A pilot trial of combination therapy with mitoxantrone and interferon beta-1b using monthly gadolinium-enhanced magnetic resonance imaging

OBJECTIVE: To examine the safety of combination therapy with mitoxantrone (MITX) and interferon beta-1b (IFNbeta-1b) in patients with multiple sclerosis (MS) and a high on-therapy relapse rate and enhancing lesions on baseline magnetic resonance imaging (MRI) scan. METHODS: Ten patients with worsening relapsing remitting or secondary progressive MS were studied using monthly MRI with triple-dose gadolinium contrast. All patients must have been on IFNbeta-1b for at least six months, have at least one enhancing lesion on a screening MRI, at least one relapse on IFNbeta-1b in the six months prior to study entry and be neutralizing antibody negative. Monthly MRI scans using triple dose contrast and a 30-minute delay between contrast administration and scanning were carried out three times over two months to obtain baseline numbers of enhancing lesions each month. At the end of the baseline phase, MITX was administered at 12 mg/m2 (month 3), and 5 mg/m2 at months 4 and 5. Dosing was continued at 5 mg/m2 every third month. Monthly MRI scanning was continued throughout the duration of MITX dosing. The primary outcome measure was the frequency of new enhancing lesions. Secondary outcome measures included relapse rate, and T1 hypointense and T2 lesion burden. RESULTS: Following the addition of MITX to IFNbeta-1b mean enhancing lesion frequency decreased 90% at month 7 (P = 0.008) and enhancing lesion volume decreased by 96% (P = 0.01). Relapse rates decreased 64% (P = 0.004). T2 lesion burden and T1 hypointense lesion burden increased slightly during the baseline phase and decreased following MITX but the difference did not reach statistical significance. There were no serious adverse events on combination therapy and no drop-outs due to toxicity. Total white blood cell count was reduced at 14 days post-MITX infusion but returned to normal levels by day 21. There were no neutropenic fevers and there was no clinically significant elevation of liver function tests. CONCLUSIONS: While the number of patients in this study was small, the results suggest that the combination is safe and well tolerated. Disease activity was substantially reduced following the addition of MITX to IFNbeta-1b.     

Emotional state of patients with relapsing-remitting MS treated with interferon beta-1b.

BACKGROUND: Depression has been cited as a possible side effect of interferon beta-1b (IFNbeta-1b) therapy in patients with MS. This association remains unproven because of a lack of longitudinal studies. OBJECTIVE: To determine the changes in emotional state in relapsing-remitting (RR) MS patients during the first 2 years of treatment with IFNbeta-1b. METHODS: Emotional state was evaluated in a sample of 90 patients at the onset of IFNbeta-1b treatment during an inclusion period of 2.5 years. Seventy-five patients were evaluated at their 12th month of treatment and 56 patients at their 24th month. We assessed their emotional state with the following psychological tests: Hamilton Depression Rating Scale, Beck Depression Inventory, and State-Trait Anxiety Inventory. RESULTS: We found significant improvement in emotional state after the first and second years of treatment. CONCLUSIONS: Our findings show that IFNbeta-1b does not increase depression or anxiety in RR MS patients during the first and second years of IFNbeta-1b treatment. In fact, slight but significant improvement in depression and anxiety symptoms was observed during this period.     

Mx proteins in blood leukocytes for monitoring interferon beta-1b therapy in patients with MS

OBJECTIVE: To correlate Mx protein (Mx) levels in lysed blood leukocytes with the clinical response to interferon (IFN) beta-1b (IFNbeta-1b) in relapsing-remitting MS (RR-MS) patients for monitoring treatment. BACKGROUND: Intracellular Mx expression is exclusively induced by the type I IFNs (IFN-alpha, -beta, and -omega) or by viruses and is strongly increased under IFN treatment. Quantitative determination of Mx allows objective assessment of biological effects of IFN. METHODS: Mx protein levels were measured in blood leukocyte lysates from IFNbeta-1b-treated RR-MS patients by ELISA and correlated to clinical parameters, including relapse rate and clinical deterioration. RESULTS: In stable IFNbeta-1b-treated MS patients, Mx levels were significantly increased compared to patients with or without immunosuppressive treatment. In IFN-1b-treated MS patients during relapse, Mx levels were significantly lower than during stable phases of the disease. Mean values of Mx (MVMx) over time of treatment in patients with a reduction of relapse rate were significantly higher than in patients without response. CONCLUSION: Mx levels in lysed blood cells may represent a useful surrogate marker for IFNbeta-1b activity corresponding to the clinical response during treatment of MS.     

