MRI outcomes in a placebo-controlled trial of natalizumab in relapsing MS

Current and future role of interferon beta in the therapy of multiple sclerosis

Interferon beta was the first specific disease-modifying therapy licensed for multiple sclerosis (MS) and in its many forms remains the most commonly prescribed agent worldwide. It, however, has a modest effect in reducing relapse rates, magnetic resonance imaging activity, and disability, and many patients are unable to tolerate it because of the associated side effects or mode of administration. With the licensing of glatiramer acetate, natalizumab and mitoxantrone as disease-modifying therapies for MS alternative options are available to people with MS. Many exciting new therapies are also in the pipeline, namely, the monoclonal antibodies alemtuzumab, rituximab, and daclizumab and the promising oral agents BG00012, cladribine, fingolimod, laquinimod, and teriflunomide. In this article we review the immunopathology of MS and the proposed mechanisms of action of currently available and anticipated treatments. We also review the efficacy of each drug, use of combination therapy strategies, and the potential role of the interferon beta preparations in the future.

The importance of clinical trials in unraveling the mysteries of multiple sclerosis

Despite a number of new therapies that are effective in reducing the inflammatory component of multiple sclerosis, the underlying cause of the disease remains uncertain. One of the most powerful tools available to an investigator to help in unraveling the underlying disease mechanisms in MS is the incorporation of careful imaging and laboratory studies into clinical trials. Regardless of the outcome of the trial with respect to modification of clinical disease, probing the biological effects of the treatment in relationship to the clinical outcome can provide important insights into the disease. Unfortunately, careful proof-of-principle laboratory studies are often not supported by the sponsors of clinical trials and mechanisms for rapid funding of supporting laboratory studies is difficult. Consequently important opportunities to better understand the disease are missed.

Neural precursors exhibit distinctly different patterns of cell migration upon transplantation during either the acute or chronic phase of EAE: a serial MR imaging study

As the complex pathogenesis of multiple sclerosis contributes to spatiotemporal variations in the trophic micromilieu of the central nervous system, the optimal intervention period for cell-replacement therapy must be systematically defined. We applied serial, 3D high-resolution magnetic resonance imaging to transplanted neural precursor cells (NPCs) labeled with superparamagnetic iron oxide nanoparticles and 5-bromo-2-deoxyuridine, and compared the migration pattern of NPCs in acute inflamed (n = 10) versus chronic demyelinated (n = 9) brains of mice induced with experimental allergic encephalomyelitis (EAE). Serial in vivo and ex-vivo 3D magnetic resonance imaging revealed that NPCs migrated 2.5 ± 1.3 mm along the corpus callosum in acute EAE. In chronic EAE, cell migration was slightly reduced (2.3 ± 1.3 mm) and only occurred in the lateral side of transplantation. Surprisingly, in 6/10 acute EAE brains, NPCs were found to migrate in a radial pattern along RECA-1(+) cortical blood vessels, in a pattern hitherto only reported for migrating glioblastoma cells. This striking radial biodistribution pattern was not detected in either chronic EAE or disease-free control brains. In both acute and chronic EAE brain, Iba1(+) microglia/macrophage number was significantly higher in central nervous system regions containing migrating NPCs. The existence of differential NPC migration patterns is an important consideration for implementing future translational studies in multiple sclerosis patients with variable disease.

Multiple Sklerose

Die multiple Sklerose (MS) ist eine der häufigsten neurologischen Erkrankungen, für deren Ursache es bislang keine einheitliche Erklärung gibt. Grundpfeiler der Diagnostik ist die Klinik, ergänzt durch die Magnetresonanztomographie (MRT). Eine Liquoruntersuchung zum Nachweis der entzündlichen Genese nachgewiesener multifokaler Störungen ist bei allen unklaren Fällen und bei älteren Patienten erforderlich. Zur Bestätigung und Verlaufskontrolle sind elektrophysiologische Verfahren hilfreich.

Axonal damage in relapsing multiple sclerosis is markedly reduced by natalizumab

OBJECTIVE

The impact of present disease-modifying treatments (DMTs) in multiple sclerosis (MS) on nerve injury and reactive astrogliosis is still unclear. Therefore, we studied the effect of natalizumab treatment on the release of 2 brain-specific tissue damage markers into cerebrospinal fluid (CSF) in MS patients.

METHODS

CSF samples from 92 patients with relapsing forms of MS were collected in a prospective manner prior to natalizumab treatment and after 6 or 12 months. In 86 cases, natalizumab was used as second-line DMT due to breakthrough of disease activity. The levels of neurofilament light (NFL) and glial fibrillary acidic protein (GFAP) were determined using highly sensitive in-house developed enzyme-linked immunosorbent assays.

