Extended interval dosing of natalizumab in multiple sclerosis.

BACKGROUND: Natalizumab (NTZ), a monoclonal antibody to human α4ß1/ß7 integrin, is an effective therapy for multiple sclerosis (MS), albeit associated with progressive multifocal leukoencephalopathy (PML). Clinicians have been extending the dose of infusions with a hypothesis of reducing PML risk. The aim of the study is to evaluate the clinical consequences of reducing NTZ frequency of infusion up to 8 weeks 5 days. METHODS: A retrospective chart review in 9 MS centres was performed in order to identify patients treated with extended interval dosing (EID) regimens of NTZ. Patients were stratified into 3 groups based on EID NTZ treatment schedule in individual centres: early extended dosing (EED; n=249) every 4 weeks 3 days to 6 weeks 6 days; late extended dosing (LED; n=274) every 7 weeks to 8 weeks 5 days; variable extended dosing (n=382) alternating between EED and LED. These groups were compared with patients on standard interval dosing (SID; n=1093) every 4 weeks. RESULTS: 17% of patients on SID had new T2 lesions compared with 14% in EID (p=0.02); 7% of patients had enhancing T1 lesions in SID compared with 9% in EID (p=0.08); annualised relapse rate was 0.14 in the SID group, and 0.09 in the EID group. No evidence of clinical or radiographic disease activity was observed in 62% of SID and 61% of EID patients (p=0.83). No cases of PML were observed in EID group compared with 4 cases in SID cohort. CONCLUSIONS: Dosing intervals up to 8 weeks 5 days did not diminish effectiveness of NTZ therapy. Further monitoring is ongoing to evaluate if the risk of PML is reduced in patients on EID.

Expansion of CD27high plasmablasts in transverse myelitis patients that utilize VH4 and JH6 genes and undergo extensive somatic hypermutation.

Patients with the autoimmune disease multiple sclerosis (MS) typically present with the clinically isolated syndromes (CIS) transverse myelitis (TM) or optic neuritis (ON). B-cell disturbances have been well documented in patients with MS and CIS patients with ON, but not in CIS patients with TM, despite the fact that these patients have the worst clinical outcome of all CIS types. The goal of this study was to characterize the B-cell populations and immunoglobulin genetics in TM patients. We found a unique expansion of CD27(high) plasmablasts in both the cerebrospinal fluid and periphery of TM patients that is not present in ON patients. Additionally, plasmablasts from TM patients show evidence for positive selection with increased somatic hypermutation accumulation in VH4(+) B cells and receptor editing that is not observed in ON patients. These characteristics unique to TM patients may impact disease severity and progression.

Evidence-based guideline: clinical evaluation and treatment of transverse myelitis: report of the Therapeutics and Technology Assessment Subcommittee of the American Academy of Neurology.

OBJECTIVE: To assess the evidence for diagnostic tests and therapies for transverse myelitis (TM) and make evidence-based recommendations. METHODS: A review of the published literature from 1966 to March 2009 was performed, with evidence-based classification of relevant articles. RECOMMENDATIONS: Level B recommendations: neuromyelitis optica (NMO)-immunoglobulin G (IgG) antibodies should be considered useful to determine TM cause in patients presenting with clinical acute complete transverse myelitis (ACTM) features. The presence of NMO-IgG antibodies (aquaporin-4-specific antibodies) should be considered useful in determining increased TM recurrence risk. Level C recommendations: in suspected TM, distinction between ACTM or acute partial transverse myelitis may be considered useful to determine TM etiology and risk for relapse (more common with APTM). Age and gender may be considered useful to determine etiology in patients presenting with TM syndrome, with spinal infarcts seen more often in older patients and more female than male patients having TM due to multiple sclerosis (MS). Brain MRI characteristics consistent with those of MS may be considered useful to predict conversion to MS after a first partial TM episode. Longer spinal lesions extending over >3 vertebral segments may be considered useful in determining NMO vs MS. CSF examination for cells and oligoclonal bands may be considered useful to determine the cause of the TM syndrome. Plasma exchange may be considered in patients with TM who fail to improve after corticosteroid treatment. Rituximab may be considered in patients with TM due to NMO to decrease the number of relapses. Level U recommendations: there is insufficient evidence to support or refute the efficacy of other TM therapies or the usefulness of ethnicity to determine the cause of a subacute myelopathy.

Cup to disc ratio by optical coherence tomography is abnormal in multiple sclerosis.