A prospective, open-label treatment trial to compare the effect of IFNbeta-1a (Avonex), IFNbeta-1b (Betaseron), and glatiramer acetate (Copaxone) on the relapse rate in relapsing--remitting multiple sclerosis: results after 18 months of therapy.

We previously reported results of a 12 month prospective, non-randomized, open-label treatment trial of immunomodulatory therapy in patients with relapsing-remitting multiple sclerosis (RRMS). We now report the results after 18 months of follow-up. Our primary objective was to compare the effect of IFNbeta-1a (Avonex), IFNbeta-1b (Betaseron), and Glatiramer Acetate (GA, Copaxone) to no treatment on the relapse rate in patients with RRMS. One hundred and fifty-six consecutive patients with clinically definite RRMS with a Kurtzke scale (EDSS) score of 4 or less were followed for 18 months. Prior 2-year relapse history and available chart information was carefully reviewed at the time of enrollment Thirty-three of 156 elected no treatment at enrollment; 40 elected IFNbeta-1a, 41 IFNbeta-1b, and 42 chose GA. There were no statistically significant differences among the four groups at enrollment. After 18 months of treatment 122 patients remained in their original treatment group. Compared to the untreated group (1.02), mean annualized number of relapses was significantly reduced only in the GA (0.49, P>0.0001) and IFNbeta-1b groups (0.55, P=0.001) in contrast to the IFNbeta-1a treated patients (0.81, P=0.106) who did not show a significant reduction. Despite limitations of the study design, the results provide helpful clinical information regarding the relative efficacy of each therapy in mildly affected treatment naive RRMS patients.     

Longitudinal MRI study: the effects of azathioprine in MS patients refractory to interferon beta-1b

An open-label study was performed to assess the effectiveness of oral azathioprine (AZA) on augmenting the response to interferon beta-1b (IFNbeta-1b) in patients with treatment-refractory relapsing-remitting MS. Six IFNbeta-1b-treated MS patients with continued disease activity were studied on IFNbeta-1b and AZA therapy for a median period of 15 months. A 69% reduction in the number of contrast-enhancing lesions was observed during the combination therapy (p = 0.002).     

Effect of interferon-beta-1b on cognitive functions in multiple sclerosis.

INTRODUCTION: Multiple sclerosis (MS) is recognised as a central nervous system disease also affecting cognition. The rate of cognitive dysfunction in MS is in the range of 45-65% and adversely affect the quality of life. OBJECTIVE: To evaluate the effect of 1 year of treatment with interferon-beta-1b (IFNbeta-1b) on cognitive functions in patients suffering from relapsing-remitting MS. METHODS: A battery of cognitive tests was used to assess verbal learning, delayed recall, visual learning and recall, complex attention, concentration and verbal fluency at baseline and after 1 year of treatment with IFNbeta-1b. A group of 23 relapsing-remitting MS patients matched for neurological disability served as controls. RESULTS: Eighteen of 23 patients treated with IFNbeta-1b (74%) completed the study. In the IFNbeta-1b-treated group, complex attention, concentration as well as visual learning and recall improved significantly (p = 0.024, p = 0.006 and p = 0.005, respectively), while no deterioration was observed in the other dimensions. In the control group, complex attention, verbal fluency, as well as visual learning and recall deteriorated significantly (p = 0.02, p = 0.004 and p = 0.01, respectively), while no deterioration was observed in the other dimensions. CONCLUSION: Immunomodulating drugs that reduce the relapse rate and slow the disease progression also inhibit cognitive deterioration in patients with MS.     

Every-other-day interferon beta-1b versus once-weekly interferon beta-1a for multiple sclerosis (INCOMIN Trial) II: analysis of MRI responses to treatment and correlation with Nab