RESULTS

Natalizumab treatment led to a 3-fold reduction of NFL levels, from a mean value of 1,300 (standard deviation [SD], 2,200) to 400 (SD, 270) ng/l (p < 0.001). The later value was not significantly different from that found in healthy control subjects (350 ng/l; SD, 170; n = 28). Subgroup analysis revealed a consistent effect on NFL release, regardless of previous DMT or whether patients had relapses or were in remission within 3 months prior to natalizumab treatment. No differences between pre- and post-treatment levels of GFAP were detected.

INTERPRETATION

Our data demonstrate that natalizumab treatment reduces the accumulation of nerve injury in relapsing forms of MS. It is anticipated that highly effective anti-inflammatory treatment can reduce axonal loss, thereby preventing development of permanent neurological disability.

Fingolimod (FTY720): discovery and development of an oral drug to treat multiple sclerosis

The discovery of fingolimod (FTY720/Gilenya; Novartis), an orally active immunomodulatory drug, has opened up new approaches to the treatment of multiple sclerosis, the most common inflammatory disorder of the central nervous system. Elucidation of the effects of fingolimod--mediated by the modulation of sphingosine 1-phosphate (S1P) receptors--has indicated that its therapeutic activity could be due to regulation of the migration of selected lymphocyte subsets into the central nervous system and direct effects on neural cells, particularly astrocytes. An improved understanding of the biology of S1P receptors has also been gained. This article describes the discovery and development of fingolimod, which was approved by the US Food and Drug Administration in September 2010 as a first-line treatment for relapsing forms of multiple sclerosis, thereby becoming the first oral disease-modifying therapy to be approved for multiple sclerosis in the United States.

Measuring myelin repair and axonal loss with diffusion tensor imaging

BACKGROUND AND PURPOSE

DTI is an MR imaging measure of brain tissue integrity and provides an attractive metric for use in neuroprotection clinical trials. The purpose of our study was to use DTI to evaluate the longitudinal changes in brain tissue integrity in a group of patients with MS.

MATERIALS AND METHODS

Twenty-one patients with MS starting natalizumab were imaged serially for 12 months. Gadolinium-enhancing lesions and 20 regions of interest from normal-appearing white and gray matter brain tissue were followed longitudinally. Average values within each region of interest were derived for FA, λ(∥), λ(⊥), and MD. New T1 black holes were identified at 12 months. Analysis was performed by using mixed-model regression analysis with slope (ie, DTI change per month) as the dependent variable.

RESULTS

During 1 year, FA increased in gadolinium-enhancing lesions but decreased in NABT (P < .0001 for both). Changes in FA within gadolinium-enhancing lesions were driven by decreased λ(⊥) (P < .001), and within NABT, by decreased λ(∥) (P < .0001). A higher λ(⊥) within gadolinium-enhancing lesions at baseline predicted conversion to T1 black holes at 12 months. MD was unchanged in both gadolinium-enhancing lesions and NABT.

CONCLUSIONS

We observed changes in DTI measures during 1 year in both gadolinium-enhancing lesions and NABT. The DTI results may represent possible remyelination within acute lesions and chronic axonal degeneration in NAWM. These results support the use of DTI as a measure of tissue integrity for studies of neuroprotective therapies.

The effect of natalizumab on cognitive function in patients with relapsing-remitting multiple sclerosis: preliminary results of a 1-year follow-up study

The objective of the study was to assess the natalizumab effect on the course of cognitive impairment in patients with relapsing-remitting multiple sclerosis (MS). Patients with active relapsing-remitting MS (n = 17) were treated with natalizumab for 1 year. The quasi control group included patients (n = 7) with clinically stable MS. Assessment of disease course [expanded disability status scale (EDSS); number of relapses] and neuropsychological impairment [Wisconsin card sorting test (WCST); controlled oral word associations; verbal/non-verbal memory tests; paced auditory serial addition test] was conducted at baseline and after 1 year. Natalizumab-treated patients experienced significantly fewer relapses compared with the previous year (P < 0.05). At 1-year follow-up, EDSS score was unchanged and neuropsychological assessments of memory/executive functions showed a significant improvement in natalizumab-treated patients (all P < 0.05). No changes were observed in the quasi control group. This preliminary study suggests that natalizumab could be effective in ameliorating cognitive functions in patients with active relapsing-remitting MS, over 1-year follow-up.

Assessment of the effectiveness and safety of natalizumab for treating relapsing-remitting multiple sclerosis

OBJECTIVE

Assessing the effectiveness and safety of natalizumab for treating relapsing-remitting multiple sclerosis in a tertiary hospital.

METHOD

Observational, prospective study of adult patients treated with natalizumab from May 2007 until February 2009.

