variety of ALS animal models can be informative about the heterogeneity of the neuropathological or genetic aspects of the disease and can support the development of new therapeutic intervention. Evolving biomarkers can contribute to the identification of differing genotypes and phenotypes, and can be used to explore whether genotypic and phenotypic differences in animal models might help to provide a better definition of the heterogeneity of ALS in humans. These include neurofilaments, peripheral blood mononuclear cells, extracellular vesicles, microRNA and imaging findings. These biomarkers might predict not only the development of the disease, but also the variability in progression, although robust validation is required. A promising area of progress in modeling the heterogeneity of human ALS is represented by the use of human induced pluripotent stem cell (iPSCs)-derived motor neurons. Although the translational value of iPSCs remains unclear, this model is attractive in the perspective of replicating the heterogeneity of sporadic ALS as a first step toward a personalized medicine strategy.

What do we know about the variability in survival of patients with amyotrophic lateral sclerosis?

INTRODUCTION

ALS is a fatal neurodegenerative disease. However, patients show variability in the length of survival after symptom onset. Understanding the mechanisms of long survival could lead to possible avenues for therapy.

AREAS COVERED

This review surveys the reported length of survival in ALS, the clinical features that predict survival in individual patients, and possible factors, particularly genetic factors, that could cause short or long survival. The authors also speculate on possible mechanisms.

EXPERT OPINION

a small number of known factors can explain some variability in ALS survival. However, other disease-modifying factors likely exist. Factors that alter motor neurone vulnerability and immune, metabolic, and muscle function could affect survival by modulating the disease process. Knowing these factors could lead to interventions to change the course of the disease. The authors suggest a broad approach is needed to quantify the proportion of variation survival attributable to genetic and non-genetic factors and to identify and estimate the effect size of specific factors. Studies of this nature could not only identify novel avenues for therapeutic research but also play an important role in clinical trial design and personalized medicine.

Establishment and evaluation of a multicenter collaborative prediction model construction framework supporting model generalization and continuous improvement: A pilot study

BACKGROUND AND OBJECTIVE

In recent years, an increasing number of clinical prediction models have been developed to serve clinical care. Establishing a data-driven prediction model based on large-scale electronic health record (EHR) data can provide a more empirical basis for clinical decision making. However, research on model generalization and continuous improvement is insufficiently focused, which also hinders the application and evaluation of prediction models in real clinical environments. Therefore, this study proposes a multicenter collaborative prediction model construction framework to build a prediction model with greater generalizability and continuous improvement capabilities while preserving patient data security and privacy.

MATERIALS AND METHODS

Based on a multicenter collaborative research network, such as the Observational Health Data Sciences and Informatics (OHDSI), a multicenter collaborative prediction model construction framework is proposed. Based on the idea of multi-source transfer learning, in each source hospital, a base classifier was trained according to the model research setting. Then, in the target hospital with missing calibration data, a prediction model was established through weighted integration of base classifiers from source hospitals based on the smoothness assumption. Moreover, a passive-aggressive online learning algorithm was used for continuous improvement of the prediction model, which can help to maintain a high predictive performance to provide reliable clinical decision-making abilities. To evaluate the proposed prediction model construction framework, a prototype system for colorectal cancer prognosis prediction was developed. To evaluate the performance of models, 70,906 patients were screened, including 70,090 from 5 US hospital-specific datasets and 816 from a Chinese hospital-specific dataset. The area under the receiver operating characteristic curve (AUC) and the estimated calibration index (ECI) were used to evaluate the discrimination and calibration of models.

RESULTS

Regarding the colorectal cancer prognosis prediction in our prototype system, compared with the reference models, our model achieved a better performance in model calibration (ECI = 9.294 [9.146, 9.441]) and a similar ability in model discrimination (AUC = 0.783 [0.780, 0.786]). Furthermore, the online learning process provided in this study can continuously improve the performance of the prediction model when patient data with specified labels arrive (the AUC value increased from 0.709 to 0.715 and the ECI value decreased from 13.013 to 9.634 after 650 patient instances with specified labels from the Chinese hospital arrived), enabling the prediction model to maintain a good predictive performance during clinical application.

CONCLUSIONS

This study proposes and evaluates a multicenter collaborative prediction model construction framework that can support the construction of prediction models with better generalizability and continuous improvement capabilities without the need to aggregate multicenter patient-level data.

Emerging Drugs for the Treatment of Amyotrophic Lateral Sclerosis: A Focus on Recent Phase 2 Trials

INTRODUCTION

Amyotrophic lateral sclerosis (ALS) is a rapidly progressive neurodegenerative disease involving both upper and lower motor neurons and resulting in increasing disability and death 3-5 years after onset of symptoms. Over 40 large clinical trials for ALS have been negative, except for Riluzole that offers a modest survival benefit, and Edaravone that modestly reduces disease progression in patients with specific characteristics. Thus, the discovery of efficient disease modifying therapy is an urgent need.