BACKGROUND: In RRMS, clinical exacerbations are usually associated with different types of active lesions at MRI, including: hyperintense lesions on T1-weighted post-gadolinium sequences; new hyperintense lesions or enlarging old lesions on PD/T2-weighted scans; or new hypointense lesions on T1-weighted pre-Gd sequences. OBJECTIVE/METHODS: Primary outcome was the occurrence of patients with at least one active MRI lesion of the different types indicated above during treatment with 250 microg every other day (EOD) interferon beta (IFNbeta)-1b or 30 microg once weekly (OW) IFNbeta-1a in outpatients with RRMS (INCOMIN Trial). RESULTS: The number of patients with at least one 'active' lesion, evaluated over the two-year follow-up, was significantly (P = 0.014) lower in the EOD IFNbeta-1 b arm (1 3/76, 17%) then in the OW IFNbeta-1a arm (25/73, 34%). NAb frequency over two-year follow-up was 22/65 (33.8%) in the EOD IFNbeta-1b arm and 4/62 (6.5%) in the OW IFNbeta-1a arm, significantly greater in the EOD IFNbeta-1b arm. CONCLUSIONS: The development of MRI active lesions is strongly reduced by EOD-IFNbeta-1b compared with OW-IFNbeta-1a, indicating that EOD-IFNbeta-1b is more effective than OW-IFNbeta-1a in reducing ongoing inflammation and demyelination in MS. Logistic regression showed that NAb status did not affect the risk of MRI activity.     

Recurrence or rebound of clinical relapses after discontinuation of natalizumab therapy in highly active MS patients

A number of studies have reported flare-up of multiple sclerosis (MS) disease activity after cessation of natalizumab, increasing to a level beyond the pre-natalizumab treatment level. Our aim was to describe the development in clinical disease activity following cessation of natalizumab therapy in a large unselected cohort of highly active patients. We studied 375 highly active patients who had suffered at least two significant relapses within 1 year or three relapses within 2 years, or had been treated with mitoxantrone for highly active disease. All patients had discontinued therapy with natalizumab after at least 24 weeks on therapy, and had been followed 3–12 months (mean 8.9 months) after cessation of natalizumab therapy. The annualised relapse rate before start of natalizumab therapy was 0.94 (95 % confidence interval [CI] 0.88–1.00), 0.47 (95 % CI 0.43–0.52) during natalizumab therapy, 0.63 (95 % CI 0.51–0.76) 1–6 months after natalizumab and 0.55 (95 % CI 0.42–0.70) 7–12 months after natalizumab. However, 83 (22 %) of the patients could be classified as showing rebound of relapses, defined as a higher individual relapse rate after cessation of natalizumab than before natalizumab. These patients had a higher annualised relapse rate during natalizumab therapy. For the whole patient group, the relapse rate after discontinuation did not exceed the pre-natalizumab relapse rate at any time, but 22 % of the patients showed rebound of relapses after discontinuation of natalizumab.     

Interferon beta in relapsing-remitting multiple sclerosis: an independent postmarketing study in southern Italy

This independent, population-based surveillance study monitored the efficacy and safety of interferon beta (IFNbeta) products in 1033 patients with relapsing-remitting multiple sclerosis (RRMS) from 15 centres in Italy. Relapses, Expanded Disability Status Scale (EDSS) scores, and adverse events were evaluated for up to 24 months. Data of patients with a baseline EDSS score < or = 3.5 are reported. The proportions of relapse-free patients were similar among the groups at 12 and 24 months (P = 0.10). IFNbeta products produced significant reductions from baseline in relapse rates at 12 and 24 months (P < 0.001), with no differences among treatments (P = 0.2). There were no significant differences in mean EDSS change among groups at 12 or 24 months. The IFNbeta-1b group showed a higher incidence of adverse events during the first year of treatment (P < 0.05) than IFNbeta-1a groups, and more withdrawals (10%) compared with Avonex (5%) at 24 months. IFNbeta products are equally effective in low disability RRMS, but IFNbeta-1a may have a more favorable efficacy/tolerability ratio.     

