Trial of celecoxib in amyotrophic lateral sclerosis

The Place of PET to Assess New Therapeutic Effectiveness in Neurodegenerative Diseases

In vivo exploration of neurodegenerative diseases by positron emission tomography (PET) imaging has matured over the last 20 years, using dedicated radiopharmaceuticals targeting cellular metabolism, neurotransmission, neuroinflammation, or abnormal protein aggregates (beta-amyloid and intracellular microtubule inclusions containing hyperphosphorylated tau). The ability of PET to characterize biological processes at the cellular and molecular levels enables early detection and identification of molecular mechanisms associated with disease progression, by providing accurate, reliable, and longitudinally reproducible quantitative biomarkers. Thus, PET imaging has become a relevant imaging method for monitoring response to therapy, approved as an outcome measure in bioclinical trials. The aim of this paper is to review and discuss the current inputs of PET in the assessment of therapeutic effectiveness in neurodegenerative diseases connected by common pathophysiological mechanisms, including Parkinson's disease, Huntington's disease, dementia, amyotrophic lateral sclerosis, multiple sclerosis, and also in psychiatric disorders. We also discuss opportunities for PET imaging to drive more personalized neuroprotective and therapeutic strategies, taking into account individual variability, within the growing framework of precision medicine.

An assessment of treatment guidelines, clinical practices, demographics, and progression of disease among patients with amyotrophic lateral sclerosis in Japan, the United States, and Europe

BACKGROUND

There is an increasing clinical research focus on neuroprotective agents in amyotrophic lateral sclerosis (ALS). However, it is unclear how generalisable clinical study trial results are between different countries and regions.

OBJECTIVE

To assess similarities and differences in clinical practice and treatment guidelines for ALS, and also to compare the demographics and rate of progression of disease in patients with ALS enrolled in clinical trials in Japan, the US, and Europe.

METHODS

We performed a review of clinical studies published since 2000 to compare the demographics and characteristics of patients with ALS. Progression of ALS disease was assessed in patients receiving placebo. The changes per month in ALSFRS-R score were calculated and compared between the studies.

RESULTS

Overall, diagnostic criteria, recognition of ALS symptoms, comorbidities, use of riluzole, and nutritional, and respiratory support were similar. Regarding demographics and characteristics, there were no clear differences in the incidence of sporadic ALS (range 91-98%), bulbar onset (range 11-41%), and median time from onset to diagnosis (range 9-14 months) among the populations despite the difference in race between regions. However, use of tracheostomy-based invasive respiratory support was higher in Japan (29-38%) than in the US (4%) and Europe (1-31%). Rate of progression of disease was similar between the US and Europe study populations (range -0.89 to -1.60 points/month), and the Japanese study populations (range -1.03 to -1.21 points/month).

CONCLUSION

There is evidence to support the generalisability of data from the Japanese ALS trial experience to the US and Europe populations in early to mid-stage of ALS.

Temporospatial Analysis and New Players in the Immunology of Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder characterized by progressive loss of lower and upper motor neurons (MN) leading to muscle weakness, paralysis and eventually death. Although a highly varied etiology results in ALS, it broadly manifests itself as sporadic and familial forms that have evident similarities in clinical symptoms and disease progression. There is a tremendous amount of knowledge on molecular mechanisms leading to loss of MNs and neuromuscular junctions (NMJ) as major determinants of disease onset, severity and progression in ALS. Specifically, two main opposing hypotheses, the dying forward and dying back phenomena, exist to account for NMJ denervation. The former hypothesis proposes that the earliest degeneration occurs at the central MNs and proceeds to the NMJ, whereas in the latter, the peripheral NMJ is the site of precipitating degeneration progressing backwards to the MN cell body. A large body of literature strongly indicates a role for the immune system in disease onset and progression via regulatory involvement at the level of both the central and peripheral nervous systems (CNS and PNS). In this review, we discuss the earliest reported immune responses with an emphasis on newly identified immune players in mutant superoxide dismutase 1 (mSOD1) transgenic mice, the gold standard mouse model for ALS.

Drugs of Muscle Wasting and Their Therapeutic Targets

Muscle wasting and weakness such as cachexia, atrophy, and sarcopenia are characterized by marked decreases in the protein content, myonuclear number, muscle fiber size, and muscle strength. This chapter focuses on the recent advances of pharmacological approach for attenuating muscle wasting.A myostatin-inhibiting approach is very intriguing to prevent sarcopenia but not muscular dystrophy in humans. Supplementation with ghrelin is also an important candidate to combat sarcopenia as well as cachexia. Treatment with soy isoflavone, trichostatin A (TSA), and cyclooxygenase 2 (Cox2) inhibitors seems to be effective modulators attenuating muscle wasting, although further systematic research is needed on this treatment in particular concerning side effects.

Correlation of Peripheral Immunity With Rapid Amyotrophic Lateral Sclerosis Progression

Importance

Amyotrophic lateral sclerosis (ALS) has an immune component, but previous human studies have not examined immune changes over time.

Objectives

To assess peripheral inflammatory markers in participants with ALS and healthy control individuals and to track immune changes in ALS and determine whether these changes correlate with disease progression.

Design, Setting, and Participants

In this longitudinal cohort study, leukocytes were isolated from peripheral blood samples from 35 controls and 119 participants with ALS at the ALS Clinic of the University of Michigan, Ann Arbor, from June 18, 2014, through May 26, 2016. Follow-up visits occurred every 6 to 12 months. Fifty-one participants with ALS provided samples at multiple points. Immune cell populations were measured and compared between control and ALS groups. Surface marker expression of CD11b+ myeloid cells was also assessed. Changes over time were correlated with disease progression using multivariate regression.