OBJECTIVE: To identify and characterize cup to disc ratio (CDR) and related optic nerve head abnormalities in multiple sclerosis (MS) using spectral domain optical coherence tomography (OCT). BACKGROUND: While CDR is routinely assessed by ophthalmologists in the evaluation of glaucoma, CDR and related optic nerve head metrics remain largely unexplored in MS. DESIGN/METHODS: Cirrus-HD (high density) OCT was used to evaluate average CDR, vertical CDR, optic disc area, optic cup volume, and neuro-retinal rim area in 105 MS patients and 88 age-matched healthy individuals. High-contrast (100%) visual acuity, 2.5% low-contrast letter acuity and 1.25% low-contrast letter acuity were assessed in 77 MS patients. Two-sample t-tests were used in the analysis of OCT-derived optic nerve head measures between healthy controls and MS patients. Multivariate regression (accounting for age and gender) was used to assess relationships between optic nerve head measures and visual function. RESULTS: Average CDR (p=0.007) and vertical CDR (p=0.005) were greater in MS patients compared to healthy controls, while neuro-retinal rim area was decreased in MS patients (p=0.001). CDR increased with retinal nerve fiber layer (RNFL) thinning (r=-0.29, p=0.001). 2.5% low-contrast (p=0.005) and 1.25% low-contrast letter acuity (p=0.03) were lower in MS patients with higher vertical CDR. CONCLUSIONS/RELEVANCE: CDR (as determined by spectral domain OCT) is abnormal in MS and correlates with visual function. OCT-derived CDR and related optic nerve head metrics may represent an objective measure by which to monitor disease progression, and potentially neuroprotection, in therapeutic MS trials.

The Global Adherence Project (GAP): a multicenter observational study on adherence to disease-modifying therapies in patients with relapsing-remitting multiple sclerosis.

BACKGROUND: most disease-modifying therapies (DMTs) for multiple sclerosis (MS) are self-injectable medications that must be taken on an ongoing basis to reduce disease activity. Thus, adherence to therapy becomes an important challenge that must be addressed to maximize benefits of therapy. This study evaluated rates of adherence to prescribed treatment and explored factors affecting adherence amongst patients with relapsing-remitting MS. METHODS: this was an observational, multicenter, multinational, phase 4 study. Patients and physicians received paper questionnaires regarding adherence to DMTs approved at the time of the study, including intramuscular interferon beta-1a (IFNß-1a), subcutaneous IFNß-1a, IFNß-1b, and glatiramer acetate. Quality of life and cognition data also were collected. Multivariate analysis was conducted to identify factors associated with adherence to long-term DMTs. RESULTS: two thousand six hundred and forty-eight patients were studied, revealing an average treatment duration of 31 months. Seventy-five percent of patients (n = 1923) were adherent to therapy. The most common reasons for non-adherence were forgetting to administer the injection (50.2%) and other injection-related reasons (32.0%). Adherent patients reported better quality of life (P < 0.05) and fewer neuropsychological issues (P < 0.001) than non-adherent patients. Adherent patients had significantly shorter duration of disease (P < 0.001) and shorter duration of therapy (P = 0.005) than non-adherent patients. Women were more likely than men to adhere to treatment. CONCLUSION: identifying factors that affect adherence to prescribed treatments is the first step in improving adherence of patients with MS to therapy, thereby helping maximize the benefits of long-term DMTs.

A unique antibody gene signature is prevalent in the central nervous system of patients with multiple sclerosis.

B cells isolated from the CSF of patients with multiple sclerosis (MS) have a unique accumulation of somatic hypermutation within the B cell receptor, termed the antibody gene signature (AGS). The focus of this study was to investigate whether the AGS could also be detected in MS brain tissue. Genetic analysis of B cells isolated from post-mortem CNS tissue samples from four MS brains demonstrated that signature enriched B cells are present at the site of tissue injury as well as in the circulating CSF.

Immunologic, clinical, and radiologic status 14 months after cessation of natalizumab therapy.

