Gender effects on intramuscular interferon beta-1a in relapsing-remitting multiple sclerosis: analysis of 1406 patients.

BACKGROUND: We aimed to evaluate effects of gender on efficacy and safety of intramuscular (IM) interferon beta (IFNß)-1a in patients with relapsing-remitting MS (RRMS) or clinically isolated syndromes (CIS) characteristic of early MS. METHODS: Pooled data from 1406 (1027 women; 379 men) patients enrolled in five clinical studies of IM IFNß-1a were analyzed. One analysis examined data for all patients treated with IM IFNß-1a from all studies. Separate analyses were conducted of pooled IM IFNß-1a-treated groups from all studies and pooled IFNß-1a-treated and placebo-treated patients from the placebo-controlled studies. Outcome measures included time to first relapse, annualized relapse rate, time to disability progression, number of gadolinium-enhanced lesions, adverse events, laboratory evaluations, and neutralizing antibodies. RESULTS: All efficacy assessments indicated similar treatment effects of IM IFNß-1a in men and women with no significant treatment-by-gender interactions. Women reported more headaches, urinary tract infections, and depression in the analysis; however, these were also common in women who received placebo. Men reported more frequent flu-like symptoms in the placebo-controlled studies only. There were no other differences in the safety profile of IM IFNß-1a between men and women. CONCLUSIONS: We conclude that no significant gender-related differences were found in the efficacy and safety of IM IFNß-1a in patients with RRMS or CIS.

Neuropsychological effects of interferon beta-1a in relapsing multiple sclerosis. Multiple Sclerosis Collaborative Research Group.

Cognitive dysfunction is common in multiple sclerosis (MS), yet few studies have examined effects of treatment on neuropsychological (NP) performance. To evaluate the effects of interferon beta-1a (IFNbeta-1a, 30 microg administered intramuscularly once weekly [Avonex]) on cognitive function, a Comprehensive NP Battery was administered at baseline and week 104 to relapsing MS patients in the phase III study, 166 of whom completed both assessments. A Brief NP Battery was also administered at 6-month intervals. The primary NP outcome measure was 2-year change on the Comprehensive NP Battery, grouped into domains of information processing and learning/memory (set A), visuospatial abilities and problem solving (set B), and verbal abilities and attention span (set C). NP effects were most pronounced in cognitive domains vulnerable to MS: IFNbeta-1a had a significant beneficial effect on the set A composite, with a favorable trend evident on set B. Secondary outcome analyses revealed significant between-group differences in slopes for Brief NP Battery performance and time to sustained deterioration in a Paced Auditory Serial Addition Test processing rate, favoring the IFNbeta-1a group. These results support and extend previous observations of significant beneficial effects of IFNbeta-1a for relapsing MS.

A longitudinal study of T1 hypointense lesions in relapsing MS: MSCRG trial of interferon beta-1a. Multiple Sclerosis Collaborative Research Group.

BACKGROUND: T1 hypointense lesions (T1 black holes) are focal areas of relatively severe CNS tissue damage detected by MRI in patients with MS. OBJECTIVE: To determine the natural history of T1 hypointense lesions in relapsing MS and the utility of T1 hypointense lesions as outcome measures in MS clinical trials. METHODS: MR studies were from the Multiple Sclerosis Collaborative Research Group trial. Longitudinal results are reported in 80 placebo- and 80 interferon beta-1a (IFNbeta-1a)-treated patients with mild to moderate disability relapsing-remitting MS. RESULTS: There was a small but significant correlation between T1 hypointense lesion volume and disability at baseline and on trial (r = 0.22, r = 0.28). In placebo patients there was a 29.2% increase in the mean volume of T1 hypointense lesions (median 124.5 mm3) over 2 years (p < 0.001 for change from baseline), as compared to an 11.8% increase (median 40 mm3) in the IFNbeta-1a-treated patients (change from baseline not significant). These treatment group comparisons did not quite reach significance. The most significant contributor to change in T1 hypointense lesions was the baseline number of enhancing lesions (model r2 = 0.554). Placebo patients with more active disease, defined by enhancing lesions at baseline, were the only group to show a significant increase in T1 hypointense lesion volume from baseline. CONCLUSION: The development of T1 hypointense lesions is strongly influenced by prior inflammatory disease activity, as indicated by enhancing lesions. These results suggest that treatment with once weekly IM IFNbeta-1a (30 mcg) slows the 2-year accumulation of these lesions in the brain.

A longitudinal study of brain atrophy in relapsing multiple sclerosis. The Multiple Sclerosis Collaborative Research Group (MSCRG).