Main Outcomes and Measures

The number of immune cells per milliliter of blood and the fold expression of cell surface markers. Multivariate regression models were used to correlate changes in immune metrics with changes on the Revised Amyotrophic Lateral Sclerosis Functional Rating Scale (ALSFRS-R).

Results

Thirty-five controls (17 women [48.6%] and 18 men [51.4%]; mean [SD] age, 63.5 [9.9] years) and 119 participants with ALS (50 women [42.0%] and 69 men [68.0%]; mean [SD] age, 61.4 [11.5] years) were enrolled. Compared with controls, participants with ALS had increased mean (SEM) counts ( × 106/mL) of total leukocytes (4.57 [0.29; 95% CI, 3.94-5.11] vs 5.53 [0.16; 95% CI, 5.21-5.84]), neutrophils (2.87 [0.23; 95% CI, 2.40-3.35] vs 3.80 [0.12; 95% CI, 3.56-4.04]), CD16+ monocytes (0.03 [0.003; 95% CI, 0.02-0.04] vs 0.04 [0.002; 95% CI, 0.03-0.04]), CD16- monocytes (0.25 [0.02; 95% CI, 0.21-0.30] vs 0.29 [0.01; 95% CI, 0.27-0.31]), and natural killer cells (0.13 [0.02; 95% CI, 0.10-0.17] vs 0.18 [0.01; 95% CI, 0.16-0.21]). We also observed an acute, transient increase in a population of CD11b+ myeloid cells expressing HLA-DR, CD11c, and CX3CR1. Finally, early changes in immune cell numbers had a significant correlation with disease progression measured by change in ALSFRS-R score, particularly neutrophils (-4.37 [95% CI, -6.60 to -2.14] per 11.47 × 104/mL [SD, 58.04 × 104/mL] per year) and CD4 T cells (-30.47 [95% CI, -46.02 to -14.94] per -3.72 × 104/mL [SD, 26.21 × 104/mL] per year).

Conclusions and Relevance

Changes in the immune system occur during ALS and may contribute to the pathologic features of ALS.

Etiogenic factors present in the cerebrospinal fluid from amyotrophic lateral sclerosis patients induce predominantly pro-inflammatory responses in microglia

Background

Microglial cell-associated neuroinflammation is considered as a potential contributor to the pathophysiology of sporadic amyotrophic lateral sclerosis. However, the specific role of microglia in the disease pathogenesis remains to be elucidated.

Methods

We studied the activation profiles of the microglial cultures exposed to the cerebrospinal fluid from these patients which recapitulates the neurodegeneration seen in sporadic amyotrophic lateral sclerosis. This was done by investigating the morphological and functional changes including the expression levels of prostaglandin E2 (PGE2), cyclooxygenase-2 (COX-2), TNF-α, IL-6, IFN-γ, IL-10, inducible nitric oxide synthase (iNOS), arginase, and trophic factors. We also studied the effect of chitotriosidase, the inflammatory protein found upregulated in the cerebrospinal fluid from amyotrophic lateral sclerosis patients, on these cultures.

Results

We report that the cerebrospinal fluid from amyotrophic lateral sclerosis patients could induce an early and potent response in the form of microglial activation, skewed primarily towards a pro-inflammatory profile. It was seen in the form of upregulation of the pro-inflammatory cytokines and factors including IL-6, TNF-α, iNOS, COX-2, and PGE2. Concomitantly, a downregulation of beneficial trophic factors and anti-inflammatory markers including VEGF, glial cell line-derived neurotrophic factor, and IFN-γ was seen. In addition, chitotriosidase-1 appeared to act specifically via the microglial cells.

Conclusion

Our findings demonstrate that the cerebrospinal fluid from amyotrophic lateral sclerosis patients holds enough cues to induce microglial inflammatory processes as an early event, which may contribute to the neurodegeneration seen in the sporadic amyotrophic lateral sclerosis. These findings highlight the dynamic role of microglial cells in the pathogenesis of the disease, thus suggesting the need for a multidimensional and temporally guarded therapeutic approach targeting the inflammatory pathways for its treatment.

Electronic supplementary material

The online version of this article (10.1186/s12974-017-1028-x) contains supplementary material, which is available to authorized users.

Shortcomings in the Current Amyotrophic Lateral Sclerosis Trials and Potential Solutions for Improvement

Amyotrophic lateral sclerosis (ALS) is a clinically progressive neurodegenerative syndrome predominantly affecting motor neurons and their associated tracts. Riluzole and edaravone are the only FDA certified drugs for treating ALS. Over the past two decades, almost all clinical trials aiming to develop a successful therapeutic strategy for this disease have failed. Genetic complexity, inadequate animal models, poor clinical trial design, lack of sensitive biomarkers, and diagnostic delays are some of the potential reasons limiting any significant development in ALS clinical trials. In this review, we have outlined the possible reasons for failure of ALS clinical trials, addressed the factors limiting timely diagnosis, and suggested possible solutions for future considerations for each of the shortcomings.