Long-term experience with interferon beta-1b (Betaferon)in multiple sclerosis

The interferon beta-1b (IFNbeta-1b, Betaferon/Betaseron) molecule was cloned some 20 years ago. In a pilot dose-finding trial involving 30 multiple sclerosis (MS) patients, the 10 MS patients receiving 250 microg (8 MIU) IFNbeta-1b every other day at 6 months showed a reduced attack frequency relative to 6 patients receiving placebo. Based on these extremely preliminary results a Phase III placebo-controlled trial was undertaken. Treatment with IFNbeta-1b was shown to reduce attack frequency and severity and to markedly reduce magnetic resonance imaging-(MRI) measured activity and disease burden. IFNbeta-1b therapy was subsequently shown to reduce MRI activity within 2 weeks of starting treatment. The benefits of treatment with IFNbeta-1b observed in the original pivotal study are maintained in the longer term, with consistent treatment effects seen after 5 years. IFNbeta-1b has subsequently been shown to reduce accumulation of disability in MS patients with early active secondary progressive disease, to increase cerebral metabolism, and to improve cognitive performance.IFNbeta-1b therapy is generally well tolerated. Classical systemic side effects related to all beta interferons can effectively be managed by dose escalation, and the use of an autoinjector minimises injection site reactions. About one-third of MS patients receiving IFNbeta-1b develop anti-interferon antibodies, typically within the first year of therapy. These antibodies have variable titres that fall with time and ultimately disappear in most patients. The clinical consequences of the presence of antibodies are presently unclear and inconsistent-some patients without antibodies respond poorly to treatment, whereas others with high-titre antibodies respond well to treatment. It is possible that immune complexes formed when anti-interferon antibodies encounter IFNbeta may enhance some of the immunomodulatory actions of the drug by improving CD8 cell-mediated suppressor function. Until the clinical relevance of antibodies is better understood, treatment decisions should be based on clinical grounds only.     

Liver injury associated with the beta-interferons for MS: a comparison between the three products

A population-based retrospective chart review of the biochemical liver tests of 844 patients with multiple sclerosis prescribed a beta-interferon (IFNbeta) product in British Columbia, Canada was performed between 1995 and 2001. Overall, 36.9% (243/659) of patients developed new elevations of alanine aminotransferase. All the IFNbetas caused elevated aminotransferase levels compared with pretreatment levels (p < 0.005) and were higher than reported in clinical trials. Their relative effect on aminotransferases can be approximated as IFNbeta-1b(subcutaneous [SC]) = IFNbeta-1a(SC) > IFNbeta-1a(IM).     

Final analysis of the European multicenter trial on IFNbeta-1b in secondary-progressive MS.

BACKGROUND: Based on a prospectively planned interim analysis, the European study of interferon beta-1b (IFNbeta-1b) provided evidence that the treatment delays neurologic deterioration in patients with secondary progressive MS (SPMS). The authors analyzed all data collected until closure of the double-blind study to further scrutinize the consistency of the findings. METHODS: The multicenter, double-blind, randomized, placebo-controlled trial treated patients for up to 36 months. The primary and all secondary endpoints of this study were evaluated using the data set at study termination, with a mean follow-up under double-blind conditions of 1054 +/- 199 and 1068 +/- 176 days for the placebo and IFNbeta-1b group. Alternative and more demanding definitions of disease progression were explored. Confirmed progression was analyzed in subgroups according to baseline demographics and baseline indicators of disease activity. RESULTS: Forty-eight of 358 placebo and 40 of 360 IFNbeta-1b-allocated patients were lost to follow-up. Time to confirmed 1.0-point Expanded Disability Status Scale (EDSS) progression for patients receiving IFNbeta-1b was delayed (p = 0.007). The proportion of patients with a confirmed 2.0-point EDSS progression was approximately 27% lower for the group treated with IFNbeta-1b, both including and excluding EDSS data collected during relapses. The proportion of patients with either progression or relapses decreased by nearly 30% in patients treated with IFNbeta-1b compared with placebo. Analysis of subgroups suggests that patients with higher prestudy disease activity (more than two relapses or EDSS progression by more than 1.0 point or both) seem to have a more pronounced treatment effect. CONCLUSION: Analysis of the data set at study termination including additional post hoc outcome measures is consistent with the original findings, thus supporting the conclusion that treatment with IFNbeta-1b is effective in patients with SPMS fulfilling the inclusion criteria of this study.     

Avonex Combination Trial in relapsing--remitting MS: rationale, design and baseline data

OBJECTIVE: To review the rationale, design and baseline data of the Avonex Combination Trial (ACT), an investigator-run study of intramuscular interferon beta-1a (IM IFNbeta-1a) combined with methotrexate (MTX) and/or IV methylprednisolone (IVMP) in relapsing-remitting multiple sclerosis (RRMS) patients with continued disease activity on IM IFNbeta-1a monotherapy. METHODS: Eligibility criteria included RRMS, Expanded Disability Status Scale score 0-5.5, and >or=1 relapse or gadolinium-enhancing MRI lesion in the prior year while on IM IFNbeta-1a monotherapy. Subjects continued IFNbeta-1a 30 mcg IM weekly and were randomized in a 2 x 2 factorial design to adjunctive weekly placebo or MTX 20 mg PO, with or without IVMP 1,000 mg/day for three days every other month. ACT was industry-supported, and collaboratively designed and governed by an Investigator Steering Committee with independent Advisory and Data Safety Monitoring Committees. Study operations, MRI analysis and aggregated data were managed by the Cleveland Clinic MS Academic Coordinating Center. RESULTS: In total 313 subjects were enrolled with clinical and MRI characteristics typical of RRMS. Most subjects (86.9%) qualified with a clinical relapse, with or without an enhancing MRI lesion, in the preceding year. At baseline, 21.4% had enhancing lesions, and 5.1% had anti-IFNbeta neutralizing antibodies. ACT's management and operational structures functioned well. CONCLUSION: This study provides an innovative model for academic-industry collaborative MS research and will enhance understanding of the utility of combination therapy for RRMS patients with continued disease activity on an established first-line treatment.     

