Disutility of Cognitive Processing Speed (CPS) Impairment in the Context of Multiple Sclerosis: A Time Trade-Off (TTO) Elicitation Study.

Introduction: Cognitive impairment, especially relating to cognitive processing speed, is a major cause of disability in people with multiple sclerosis (MS). Utility values are quantitative estimates of the quality of life experienced in specific health states and are a key component of cost-effectiveness modelling. However, existing health state utility values in MS typically focus on physical ability and are generally derived using generic (not disease-specific) measures of quality of life. The objective of the current study was to generate health state utility values for levels of cognitive impairment. We used a direct utility elicitation approach called the time trade-off (TTO) methodology. Materials and Methods: Health state descriptions were created following interviews with healthcare professionals, patients, and caregivers in the United States (n=35), and with healthcare professionals in the UK (n=5). Three health states (mild, moderate, and severe impairment) were defined based upon a well-established and validated test for cognitive dysfunction called the Symbol Digit Modalities Test (SDMT) and described using qualitative interview findings. Next, interviews with members of the general public in the UK were conducted to estimate utility values for each health state using the TTO methodology. The procedure was based on the established Measurement and Valuation of Health (MVH) protocol, which generates values on a scale from 0.0 to 1.0. Results: Mean health state utility values were 0.77 ± 0.24 in "mild impairment" (SDMT 43-40), 0.57 ± 0.26 in "moderate impairment" (SDMT 39-32), and 0.34 ± 0.28 in "severe impairment" (SDMT ≤ 31). Discussion: Results indicate that the public perceives that health states of cognitive slowing (as observed in MS) are associated with a substantial reduction in affected individuals' health-related quality of life, quantified using the TTO methodology. Future economic modeling should consider how utility impacts of both cognitive and physical disability can be appropriately incorporated.

Efficacy of Ofatumumab and Teriflunomide in Patients With Relapsing MS From Racial/Ethnic Minority Groups: ASCLEPIOS I/II Subgroup Analyses.

BACKGROUND AND OBJECTIVES: Race and ethnicity may influence the efficacy of disease-modifying therapies in patients with multiple sclerosis (MS). Incidence of MS in ethnically diverse groups may be higher; however, these populations are under-represented in MS trials. This post hoc analysis compared the proportion of patients achieving 3-parameter no evidence of disease activity (NEDA-3) with ofatumumab vs teriflunomide in participants with relapsing MS (RMS) enrolled in the ASCLEPIOS I/II trials by race/ethnicity subgroup. METHODS: ASCLEPIOS I/II were identical, double-blind, double-dummy, active-controlled, multicenter, phase 3 trials. Participants were randomized (1:1) to receive ofatumumab 20 mg every 4 weeks or teriflunomide 14 mg once daily for up to 30 months. Pooled data were used to determine the efficacy/safety of ofatumumab vs teriflunomide in participants who self-identified as non-Hispanic Black, non-Hispanic Asian, Hispanic/Latino, or non-Hispanic White. Participants who did not self-identify into one of these groups were classified as other/unknown. RESULTS: Of the 1,882 participants, 64 (3.4%) self-identified as non-Hispanic Black, 71 (3.8%) as non-Hispanic Asian, 145 (7.7%) as Hispanic/Latino, and 1,538 (81.7%) as non-Hispanic White. Baseline participant demographics/characteristics were largely balanced across subgroups, aside from minor variations in sex, disease duration, and MRI lesions. From months 0 to 24, the proportion of ofatumumab vs teriflunomide-treated patients achieving NEDA-3 (odds ratio [95% CI]) was as follows: non-Hispanic Black, 33.3% vs 3.4% (15.9 [1.67-151.71; p = 0.0162]); non-Hispanic Asian, 42.9% vs 21.9% (3.18 [0.95-10.59; p = 0.06]); Hispanic/Latino, 36.6% vs 18.6% (3.21 [1.32-7.79; p = 0.01]); and non-Hispanic White, 37.4% vs 16.6% (3.57 [2.73-4.67; p < 0.0001]). Rates of AEs were generally similar between treatment groups and across race/ethnicity subgroups; no new or unexpected safety signals were identified. DISCUSSION: Ofatumumab was associated with greater proportions of NEDA-3 achievement than teriflunomide across race/ethnicity subgroups in the ASCLEPIOS trials. Within each treatment group, the proportion of patients achieving NEDA-3 from months 0 to 24 was similar across the subgroups and overall pooled population. Both ofatumumab and teriflunomide were well tolerated. Future MS trials should include ethnically diverse groups to better inform treatment decisions and improve real-world patient outcomes. TRIAL REGISTRATION INFORMATION: ClinicalTrials.gov: NCT02792218 (clinicaltrials.gov/ct2/show/NCT02792218), NCT02792231 (clinicaltrials.gov/ct2/show/NCT02792231). Submission date: June 2, 2016. First enrollment: August 26, 2016. CLASSIFICATION OF EVIDENCE: This study provides Class II evidence that among patients aged 18-55 years with RMS, the improvement in NEDA-3 with ofatumumab was comparably better than with teriflunomide among patients self-identified as non-Hispanic Black, non-Hispanic Asian, non-Hispanic White, Hispanic/Latino, and other/unknown.