Immune Modulation in the Treatment of Amyotrophic Lateral Sclerosis: A Review of Clinical Trials

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease characterized by the degeneration of motor neurons. Though many molecular and genetic causes are thought to serve as predisposing or disease propagating factors, the underlying pathogenesis of the disease is not known. Recent discoveries have demonstrated the presence of inflammation propagating substrates in the central nervous system of patients afflicted with ALS. Over the past decade, this hypothesis has incited an effort to better understand the role of the immune system in ALS and has led to the trial of several potential immune-modulating therapies. Here, we briefly review advances in the role of such therapies. The clinical trials discussed here are currently ongoing or have been concluded at the time of writing.

Role of Neuroinflammation in Amyotrophic Lateral Sclerosis: Cellular Mechanisms and Therapeutic Implications

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease that affects upper motor neurons (MNs) comprising the corticospinal tract and lower MNs arising from the brain stem nuclei and ventral roots of the spinal cord, leading to fatal paralysis. Currently, there are no effective therapies for ALS. Increasing evidence indicates that neuroinflammation plays an important role in ALS pathogenesis. The neuroinflammation in ALS is characterized by infiltration of lymphocytes and macrophages, activation of microglia and reactive astrocytes, as well as the involvement of complement. In this review, we focus on the key cellular players of neuroinflammation during the pathogenesis of ALS by discussing not only their detrimental roles but also their immunomodulatory actions. We will summarize the pharmacological therapies for ALS that target neuroinflammation, as well as recent advances in the field of stem cell therapy aimed at modulating the inflammatory environment to preserve the remaining MNs in ALS patients and animal models of the disease.

Comprehensive immune profiling reveals substantial immune system alterations in a subset of patients with amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease with a median lifespan of 2-3 years after diagnosis. There are few meaningful treatments that alter progression in this disease. Preclinical and clinical studies have demonstrated that neuroinflammation may play a key role in the progression rate of ALS. Despite this, there are no validated biomarkers of neuroinflammation for use in clinical practice or clinical trials. Biomarkers of neuroinflammation could improve patient management, provide new therapeutic targets, and possibly help stratify clinical trial selection and monitoring. However, attempts to identify a singular cause of neuroinflammation have not been successful. Here, we performed multi-parameter flow cytometry to comprehensively assess 116 leukocyte populations and phenotypes from lymphocytes, monocytes, and granulocytes in a cohort of 80 ALS patients. We identified 32 leukocyte phenotypes that were altered in ALS patients compared to age and gender matched healthy volunteers (HV) that included phenotypes of both inflammation and immune suppression. Unsupervised hierarchical clustering and principle component analysis of ALS and HV immunophenotypes revealed two distinct immune profiles of ALS patients. ALS patients were clustered into a profile distinct from HVs primarily due to differences in a multiple T cell phenotypes, CD3+CD56+ T cells and HLA-DR on monocytes. Patients clustered into an abnormal immune profile were younger, more likely to have a familial form of the disease, and survived longer than those patients who clustered similarly with healthy volunteers (344 weeks versus 184 weeks; p = 0.012). The data set generated from this study establishes an extensive accounting of immunophenotypic changes readily suitable for biomarker validation studies. The extensive immune system changes measured in this study indicate that normal immune homeostatic mechanisms are disrupted in ALS patients, and that multiple immune states likely exist within a population of patients with ALS.

Evidence for an early innate immune response in the motor cortex of ALS

Background

Recent evidence indicates the importance of innate immunity and neuroinflammation with microgliosis in amyotrophic lateral sclerosis (ALS) pathology. The MCP1 (monocyte chemoattractant protein-1) and CCR2 (CC chemokine receptor 2) signaling system has been strongly associated with the innate immune responses observed in ALS patients, but the motor cortex has not been studied in detail.

Methods

After revealing the presence of MCP1 and CCR2 in the motor cortex of ALS patients, to elucidate, visualize, and define the timing, location and the extent of immune response in relation to upper motor neuron vulnerability and progressive degeneration in ALS, we developed MCP1-CCR2-hSOD1^G93A mice, an ALS reporter line, in which cells expressing MCP1 and CCR2 are genetically labeled by monomeric red fluorescent protein-1 and enhanced green fluorescent protein, respectively.

Results

In the motor cortex of MCP1-CCR2-hSOD1^G93A mice, unlike in the spinal cord, there was an early increase in the numbers of MCP1+ cells, which displayed microglial morphology and selectively expressed microglia markers. Even though fewer CCR2+ cells were present throughout the motor cortex, they were mainly infiltrating monocytes. Interestingly, MCP1+ cells were found in close proximity to the apical dendrites and cell bodies of corticospinal motor neurons (CSMN), further implicating the importance of their cellular interaction to neuronal pathology. Similar findings were observed in the motor cortex of ALS patients, where MCP1+ microglia were especially in close proximity to the degenerating apical dendrites of Betz cells.

Conclusions

Our findings reveal that the intricate cellular interplay between immune cells and upper motor neurons observed in the motor cortex of ALS mice is indeed recapitulated in ALS patients. We generated and characterized a novel model system, to study the cellular and molecular basis of this close cellular interaction and how that relates to motor neuron vulnerability and progressive degeneration in ALS.

Electronic supplementary material

The online version of this article (doi:10.1186/s12974-017-0896-4) contains supplementary material, which is available to authorized users.

Should We Stop Saying 'Glia' and 'Neuroinflammation'?