The importance of maintaining effective therapy in multiple sclerosis

The INCOMIN study (INdependent COMparison of INterferons) lends further support to the growing body of evidence that both dose and frequency of interferon beta (IFNbeta) administration are important in the treatment of multiple sclerosis (MS). High-dose, high-frequency IFNbeta (IFNbeta-1b 250 microg eod sc and IFNbeta-1a 44 microg sc) treatment offers greater therapeutic benefit, in terms of clinical and magnetic resonance imaging (MRI) outcome measures, compared with low-dose, once-weekly administration of IFNbeta. The importance of maintaining the most effective treatment regimen has been shown in another study. The data from this study suggested that patients who have 'stable' disease (i. e. no evidence of clinical or MRI disease activity) during long-term treatment with IFNbeta-1b 250 microg, who are subsequently treated with low-dose, once-weekly IFNbeta-1a 30 microg, are more likely to experience relapses, disease progression or MRI activity compared with those remaining on IFNbeta-1b 250 microg. These data clearly indicate that frequently administered therapy must be maintained to achieve the optimal therapeutic benefit for patients. Those patients who had their IFNbeta-1b 250 microg therapy reduced to low-dose, once-weekly IFNbeta-1a and experienced a resumption of disease activity were returned to their previous regimen. However, after 1 year of additional follow-up, many of these patients still had clinical or MRI signs of disease activity, highlighting further the risks associated with the reduction of IFNbeta dose and frequency of administration. Taking into consideration the evidence supporting the greater efficacy of IFNbeta-1b 250 microg or IFNbeta-1a 44 microg in MS it is of considerable interest to examine whether it is useful to increase the dose of IFNbeta-1b in patients who do not respond satisfactorily to the approved standard dose. This is the rationale for the recently completed OPTIMS (OPTimization of Interferon for MS) study, in which partially responding patients were randomised to IFNbeta-1b 250 or 375 microg every other day. An interim safety analysis of OPTIMS patients has not raised any safety or tolerability concerns. In summary, there is consistent evidence to support the importance of maintaining frequently administered IFNbeta (IFNbeta-1b 250 microg or IFNbeta-1a 44 microg) for the treatment of MS.     

Differing immunogenic potentials of interferon beta preparations in multiple sclerosis patients

Interferon beta (IFNbeta) is a first-line therapy for multiple sclerosis (MS). However, some patients experience a decline in efficacy with continued therapy due to the development of anti-IFNbeta neutralizing antibodies (NAb). We investigated the frequency of NAb cross-sectionally in 846 MS patients who were receiving IFNbeta-1b, IFNbeta-1a im, or IFNbeta-1a sc. The frequency of NAb in patients receiving IFNbeta-1a im was lower (5%) than in patients treated with any other form of IFNbeta (22-35%) (P < 0.0001). Binding antibodies (BAb) were measured in 808 patients. The frequency differed significantly between treatment groups, ranging from 45% (IFNbeta-1a im) to 88% (IFNbeta-1b). The proportion of NAb-positive patients within the BAb-positive group differed significantly among treatment groups, ranging between 12% (IFNbeta-1a im) and 51% (IFNbeta-1a sc). The median NAb titer from all IFNbeta-1a-treated patients was higher than from IFNbeta-1b-treated patients (446 versus 171 NU/ mL, P = 0.04). Among NAb-positive patients, the frequency of NAb titers > 100 NU/mL was 71% for IFNbeta-1a compared with 58% for IFNbeta-1b (P = 0.04). Except for conflicting data regarding IFNbeta-1a sc, the results are generally consistent with the literature and together with the differing proportion of NAb-positive patients within the BAb-positive group, provide further insight into the immunogenicity of the IFNbeta preparations.     