Effects of baseline age and disease duration on the efficacy and safety of siponimod in patients with active SPMS: Post hoc analyses from the EXPAND study.

BACKGROUND: Older age and longer disease duration (DD) may impact the effectiveness of disease-modifying therapies in patients with multiple sclerosis (MS). Siponimod is a sphingosine 1-phosphate receptor modulator approved for the treatment of active secondary progressive MS (SPMS) in many countries. The pivotal phase 3 EXPAND study examined siponimod versus placebo in a broad SPMS population with both active and non-active disease. In this population, siponimod demonstrated significant efficacy, including a reduction in the risk of 3-month confirmed disability progression (3mCDP) and 6-month confirmed disability progression (6mCDP). Benefits of siponimod were also observed across age and DD subgroups in the overall EXPAND population. Herein we sought to assess the clinical impact of siponimod across age and disease duration subgroups, specifically in participants with active SPMS. METHODS: This study is a post hoc analysis of a subgroup of EXPAND participants with active SPMS (≥ 1 relapse in the 2 years before the study and/or ≥ 1 T1 gadolinium-enhancing magnetic resonance imaging lesion at baseline) receiving oral siponimod (2 mg/day) or placebo during EXPAND. Data were analyzed for participant subgroups stratified by age at baseline (primary cut-off: < 45 year ≥ 45 years; and secondary cut-off: < 50 years or ≥ 50 years) and by DD at baseline (< 16 years or ≥ 16 years). Efficacy endpoints were 3mCDP and 6mCDP. Safety assessments included adverse events (AEs), serious AEs, and AEs leading to treatment discontinuation. RESULTS: Data from 779 participants with active SPMS were analyzed. All age and DD subgroups had 31-38% (3mCDP) and 27-43% (6mCDP) risk reductions with siponimod versus placebo. Compared with placebo, siponimod significantly reduced the risk of 3mCDP in participants aged ≥ 45 years (hazard ratio [HR]: 0.68; 95% confidence interval [CI]: 0.48-0.97), < 50 years (HR: 0.69; 95% CI: 0.49-0.98), ≥ 50 years (HR: 0.62; 95% CI: 0.40-0.96), and in participants with < 16 years DD (HR: 0.68; 95% CI: 0.47-0.98). The risk of 6mCDP was significantly reduced with siponimod versus placebo for participants aged < 45 years (HR: 0.60; 95% CI: 0.38-0.96), ≥ 45 years (HR: 0.67; 95% CI: 0.45-0.99), < 50 years (HR: 0.62; 95% CI: 0.43-0.90), and in participants with < 16 years DD (HR: 0.57; 95% CI: 0.38-0.87). Increasing age or longer MS duration did not appear to increase the risk of AEs, with an observed safety profile that remained consistent with the overall active SPMS and overall SPMS populations in EXPAND. CONCLUSIONS: In participants with active SPMS, treatment with siponimod demonstrated a statistically significant reduction in the risk of 3mCDP and 6mCDP compared with placebo. Although not every outcome reached statistical significance in the subgroup analyses (possibly a consequence of small sample sizes), benefits of siponimod were seen across a spectrum of ages and DD. Siponimod was generally well tolerated by participants with active SPMS, regardless of baseline age and DD, and AE profiles were broadly similar to those observed in the overall EXPAND population.

The Two Sides of Siponimod: Evidence for Brain and Immune Mechanisms in Multiple Sclerosis.