Central nervous system (CNS) therapeutics based on the theoretical framework of neuroinflammation have only barely succeeded. We argue that a problem may be the wrong use of the term 'neuroinflammation' as a distinct nosological entity when, based on recent evidence, it may not explain CNS disease pathology. Indeed, the terms 'neuroinflammation' and 'glia' could be obsolete. First, unbiased molecular profiling of CNS cell populations and individual cells reveals striking phenotypic heterogeneity in health and disease. Second, astrocytes, microglia, oligodendrocytes, and NG2 cells may contribute to higher-brain functions by performing actions beyond housekeeping. We propose that CNS diseases be viewed as failed circuits caused in part by disease-specific dysfunction of cells traditionally called 'glia', and hence, favor therapies promoting their functional recovery.

Molecular Targets for PET Imaging of Activated Microglia: The Current Situation and Future Expectations

Microglia, as cellular mediators of neuroinflammation, are implicated in the pathogenesis of a wide range of neurodegenerative diseases. Positron emission tomography (PET) imaging of microglia has matured over the last 20 years, through the development of radiopharmaceuticals targeting several molecular biomarkers of microglial activation and, among these, mainly the translocator protein-18 kDa (TSPO). Nevertheless, current limitations of TSPO as a PET microglial biomarker exist, such as low brain density, even in a neurodegenerative setting, expression by other cells than the microglia (astrocytes, peripheral macrophages in the case of blood brain barrier breakdown), genetic polymorphism, inducing a variation for most of TSPO PET radiopharmaceuticals’ binding affinity, or similar expression in activated microglia regardless of its polarization (pro- or anti-inflammatory state), and these limitations narrow its potential interest. We overview alternative molecular targets, for which dedicated radiopharmaceuticals have been proposed, including receptors (purinergic receptors P2X7, cannabinoid receptors, α7 and α4β2 nicotinic acetylcholine receptors, adenosine 2A receptor, folate receptor β) and enzymes (cyclooxygenase, nitric oxide synthase, matrix metalloproteinase, β-glucuronidase, and enzymes of the kynurenine pathway), with a particular focus on their respective contribution for the understanding of microglial involvement in neurodegenerative diseases. We discuss opportunities for these potential molecular targets for PET imaging regarding their selectivity for microglia expression and polarization, in relation to the mechanisms by which microglia actively participate in both toxic and neuroprotective actions in brain diseases, and then take into account current clinicians’ expectations.

ALS Clinical Trials Review: 20 Years of Failure. Are We Any Closer to Registering a New Treatment?

Amyotrophic lateral sclerosis (ALS) is a devastating condition with an estimated mortality of 30,000 patients a year worldwide. The median reported survival time since onset ranges from 24 to 48 months. Riluzole is the only currently approved mildly efficacious treatment. Riluzole received marketing authorization in 1995 in the USA and in 1996 in Europe. In the years that followed, over 60 molecules have been investigated as a possible treatment for ALS. Despite significant research efforts, the overwhelming majority of human clinical trials (CTs) have failed to demonstrate clinical efficacy. In the past year, oral masitinib and intravenous edaravone have emerged as promising new therapeutics with claimed efficacy in CTs in ALS patients. Given their advanced phase of clinical development one may consider these drugs as the most likely near-term additions to the therapeutic arsenal available for patients with ALS. In terms of patient inclusion, CT with masitinib recruited a wider, more representative, less restrictive patient population in comparison to the only successful edaravone CT (edaravone eligibility criteria represents only 18% of masitinib study patients). The present manuscript reviews >50 CTs conducted in the last 20 years since riluzole was first approved. A special emphasis is put on the analysis of existing evidence in support of the clinical efficacy of edaravone and masitinib and the possible implications of an eventual marketing authorisation in the treatment of ALS.

Fluid-Based Biomarkers for Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is a highly heterogeneous disease with no effective treatment. Drug development has been hampered by the lack of biomarkers that aid in early diagnosis, demonstrate target engagement, monitor disease progression, and can serve as surrogate endpoints to assess the efficacy of treatments. Fluid-based biomarkers may potentially address these issues. An ideal biomarker should exhibit high specificity and sensitivity for distinguishing ALS from control (appropriate disease mimics and other neurologic diseases) populations and monitor disease progression within individual patients. Significant progress has been made using cerebrospinal fluid, serum, and plasma in the search for ALS biomarkers, with urine and saliva biomarkers still in earlier stages of development. A few of these biomarker candidates have demonstrated use in patient stratification, predicting disease course (fast vs slow progression) and severity, or have been used in preclinical and clinical applications. However, while ALS biomarker discovery has seen tremendous advancements in the last decade, validating biomarkers and moving them towards the clinic remains more elusive. In this review, we highlight biomarkers that are moving towards clinical utility and the challenges that remain in order to implement biomarkers at all stages of the ALS drug development process.

Strength Testing in Motor Neuron Diseases

Loss of muscle strength is a cardinal feature of all motor neuron diseases. Functional loss over time, including respiratory dysfunction, inability to ambulate, loss of ability to perform activities of daily living, and others are due, in large part, to decline in strength. Thus, the accurate measurement of limb muscle strength is essential in therapeutic trials to best understand the impact of therapy on vital function. While qualitative strength measurements show declines over time, the lack of reproducibility and linearity of measurement make qualitative techniques inadequate. A variety of quantitative measures have been developed; all have both positive attributes and limitations. However, with careful training and reliability testing, quantitative measures have proven to be reliable and sensitive indicators of both disease progression and the impact of experimental therapy. Quantitative strength measurements have demonstrated potentially important therapeutic effects in both amyotrophic lateral sclerosis and spinobulbar muscular atrophy, and have been shown feasible in children with spinal muscular atrophy. The spectrum of both qualitative and quantitative strength measurements are reviewed and their utility examined in this review.