OBJECTIVE: Natalizumab is a humanized recombinant monoclonal antibody against very late activation antigen-4 approved for the treatment of patients with multiple sclerosis (MS). A phase II study failed to demonstrate a difference between natalizumab treatment groups and the placebo group with regard to gadolinium enhancing lesions on MRI 3 months after discontinuation of therapy. The objective of this study was to assess clinical MS disease activity, surrogate disease markers on MRI, immunologic parameters in peripheral blood and CSF, as well as safety in patients with MS after discontinuation of natalizumab therapy. METHODS: This study is a longitudinal and serial cross-sectional assessment, in which 23 patients who were treated with natalizumab in the context of two phase III clinical trials were originally enrolled. A subgroup of patients was followed over 14 months. The annual relapse rate, neurologic disease progression assessed by the Expanded Disability Status Scale, disease surrogate markers on MRI, cellular and humoral immune markers in peripheral blood and CSF, and adverse events of the drug were monitored. RESULTS: With regard to clinical disease activity, neuroimaging, and immune responses, the majority of patients in our cohort were stable. Decreased lymphocyte cell numbers and altered cell ratios returned to normal 14 months after cessation of natalizumab. No infectious complications were observed. CONCLUSION: This is the first long-term follow-up of patients who discontinued natalizumab. We did not observe a clinical, radiographic, or immunologic rebound phenomenon after discontinuation of natalizumab therapy.

Retinal architecture predicts pupillary reflex metrics in MS.

OBJECTIVE: To study the relation of retinal nerve fiber layer thinning to clinical and physiologic measures of visual function in patients with MS or neuromyelitis optica and unilateral optic neuropathy. METHODS: We studied a cohort of control subjects (n = 64) and patients (n = 24) with evidence of unilateral thinning of their average retinal nerve fiber layer as measured by optical coherence tomography in order to characterize the relationship between ganglion cell axonal degeneration and its impact upon vision and pupillary light reflex metrics using infrared pupillometry. RESULTS: When compared to the normal fellow eye, and with respect to normal subjects' eyes, we confirmed significant abnormalities in retinal nerve fiber layer thickness, total macular volume, low-contrast letter acuity, and pupillary reflex metrics in the eye with the thinner retinal nerve fiber layer. For each -5% change in pupil diameter, there was a corresponding 7.1 Amicrom reduction in the average retinal nerve fiber layer thickness. There was a significant difference between the pupillary metric of percent change in diameter and a decrease in low-contrast letter acuity (P < 0.001). Each -5% change in pupil diameter was associated with a substantial 3.4 line loss of low-contrast letter acuity (P < 0.001). Each -5% change in pupil diameter was associated with a 0.2 mm(2) decrease in total macular volume (P < 0.001). CONCLUSION: These findings further corroborate the hypothesis that the retina can be utilized as a model to advance our understanding of the mechanisms of axonal and neurodegeneration, and the corresponding impact of these processes upon the pathophysiology of MS and related disorders.

Mechanisms of action of disease-modifying agents and brain volume changes in multiple sclerosis.

Disease-modifying agents (DMAs), including interferon beta (IFNbeta) and glatiramer acetate (GA), are the mainstays of long-term treatment of multiple sclerosis (MS). Other potent anti-inflammatory agents like natalizumab and different types of chemotherapeutics are increasingly being used for treatment of MS, particularly in patients with breakthrough disease activity. Brain volume (BV) loss occurs early in the disease process, accelerates over time, and may be only partially affected by DMA therapy. Low-dose, low frequency IFNbeta administered once weekly and GA appear to partially reduce BV decline over the second and third years of treatment. High dose, high frequency IFNbeta demonstrated no clear effect on BV loss during this time period. Current evidence suggests that changes in BV after immunoablation may not be due entirely to the resolution of edema but may be related to potential chemotoxicity of high dose cyclophosphamide. Natalizumab reduces the development of BV decline in the second and third years of treatment. IV immunoglobulin showed a positive effect on decelerating BV reduction in relapsing and advanced stages of MS. These differences between DMAs may be explained by the extent of their therapeutic effects on inflammation and on the balance between inhibition or promotion of remyelination and neuronal repair in the CNS. We described the mechanisms of action by which DMAs induce accelerated, non-tissue-related BV loss (pseudoatrophy) in the short term but, in the long run, may still potentially lead to permanent BV decline. The effects of corticosteroid therapy on changes in BV in patients with MS help clarify the mechanisms through which potent anti-inflammatory treatments may prevent, stabilize, or induce BV loss.

Pearls & Oy-sters: The medial longitudinal fasciculus in ocular motor physiology.

OBJECTIVE: To review the role played by the medial longitudinal fasciculus (MLF) in ocular motor physiology and to characterize a number of syndromes that result from lesions in this eloquent brainstem tract system. BACKGROUND: The MLF is responsible for transmitting information that is crucial for the coordination and synchronization of all major classes of eye movements. A number of disease processes can produce lesions within this small yet highly strategic white matter pathway resulting in a myriad of neuro-ophthalmologic signs and symptoms. METHODS: We carefully reviewed both the literature and our collective experiences to systematically consider the neuroanatomy and physiology of the MLF and the pathophysiologic mechanisms that underlie syndromes deriving from lesions in this pathway. RESULTS: The MLF is an important structure and is composed of numerous projection systems involved in the regulation of eye movements. Pathology at this location can produce a constellation of abnormalities, many of which can be identified upon careful bedside neurologic examination. CONCLUSION: This review of the medial longitudinal fasciculus and its constituent pathways is germane to understanding a number of important principles in neuro-ophthalmology.

