Are Corticosteroids Efficacious for Preventing or Treating Neutralizing Antibodies in Multiple Sclerosis Patients Treated With Beta-Interferons?: A Critically Appraised Topic

Therapeutic Plasma Exchange in Multiple Sclerosis Patients with Abolished Interferon-beta Bioavailability

BACKGROUND

Neutralizing antibodies (NAb) to interferon-beta (IFN-β) are associated with reduced bioactivity and efficacy of IFN-β in multiple sclerosis (MS). The myxovirus resistance protein A (MxA) gene expression is one of the most appropriate markers of biological activity of exogenous IFN-β. We hypothesized that therapeutic plasma exchange (TPE) can restore the ability of IFN-β to induce the MxA mRNA expression and that maintenance plasmapheresis can sustain the bioavailability of IFN-β.

MATERIAL AND METHODS

Eligible patients underwent 4 primary separate plasma exchange sessions. After the induction TPE sessions, they were transferred to maintenance plasmapheresis. Bioactivity of IFN-β was expressed as in vivo MxA mRNA induction in whole blood using RT-qPCR.

RESULTS

Six patients with low IFN-β bioavailability detected by the MxA mRNA response were included. Four patients became biological responders after induction plasmapheresis. In 2 patients an increase of MxA mRNA expression was found, but the values persisted below the cut-off and the patients remained as "poor biological responders". The effect of maintenance plasmapheresis was transient: MxA mRNA expression values reverted to the baseline levels after 1-2 months.

CONCLUSIONS

Therapeutic plasma exchange is able to restore the bioavailability of IFN-β in the majority of studied patients, but the effect of TPE on the IFN-β bioavailability was transient.

Therapeutic approaches to disease modifying therapy for multiple sclerosis in adults: an Australian and New Zealand perspective: part 1 historical and established therapies. MS Neurology Group of the Australian and New Zealand Association of Neurologists

Multiple sclerosis (MS) is a potentially life-changing immune mediated disease of the central nervous system. Until recently, treatment has been largely confined to acute treatment of relapses, symptomatic therapies and rehabilitation. Through persistent efforts of dedicated physicians and scientists around the globe for 160 years, a number of therapies that have an impact on the long term outcome of the disease have emerged over the past 20 years. In this three part series we review the practicalities, benefits and potential hazards of each of the currently available and emerging treatment options for MS. We pay particular attention to ways of abrogating the risks of these therapies and provide advice on the most appropriate indications for using individual therapies. In Part 1 we review the history of the development of MS therapies and its connection with the underlying immunobiology of the disease. The established therapies for MS are reviewed in detail and their current availability and indications in Australia and New Zealand are summarised. We examine the evidence to support their use in the treatment of MS.

Frequency and magnitude of interferon β neutralizing antibodies in the evaluation of interferon β immunogenicity in patients with multiple sclerosis

Patients with multiple sclerosis (MS) treated with interferon β (IFNβ) preparations develop varying levels of antibodies that neutralize the biological effects of IFNβ, reduce its in vivo bioavailability, and diminish its therapeutic efficacy. The aim was to determine as distinct measures of immunogenicity the occurrence (frequency) and the magnitude (level) of IFNβ neutralizing antibody (NAb) formation in a large Canadian population as a cross-sectional study of patients with MS treated in a clinical practice setting with different, equally available IFNβ products: Avonex(®) (intramuscular IFNβ-1a), Rebif(®) (subcutaneous (SC) IFNβ-1a) at 22 and 44 μg, and Betaseron(®) (SC IFNβ-1b). Over a 3-year period 3,124 serum samples from 2,711 patients with MS were submitted by neurologists in MS clinics distributed across Canada and tested for NAbs in a single independent laboratory, utilizing a quantitative, standardized NAb bioassay. NAb frequency was greatest (35%) with Rebif (SC IFNβ-1a) 44 μg and least (7.5%) with Avonex (intramuscular IFNβ-1a), whereas Betaseron (IFNβ-1b) and Rebif 22 μg were in between (22%). NAb serum levels at magnitudes considered high, ≥100 tenfold reduction units (TRU)/mL, were found in 65%-83% of patients with detectable NAbs. Nearly half (42%-47%) of NAb-positive patients given IFNβ-1a preparations had very high titers (≥ 1,000 TRU/mL), whereas only 22% of NAb-positive patients on Betaseron had titers >1,000 TRU/mL. Differences in patterns of NAb formation among the four IFNβ product-dose combinations became more evident in patients with MS when both NAb frequency and the full range of NAb titer magnitude were measured.