Anti-John Cunnigham virus antibody prevalence in multiple sclerosis patients: baseline results of STRATIFY-1

Pharmacotherapeuetic Options for the Treatment of Multiple Sclerosis

Multiple sclerosis is the most common progressive and disabling neurological condition in young adults. Neuro-inflammation is an early and persistent change and forms the basis of most pharmacotherapy for this disease. Immunomodulatory drugs are mainly biologies (β-interferons, a four amino acid peptide, and a monoclonal antibody to a cell adhesion molecule on the blood-CNS barrier) that either attenuate the inflammatory response or block the movement of immune cells into the CNS. They reduce the rate of relapse, but have little or no effect on the progression of disability. The market landscape for MS drugs is in the midst of major change because the patent life of many of these medicines will soon expire, which will lead to the emergence of biosimilars. In addition, new small molecule immunomodulatory and palliative drugs have entered the market, with more in the pipeline; a number of monoclonal antibodies and other immunomodulatory drugs are also in clinical development.

Risk of natalizumab-associated progressive multifocal leukoencephalopathy

BACKGROUND

Progressive multifocal leukoencephalopathy (PML) is associated with natalizumab treatment. We quantified the risk of PML in patients with multiple sclerosis, according to the presence or absence of three risk factors: positive status with respect to anti-JC virus antibodies, prior use of immunosuppressants, and increasing duration of natalizumab treatment.

METHODS

We used data from postmarketing sources, clinical studies, and an independent Swedish registry to estimate the incidence of PML among natalizumab-treated patients with multiple sclerosis, according to positive or negative status with respect to anti-JC virus antibodies, prior or no prior use of immunosuppressants, and duration of treatment (1 to 24 months vs. 25 to 48 months). Blood samples were available for anti-JC virus antibody testing from 5896 patients with multiple sclerosis and from 54 patients with multiple sclerosis who were treated with natalizumab and in whom PML later developed.

RESULTS

As of February 29, 2012, there were 212 confirmed cases of PML among 99,571 patients treated with natalizumab (2.1 cases per 1000 patients). All 54 patients with PML for whom samples were available before the diagnosis were positive for anti-JC virus antibodies. When the risk of PML was stratified according to three risk factors, the risk of PML was lowest among the patients who were negative for anti-JC virus antibodies, with the incidence estimated to be 0.09 cases or less per 1000 patients (95% confidence interval [CI], 0 to 0.48). Patients who were positive for anti-JC virus antibodies, had taken immunosuppressants before the initiation of natalizumab therapy, and had received 25 to 48 months of natalizumab treatment had the highest estimated risk (incidence, 11.1 cases per 1000 patients [95% CI, 8.3 to 14.5]).

CONCLUSIONS

Positive status with respect to anti-JC virus antibodies, prior use of immunosuppressants, and increased duration of natalizumab treatment, alone or in combination, were associated with distinct levels of PML risk in natalizumab-treated patients with multiple sclerosis. (Funded by Biogen Idec and Elan Pharmaceuticals.).

Anti-JCV antibody prevalence in a French cohort of MS patients under natalizumab therapy

To measure the prevalence of JCV-specific antibodies in a French cohort of MS patients treated with natalizumab and to identify risk factor(s) of JCV seropositivity. Progressive multifocal leukoencephalopathy (PML) risk may be stratified by anti-JCV antibody status, duration of natalizumab therapy (≥24 months) and prior exposure to immunosuppressive (IS) drugs. No data are available in France on the prevalence of anti-JCV antibodies and distribution of PML risk factors in patients treated with natalizumab. Sera of 361 patients under natalizumab therapy in two MS centers were analyzed using a previously validated ELISA test. We studied different characteristics: demographic, ethnic, radiological, clinical, prior use of immunomodulatory (IM) or IS drugs and natalizumab exposure duration. The JCV seropositivity rate was 51 % for the whole cohort. Mean natalizumab exposure duration was 27.27 months ± 15.57 (mean ± SD), and prior use of IS drugs was observed in 15.24 % of patients. Twenty-three patients (6.4 %) presented the three PML risk factors. By multivariate analysis, presence of anti-JCV antibodies was significantly linked to age, North African origin and natalizumab exposure duration. Anti-JCV antibody prevalence was similar to previously published data. Anti-JCV antibody status was linked to age. We also suggested that anti-JCV antibody status could be linked to natalizumab exposure duration and ethnic characteristics.

Spanish consensus on the use of natalizumab (Tysabri(®))--2011

INTRODUCTION

Natalizumab is very effective at reducing relapses and delaying disease progression in patients with relapsing-remitting multiple sclerosis (RRMS). However, treatment has also been associated with a risk of progressive multifocal leukoencephalopathy (PML). The aim of this article is to provide a consensus view on the assessment and stratification of these risks, and to improve the management of natalizumab-treated patients.

DEVELOPMENT

At an initial meeting of experts on multiple sclerosis (the authors of this consensus), the relevant topics of the consensus were determined and assigned for further elaboration. Topics included how to establish benefit and risk in general, stratification for risk of PML, informing patients of benefits/risks, and how to monitor patients during treatment and after discontinuing treatment. During the drafting phase, all available information published or presented at international meetings was reviewed. After a series of review sessions and meetings, the final draft was produced.

CONCLUSIONS

Although natalizumab is a very effective drug, its use needs to be considered carefully in view of possible adverse effects and the risk of PML in particular. The neurologist should carefully explain the risks and benefits of treatment in terms the patient can best understand. Before starting treatment, baseline laboratory tests and magnetic resonance imaging (MRI) should be available for future comparisons in the event of suspected PML. The risk of PML should be stratified into high, medium and low risk groups according to presence or absence of anti-JC virus antibodies, prior immunosuppressive therapy, and treatment duration. The follow-up, and frequency of MRI scans in particular, should depend on the risk group to which patient belongs. As our understanding of the risk factors for PML develops, it should be possible to offer patients increasingly individualised therapy. This is a consensus that establishes general recommendations, but neurologists must use their clinical expertise to monitor patients individually.