Siponimod is a selective sphingosine 1-phosphate receptor subtype 1 (S1P1) and 5 (S1P5) modulator approved in the United States and the European Union as an oral treatment for adults with relapsing forms of multiple sclerosis (RMS), including active secondary progressive multiple sclerosis (SPMS). Preclinical and clinical studies provide support for a dual mechanism of action of siponimod, targeting peripherally mediated inflammation and exerting direct central effects. As an S1P1 receptor modulator, siponimod reduces lymphocyte egress from lymph nodes, thus inhibiting their migration from the periphery to the central nervous system. As a result of its peripheral immunomodulatory effects, siponimod reduces both magnetic resonance imaging (MRI) lesion (gadolinium-enhancing and new/enlarging T2 hyperintense) and relapse activity compared with placebo. Independent of these effects, siponimod can penetrate the blood-brain barrier and, by binding to S1P1 and S1P5 receptors on a variety of brain cells, including astrocytes, oligodendrocytes, neurons, and microglia, exert effects to modulate neural inflammation and neurodegeneration. Clinical data in patients with SPMS have shown that, compared with placebo, siponimod treatment is associated with reductions in levels of neurofilament light chain (a marker of neuroaxonal damage) and thalamic and cortical gray matter atrophy, with smaller reductions in MRI magnetization transfer ratio and reduced confirmed disability progression. This review examines the preclinical and clinical data supporting the dual mechanism of action of siponimod in RMS.

Advancing Care and Outcomes for African American Patients With Multiple Sclerosis.

Multiple sclerosis (MS) has historically been underdiagnosed and undertreated among African Americans. Recent evidence suggests that African Americans with MS have a different clinical presentation, increased disease incidence and burden, and worse long-term outcomes vs their White counterparts. Due to limited data available for African Americans in MS clinical trials, it is difficult to make informed, generalizable conclusions about the natural history, prognosis, and therapeutic response in this population. In this narrative review, we highlight the nature and magnitude of the health disparities experienced by African Americans with MS and underscore the pressing need to increase knowledge about and understanding of MS disease manifestations in this group. In addition, we describe the mission and objectives of the recently established National African Americans with Multiple Sclerosis Registry, which is intended to be a platform to advance the care of African Americans with MS and address health disparities they may experience.

Interferons and Multiple Sclerosis: Lessons from 25 Years of Clinical and Real-World Experience with Intramuscular Interferon Beta-1a (Avonex).

Recombinant interferon (IFN) ß-1b was approved by the US Food and Drug Administration as the first disease-modifying therapy (DMT) for multiple sclerosis (MS) in 1993. Since that time, clinical trials and real-world observational studies have demonstrated the effectiveness of IFN therapies. The pivotal intramuscular IFN ß-1a phase III trial published in 1996 was the first to demonstrate that a DMT could reduce accumulation of sustained disability in MS. Patient adherence to treatment is higher with intramuscular IFN ß-1a, given once weekly, than with subcutaneous formulations requiring multiple injections per week. Moreover, subcutaneous IFN ß-1a is associated with an increased incidence of injection-site reactions and neutralizing antibodies compared with intramuscular administration. In recent years, revisions to MS diagnostic criteria have improved clinicians' ability to identify patients with MS and have promoted the use of magnetic resonance imaging (MRI) for diagnosis and disease monitoring. MRI studies show that treatment with IFN ß-1a, relative to placebo, reduces T2 and gadolinium-enhancing lesions and gray matter atrophy. Since the approval of intramuscular IFN ß-1a, a number of high-efficacy therapies have been approved for MS, though the benefit of these high-efficacy therapies should be balanced against the increased risk of serious adverse events associated with their long-term use. For some subpopulations of patients, including pregnant women, the safety profile of IFN ß formulations may provide a particular benefit. In addition, the antiviral properties of IFNs may indicate potential therapeutic opportunities for IFN ß in reducing the risk of viral infections such as COVID-19.

Effectiveness of Dimethyl Fumarate in Patients With Relapsing Multiple Sclerosis Switching After Suboptimal Response to Glatiramer Acetate, Including Patients With Early Multiple Sclerosis: Subgroup Analysis of RESPOND.