Modeling Uhthoff's phenomenon in MS patients with internuclear ophthalmoparesis.

OBJECTIVE: The goal of this investigation was to demonstrate that internuclear ophthalmoparesis (INO) can be utilized to model the effects of body temperature-induced changes on the fidelity of axonal conduction in multiple sclerosis (Uhthoff's phenomenon). METHODS: Ocular motor function was measured using infrared oculography at 10-minute intervals in patients with multiple sclerosis (MS) with INO (MS-INO; n = 8), patients with MS without INO (MS-CON; n = 8), and matched healthy controls (CON; n = 8) at normothermic baseline, during whole-body heating (increase in core temperature 0.8 degrees C as measured by an ingestible temperature probe and transabdominal telemetry), and after whole-body cooling. The versional disconjugacy index (velocity-VDI), the ratio of abducting/adducting eye movements for velocity, was calculated to assess changes in interocular disconjugacy. The first pass amplitude (FPA), the position of the adducting eye when the abducting eye achieves a centrifugal fixation target, was also computed. RESULTS: Velocity-VDI and FPA in MS-INO patients was elevated (p < 0.001) following whole body heating with respect to baseline measures, confirming a compromise in axonal electrical impulse transmission properties. Velocity-VDI and FPA in MS-INO patients was then restored to baseline values following whole-body cooling, confirming the reversible and stereotyped nature of this characteristic feature of demyelination. CONCLUSIONS: We have developed a neurophysiologic model for objectively understanding temperature-related reversible changes in axonal conduction in multiple sclerosis. Our observations corroborate the hypothesis that changes in core body temperature (heating and cooling) are associated with stereotypic decay and restoration in axonal conduction mechanisms.

Retinal nerve fiber layer is associated with brain atrophy in multiple sclerosis.

OBJECTIVE: Optical coherence tomography (OCT) noninvasively quantifies retinal nerve fiber layer (RNFL) thickness. Studies show RNFL thinning in multiple sclerosis (MS), and we assessed its association with brain atrophy. METHODS: RNFL thickness was measured in 40 patients with MS and 15 controls. Brain parenchymal fraction (BPF) and partial brain volumes were estimated from cranial MRI scans using SIENA-X. Multiple linear regression modeling assessed the association between OCT and MRI measures of atrophy. RESULTS: Minimum RNFL thickness and subject age together predict 21% (p = 0.005) of the variance in BPF in all patients with MS and 43% (p = 0.003) of the variance in BPF in the subgroup with relapsing remitting MS (RRMS; n = 20). The partial correlation coefficient between BPF and minimum RNFL thickness, controlling for age, is 0.46 (p = 0.003) in all patients with MS and 0.69 (p = 0.001) in patients with RRMS. These associations are driven by CSF volume but not by gray or white matter volume. There is no significant association of these variables among controls. CONCLUSIONS: In multiple sclerosis (MS), retinal nerve fiber layer thickness is associated with brain parenchymal fraction and CSF volume. These data suggest that quantification of axonal thickness in the retina by optical coherence tomography (OCT) provides concurrent information about MRI brain abnormality in MS. OCT should be examined in longitudinal studies to determine if it could be used as an outcome measure in clinical trials of neuroprotective drugs.

Neutralizing antibodies to interferon beta: assessment of their clinical and radiographic impact: an evidence report: report of the Therapeutics and Technology Assessment Subcommittee of the American Academy of Neurology.