TREATMENT

300 mg natalizumab every four weeks. Response criteria: assessment of disease progression, appearance of flare-ups and assessment of magnetic resonance images. Adverse reactions during treatment with natalizumab were recorded.

RESULTS

Thirty patients (73% female); average age 34 ± 8.4 years; mean baseline EDSS 3.4 ± 1.3; number of flare-ups in the past year 2.1 ± 1.2. TREATMENT was discontinued in five patients, due to refusal in one case, ineffectiveness in two cases and anaphylaxis in the other two cases. Fourteen patients completed one year of treatment with satisfactory results. A lower EDSS score by 36%, 47%, 31%, 54% and 28% was obtained at 3, 6, 9, 12 and 15 months of treatment respectively. The prevalence of relapse-free patients was 94%, 76% and 54% at 3, 6 and 12 months. MRI imaging studies in 11 patients one year after they began treatment showed no new lesions. Two patients suffered severe anaphylactic shock and another one had an outbreak of urticaria. The presence of neutralising antibodies was the reason for suspending treatment in 6.6% of the patients.

CONCLUSIONS

The treatment's effectiveness and safety in our patient group suggest that natalizumab is a treatment for refractory patients or those with aggressive types of multiple sclerosis, although we do not yet know about its long-term effects and the evolution of the appearance of neutralising antibodies.

Black holes in multiple sclerosis: definition, evolution, and clinical correlations

Magnetic resonance imaging (MRI) is a sensitive paraclinical test for diagnosis and assessment of disease progression in multiple sclerosis (MS) and is often used to evaluate therapeutic efficacy. The formation of new T2-hyperintense MRI lesions is commonly used to measure disease activity, but lacks specificity because edema, inflammation, gliosis, and axonal loss all contribute to T2 lesion formation. As the role of neurodegeneration in the pathophysiology of MS has become more prominent, the formation and evolution of chronic or persistent Tl-hypointense lesions (black holes) have been used as markers of axonal loss and neuronal destruction to measure disease activity. Despite the use of various detection methods, including advanced imaging techniques such as magnetization transfer imaging and magnetic resonance spectroscopy, correlation of persistent black holes with clinical outcomes in patients with MS remains uncertain. Furthermore, although axonal loss and neuronal tissue destruction are known to contribute to irreversible disability in patients with MS, there are limited data on the effect of therapy on longitudinal change in Tl-hypointense lesion volume. Measurement of black holes in clinical studies may elucidate the underlying pathophysiology of MS and may be an additional method of evaluating therapeutic efficacy.

Lamotrigine for neuroprotection in secondary progressive multiple sclerosis: a randomised, double-blind, placebo-controlled, parallel-group trial

BACKGROUND

Partial blockade of voltage-gated sodium channels is neuroprotective in experimental models of inflammatory demyelinating disease. In this phase 2 trial, we aimed to assess whether the sodium-channel blocker lamotrigine is also neuroprotective in patients with secondary progressive multiple sclerosis.

METHODS

Patients with secondary progressive multiple sclerosis who attended the National Hospital for Neurology and Neurosurgery or the Royal Free Hospital, London, UK, were eligible for inclusion in this double-blind, parallel-group trial. Patients were randomly assigned via a website by minimisation to receive lamotrigine (target dose 400 mg/day) or placebo for 2 years. Treating physicians, evaluating physicians, and patients were masked to treatment allocation. The primary outcome was the rate of change of partial (central) cerebral volume over 24 months. All patients who were randomly assigned were included in the primary analysis. This trial is registered with ClinicalTrials.gov, NCT00257855.

FINDINGS

120 patients were randomly assigned to treatment (87 women and 33 men): 61 to lamotrigine and 59 to placebo. 108 patients were analysed for the primary endpoint: 52 in the lamotrigine group and 56 in the placebo group. The mean change in partial (central) cerebral volume per year was -3.18 mL (SD -1.25) in the lamotrigine group and -2.48 mL (-0.97) in the placebo group (difference -0.71 mL, 95% CI -2.56 to 1.15; p=0.40). However, in an exploratory modelling analysis, lamotrigine treatment seemed to be associated with greater partial (central) cerebral volume loss than was placebo in the first year (p=0.04), and volume increased partially after treatment stopped (p=0.04). Lamotrigine treatment reduced the deterioration of the timed 25-foot walk (p=0.02) but did not affect other secondary clinical outcome measures. Rash and dose-related deterioration of gait and balance were experienced more by patients in the lamotrigine group than the placebo group.

