MRI and clinical activity in MS patients after terminating treatment with interferon beta-1b

Disease-modifying drug initiation patterns in commercially insured multiple sclerosis patients: a retrospective cohort study

BACKGROUND

The goal of this research was to compare the demographics, clinical characteristics and treatment patterns for newly diagnosed multiple sclerosis (MS) patients in a commercial managed care population who received disease-modifying drug (DMD) therapy versus those not receiving DMD therapy.

METHODS

A retrospective cohort study using US administrative healthcare claims identified individuals newly diagnosed with MS (no prior MS diagnosis 12 months prior using ICD-9-CM 340) and ≥18 years old during 2001-2007 to characterize them based on demographics, clinical characteristics, and pharmacologic therapy for one year prior to and a minimum of one year post-index. The index date was the first MS diagnosis occurring in the study period. Follow-up of subjects was done by ICD-9-CM code identification and not by actual chart review. Multivariate analyses were conducted to adjust for confounding variables.

RESULTS

Patients were followed for an average of 35.7±17.5 months after their index diagnosis. Forty-three percent (n=4,462) of incident patients received treatment with at least one of the DMDs during the post-index period. Treated patients were primarily in the younger age categories of 18-44 years of age, with DMD therapy initiated an average of 5.3±9.1 months after the index diagnosis. Once treatment was initiated, 27.7% discontinued DMD therapy after an average of 17.6±14.6 months, and 16.5% had treatment gaps in excess of 60 days.

CONCLUSIONS

Nearly 60% of newly-diagnosed MS patients in this commercial managed care population remained untreated while over a quarter of treated patients stopped therapy and one-sixth experienced treatment gaps despite the risk of disease progression or a return of pre-treatment disease activity.

Neutralizing antibodies in multiple sclerosis: a complex impact on interferon responses, magnetic resonance imaging findings and clinical outcomes

Interferon beta (IFN-β) therapy reduces relapse rate, MRI lesion development, and delays the progression of disability in relapsing forms of multiple sclerosis. As with other protein therapies, some patients develop neutralizing antibodies (NAbs) that could limit the efficacy of IFN-β. The clinical impact of NAbs is hotly debated. Non-standardized NAb assays, NAb persistence and disappearance, plus a six-month lag before a clinical effect, different IFN-β species and formulations, variable trial duration, have made interpretation of the significance of NAbs a challenging task. There is a correlation between the presence of NAb and reduced efficacy of IFN-β therapy in two- to four-year trials. However, patients destined to become NAb positive do better in the first year of IFN-β therapy. Patients with clinical worsening have surprisingly low NAb frequency and titers. Understanding the true clinical implications of NAbs will require well-controlled longitudinal studies instead of simple cross-sectional analyses, plus innovative trial designs with immune biomarkers. Multiple Sclerosis 2007; 13: S53—S62. http://msj.sagepub.com

MxA gene expression analysis as an interferon-beta bioactivity measurement in patients with multiple sclerosis and the identification of antibody-mediated decreased bioactivity

BACKGROUND

Interferon-beta (IFNbeta) has proven to be an important advance in the therapy of multiple sclerosis (MS), but optimal markers for bioactivity have not been identified. To accurately measure bioactivity in MS patients treated with IFNbeta, we developed and tested a real-time reverse transcriptase (RT)-PCR assay for gene expression of MxA, an IFNbeta-induced gene in the peripheral blood of patients treated with IFNbeta.

METHODS

We compared IFNbeta-treated patients with MS to controls in expression of MxA relative to the house-keeping gene, GAPDH. 2'-5'oligoadenylate synthetase (OAS) gene expression was also tested by real-time RT-PCR on RNA from the same patient specimens. Anti-IFNbeta antibody was measured by ELISA and a cytopathic effect assay.

RESULTS

Seven of 54 patients were found to have complete loss of bioactivity. MxA expression correlated well with OAS expression. All patients with lost bioactivity had high levels of binding antibodies or neutralizing antibodies.

CONCLUSIONS

This is the first demonstration that a real-time RT-PCR assay can be used to monitor therapy with interferons. These data identify MxA mRNA as an excellent biomarker for INFbeta action on the IFN receptor, and clarify the relationship between anti-IFNbeta antibodies and bioactivity in patients with MS treated with IFNbeta.

Late pregnancy suppresses relapses in experimental autoimmune encephalomyelitis: evidence for a suppressive pregnancy-related serum factor

Women with multiple sclerosis have significantly diminished disease activity during pregnancy. The purpose of our study was to identify the underlying mechanism for the diminished disease activity. We found that during the period of late pregnancy there is protection against paralysis, during both the induction and effector phases of relapsing experimental autoimmune encephalomyelitis, a mouse model of multiple sclerosis. We did not find any changes in the cytokine secretion profiles or the proliferative activity of autoreactive T cells from mice induced during late pregnancy compared with virgin controls. In mice mated after disease onset, the inflammatory histologic lesions did not clear, despite marked clinical improvement during pregnancy. We found evidence for a serum factor present in late pregnancy that suppresses T cell activation. In the presence of sera taken from mice late in pregnancy, the proliferative response and IL-2 production of proteolipid protein p139-151-specific T cells were significantly diminished as compared with stimulation in the presence of normal mouse sera. In conclusion, serum from late pregnancy has the capacity to down-regulate T cell responses and might be associated with the amelioration of disease activity in experimental autoimmune encephalomyelitis.