INTRODUCTION: This post hoc subset analysis of RESPOND evaluated the effectiveness of dimethyl fumarate (DMF) 240 mg twice daily in patients with relapsing multiple sclerosis (RMS) after suboptimal response to glatiramer acetate (GA; "first switch" patients), including patients with early MS ("early MS switch" patients). METHODS: Patients had discontinued GA due to suboptimal response and initiated DMF treatment within 60 days after enrollment. Relapse data were collected from medical records. First switch patients had had one prior approved MS therapy (GA) before initiating DMF treatment. Early MS switch patients were first switch patients with baseline Patient-Reported Expanded Disability Status Scale (PR-EDSS) score ≤ 3.5, ≤ 1 relapses in the past 1 year, or both. RESULTS: Among first switch patients (n = 231), the annualized relapse rate (ARR) was 0.48 (95% confidence interval [CI] 0.40-0.58) for 12 months before DMF initiation and 0.11 (95% CI 0.06-0.18) for 12 months after DMF initiation, a 78% decrease in ARR. Among early MS switch patients with baseline PR-EDSS score ≤ 3.5 (n = 120), ≤ 1 relapses in the prior year (n = 219), or both (n = 114), the ARRs (95% CIs) for 12 months before DMF initiation were 0.47 (0.37-0.59), 0.37 (0.32-0.44), and 0.39 (0.31-0.49), respectively; values for 12 months after DMF initiation were 0.06 (0.02-0.19), 0.09 (0.05-0.17), and 0.06 (0.02-0.20), respectively, an 87, 75, and 83% decrease in ARR. The proportion of patients relapse-free 12 months after DMF initiation versus 12 months before were 94 versus 59% in first switch patients, and 97 versus 58%, 94 versus 63%, and 97 versus 61% in early MS switch patients in the PR-EDSS score ≤ 3.5, ≤ 1 relapses in the prior year, or PR-EDSS score ≤ 3.5 and ≤ 1 relapses subgroups, respectively. After 12 months of DMF treatment, most patient-reported outcomes scores showed significant improvement. CONCLUSIONS: DMF may be an effective treatment option in first switch and early MS switch patients with RMS who experience a suboptimal response to GA. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT01903291.

Daclizumab: Mechanisms of Action, Therapeutic Efficacy, Adverse Events and Its Uncovering the Potential Role of Innate Immune System Recruitment as a Treatment Strategy for Relapsing Multiple Sclerosis.

Daclizumab (DAC) is a humanized, monoclonal antibody that blocks CD25, a critical element of the high-affinity interleukin-2 receptor (IL-2R). DAC HYP blockade of CD25 inhibits effector T cell activation, regulatory T cell expansion and survival, and activation-induced T-cell apoptosis. Because CD25 blockade reduces IL-2 consumption by effector T cells, it increases IL-2 bioavailability allowing for greater interaction with the intermediate-affinity IL-2R, and therefore drives the expansion of CD56bright natural killer (NK) cells. Furthermore, there appears to be a direct correlation between CD56bright NK cell expansion and DAC HYP efficacy in reducing relapses and MRI evidence of disease activity in patients with RMS in phase II and phase III double-blind, placebo- and active comparator-controlled trials. Therapeutic efficacy was maintained during open-label extension studies. However, treatment was associated with an increased risk of rare adverse events, including cutaneous inflammation, autoimmune hepatitis, central nervous system Drug Reaction with Eosinophilia Systemic Symptoms (DRESS) syndrome, and autoimmune Glial Fibrillary Acidic Protein (GFAP) alpha immunoglobulin-associated encephalitis. As a result, DAC HYP was removed from clinical use in 2018. The lingering importance of DAC is that its use led to a deeper understanding of the underappreciated role of innate immunity in the potential treatment of autoimmune disease.

Reducing return of disease activity in patients with relapsing multiple sclerosis transitioned from natalizumab to teriflunomide: 12-month interim results of teriflunomide therapy.