INTERPRETATION

The effect of lamotrigine on cerebral volume of patients with secondary progressive multiple sclerosis did not differ from that of placebo over 24 months, but lamotrigine seemed to cause early volume loss that reversed partially on discontinuation of treatment. Future trials of neuroprotection in multiple sclerosis should include investigation of complex early volume changes in different compartments of the CNS, effects unrelated to neurodegeneration, and targeting of earlier and more inflammatory disease.

FUNDING

Multiple Sclerosis Society of Great Britain and Northern Ireland.

Activated T-cells inhibit neurogenesis by releasing granzyme B: rescue by Kv1.3 blockers

There is a great need for pharmacological approaches to enhance neural progenitor cell (NPC) function particularly in neuroinflammatory diseases with failed neuroregeneration. In diseases such as multiple sclerosis and stroke, T-cell infiltration occurs in periventricular zones where NPCs are located and is associated with irreversible neuronal loss. We studied the effect of T-cell activation on NPC functions. NPC proliferation and neuronal differentiation were impaired by granzyme B (GrB) released by the T-cells. GrB mediated its effects by the activation of a Gi-protein-coupled receptor leading to decreased intracellular levels of cAMP and subsequent expression of the voltage-dependent potassium channel, Kv1.3. Importantly, blocking channel activity with margatoxin or blocking its expression reversed the inhibitory effects of GrB on NPCs. We have thus identified a novel pathway in neurogenesis. The increased expression of Kv1.3 in pathological conditions makes it a novel target for promoting neurorestoration.

Natalizumab plus interferon beta-1a reduces lesion formation in relapsing multiple sclerosis

The SENTINEL study showed that the addition of natalizumab improved outcomes for patients with relapsing multiple sclerosis (MS) who had experienced disease activity while receiving interferon beta-1a (IFNbeta-1a) alone. Previously unreported secondary and tertiary magnetic resonance imaging (MRI) measures are presented here. Patients received natalizumab 300 mg (n=589) or placebo (n=582) intravenously every 4 weeks plus IFNbeta-1a 30 microg intramuscularly once weekly. Annual MRI scans allowed comparison of a range of MRI end points versus baseline. Over 2 years, 67% of patients receiving natalizumab plus IFNbeta-1a remained free of new or enlarging T2-lesions compared with 30% of patients receiving IFNbeta-1a alone. The mean change from baseline in T2 lesion volume over 2 years decreased in patients receiving natalizumab plus IFNbeta-1a and increased in those receiving IFNbeta-1a alone (-277.5mm(3) versus 525.6mm(3); p<0.001). Compared with IFNbeta-1a alone, add-on natalizumab therapy resulted in a smaller increase in mean T1-hypointense lesion volume after 2 years (1821.3mm(3) versus 2210.5mm(3); p<0.001), a smaller mean number of new T1-hypointense lesions over 2 years (2.3 versus 4.1; p<0.001), and a slower rate of brain atrophy during the second year of therapy (-0.31% versus -0.40%; p=0.020). Natalizumab add-on therapy reduced gadolinium-enhancing, T1-hypointense, and T2 MRI lesion activity and slowed brain atrophy progression in patients with relapsing MS who experienced disease activity despite treatment with IFNbeta-1a alone.

Molecular regulators of leucocyte chemotaxis during inflammation

A fundamental feature of any immune response is the movement of leucocytes from one site in the body to another to provide effector functions. Therefore, elucidating the molecular mechanisms underlying the migration of leucocytes from the blood to tissues is critical to our understanding of immune function during inflammation. The classic steps of leucocyte trafficking involve leucocyte tethering and rolling on vessel walls of the vasculature, followed by firm adhesion to the endothelium. Recent evidence suggests that upon adhering, leucocytes crawl within the vessels before transmigrating across vessel walls and crawling into targeted tissues. The directed nature of the crawling events is orchestrated by a complex array of soluble factors and molecular regulators in combination with the local intravascular and extracellular environment. In fact, this process is known as chemotaxis and orientates cell movement in relation to the ligand gradient. Several signalling pathways have been proposed to be involved in this gradient-sensing and amplification process, but the best studied, discussed in detail here, is the phosphatidylinositol 3-kinase pathway. Substantial progress has been made in understanding how cells roll and adhere in blood vessels; however, how cells crawl in blood vessels, emigrate, and then crawl in tissues has received much less attention. Therefore, the focus of this review is to provide recent insights into molecular mechanisms and cellular processes that mediate leucocyte crawling in blood vessels and tissues during the inflammatory response.