The clinical and radiologic impact of developing neutralizing antibodies (NAbs) to interferon beta (IFNbeta) while on this therapy for multiple sclerosis (MS) is assessed. On the basis of Class II and III evidence, it is concluded that treatment of patients with MS with IFNbeta (Avonex, Betaseron, or Rebif) is associated with the production of NAbs (Level A). NAbs in the serum are probably associated with a reduction in the radiographic and clinical effectiveness of IFNbeta treatment (Level B). In addition, the rate of NAb production is probably less with IFNbeta-1a treatment than with IFNbeta-1b treatment, although the magnitude and persistence of this difference is difficult to determine (Level B). Finally, it is probable that there is a difference in seroprevalence due to variability in the dose of IFNbeta injected or in the frequency or route of its administration (Level B). Regardless of the explanation, it seems clear that IFNbeta-1a (as it is currently formulated for IM injection) is less immunogenic than the current IFNbeta preparations (either IFNbeta-1a or IFNbeta-1b) given multiple times per week subcutaneously (Level A). However, because NAbs disappear in some patients even with continued IFNbeta treatment (especially in patients with low titers), the persistence of this difference is difficult to determine (Level B). Although the finding of sustained high-titer NAbs (>100 to 200 NU/mL) is associated with a reduction in the therapeutic effects of IFNbeta on radiographic and clinical measures of MS disease activity, there is insufficient information on the utilization of NAb testing to provide specific recommendations regarding when to test, which test to use, how many tests are necessary, or which cutoff titer to apply (Level U).

Azathioprine myelosuppression in multiple sclerosis: characterizing thiopurine methyltransferase polymorphisms.

We describe two multiple sclerosis patients who developed pancytopenia following treatment with azathioprine. They were found to have the homozygous polymorphism for thiopurine methyltransferase deficiency and recovered after cessation of drug therapy. We review the literature concerning this molecular derangement and underscore the importance of performing surveillance testing for allelic characterization prior to treatment intervention with this agent for immune-mediated disorders.

Characterizing the mechanisms of progression in multiple sclerosis: evidence and new hypotheses for future directions.

Major advancements have been achieved in our ability to diagnose multiple sclerosis (MS) and to commence treatment intervention with agents that can favorably affect the disease course. Although MS exacerbations and the emergence of disability constitute the more conspicuous aspects of the disease process, evidence has confirmed that most of the disease occurs on a constitutive and occult basis. Disease-modifying therapies appear to be modest in the magnitude of their treatment effects, particularly in the progressive stage of the disease. Therapeutic strategies currently used for MS primarily target the inflammatory cascade. Several potential mechanisms appear to be involved in the progression of MS. Characterizing these mechanisms will result in a better understanding of the various forms of the disorder and how to effectively treat its clinical manifestations. It is our objective within this 2-part series on progression in MS to offer both evidence-based observations and hypothesis-driven expert perspectives on what constitutes the cause of progression in MS. We have chosen areas of inquiry that appear to have been most productive in helping us to better conceptualize the landscape of what MS looks like pathologically, immunologically, neuroscientifically, radiographically, and genetically. We have attempted to advance hypotheses focused on a deeper understanding of what contributes to the progression of this illness and to illustrate new technical capabilities that are catalyzing novel research initiatives targeted at achieving a more complete understanding of progression in MS.

Disease modifying agent related skin reactions in multiple sclerosis: prevention, assessment, and management.

BACKGROUND: The objective for this article is to highlight some of the adverse skin manifestations associated with injectable disease modifying therapy for multiple sclerosis (MS). Early identification and intervention can often lead to minimal consequences and prolonged patient tolerance and compliance with these agents. At the University of Texas Southwestern Medical Center at Dallas and Texas Neurology in Dallas we actively follow approximately 5000 MS patients. The majority of our patients with relapsing-remitting MS (RRMS) or secondary progressive MS (SPMS) are treated with one of the currently available disease modifying agents (DMAs). Our experience with these patients, and the challenges they face in continuing long-term treatment, constitutes the basis of our proposed treatment strategies. CONCLUSION: Skin reactions in response to injectable DMA therapy in MS are generally mild. However, some reactions can evolve into potentially serious lesions culminating in infection, necrosis, and in some circumstances requiring surgical repair.

The use of mitoxantrone (Novantrone) for the treatment of multiple sclerosis: report of the Therapeutics and Technology Assessment Subcommittee of the American Academy of Neurology.

Mitoxantrone is the first drug approved for the treatment of secondary progressive multiple sclerosis (SPMS) in the United States. This assessment considers use of mitoxantrone in the treatment of MS. Mitoxantrone probably reduces the clinical attack rate and reduces attack-related MRI outcomes in patients with relapsing MS (Type B recommendation). Also, mitoxantrone may have a beneficial effect on disease progression in patients with MS whose clinical condition is worsening (Type B recommendation). The potential for serious toxicity of mitoxantrone, however, must be taken into account when considering this therapy in individual patients. Moreover, because the potential clinical benefits on disease progression appear to be only modest, the results of the single phase III trial should be replicated in another (and hopefully much larger) clinical study before this agent is widely recommended for the treatment of patients with MS.