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Two methods were used to estimate the long-term impact of disease-modifying drug therapy (DMDT) in patients with relapsing multiple sclerosis (MS) who completed a placebo-controlled, randomized clinical trial of interferon beta-1a (IFNbeta-1a). The study cohort consisted of patients with ambulatory relapsing MS who had previously participated in a placebo-controlled clinical trial for two years. At its end, patients were managed in an unstructured fashion by their neurologists and re-evaluated at an average of 6.1 years after the end of the trial. Follow-up evaluation was obtained for 93% of the 172 eligible patients. Because study inclusion criteria required that all patients have an Expanded Disability Status Scale (EDSS) score of < or = 3.5 at entry, disability progression at follow-up was defined as EDSS > or = 6.0. Two methods were used to estimate the expected proportions that reached EDSS > or = 6.0 at follow-up. Estimates were compared with observed proportions. Method 1 used progression rates observed during the two-year phase III clinical trial and the percentage of time that patients were on DMDT during the follow-up period. Method 2 used progression rates from a natural history comparison group of relapsing-remitting MS patients. At the eight-year follow-up, 42.0% of the original placebo patients and 29.1% of the original IFNbeta-1a patients reached an EDSS > or = 6.0, an observed treatment effect of approximately 30%. Using method 1, it was estimated that 36.3% of the original placebo patients and 27.6% of the original IFNbeta-1a patients should have reached an EDSS > or = 6.0. Use of the natural history control group (method 2) predicted less plausible outcomes. Estimated proportions of patients reaching the endpoint were 63.3% for the original placebo group and 55.8% for the original IFNbeta-1a group. Treatment effect sizes of 75-90% would be required to match estimates from method 2 with the observed outcome. The paucity of data on the long-term treatment of patients with MS may be aided by applying these or similar methods to vigorously followed cohorts of patients.

Brain atrophy measurement can provide an estimate of the amount of tissue destruction due to the pathologic processes in multiple sclerosis. The potential usefulness of atrophy as a marker of disease progression depends upon the concurrent and predictive relationships between atrophy and disability. A follow-up study was performed to measure atrophy and disability scores in patients from the Multiple Sclerosis Collaborative Research Group's phase III trial of IFNbeta-1a (Avonex) in relapsing- remitting multiple sclerosis. New data were obtained on 160 out of 172 eligible patients from the original trial were enrolled in the follow-up study approximately 8 years after randomization. The follow-up visit consisted of several tests and questionnaires including a clinical exam to determine Expanded Disability Status Score (EDSS) and Multiple Sclerosis Functional Composite (MSFC), and a magnetic resonance imaging exam to calculate the brain parenchymal fraction. Brain parenchymal fraction was correlated with both EDSS and MSFC at each of the four time points for which data were available (baseline 1, 2 and 8 years). Furthermore, the change in BPF was correlated with the changes in disability scores from the end of the phase III trial to the follow-up exam. These data suggest that brain atrophy may be a useful and clinically relevant marker of disease progression in relapsing--remitting MS.

Background and Objective: This report provides results of CSF analyses done in a subset of relapsing remitting MS patients participating in a placebo-controlled, double-blind, phase III clinical trial of IFNbeta-Studies supported by the National Multiple Sclerosis Society (grants RG2019, RG2827),a (Avonex , Biogen). The clinical trial demonstrated that IFNbeta-1a treatment resulted in significantly reduced disability progression, annual relapse rate, and new brain lesions visualized by cranial magnetic resonance imaging. The objectives of the current study were to determine: (a) whether CSF abnormalities in MS patients correlated with disease or MRI characteristics, and (b) effects of IFNbeta-1a therapy on these CSF abnormalities., Methods: CSF was analyzed from 262 (87%) of the 301 study subjects at entry into the clinical trial, and a second CSF sample was analyzed from 137 of these 262 subjects after 2 years of therapy. CSF cell counts, oligoclonal bands (OCB), IgG index, and free kappa light chains were measured using standard assays. Baseline CSF results were compared with demographic, disease, and MRI parameters. Differences in on-study relapse rate, gadolinium enhancement, and EDSS change according to baseline CSF status was used to determine the predictive value of CSF for subsequent clinical and MRI disease activity. Change in CSF parameters after 104 weeks were used to determine the effects of treatment., Results: (1) At study baseline, 37% of the subjects had abnormal CSF WBC counts, 61% had abnormal levels of CSF free kappa light chains, 84% had abnormal IgG index values, and 90% were positive for OCB. (2) Baseline IgG index, kappa light chains, and OCB showed weakly positive, statistically significant correlations with Gd-enhanced lesion volume and T2 lesion volume. WBC showed a statistically significant correlation with Gd-enhancing lesion volume but was uncorrelated with T2 lesion volume. (3) There was an associated between baseline CSF WBC counts and on-study clinical and MRI disease activity in placebo recipients. (4) IFNbeta-1a treatment resulted in significantly reduced CSF WBC counts, but there was no treatment-related change in CSF IgG index, kappa light chains, or OCB, which remained relatively stable over time in both patient groups., Conclusions: The current study documents significant reductions in CSF WBC counts in patients treated with IFNbeta-1a for 104 weeks. This finding is considered relevant to the therapeutic response, since CSF WBC counts were found to be positively correlated with subsequent clinical and MRI disease activity in placebo-treated relapsing MS patients.