Multiple sclerosis lesions: insights from imaging techniques

The hallmark of multiple sclerosis (MS) pathology is the presence of inflammatory demyelinated lesions distributed throughout the CNS. Along with more diffuse tissue abnormalities, it is considered one of the major determinants of neurological deficit in MS. Conventional MRI has contributed to improve our understanding of MS pathology and has provided objective and reliable measures to monitor the effect of treatments. Advanced MRI techniques have offered the opportunity to quantify pathological changes in lesions, as well as in normal-appearing brain tissue and to characterize their dynamics. This review will discuss the characteristics and development of MS lesions and the contribution of conventional and quantitative MRI techniques to understanding pathological changes associated with them.

Clinical efficacy and benefit of natalizumab

Natalizumab is the first α4-integrin antagonist indicated for the treatment of relapsing multiple sclerosis (MS). Natalizumab has been shown to delay the accumulation of physical disability and reduce relapses. In two large, double-blind, randomized, placebo-controlled, phase 3 clinical trials, natalizumab was effective as a monotherapy as compared with placebo, and in combination with interferon β as compared with placebo and interferon β. Natalizumab in combination with glatiramer acetate was also effective in a phase 2 clinical trial when compared with placebo and glatiramer acetate. Natalizumab monotherapy achieved a 68% relative reduction in annualized relapse rate, and 42% and 54% reductions in disability progression sustained for 12 and 24 weeks, respectively. In a subset of patients with highly active disease, natalizumab proved more effective, decreasing relapse rates by 81% and progression of disability (sustained for 24 weeks) by 64%. Natalizumab-treated patients experienced significant improvements in quality of life, as measured by the Short Form-36, as well as a 35% reduction in risk of clinically significant vision loss. Recent analyses also have demonstrated the potential for natalizumab to induce a state of ‘no disease activity’ and actual improvement in physical disability. The purpose of this paper is to review evidence for the efficacy of natalizumab, and put its use in MS into perspective.

Neutralizing antibodies to interferon-beta and other immunological treatments for multiple sclerosis: prevalence and impact on outcomes

Biopharmaceuticals can induce antibodies, which interact with and neutralize the therapeutic effect of such drugs and are therefore termed neutralizing antibodies (NAbs). In the treatment of multiple sclerosis, NAbs against interferon (IFN)-beta and natalizumab have been recognized. The prevalence of NAbs against different IFNbeta preparations varies widely, mainly depending on the product but also on other factors such as amino acid sequence variations, glycosylation, formulation, route and frequency of application, dose, duration of treatment and patient characteristics (human leukocyte antigen [HLA] status). IFNbeta-1a given intramuscularly induces significantly less NAbs than any other IFNbeta formulation. The longitudinal development of NAbs also differs between IFNbeta preparations, with higher reversion rates in IFNbeta-1b-treated compared with IFNbeta-1a-treated patients. The negative effect of NAbs on various outcome measures is very consistent across many studies, specifically when observation periods are longer than 2 years. NAbs against natalizumab occur less frequently (6%) and, like NAbs against IFNbeta, they are associated with a loss of clinical and radiological efficacy of the drug.

Current approaches to the identification and management of breakthrough disease in patients with multiple sclerosis

Disease-modifying drugs (DMDs) for relapsing-remitting multiple sclerosis (RRMS) are only partly effective -- breakthrough disease commonly occurs despite treatment. Breakthrough disease is predictive of continued disease activity and a poor prognosis. Availability of several DMDs offers the possibility of tailoring treatment to individual patients with RRMS and altering treatment in patients with breakthrough disease. However, no biological or imaging markers have been validated to guide initial treatment, markers of individual responsiveness to DMDs are scarce, and there is no class 1 evidence to guide alternative therapy in patients with breakthrough disease. In this Review, we discuss proposed strategies to monitor patients with RRMS being treated with DMDs, outline approaches to identifying therapeutic response in individual patients, review MRI and biological markers of treatment response, and summarise the role of antibodies in biological therapies. We also outline possible strategies for the management of patients with breakthrough disease and highlight areas in which research is needed.

Sensorimotor dysfunction in multiple sclerosis and column-specific magnetization transfer-imaging abnormalities in the spinal cord