Potential new complication in drug therapy development for amyotrophic lateral sclerosis

INTRODUCTION

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease characterized by motor neuron degeneration in the brain and spinal cord. Treatment development for ALS is complicated by complex underlying disease factors. Areas covered: Numerous tested drug compounds have shown no benefits in ALS patients, although effective in animal models. Discrepant results of pre-clinical animal studies and clinical trials for ALS have primarily been attributed to limitations of ALS animal models for drug-screening studies and methodological inconsistencies in human trials. Current status of pre-clinical and clinical trials in ALS is summarized. Specific blood-CNS barrier damage in ALS patients, as a novel potential reason for the clinical failures in drug therapies, is discussed. Expert commentary: Pathological perivascular collagen IV accumulation, one unique characteristic of barrier damage in ALS patients, could be hindering transport of therapeutics to the CNS. Restoration of B-CNS-B integrity would foster delivery of therapeutics to the CNS.

Why is ALS so Difficult to Treat?

Amyotrophic lateral sclerosis (ALS) is proving intractable. Difficulties in pre-clinical studies contribute in small measure to this futility, but the chief reason for failure is an inadequate understanding of disease pathogenesis. Many acquired and inherited processes have been advanced as potential causes of ALS but, while they may predispose to disease, it seems increasingly likely that none leads directly to ALS. Rather, two recent overlapping considerations, both involving aberrant protein homeostasis, may provide a better explanation for a common disease phenotype and a common terminal pathogenesis. If so, therapeutic approaches will need to be altered and carefully nuanced, since protein homeostasis is essential and highly conserved. Nonetheless, these considerations provide new optimism in a difficult disease which has hitherto defied treatment.

Advances in the Development of Disease-Modifying Treatments for Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is a progressive adult-onset, neurodegenerative disease characterized by the degeneration of upper and lower motor neurons. Over recent years, numerous genes ha ve been identified that promote disease pathology, including SOD1, TARDBP, and the expanded hexanucleotide repeat (GGGGCC) within C9ORF72. However, despite these major advances in identifying genes contributing to ALS pathogenesis, there remains only one currently approved therapeutic: the glutamate antagonist, riluzole. Seminal breakthroughs in the pathomechanisms and genetic factors associated with ALS have heavily relied on the use of rodent models that recapitulate the ALS phenotype; however, while many therapeutics have proved to be significant in animal models by prolonging life and rescuing motor deficits, they have failed in human clinical trials. This may be due to fundamental differences between rodent models and human disease, the fact that animal models are based on overexpression of mutated genes, and confounding issues such as difficulties mimicking the dosing schedules and regimens implemented in mouse models to humans. Here, we review the major pathways associated with the pathology of ALS, the rodent models engineered to test efficacy of candidate drugs, the advancements being made in stem cell therapy for ALS, and what strategies may be important to circumvent the lack of successful translational studies in the clinic.

A Multiplex Protein Panel Applied to Cerebrospinal Fluid Reveals Three New Biomarker Candidates in ALS but None in Neuropathic Pain Patients

The objective of this study was to develop and apply a novel multiplex panel of solid-phase proximity ligation assays (SP-PLA) requiring only 20 μL of samples, as a tool for discovering protein biomarkers for neurological disease and treatment thereof in cerebrospinal fluid (CSF). We applied the SP-PLA to samples from two sets of patients with poorly understood nervous system pathologies amyotrophic lateral sclerosis (ALS) and neuropathic pain, where patients were treated with spinal cord stimulation (SCS). Forty-seven inflammatory and neurotrophic proteins were measured in samples from 20 ALS patients and 15 neuropathic pain patients, and compared to normal concentrations in CSF from control individuals. Nineteen of the 47 proteins were detectable in more than 95% of the 72 controls. None of the 21 proteins detectable in CSF from neuropathic pain patients were significantly altered by SCS. The levels of the three proteins, follistatin, interleukin-1 alpha, and kallikrein-5 were all significantly reduced in the ALS group compared to age-matched controls. These results demonstrate the utility of purpose designed multiplex SP-PLA panels in CSF biomarker research for understanding neuropathological and neurotherapeutic mechanisms. The protein changes found in the CSF of ALS patients may be of diagnostic interest.

Intraspinal stem cell transplantation for amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disorder in which the loss of upper and lower motor neurons produces progressive weakness and eventually death. In the decades since the approval of riluzole, the only US Food and Drug Administration-approved medication to moderately slow progression of ALS, no new therapeutics have arisen to alter the course of the disease. This is partly due to our incomplete understanding of the complex pathogenesis of motor neuron degeneration. Stem cells have emerged as an attractive option in treating ALS, because they come armed with equally complex cellular machinery and may modulate the local microenvironment in many ways to rescue diseased motor neurons. Various stem cell types are being evaluated in preclinical and early clinical applications; here, we review the preclinical strategies and advances supporting the recent clinical translation of neural progenitor cell therapy for ALS. Specifically, we focus on the use of spinal cord neural progenitor cells and the pipeline starting from preclinical studies to the designs of phase I and IIa clinical trials involving direct intraspinal transplantation in humans.