AREAS COVERED

Although the cause of ALS remains unclear, many studies have demonstrated that neuroinflammation, proteinopathies, glutamate-induced excitotoxicity, microglial activation, oxidative stress, and mitochondrial dysfunction may play a key role in the pathogenesis. This review highlights recent discoveries relating to these diverse mechanisms and their implications for the development of therapy. Ongoing phase 2 clinical trials aimed to interfere with these pathophysiological mechanisms are discussed.

EXPERT OPINION

This review describes the challenges that the discovery of an efficient drug therapy faces and how these issues may be addressed. With the continuous advances coming from basic research, we provided possible suggestions that may be considered to improve performance of clinical trials and turn ALS research into a 'fertile ground' for drug development for this devastating disease.

What Is in the Literature

This installment of what is in the literature is on amyotrophic lateral sclerosis (ALS). The pathophysiology of ALS remains open and the role of genes, a foothold into pathophysiology, but there are >22 genes identified, and the mechanisms are not known for any. Despite the lack of a firm understanding of pathophysiology, drug trials continue based on possible mechanisms, but no new drugs beyond riluzole and edaravone have been positive in phase 3 trials. There are a number of formal stem cell trials underway, and the results of a phase 2 trial are described. Major efforts to make trials more sensitive are being considered. There are a number of articles with helpful and practical findings for the diagnosis and management of ALS.

Multimodal longitudinal study of structural brain involvement in amyotrophic lateral sclerosis

OBJECTIVE

To understand the progressive nature of amyotrophic lateral sclerosis (ALS) by investigating differential brain patterns of gray and white matter involvement in clinically or genetically defined subgroups of patients using cross-sectional, longitudinal, and multimodal MRI.

METHODS

We assessed cortical thickness, subcortical volumes, and white matter connectivity from T1-weighted and diffusion-weighted MRI in 292 patients with ALS (follow-up: n = 150) and 156 controls (follow-up: n = 72). Linear mixed-effects models were used to assess changes in structural brain measurements over time in patients compared to controls.

RESULTS

Patients with a C9orf72 mutation (n = 24) showed widespread gray and white matter involvement at baseline, and extensive loss of white matter integrity in the connectome over time. In C9orf72-negative patients, we detected cortical thinning of motor and frontotemporal regions, and loss of white matter integrity of connections linked to the motor cortex. Patients with spinal onset displayed widespread white matter involvement at baseline and gray matter atrophy over time, whereas patients with bulbar onset started out with prominent gray matter involvement. Patients with unaffected cognition or behavior displayed predominantly motor system involvement, while widespread cerebral changes, including frontotemporal regions with progressive white matter involvement over time, were associated with impaired behavior or cognition. Progressive loss of gray and white matter integrity typically occurred in patients with shorter disease durations (<13 months), independent of progression rate.

CONCLUSIONS

Heterogeneity of phenotype and C9orf72 genotype relates to distinct patterns of cerebral degeneration. We demonstrate that imaging studies have the potential to monitor disease progression and early intervention may be required to limit cerebral degeneration.

Burden of Rare Variants in ALS and Axonal Hereditary Neuropathy Genes Influence Survival in ALS: Insights from a Next Generation Sequencing Study of an Italian ALS Cohort

Although the genetic architecture of amyotrophic lateral sclerosis (ALS) is incompletely understood, recent findings suggest a complex model of inheritance in ALS, which is consistent with a multistep pathogenetic process. Therefore, the aim of our work is to further explore the architecture of ALS using targeted next generation sequencing (NGS) analysis, enriched in motor neuron diseases (MND)-associated genes which are also implicated in axonal hereditary motor neuropathy (HMN), in order to investigate if disease expression, including the progression rate, could be influenced by the combination of multiple rare gene variants. We analyzed 29 genes in an Italian cohort of 83 patients with both familial and sporadic ALS. Overall, we detected 43 rare variants in 17 different genes and found that 43.4% of the ALS patients harbored a variant in at least one of the investigated genes. Of note, 27.9% of the variants were identified in other MND- and HMN-associated genes. Moreover, multiple gene variants were identified in 17% of the patients. The burden of rare variants is associated with reduced survival and with the time to reach King stage 4, i.e., the time to reach the need for percutaneous endoscopic gastrostomy (PEG) positioning or non-invasive mechanical ventilation (NIMV) initiation, independently of known negative prognostic factors. Our data contribute to a better understanding of the molecular basis of ALS supporting the hypothesis that rare variant burden could play a role in the multistep model of disease and could exert a negative prognostic effect. Moreover, we further extend the genetic landscape of ALS to other MND-associated genes traditionally implicated in degenerative diseases of peripheral axons, such as HMN and CMT2.