The human spinal cord contains segregated sensory and motor pathways that have been difficult to quantify using conventional magnetic resonance imaging (MRI) techniques. Multiple sclerosis is characterized by both focal and spatially diffuse spinal cord lesions with heterogeneous pathologies that have limited attempts at linking MRI and behaviour. We used a novel magnetization-transfer-weighted imaging approach to quantify damage to spinal white matter columns and tested its association with sensorimotor impairment. We studied 42 participants with multiple sclerosis who each underwent MRI at 3 Tesla and quantitative tests of sensorimotor function. We measured cerebrospinal-fluid-normalized magnetization-transfer signals in the dorsal and lateral columns and grey matter of the cervical cord. We also measured brain lesion volume, cervical spinal cord lesion number and cross-sectional area, vibration sensation, strength, walking velocity and standing balance. We used linear regression to assess the relationship between sensorimotor impairment and MRI abnormalities. We found that the dorsal column cerebrospinal-fluid-normalized magnetization-transfer signal specifically correlated with vibration sensation (R = 0.58, P < 0.001) and the lateral column signal with strength (R = -0.45, P = 0.003). Spinal cord signal measures also correlated with walking and balance dysfunction. A stepwise multiple regression showed that the dorsal column signal and diagnosis subtype alone explained a significant portion of the variance in sensation (R(2) = 0.54, P < 0.001), whereas the lateral column signal and diagnosis subtype explained a significant portion of the variance in strength (R(2) = 0.30, P < 0.001). These results help to understand the anatomic basis of sensorimotor disability in multiple sclerosis and have implications for testing the effects of neuroprotective and reparative interventions.

Multiple sclerosis: clinical features, pathophysiology, neuroimaging and future therapies

Multiple sclerosis (MS) is a common immune-mediated progressive neurodegenerative disease of the CNS that typically manifests with periods of disease activity followed by intervals of remission. The etiology of MS remains unknown; however, existing evidence indicates that MS is a ‘whole-brain disease’ that is driven by a potent immune response against CNS antigen(s), particularly myelin peptide antigens. The immunopathogenesis of MS includes both the cell- and humorally-mediated arms of the immune system. Genetic and environmental factors play important roles in the development of MS. Application of various neuroimaging techniques to the world of MS have expanded our knowledge concerning its pathogenesis and assist us in the more accurate diagnosis of MS versus its imitators. Current treatments target acute attacks and aim to reduce future clinical relapses. A summary of the potential future therapies for MS is presented.

High-dose cyclophosphamide in the treatment of multiple sclerosis

High dose cyclophosphamide (HDC) has been successfully used for the treatment of a variety of autoimmune diseases. In this study, we sought to determine whether the use of high dose cyclophosphamide provided stabilization of relapsing remitting MS (RRMS), secondary progressive MS (SPMS), or primary progressive MS (PPMS). The parameters evaluated were EDSS scores, lesion load and brain volumes by MRI and frequency of relapses. Twenty-three patients underwent immunoablative therapy with HDC and were followed for 3.5 years. Nine were relapsing remitting (RRMS), 11 secondary progressive (SPMS), and 3 primary progressive (PPMS). Four of 9 RRMS have had no clinical progression up to 3.5 years following treatment. Three of 9 patients maintained a normal neurologic examination with improved EDSS scores. Seven of the nine RRMS patients had reduction in flare frequency which was maintained for 3.5 years following treatment or no immunomodulating agents. Subgroup analysis in the RRMS patients of lesion load and brain parenchymal volume revealed a favorable trend in these parameters which did not reach statistical significance. The treatment was generally ineffective for SPMS and failed in the 2 PPMS patients. HDC was well tolerated, demonstrated a good safety profile and had minimal adverse effects. These results along with previous reports suggest that early use of HDC therapy in RRMS is promising.

Sample sizes for brain atrophy outcomes in trials for secondary progressive multiple sclerosis

BACKGROUND

Progressive brain atrophy in multiple sclerosis (MS) may reflect neuroaxonal and myelin loss and MRI measures of brain tissue loss are used as outcome measures in MS treatment trials. This study investigated sample sizes required to demonstrate reduction of brain atrophy using three outcome measures in a parallel group, placebo-controlled trial for secondary progressive MS (SPMS).

METHODS

Data were taken from a cohort of 43 patients with SPMS who had been followed up with 6-monthly T1-weighted MRI for up to 3 years within the placebo arm of a therapeutic trial. Central cerebral volumes (CCVs) were measured using a semiautomated segmentation approach, and brain volume normalized for skull size (NBV) was measured using automated segmentation (SIENAX). Change in CCV and NBV was measured by subtraction of baseline from serial CCV and SIENAX images; in addition, percentage brain volume change relative to baseline was measured directly using a registration-based method (SIENA). Sample sizes for given treatment effects and power were calculated for standard analyses using parameters estimated from the sample.

RESULTS

For a 2-year trial duration, minimum sample sizes per arm required to detect a 50% treatment effect at 80% power were 32 for SIENA, 69 for CCV, and 273 for SIENAX. Two-year minimum sample sizes were smaller than 1-year by 71% for SIENAX, 55% for CCV, and 44% for SIENA.

CONCLUSION

SIENA and central cerebral volume are feasible outcome measures for inclusion in placebo-controlled trials in secondary progressive multiple sclerosis.