Global rank tests for multiple, possibly censored, outcomes

Clinical trials often collect multiple outcomes on each patient, as the treatment may be expected to affect the patient on many dimensions. For example, a treatment for a neurological disease such as ALS is intended to impact several dimensions of neurological function as well as survival. The assessment of treatment on the basis of multiple outcomes is challenging, both in terms of selecting a test and interpreting the results. Several global tests have been proposed, and we provide a general approach to selecting and executing a global test. The tests require minimal parametric assumptions, are flexible about weighting of the various outcomes, and are appropriate even when some or all of the outcomes are censored. The test we propose is based on a simple scoring mechanism applied to each pair of subjects for each endpoint. The pairwise scores are then reduced to a summary score, and a rank-sum test is applied to the summary scores. This can be seen as a generalization of previously proposed nonparametric global tests (e.g., O'Brien, 1984). We discuss the choice of optimal weighting schemes based on power and relative importance of the outcomes. As the optimal weights are generally unknown in practice, we also propose an adaptive weighting scheme and evaluate its performance in simulations. We apply the methods to analyze the impact of a treatment on neurological function and death in an ALS trial.

Novel Neuroprotective Multicomponent Therapy for Amyotrophic Lateral Sclerosis Designed by Networked Systems

Amyotrophic Lateral Sclerosis is a fatal, progressive neurodegenerative disease characterized by loss of motor neuron function for which there is no effective treatment. One of the main difficulties in developing new therapies lies on the multiple events that contribute to motor neuron death in amyotrophic lateral sclerosis. Several pathological mechanisms have been identified as underlying events of the disease process, including excitotoxicity, mitochondrial dysfunction, oxidative stress, altered axonal transport, proteasome dysfunction, synaptic deficits, glial cell contribution, and disrupted clearance of misfolded proteins. Our approach in this study was based on a holistic vision of these mechanisms and the use of computational tools to identify polypharmacology for targeting multiple etiopathogenic pathways. By using a repositioning analysis based on systems biology approach (TPMS technology), we identified and validated the neuroprotective potential of two new drug combinations: Aliretinoin and Pranlukast, and Aliretinoin and Mefloquine. In addition, we estimated their molecular mechanisms of action in silico and validated some of these results in a well-established in vitro model of amyotrophic lateral sclerosis based on cultured spinal cord slices. The results verified that Aliretinoin and Pranlukast, and Aliretinoin and Mefloquine promote neuroprotection of motor neurons and reduce microgliosis.

Interleukin-1 Antagonist Anakinra in Amyotrophic Lateral Sclerosis--A Pilot Study

Preclinical studies show that blocking Interleukin–1 (IL–1) retards the progression of Amyotrophic Lateral Sclerosis (ALS). We assessed the safety of Anakinra (ANA), an IL–1 receptor antagonist, in ALS patients. In a single arm pilot study we treated 17 ALS patients with ANA (100 mg) daily for one year. We selected patients with dominant or exclusive lower motor neuron degeneration (LMND) presentation, as peripheral nerves may be more accessible to the drug. Our primary endpoint was safety and tolerability. Secondary endpoints included measuring disease progression with the revised ALS functional rating scale (ALSFRSr). We also quantified serum inflammatory markers. For comparison, we generated a historical cohort of 47 patients that fit the criteria for enrolment, disease characteristics and rate of progression of the study group. Only mild adverse events occurred in ALS patients treated with ANA. Notably, we observed lower levels of cytokines and the inflammatory marker fibrinogen during the first 24 weeks of treatment. Despite of this, we could not detect a significant reduction in disease progression during the same period in patients treated with ANA compared to controls as measured by the ALSFRSr. In the second part of the treatment period we observed an increase in serum inflammatory markers. Sixteen out of the 17 patients (94%) developed antibodies against ANA. This study showed that blocking IL–1 is safe in patients with ALS. Further trials should test whether targeting IL–1 more efficiently can help treating this devastating disease.

A retrospective review of the progress in amyotrophic lateral sclerosis drug discovery over the last decade and a look at the latest strategies

INTRODUCTION

Drug discovery for amyotrophic lateral sclerosis (ALS) has experienced a surge in clinical studies and remarkable preclinical milestones utilizing a variety of mutant superoxide dismutase 1 model systems. Of the drugs that were tested and showed positive preclinical effects, none demonstrated therapeutic benefits to ALS patients in clinical settings.

AREAS COVERED

This review discusses the advances made in drug discovery for ALS and highlights why drug development is proving to be so difficult. It also discusses how a closer look at both preclinical and clinical studies could uncover the reasons why these preclinical successes have yet to result in the availability of an effective drug for clinical use.

EXPERT OPINION

Valuable lessons from the numerous preclinical and clinical studies supply the biggest advantage in the monumental task of finding a cure for ALS. Obviously, a single design type for ALS clinical trials has not yielded success. The authors suggest a two-pronged approach that may prove essential to achieve clinical efficacy in the identification of novel targets and preclinical testing in multiple models to identify biomarkers that can function in diagnostic, predictive and prognostic roles, and changes to clinical trial design and patient recruitment criteria. The advancement of technology and invention of more powerful tools will further enhance the above. This will give rise to more sophisticated clinical trials with consideration of a range of criteria from: optimum dose, route of delivery, specific biomarkers, pharmacokinetics, pharmacodynamics and toxicology to biomarkers, timing for trial and patients' clinical status.

Amyotrophic lateral sclerosis: Current perspectives from basic research to the clinic

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterized by progressive degeneration of upper and lower motoneurons, leading to muscle weakness and paralysis, and finally death. Considerable recent advances have been made in basic research and preclinical therapeutic attempts using experimental models, leading to increasing clinical and translational research in the context of this disease. In this review we aim to summarize the most relevant findings from a variety of aspects about ALS, including evaluation methods, animal models, pathophysiology, and clinical findings, with particular emphasis in understanding the role of every contributing mechanism to the disease for elucidating the causes underlying degeneration of motoneurons and the development of new therapeutic strategies.