BACKGROUND: Natalizumab is an effective treatment for relapsing multiple sclerosis. Return of disease activity upon natalizumab discontinuance creates the need for follow-up therapeutic strategies. OBJECTIVE: To assess the efficacy of teriflunomide following natalizumab discontinuance in relapsing multiple sclerosis patients. METHODS: Clinically stable relapsing multiple sclerosis patients completing 12 or more consecutive months of natalizumab, testing positive for anti-John Cunningham virus antibody, started teriflunomide 14 mg/day, 28 ± 7 days after their final natalizumab infusion. Physical examination, Expanded Disability Status Scale, laboratory assessments, and brain magnetic resonance imaging were performed at screening and multiple follow-up visits. RESULTS: Fifty-five patients were enrolled in the study. The proportion of patients relapse-free was 0.94, restricted mean time to first gadolinium-enhancing lesion was 10.9 months and time to 3-month sustained disability worsening was 11.8 months. The mean number of new or enlarging T2 lesions per patient at 12 months was 0.42. Exploratory analyses revealed an annualized relapse rate of 0.08, and a proportion of patients with no evidence of disease activity of 0.68. Forty-seven patients (85.5%) reported adverse events, 95% of which were mild to moderate. CONCLUSIONS: Teriflunomide therapy initiated without natalizumab washout resulted in a low rate of return of disease activity. Clinicians may consider this a worthwhile strategy when transitioning clinically stable patients off natalizumab to another therapy.ClinicalTrials.gov Identifier: NCT01970410.

Clinical outcomes in patients with relapsing-remitting multiple sclerosis who switch from natalizumab to delayed-release dimethyl fumarate: A multicenter retrospective observational study (STRATEGY).

BACKGROUND: Delayed-release dimethyl fumarate (DMF) may be a therapeutic option for patients with relapsing-remitting multiple sclerosis (RRMS) who are treated with natalizumab and require a change in therapy. However, there is limited information regarding predictors of favorable treatment outcomes in patients switching from natalizumab to DMF. Clinical practices and sequencing protocols vary. Herein, we present the clinical results, including annualized relapse rate (ARR) and risk of relapse, of a phase 4 retrospective observational study of patients with RRMS who switched from natalizumab to DMF in a community practice setting (STRATEGY). METHODS: STRATEGY was performed through a single time point medical record abstraction; no study visits or procedures were required. Key inclusion criteria included age ≥ 18 years, RRMS diagnosis (McDonald criteria, 2010 revised), ≥ 12 months of continuous treatment with natalizumab monotherapy before DMF initiation, and initiation of DMF ≥ 12 months before enrollment. Patients were eligible to enroll regardless of current DMF use. RESULTS: A total of 530 patients at 45 US sites enrolled, and 506 met the inclusion criteria and were included in the modified evaluable population for analysis. Mean (SD) age at DMF initiation was 47.0 (10.9) years, with a mean (SD) of 12.7 (7.2) years since MS diagnosis. The mean (SD) duration of natalizumab treatment was 3.4 (1.9) years, and the mean (SD) washout from natalizumab discontinuation to DMF initiation (n = 502) was 101.6 (164.0) days. Overall risk of relapse 12 months after DMF initiation was 19.6%. Overall unadjusted ARR was higher during the 12 months following initiation of DMF treatment compared with the 12 months following initiation of natalizumab treatment (rate ratio, 2.32 [95% CI, 1.69-3.18]; p < 0.0001), but was lower compared with that observed in the year before initiation of natalizumab (rate ratio, 0.51 [95% CI, 0.40-0.64]; p < 0.0001). At 1 year following initiation of DMF treatment, the relapse rate was lower for patients who did not experience a relapse during 1 year following initiation of natalizumab treatment than for those who did (rate ratio for relapse rate, 0.47 [95% CI, 0.16-1.38]; p = 0.1664). The relapse rate for patients who did not relapse during natalizumab treatment was significantly lower with a washout period of ≤ 90 days as compared with a washout period of > 90 days (rate ratio for relapse rate, 0.49 [95% CI, 0.26-0.90]; p = 0.0216). A total of 42 (8%) patients reported ≥ 1 adverse event leading to DMF discontinuation during the study; the most commonly reported events were gastrointestinal disorders (n = 21; 4%). CONCLUSIONS: Results from this multicenter retrospective observational study suggest that DMF may be an effective treatment option for patients who discontinue natalizumab in routine clinical practice. ARR was lower in patients who initiated DMF within 90 days of natalizumab discontinuation compared with patients who initiated DMF after 90 days of natalizumab discontinuation. TRIAL REGISTRATION NUMBER: ClinicalTrials.gov identifier NCT02159573.

BG-12 (dimethyl fumarate): a review of mechanism of action, efficacy, and safety.