Monoclonal antibody treatments for multiple sclerosis

Monoclonal antibodies (MAbs) may have great potential as therapies for autoimmune diseases. Their development as treatments for multiple sclerosis (MS) is promising. Partially effective immunomodulatory therapies have been helpful for many MS patients; however, for patients failing these immunomodulatory treatments, MAbs are an important new treatment option. Currently, MAbs are approved by the US Food and Drug Administration for treatment of many conditions, including autoimmune diseases. Four MAbs that have been investigated as potential treatments for MS are reviewed in this article. Of these MAbs, natalizumab is approved for treatment of MS. The other three MAbs (alemtuzumab, rituximab, and daclizumab) are all promising therapies in development for treatment of MS. Adverse effects are relatively mild for these MAbs; however, care in administration and management of these agents is emphasized. Overall, these MAb therapies have great promise in the treatment of MS.

New treatment measurements for treatment effects on relapses and progression

Multiple sclerosis (MS) is considered to be a two stage disease: a first stage in which inflammatory phenomena are crucial and a later one in which degenerative processes become the hallmark. The role of magnetic resonance imaging (MRI) is nowadays of great help both to establish the diagnosis and to rule out other conditions. At the clinically isolated syndrome (CIS) stage, MRI is an important tool both to predict the appearance of a second attack or the development of disability at long term. In the relapsing-remitting (RR) phase of the disease conventional MRI is probably less helpful to predict future relapses and disability. Cross sectional and longitudinal studies have shown very weak correlations between lesion burden on brain T2 and disability in the progressive forms of MS. Regarding T2 burden of disease, a plateau effect for EDSS values greater than 4.5 has been observed. Measures related to brain or spinal cord atrophy together with MR Spectroscopy, Magnetization Transfer Imaging and Diffusion Tensor Imaging may be useful in the future to better monitor disease progression in the late degenerative phase of the condition. MRI has also been of great help in monitoring the effect of immunomodulatory drugs in CIS or RRMS clinical trials. Its role to predict treatment response is still controversial on an individual basis.

MRI in multiple sclerosis: current status and future prospects

Many promising MRI approaches for research or clinical management of multiple sclerosis (MS) have recently emerged, or are under development or refinement. Advanced MRI methods need to be assessed to determine whether they allow earlier diagnosis or better identification of phenotypes. Improved post-processing should allow more efficient and complete extraction of information from images. Magnetic resonance spectroscopy should improve in sensitivity and specificity with higher field strengths and should enable the detection of a wider array of metabolites. Diffusion imaging is moving closer to the goal of defining structural connectivity and, thereby, determining the functional significance of lesions at specific locations. Cell-specific imaging now seems feasible with new magnetic resonance contrast agents. The imaging of myelin water fraction brings the hope of providing a specific measure of myelin content. Ultra-high-field MRI increases sensitivity, but also presents new technical challenges. Here, we review these recent developments in MRI for MS, and also look forward to refinements in spinal-cord imaging, optic-nerve imaging, perfusion MRI, and functional MRI. Advances in MRI should improve our ability to diagnose, monitor, and understand the pathophysiology of MS.

Magnetic resonance imaging in clinical trials

PURPOSE OF REVIEW

The aim of this article is to review the latest clinical trials in neurological diseases where magnetic resonance imaging was used to assess treatment outcome.

RECENT FINDINGS

The unique sensitivity of magnetic resonance imaging for detecting disorders in the brain has made it an attractive noninvasive tool for assessing treatment efficacy in several diseases. Volumetric and functional magnetic resonance imaging have proved to represent robust biomarkers for the evaluation of anti-Alzheimer treatments, and have demonstrated a significant impact of cholinesterase inhibitors. The optimization of thrombolytic therapy in acute ischemic stroke has concentrated on the quantification of the ischemic penumbra, using perfusion-weighted and diffusion-weighted imaging. Standard assessment of T2 or fluid-attenuated inversion recovery lesion load remains the method of choice to evaluate new therapeutic strategy in multiple sclerosis. Other nonconventional quantitative magnetic resonance imaging techniques such as magnetic resonance volumetry, magnetization transfer imaging, diffusion-weighted imaging, or magnetic resonance spectroscopy are increasingly used in the field.

SUMMARY

Magnetic resonance imaging has become a major surrogate marker of treatment response in clinical trials of neurological disorders, offering the possibility to reduce the required sample size or to shorten the duration of the trial.