We compared the ability of the Kurtzke Expanded Disability Status Scale (EDSS) and a composite outcome of non-physician-based measures of time to ambulate 25 feet (TA) and manual dexterity (the Box and Block Test [BBT], and 9-Hole Peg Test [9HPT]) to discriminate treatment effects in the Phase III study of interferon beta-1a. A log-rank comparison of Kaplan-Meier curves by treatment group showed the non-physician-based composite of BBT, 9HPT, and TA was of comparable sensitivity (P = 0.013) in discriminating sustained treatment failure as the EDSS alone (P = 0.029). The composite of BBT, 9HPT, TA, and EDSS was more sensitive (P = 0.009) in discriminating sustained treatment failure than the EDSS alone. Compositive outcomes of the EDSS and non-physician-based measures of manual dexterity and timed ambulation provide an appealing strategy to reduce the number of patients required to discriminate treatment effects in MS clinical trials.

The accepted standard treatment of relapsing multiple sclerosis consists of medications for disease symptoms, including treatment for acute exacerbations. However, currently there is no therapy that alters the progression of physical disability associated with this disease. The purpose of this study was to determine whether interferon beta-1a could slow the progressive, irreversible, neurological disability of relapsing multiple sclerosis. Three hundred one patients with relapsing multiple sclerosis were randomized into a double-blinded, placebo-controlled, multicenter phase III trial of interferon beta-1a. Interferon beta-1a, 6.0 million units (30 micrograms¿, was administered by intramuscular injection weekly. The primary outcome variable was time to sustained disability progression of at least 1.0 point on the Kurtzke Expanded Disability Status Scale (EDSS). Interferon beta-1a treatment produced a significant delay in time to sustained EDSS progression (p = 0.02). The Kaplan-Meier estimate of the proportion of patients progressing by the end of 104 weeks was 34.9% in the placebo group and 21.9% in the interferon beta-1a-treated group. Patients treated with interferon beta-1a also had significantly fewer exacerbations (p = 0.03) and a significantly lower number and volume of gadolinium-enhanced brain lesions on magnetic resonance images (p-values ranging between 0.02 and 0.05). Over 2 years, the annual exacerbation rate was 0.90 in placebo-treated patients versus 0.61 in interferon beta-1a-treated patients. There were no major adverse events related to treatment. Interferon beta-1a had a significant beneficial impact in relapsing multiple sclerosis patients by reducing the accumulation of permanent physical disability, exacerbation frequency, and disease activity measured by gadolinium-enhanced lesions on brain magnetic resonance images. This treatment may alter the fundamental course of relapsing multiple sclerosis.

Cell suspensions of cultured purified rat oligodendrocytes prepared by the differential substrate adhesion method were applied to neonatal mouse cerebellar explant cultures in which myelination and oligodendrocyte maturation had been irreversibly inhibited by exposure to cytosine arabinoside. Myelination of Purkinje cell axons within 92% of the host explants was observed 2-5 days after oligodendrocyte application. Ultrastructurally, mature oligodendrocytes and axons surrounded by compact myelin, as well as spherules of compact myelin membranes without axons, were present within the cerebellar explants. It is evident that cultured dissociated purified oligodendrocytes retain the ability to myelinate appropriate axons. Such oligodendrocytes may be hyperreactive with regard to myelin membrane formation, as suggested by the presence of spheres of compact myelin without axons.