Rodent Models of Amyotrophic Lateral Sclerosis

Amyotrophic Lateral Sclerosis (ALS) is a motor neuron disease affecting upper and lower motor neurons in the central nervous system. Patients with ALS develop extensive muscle wasting and atrophy leading to paralysis and death 3 to 5 years after disease onset. The condition may be familial (fALS 10%) or sporadic ALS (sALS, 90%). The large majority of fALS cases are due to genetic mutations in the Superoxide dismutase 1 gene (SOD1, 15% of fALS) and repeat nucleotide expansions in the gene encoding C9ORF72 (∼ 40% to 50% of fALS and ∼ 10% of sALS). Studies suggest that ALS is mediated through aberrant protein homeostasis (i.e., ER stress and autophagy) and/or changes in RNA processing (as in all non-SOD1-mediated ALS). In all of these cases, animal models suggest that the disorder is mediated non-cell autonomously, i.e., not only motor neurons are involved, but glial cells including microglia, astrocytes, and oligodendrocytes, and other neuronal subpopulations are also implicated in the pathogenesis. Provided in this unit is a review of ALS rodent models, including discussion of their relative advantages and disadvantages. Emphasis is placed on correlating the model phenotype with the human condition and the utility of the model for defining the disease process. Information is also presented on RNA processing studies in ALS research, with particular emphasis on the newest ALS rodent models.

Pre-morbid type 2 diabetes mellitus is not a prognostic factor in amyotrophic lateral sclerosis

INTRODUCTION

The aim of this study was to determine whether a history of pre-morbid type 2 diabetes mellitus (DM2) is a prognostic factor in amyotrophic lateral sclerosis (ALS).

METHODS

The relationship between DM2 and survival was analyzed in a study population consisting of 1,322 participants from 6 clinical trials.

RESULTS

Survival did not differ by diabetes status (log-rank test, P = 0.98), but did differ by body mass index (BMI) (log-rank test, P = 0.008). In multivariate analysis, there was no significant association between diabetes and survival (P = 0.18), but the risk of reaching a survival endpoint decreased by 4% for each unit increase in baseline BMI (HR 0.96, 95% CI 0.94-0.99, P = 0.001). DM2 was less prevalent among ALS clinical trial participants than predicted.

CONCLUSIONS

A history of pre-morbid DM2 is not an independent prognostic factor in ALS clinical trial databases. The low DM2 prevalence rate should be examined in a large, prospective study to determine whether DM2 affects ALS risk.

A multi-center screening trial of rasagiline in patients with amyotrophic lateral sclerosis: Possible mitochondrial biomarker target engagement

Rasagiline, a monoamine oxidase B inhibitor, slowed disease progression in the SOD1 mouse, and in a case series of patients with amyotrophic lateral sclerosis (ALS). Here we determine whether rasagiline is safe and effective in ALS compared to historical placebo controls, and whether it alters mitochondrial biomarkers. We performed a prospective open-label, multicenter screening trial of 36 ALS patients treated with 2 mg oral rasagiline daily for 12 months. Outcomes included the slope of deterioration of the revised ALS Functional Rating Scale (ALSFRS-R), adverse event monitoring, time to treatment failure, and exploratory biomarkers. Participants experienced no serious drug-related adverse events, and the most common adverse event was nausea (11.1%). Rasagiline did not improve the rate of decline in the ALSFRS-R; however, differences in symptom duration compared to historical placebo controls differentially affected ALSFRS-R slope estimates. Rasagiline changed biomarkers over 12 months, such that the mitochondrial membrane potential increased (JC-1 red/green fluorescent ratio 1.92, p = 0.0001) and apoptosis markers decreased (Bcl-2/Bax ratio 0.24, p < 0.0001). In conclusion, engagement of exploratory biomarkers and questions about comparability of baseline characteristics lead us to recommend a further placebo-controlled trial.

Being PRO-ACTive: What can a Clinical Trial Database Reveal About ALS?

Advancing research and clinical care, and conducting successful and cost-effective clinical trials requires characterizing a given patient population. To gather a sufficiently large cohort of patients in rare diseases such as amyotrophic lateral sclerosis (ALS), we developed the Pooled Resource Open-Access ALS Clinical Trials (PRO-ACT) platform. The PRO-ACT database currently consists of >8600 ALS patient records from 17 completed clinical trials, and more trials are being incorporated. The database was launched in an open-access mode in December 2012; since then, >400 researchers from >40 countries have requested the data. This review gives an overview on the research enabled by this resource, through several examples of research already carried out with the goal of improving patient care and understanding the disease. These examples include predicting ALS progression, the simulation of future ALS clinical trials, the verification of previously proposed predictive features, the discovery of novel predictors of ALS progression and survival, the newly identified stratification of patients based on their disease progression profiles, and the development of tools for better clinical trial recruitment and monitoring. Results from these approaches clearly demonstrate the value of large datasets for developing a better understanding of ALS natural history, prognostic factors, patient stratification, and more. The increasing use by the community suggests that further analyses of the PRO-ACT database will continue to reveal more information about this disease that has for so long defied our understanding.