Measurement of brain atrophy in subcortical vascular disease: a comparison of different approaches and the impact of ischaemic lesions

Measurement of brain atrophy has been proposed as a surrogate marker in MS and degenerative dementias. Although cerebral small vessel disease predominantly affects white and subcortical grey matter, recent data suggest that whole brain atrophy is also a good indicator of clinical and cognitive status in this disease. Automated methods to measure atrophy are available that are accurate and reproducible in disease-free brains. However, optimal methods in small vessel disease have not been established and the impact of ischaemic lesions on different techniques has not been explored systematically. In this study, three contrasting techniques -- Statistical Parametric Mapping 5 (SPM5), SIENAX and BrainVisa -- were applied to measure cross-sectional atrophy (brain parenchymal fraction or BPF) in a large (n=143) two-centre cohort of patients with CADASIL, a genetic model of small vessel disease. All three techniques showed similar sensitivity to trends in BPF associated with age and lesion load. No single technique was particularly vulnerable to error as a result of lesions. Provided major errors in registration were excluded by visual inspection, manual correction of segmentations had a negligible impact with mean errors of 0.41% for SIENAX and 0.46% for BrainVisa. BPF correlated strongly with global cognitive function and physical disability, independent of the technique used. Correlation coefficients with the Minimental State Examination score were: BrainVisa 0.58, SIENAX 0.58, SPM5 0.60 (for all, p<0.001). These results suggest that all three methods can be applied reliably in patients with ischaemic lesions. Choice of analysis approach for this kind of clinical question will be determined by factors other than their robustness and precision, such as a desire to explore subtle localised changes using extensions of these processing tools.

Towards immunotherapeutic drugs and vaccines against multiple sclerosis

Multiple sclerosis (MS) is an autoimmune, demyelinating disease of the central nervous system. Numerous treatment options are available to MS patients; however, these options need to be improved. Herein, we review the current drugs and therapeutic approaches available to MS patients, preclinical trial interventions and recent animal model studies for the potential therapy of MS. Since the current treatment of MS remains elusive and is limited, animal studies and clinical research offers an optimistic outlook.

Treating multiple sclerosis with monoclonal antibodies

Therapeutic monoclonal antibodies (mAbs) are potent new tools for a molecular targeted approach to modify the course of multiple sclerosis (MS). Besides natalizumab, which was approved in 2006, three other mAbs (alemtuzumab, rituximab and daclizumab) were successfully tested in Phase II MS trials. In this review, introductory notes on the development and systematic nomenclature of therapeutic mAbs in general, set the stage for a detailed discussion of the four mAbs mentioned. We summarize non-MS indications, expression and function of target antigens, scientific rationales for MS therapy, putative modes of action and pharmacological aspects. Particularly, we provide a critical discussion of clinical MS trials, including protocols and interim analyses of trials currently underway. The natalizumab section pays special attention to the clinical handling of safety issues and the diagnostic use of neutralizing antibodies. We finally develop a scenario for how each of the four mAbs might evolve into the market of MS therapeutics within the coming years.

Radiological interpretation 2020: toward quantitative image assessment

The interpretation of medical images by radiologists is primarily and fundamentally a subjective activity, but there are a number of clinical applications such as tumor imaging where quantitative imaging (QI) metrics (such as tumor growth rate) would be valuable to the patient's care. It is predicted that the subjective interpretive environment of the past will, over the next decade, evolve toward the increased use of quantitative metrics for evaluating patient health from images. The increasing sophistication and resolution of modern tomographic scanners promote the development of meaningful quantitative end points, determined from images which are in turn produced using well-controlled imaging protocols. For the QI environment to expand, medical physicists, physicians, other researchers and equipment vendors need to work collaboratively to develop the quantitative protocols for imaging, scanner calibrations, and robust analytical software that will lead to the routine inclusion of quantitative parameters in the diagnosis and therapeutic assessment of human health. Most importantly, quantitative metrics need to be developed which have genuine impact on patient diagnosis and welfare, and only then will QI techniques become integrated into the clinical environment.

MRI in multiple sclerosis: what's inside the toolbox?

Magnetic resonance imaging (MRI) has played a central role in the diagnosis and management of multiple sclerosis (MS). In addition, MRI metrics have become key supportive outcome measures to explore drug efficacy in clinical trials. Conventional MRI measures have contributed to the understanding of MS pathophysiology at the macroscopic level yet have failed to provide a complete picture of underlying MS pathology. They also show relatively weak relationships to clinical status such as predictive strength for clinical progression. Advanced quantitative MRI measures such as magnetization transfer, spectroscopy, diffusion imaging, and relaxometry techniques are somewhat more specific and sensitive for underlying pathology. These measures are particularly useful in revealing diffuse damage in cerebral white and gray matter and therefore may help resolve the dissociation between clinical and conventional MRI findings. In this article, we provide an overview of the array of tools available with brain and spinal cord MRI technology as it is applied to MS. We review the most recent data regarding the role of conventional and advanced MRI techniques in the assessment of MS. We focus on the most relevant pathologic and clinical correlation studies relevant to these measures.