JC virus granule cell neuronopathy and GCN-IRIS under natalizumab treatment.

Progressive multifocal leukoencephalopathy is the most common clinical presentation of JC virus (JCV)-associated central nervous system (CNS) disease and has emerged as a major safety concern in multiple sclerosis patients treated with the monoclonal antibody natalizumab. Here we report clinical, radiological, and histological findings of a case of cerebellar granule cell neuronopathy (GCN), a JCV-associated CNS disease, so far unreported amongst patients treated with natalizumab. GCN should be considered as a JCV CNS manifestation in patients with newly developed, progressive cerebellar signs under natalizumab treatment, especially in cases where cerebellar atrophy can be visualized by magnetic resonance imaging.

The prevalence of injection-site reactions with disease-modifying therapies and their effect on adherence in patients with multiple sclerosis: an observational study.

BACKGROUND: Interferon beta (IFNß) and glatiramer acetate (GA) are administered by subcutaneous (SC) or intramuscular (IM) injection. Patients with multiple sclerosis (MS) often report injection-site reactions (ISRs) as a reason for noncompliance or switching therapies. The aim of this study was to compare the proportion of patients on different formulations of IFNß or GA who experienced ISRs and who switched or discontinued therapy because of ISRs. METHODS: The Swiss MS Skin Project was an observational multicenter study. Patients with MS or clinically isolated syndrome who were on the same therapy for at least 2 years were enrolled. A skin examination was conducted at the first study visit and 1 year later. RESULTS: The 412 patients enrolled were on 1 of 4 disease-modifying therapies for at least 2 years: IM IFNß-1a (n = 82), SC IFNß-1b (n = 123), SC IFNß-1a (n = 184), or SC GA (n = 23). At first evaluation, ISRs were reported by fewer patients on IM IFNß-1a (13.4%) than on SC IFNß-1b (57.7%; P < 0.0001), SC IFNß-1a (67.9%; P < 0.0001), or SC GA (30.4%; P = not significant [NS]). No patient on IM IFNß-1a missed a dose in the previous 4 weeks because of ISRs, compared with 5.7% of patients on SC IFNß-1b (P = 0.044), 7.1% of patients on SC IFNß-1a (P = 0.011), and 4.3% of patients on SC GA (P = NS). Primary reasons for discontinuing or switching therapy were ISRs or lack of efficacy. Similar patterns were observed at 1 year. CONCLUSIONS: Patients on IM IFNß-1a had fewer ISRs and were less likely to switch therapies than patients on other therapies. This study may have implications in selecting initial therapy or, for patients considering switching or discontinuing therapy because of ISRs, selecting an alternative option.