BACKGROUND: Multiple sclerosis (MS) is a chronic inflammatory disease, affecting more than 2.5 million people worldwide with more 400,000 cases in the United States alone. There has been considerable improvement in the treatment of MS, with the introduction of disease-modifying drugs; however, new oral therapies may provide additional benefit by providing an alternative treatment modality and the potential for improved adherence by avoiding the injection-associated side effects and anxiety encountered with some first-line agents. BG-12 (dimethyl fumarate) is an oral agent approved in the United States for the treatment of relapsing forms of MS. SCOPE: We review published literature about what is known about the mechanism of action of BG-12, and key efficacy and safety findings from three clinical studies in patients with relapsing-remitting MS (RRMS). FINDINGS: Data from preclinical studies have demonstrated that BG-12 may promote anti-inflammatory and cytoprotective activities that are mediated, at least in part, by the nuclear factor (erythroid-derived 2)-like 2 (Nrf2) antioxidant response pathway. Studies in animals have shown a protective effect of BG-12 on neuronal, axonal and myelin integrity. Results from a phase 2 study and two randomized double-blind placebo-controlled phase 3 studies, CONFIRM and DEFINE, have shown that BG-12 provides clinical and radiologic efficacy in patients with RRMS. At 2 years, BG-12 240 mg twice and three times daily reduced annualized relapse rate (CONFIRM primary endpoint) by 44% and 51% and the risk of relapse (DEFINE primary endpoint) by 49% and 50%, respectively, compared with placebo (all p < 0.001). BG-12 was generally well tolerated and had an acceptable safety profile, with a similar incidence of adverse events across treatment groups. CONCLUSIONS: BG-12 may have cytoprotective and anti-inflammatory properties that contribute to its efficacy among patients with RRMS. Findings from phase 2 and 3 studies further support BG-12 as an effective initial therapy. ClinicalTrials.gov ID: NCT00168701; NCT00420212: NCT00451451.

Eight-year immunogenicity and safety of interferon beta-1a-Avonex treatment in patients with multiple sclerosis.

An open-label extension study of the phase III trial of intramuscular interferon beta-1a (IFNbeta-1a-Avonex) was conducted to evaluate the immunogenicity and safety of IFNbeta-1a-Avonex over six years in patients with relapsing multiple sclerosis (MS). Patients who participated in the pivotal phase III study were offered enrolment; entry was also open to patients who had not participated. All patients received IFNbeta-1a-Avonex 30 microg intramuscularly once weekly for six years, for a treatment duration of up to eight years in patients who received IFNbeta-1a-Avonex in the phase III trial. Serum levels of IFNbeta antibodies were measured every six months using a screening enzyme-linked immunosorbent assay (ELISA) followed by an antiviral cytopathic effect assay to detect neutralizing antibodies (NAbs) in serum samples positive on ELISA. The incidence of adverse events and laboratory test results assessed safety. Of 382 total patients, 218 had participated in the phase III study (103 placebo, 115 IFNbeta-1a-Avonex) and 164 had not participated; 24 of the 164 were IFNbeta-naïve. At baseline, 281 patients were negative for IFNbeta antibodies (NAb-). NAbs (titre > or = 20) developed at any time over six years in 5% of these patients. Of 140 patients who had been on IFNbeta-1b-Betaseron, 49 were positive for NAbs (NAb+) at baseline; 11 of 115 who had been on IFNbeta-1a-Avonex were NAb+ at baseline. Thirty-nine of 49 patients who had been on Betaseron and were NAb+ had titres < 100; 36 of these 39 seroconverted to NAb- while on IFNbeta-1a-Avonex, with a median time of approximately six months. Ten patients who had been on Betaseron had NAb titres > or = 100; five remained NAb+ during six years on IFNbeta-1a-Avonex and five seroconverted to NAb-, but only after at least two years. Five patients who had been on IFNbeta-1a-Avonex during the clinical trial were NAb+ with titres < 100 at baseline; four seroconverted to NAb-, with a median time of two to three years. Six patients who had been on IFNbeta-1a-Avonex had NAb titres > or = 100; five of these remained NAb+ at six years. No patient with a NAb titre > 1000 seroconverted to NAb-, whether initially treated with IFNbeta-1a-Avonex or -Betaseron. Adverse events were similar to those observed in the pivotal phase III trial. Results from this trial indicated that IFNbeta-1a-Avonex was associated with a low incidence of NAbs and was well tolerated for up to eight years. Further, the results indicate that persistence of NAbs is dependent on titre and IFNbeta product.