Protective and Toxic Neuroinflammation in Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is a clinically heterogeneous disorder characterized by loss of motor neurons, resulting in paralysis and death. Multiple mechanisms of motor neuron injury have been implicated based upon the more than 20 different genetic causes of familial ALS. These inherited mutations compromise diverse motor neuron pathways leading to cell-autonomous injury. In the ALS transgenic mouse models, however, motor neurons do not die alone. Cell death is noncell-autonomous dependent upon a well orchestrated dialogue between motor neurons and surrounding glia and adaptive immune cells. The pathogenesis of ALS consists of 2 stages: an early neuroprotective stage and a later neurotoxic stage. During early phases of disease progression, the immune system is protective with glia and T cells, especially M2 macrophages/microglia, and T helper 2 cells and regulatory T cells, providing anti-inflammatory factors that sustain motor neuron viability. As the disease progresses and motor neuron injury accelerates, a second rapidly progressing phase develops, characterized by M1 macrophages/microglia, and proinflammatory T cells. In rapidly progressing ALS patients, as in transgenic mice, neuroprotective regulatory T cells are significantly decreased and neurotoxicity predominates. Our own therapeutic efforts are focused on modulating these neuroinflammatory pathways. This review will focus on the cellular players involved in neuroinflammation in ALS and current therapeutic strategies to enhance neuroprotection and suppress neurotoxicity with the goal of arresting the progressive and devastating nature of ALS.

Evaluation of WO 2012/177618 A1 and US-2014/0179750 A1: novel small molecule antagonists of prostaglandin-E2 receptor EP2

Recent studies underscore that prostaglandin-E2 exerts mostly proinflammatory effects in chronic CNS and peripheral disease models, mainly through a specific prostanoid receptor EP2. However, very few highly characterized EP2 receptor antagonists have been reported until recently, when Pfizer and Emory University published two distinct classes of EP2 antagonists with good potency, selectivity and pharmacokinetics. The purpose of this article is to evaluate recently published patents WO 2012/177618 A1 and US-2014/0179750 A1 from Emory, which describe a number of cinnamic amide- and amide-derivatives as a potent antagonists of EP2 receptor, and their neuroprotective effects in in vitro and in an in vivo model. A selected compound from this patent(s) also attenuates prostate cancer cell growth and invasion in vitro, suggesting these compounds should be developed for therapeutic use.

The PRO-ACT database: design, initial analyses, and predictive features

OBJECTIVE

To pool data from completed amyotrophic lateral sclerosis (ALS) clinical trials and create an open-access resource that enables greater understanding of the phenotype and biology of ALS.

METHODS

Clinical trials data were pooled from 16 completed phase II/III ALS clinical trials and one observational study. Over 8 million de-identified longitudinally collected data points from over 8,600 individuals with ALS were standardized across trials and merged to create the Pooled Resource Open-Access ALS Clinical Trials (PRO-ACT) database. This database includes demographics, family histories, and longitudinal clinical and laboratory data. Mixed effects models were used to describe the rate of disease progression measured by the Revised ALS Functional Rating Scale (ALSFRS-R) and vital capacity (VC). Cox regression models were used to describe survival data. Implementing Bonferroni correction, the critical p value for 15 different tests was p = 0.003.

RESULTS

The ALSFRS-R rate of decline was 1.02 (±2.3) points per month and the VC rate of decline was 2.24% of predicted (±6.9) per month. Higher levels of uric acid at trial entry were predictive of a slower drop in ALSFRS-R (p = 0.01) and VC (p < 0.0001), and longer survival (p = 0.02). Higher levels of creatinine at baseline were predictive of a slower drop in ALSFRS-R (p = 0.01) and VC (p < 0.0001), and longer survival (p = 0.01). Finally, higher body mass index (BMI) at baseline was associated with longer survival (p < 0.0001).

CONCLUSION

The PRO-ACT database is the largest publicly available repository of merged ALS clinical trials data. We report that baseline levels of creatinine and uric acid, as well as baseline BMI, are strong predictors of disease progression and survival.

Assessment of disease progression and functional benefit in neurodegenerative disease: can we tell the difference?

Therapeutic strategies for neurodegenerative diseases include modalities intended to modulate disease progression as well as those whose intent is to improve or maintain functional capacity. As the search for pharmacodynamic markers has proved elusive, treatment outcomes most commonly reflect patient function. As a result, even when clinical trials show a beneficial effect, the underlying etiology of that benefit can be difficult to determine. This review summarizes recent trials in ALS and Parkinson's disease, with the goal of increasing understanding of how the choice of outcome measures influences what can be concluded from the results. Although most ALS trials have been negative in recent years, outcomes are reviewed in terms of potential conclusions that could have been drawn. Functional benefit has been established in a number of recent trials; however, the outcomes used have lead to uncertainty as to whether specific agents modify disease or alter function. In the absence of specific markers sensitive to alteration of disease specific pathways, the distinction between agents that alter underlying disease versus those that affect function may depend on underlying hypotheses rather than clinical trial results.

Sensory-motor assessment in clinical research trials

The assessment of changes in sensory-motor function in clinical research presents a unique set of difficulties. Clinimetrics is the science of measurement as related to the identification of a clinical disorder, the tracing of the progression of the condition under study, and calculation of its impact. The selection of appropriate measures for clinical studies of sensory-motor function must consider validity, sensitivity, specificity, responsiveness, reliability, and feasibility. Reasonable measures of motor function in clinical research include manual examination of muscle strength, electrophysiology, functional scales, patient-reported outcomes (e.g., quality of life), and for severe conditions such as ALS, survival. The assessment of sensory function includes targeted electrophysiology and QOL, as well as more focused measures such as quantitative sensory testing and the scoring of positive symptoms. Each individual measure and each combination of endpoints has its strengths and limitations.