OBJECTIVE: To determine if progressive brain atrophy could be detected over 1- and 2-year intervals in relapsing MS, based on annual MR studies from the Multiple Sclerosis Collaborative Research Group (MSCRG) trial of interferon beta-1a (Avonex). METHODS: All subjects had mild to moderate disability, with baseline expanded disability status scores ranging from 1.0 to 3.5, and at least two relapses in the 3 years before study entry. Atrophy measures included third and lateral ventricle width, brain width, and corpus callosum area. RESULTS: Significant increases were detected in third ventricle width at year 2 and lateral ventricle width at 1 and 2 years. Significant decreases in corpus callosum area and brain width were also observed at 1 and 2 years. Multiple regression analyses suggested that the number of gadolinium-enhancing lesions at baseline was the single significant contributor to change in third ventricle width. Atrophy over 1 and 2 years as indicated by enlargement of the third and lateral ventricle and shrinkage of the corpus callosum was greater for patients entering the trial with enhancing lesions. Greater disability increments over 1 and 2 years were associated with more severe third ventricle enlargement. CONCLUSION: In patients with relapsing MS and only mild to moderate disability, significant cerebral atrophy is already developing that can be measured over periods of only 1 to 2 years. The course of cerebral atrophy in MS appears to be influenced by prior inflammatory disease activity as indicated by the presence of enhancing lesions. Brain atrophy measures are important markers of MS disease progression because they likely reflect destructive and irreversible pathologic processes.

Cerebrospinal fluid abnormalities in a phase III trial of Avonex (IFNbeta-1a) for relapsing multiple sclerosis. The Multiple Sclerosis Collaborative Research Group.

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.

Incidence and significance of neutralizing antibodies to interferon beta-1a in multiple sclerosis. Multiple Sclerosis Collaborative Research Group (MSCRG)

BACKGROUND: Interferon beta is an effective treatment for relapsing multiple sclerosis (MS). As with other protein drugs, neutralizing antibodies (NAB) can develop that reduce the effectiveness of treatment. OBJECTIVES: To determine the incidence and biological significance of NAB to interferon beta-la (IFN-beta-1a; Avonex; Biogen, Cambridge, MA) in MS patients. METHODS: A two-step assay for NAB to IFN-beta-1a was developed and used to assay serum samples from participants in the phase III clinical trial of IFN-beta-1a, and from patients in an ongoing open-label study of IFN-beta-1a. The biological significance of NAB to IFN-beta-1a was determined by relating the NAB assay result to in vivo induction of the IFN-inducible molecules neopterin and beta-2 microglobulin, and the clinical significance was determined by comparing clinical and MRI measures of disease activity after 2 years of IFN-beta-1a therapy in patients who were NAB+ and NAB-. The incidence of NAB was compared in MS patients who had used only IFN-beta-1a with the incidence in MS patients who had used only IFN-beta-1b. RESULTS: In patients in the open-label study, development of NAB to IFN-beta-1a resulted in a titer-dependent reduction in neopterin induction after interferon injections. In patients in the phase III study, development of NAB was associated with a reduction in beta-2 microglobulin induction. In the phase III study, a trend toward reduced benefit of IFN-beta-1a on MRI activity in NAB+ versus NAB- patients was observed. The incidence of NAB to IFN-beta-1a in the open-label study was approximately 5% over 24 months of treatment of IFN-beta-1a therapy, but was four- to sixfold higher using the same assay for patients exposed only to IFN-beta-1b for a similar duration. There were no clinical, MRI, or CSF characteristics that were predictive of which patients would develop NAB. CONCLUSIONS: NAB directed against IFN-beta have in vivo biological consequences in patients with MS. The frequency with which MS patients develop NAB against IFN-beta is significantly greater with IFN-beta-1b therapy compared with IFN-beta-1a therapy. Treatment decisions in MS patients treated with IFN-beta should take into account development of NAB.

Magnetic resonance studies of intramuscular interferon beta-1a for relapsing multiple sclerosis. The Multiple Sclerosis Collaborative Research Group.

The Multiple Sclerosis Collaborative Research Group trial was a double-blind, randomized, multicenter, phase III, placebo-controlled study of interferon beta-1a (IFNbeta-1a; AVONEX) in relapsing forms of multiple sclerosis. Initial magnetic resonance imaging results have been published; this report provides additional results. Treatment with IFNbeta-1a, 30 microg once weekly by intramuscular injection, resulted in a significant decrease in the number of new, enlarging, and new plus enlarging T2 lesions over 2 years. The median increase in T2 lesion volume in placebo and IFNbeta-1a patients was 455 and 152 mm3, respectively, at 1 year and 1,410 and 628 mm3 at 2 years, although the treatment group differences did not reach statistical significance. For active patients, defined as those with gadolinium enhancement at baseline, the median change in T2 lesion volume in placebo and IFNbeta-1a patients was 1,578 and -12 mm3 and 2,980 and 1,285 mm3 at 1 and 2 years, respectively. Except for a minimal correlation of 0.30 between relapse rate and the number of gadolinium-enhanced lesions, correlations between MR and clinical measures at baseline and throughout the study were in general poor. Once weekly intramuscular IFNbeta-1a appears to impede the development of multiple sclerosis lesions at an early stage and has a favorable impact on the long-term sequelae of these inflammatory events as indicated by the slowed accumulation of T2 lesions.

