Immunological time-course of gadolinium-enhancing MRI lesions in patients with multiple sclerosis

Superior MRI outcomes with alemtuzumab compared with subcutaneous interferon β-1a in MS

Objective:

To describe detailed MRI results from 2 head-to-head phase III trials, Comparison of Alemtuzumab and Rebif Efficacy in Multiple Sclerosis Study I (CARE-MS I; NCT00530348) and Study II (CARE-MS II; NCT00548405), of alemtuzumab vs subcutaneous interferon β-1a (SC IFN-β-1a) in patients with active relapsing-remitting multiple sclerosis (RRMS).

Methods:

The impact of alemtuzumab 12 mg vs SC IFN-β-1a 44 μg on MRI measures was evaluated in patients with RRMS who were treatment-naive (CARE-MS I) or who had an inadequate response, defined as at least one relapse, to prior therapy (CARE-MS II).

Results:

Both treatments prevented T2-hyperintense lesion volume increases from baseline. Alemtuzumab was more effective than SC IFN-β-1a on most lesion-based endpoints in both studies (p < 0.05), including decreased risk of new/enlarging T2 lesions over 2 years and gadolinium-enhancing lesions at year 2. Reduced risk of new T1 lesions (p < 0.0001) and gadolinium-enhancing lesion conversion to T1-hypointense black holes (p = 0.0078) were observed with alemtuzumab vs SC IFN-β-1a in CARE-MS II. Alemtuzumab slowed brain volume loss over 2 years in CARE-MS I (p < 0.0001) and II (p = 0.012) vs SC IFN-β-1a.

Conclusions:

Alemtuzumab demonstrated greater efficacy than SC IFN-β-1a on MRI endpoints in active RRMS. The superiority of alemtuzumab was more prominent during the second year of both studies. These findings complement the superior clinical efficacy of alemtuzumab over SC IFN-β-1a in RRMS.

ClinicalTrials.gov identifier:

NCT00530348 and NCT00548405.

Classification of evidence:

The results reported here provide Class I evidence that, for patients with active RRMS, alemtuzumab is superior to SC IFN-β-1a on multiple MRI endpoints.

Segmentation of magnetization transfer ratio lesions for longitudinal analysis of demyelination and remyelination in multiple sclerosis

We demonstrate a new technique to quantify longitudinal changes in magnetization transfer ratio (MTR) magnetic resonance imaging (MRI). These changes are indicative of demyelination and remyelination. This technique comprises a definition of ΔMTR lesions, which are identified directly from the MTR images, and an automatic procedure for segmenting these lesions. We used this technique to analyze MTR changes in lesions of subjects with rapidly progressing multiple sclerosis before and after treatment with immunoablation and autologous stem cell transplant. Subjects who experienced clinical improvement after treatment showed significantly improved MTR recovery in lesions that were recovering during treatment (p<0.0001) while those who were clinically stable after treatment showed significantly poorer MTR recovery (p=0.002). The statistical power of this technique to detect treatment effects on MTR recovery was shown to be considerably better than previous methods. These results suggest that longitudinal measurements of MTR in ΔMTR lesions may be an important technique for the assessment of treatment effects on remyelination in clinical trials.

Is multiple sclerosis a generalized disease of the central nervous system? An MRI perspective

PURPOSE OF REVIEW

Is multiple sclerosis (MS) a generalized disease of the central nervous system? Or put another way, is MS pathology primarily focal with global consequences or global with focal consequences? Consideration of this question depends on how you view it both spatially and temporally. In this review, we address some of the main themes underlying this issue, drawing on evidence especially from MRI, but also from histopathological studies.

RECENT FINDINGS

Pathology in MS is not confined only to white matter lesions; apparently normal appearing tissues, including the grey matter, are also affected. Within what is classified as normal-appearing tissue, there may be variable degrees of demyelination, particularly in the grey matter, along with regions that will eventually become overtly lesion containing and areas of remyelination. It remains uncertain whether changes within the normal-appearing tissues are immediately associated with, or a direct consequence of, lesion formation.

SUMMARY

At present, it is not possible to determine whether lesion formation, or a more diffuse process, is the principal pathological event in MS.

[Magnetic resonance imaging of central nervous system inflammation]

Magnetic resonance imaging (MRI) is widely used to explore central nervous system inflammatory disorders, especially multiple sclerosis (MS). Advanced MRI methods are bringing more sensitive and specific tools for each step of the inflammatory process. In this review, we discuss the different MRI approaches for inflammatory disorders exploration, especially MS. We give particular emphasize on sensibility and specificity of each MRI approach and we also discuss the current knowledge concerning biological and histopathological substratum that could explain MRI signal with each modality.

Myeloperoxidase-targeted imaging of active inflammatory lesions in murine experimental autoimmune encephalomyelitis

Inflammatory demyelinating plaques are the pathologic hallmark of active multiple sclerosis and often precede clinical manifestations. Non-invasive early detection of active plaques would thus be crucial in establishing pre-symptomatic diagnosis and could lead to early preventive treatment strategies. Using murine experimental autoimmune encephalomyelitis as a model of multiple sclerosis, we demonstrate that a prototype paramagnetic myeloperoxidase (MPO) sensor can detect and confirm more, smaller, and earlier active inflammatory lesions in living mice by in vivo MRI. We show that MPO expression corresponded with areas of inflammatory cell infiltration and demyelination, and higher MPO activity as detected by MPO imaging, biochemical assays, and histopathological analyses correlated with increased clinical disease severity. Our findings present a potential new translational approach for specific non-invasive inflammatory plaque imaging. This approach could be used in longitudinal studies to identify active demyelinating plaques as well as to more accurately track disease course following treatment in clinical trials.

Non-invasive measurement of brain damage in a primate model of multiple sclerosis

Early recognition of whether a product has potential as a new therapy for treating multiple sclerosis (MS) relies upon the quality of the animal models used in the preclinical trials. The promising effects of new treatments in rodent models of experimental autoimmune encephalomyelitis (EAE) have rarely been reproduced in patients suffering from MS. EAE in outbred marmoset monkeys, Callithrix jacchus, is a valid new model, and might provide an experimental link between EAE in rodent models and human MS. Using magnetic resonance imaging techniques similar to those used in patients suffering from MS pathological abnormalities in the brain, white matter of the animal can be visualized and quantified. Moreover, NMR spectroscopy, in combination with pattern recognition, offers an advanced uroscopic technique for the identification of biomarkers of inflammatory demyelination.