Comparing the ability of various compositive outcomes to discriminate treatment effects in MS clinical trials. The Multiple Sclerosis Collaborative Research Group (MSCRG).

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.

Treatment of multiple sclerosis with the interferon-betas: comparative risks and benefits.

Several inteferons (IFNs) have recently been introduced for the treatment of multiple sclerosis (MS). These are IFNbeta-1b (Betaseron) and 2 IFNbeta-1a preparations (Avonex and Rebif). All 3 drugs reduce the number of acute exacerbations in relapsing remitting MS by about one-third but, because of differences in the trials and trial design, direct comparison of efficacy is difficult. Only the IFNbeta-1a preparations have been demonstrated to have an effect in slowing disability. Possible reasons for disparate results with the 3 IFNbetas include substantial differences in trial design, antigenicity, route of administration and bioavailability. Adverse effects differ among the various preparations. Avonex, which is given intramuscularly once weekly, has the fewest adverse effects and the lowest incidence of neutralising antibody formation at 5 to 7%. IFNbeta-1b has the highest incidence at 30 to 39%, and Rebif is intermediate at 13 to 24%. Additionally, IFNbeta-1b and Rebif often cause significant skin reactions, and the former causes occasional skin necrosis at injection sites, a problem not seen with Avonex. On the basis of the available information, the IFNbeta-1a preparations are preferred in terms of tolerability, effects on exacerbation rate and disability, less frequent antibody formation and convenience. The available preparations, Avonex and Rebif, have shown similar effectiveness although dose, route of administration and dosage regimens differ. The administered dose of IFNbeta-1b and Rebif appears to be somewhat higher than that of Avonex, but the differences in effect are small. Further information regarding the effect of different doses and dosage regimens with the various preparations is expected to become available over the next few years.

Impact of interferon beta-1a on neurologic disability in relapsing multiple sclerosis. The Multiple Sclerosis Collaborative Research Group (MSCRG).

BACKGROUND AND OBJECTIVE: A phase III double-blind, placebo-controlled clinical trial demonstrated that interferon beta-1a (IFN beta-1a) (Avonex, Biogen) significantly delayed progression of disability in relapsing MS patients. The primary clinical outcome was time from study entry until disability progression, defined as > or = 1.0 point worsening from baseline Kurtzke Expanded Disability Status Scale (EDSS) score persisting for at least two consecutive scheduled visits separated by 6 months. The objective of this study was to examine the magnitude of benefit on EDSS and its clinical significance. METHODS: Post hoc analyses related to disability outcomes using data collected during the double-blind, placebo-controlled phase III clinical trial. RESULTS: (1) Clinical efficacy related to disability did not depend on the definition of disability progression. A significant benefit in favor of IFN beta-1a was observed when > or = 2.0 point worsening from baseline EDSS was required or when worsening was required to persist for > or = 1.0 year. (2) Placebo recipients who reached the primary clinical outcome worsened by a larger amount from baseline EDSS than did IFN beta-1a recipients who reached the primary study outcome. (3) Significantly fewer IFN beta-1a recipients progressed to EDSS milestones of 4.0 (relatively severe impairment) or 6.0 (unilateral assistance needed to walk). (4) Cox proportional hazards models demonstrated that the only baseline characteristic strongly correlated with longer time to disability progression was IFN beta-1a treatment. CONCLUSIONS: The primary clinical outcome for the IFN beta-1a clinical trial underestimated clinical benefits of treatment. Results in this report demonstrate that IFN beta-1a treatment is associated with robust, clinically important beneficial effects on disability progression in relapsing MS patients.

Intramuscular interferon beta-1a for disease progression in relapsing multiple sclerosis. The Multiple Sclerosis Collaborative Research Group (MSCRG)

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.

Evasion of immunologic defenses and emerging viral threats.

New viruses and virus strains appear at irregular but frequent intervals in the human population. Those that represent a widespread serious threat to human populations have evolved mechanisms for either short-term or longer-term evasion of immunologic recognition and neutralization. These mechanisms include (1) antigenic shift, (2) intracellular transport, (3) intracellular latency, (4) direct infection and destruction of cells of the immune system, (5) infection in utero or early infancy so the developing immune system regards it as part of the host repertoire of antigens, and probably (6) nonantigenicity. In this article, I discuss these mechanisms and their relationship to the threat constituted by emerging viral agents.