Interferon beta-1a in relapsing multiple sclerosis: four-year extension of the European IFNbeta-1a Dose-Comparison Study

BACKGROUND: Multiple sclerosis (MS) is a chronic disease requiring long-term monitoring of treatment. OBJECTIVE: To assess the four-year clinical efficacy of intramuscular (IM) IFNbeta-1a in patients with relapsing MS from the European IFNbeta-1a Dose-Comparison Study. METHODS: Patients who completed 36 months of treatment (Part 1) of the European IFNbeta-1a Dose-Comparison Study were given the option to continue double-blind treatment with IFNbeta-1a 30 mcg or 60 mcg IM once weekly (Part 2). Analyses of 48-month data were performed on sustained disability progression, relapses, and neutralizing antibody (NAb) formation. RESULTS: Of 608/802 subjects who completed 36 months of treatment, 493 subjects continued treatment and 446 completed 48 months of treatment and follow-up. IFNbeta-1a 30 mcg and 60 mcg IM once weekly were equally effective for up to 48 months. There were no significant differences between doses over 48 months on any of the clinical endpoints, including rate of disability progression, cumulative percentage of patients who progressed (48% and 43%, respectively), and annual relapse rates; relapses tended to decrease over 48 months. The incidence of patients who were positive for NAbs at any time during the study was low in both treatment groups. CONCLUSION: Compared with 60-mcg IM IFNbeta-1a once weekly, a dose of 30 mcg IM IFNbeta-1a once weekly maintains the same clinical efficacy over four years.     

The combination of cyclophosphamide plus interferon beta as rescue therapy could be used to treat relapsing–remitting multiple sclerosis patients

The aim of the present study was to evaluate the efficacy of the combination of cyclophosphamide (CTX) and interferon beta (IFN β) in a group of relapsing remitting (RR) multiple sclerosis (MS) patients who experienced treatment failure during IFN β therapy. It is the general experience that immunomodulatory agents (IMA) are only partially effective in RR patients. Recent data on the efficacy of immunosuppressive therapies for these patients are encouraging. The anti–inflammatory and immunosuppressive effects of CTX have been utilized to treat selected cases of multiple sclerosis with a progressive and worsening course as rescue therapy. Thirty RR MS patients with clinically defined MS who experienced treatment failure during IFN β therapy (2 or more relapses per year or 1.5 EDSS point worsening in one year) were enrolled in the study and treated with CTX iv pulse therapy added to IFN β and followed up for 24 months. As primary endpoints we evaluated the yearly relapse rate. We also evaluated the percentage of patients free of relapses and of EDSS variations. We analysed the results at one year before entry (T0: IFN β alone), 12 (T1) and 24 (T2) months after entry. Brain MRI was performed at T0, at T1 and T2. The 30 RR patients who had experienced a high number of relapses (r r =1.4) at T0 showed a significant improvement in yearly relapse rate (rr = 0.4) at T1 and a further improvement (rr = 0.17) at T2 (p < 0.001). The percentage of patients free of relapse was 70% at T2 (p < 0.0001). EDSS score changed from 2.6±1.23 at T0 to 2.2 ± 1.5 at T2, showing only a trend of improvement.No significant variation of MRI lesion load and no severe adverse events were recorded during the study. These data showed that the combination of CTX plus IFN β halted the progression of disease in active and deteriorating MS patients suggesting the necessity of RCTs to test the efficacy of this combination therapy in active RRMS patients or in patients who experienced treatment failure in response to disease modifying drugs (DMDs).     

Quality Assessment in Multiple Sclerosis Therapy (QUASIMS)

Interferon beta (IFN beta) preparations are the most frequently prescribed therapies for patients with relapsing multiple sclerosis (MS). Several open-label observational studies report similar efficacy among IFN beta preparations. The Quality Assessment in Multiple Sclerosis Therapy (QUASIMS) study is a large, open-label observational study designed to compare the effectiveness and tolerability of available IFN beta preparations as disease-modifying therapies for relapsing MS across a wide range of clinical practice settings. This retrospective, controlled cohort study was conducted by chart review at 510 sites in Germany, Austria, and Switzerland. Enrolled patients had received one of the four available IFN beta preparations/dosing regimens (intramuscular IFN beta-1a 30 microg 1x/week [Avonex], subcutaneous (SC) IFN beta-1a 22 or 44 microg 3 x/week [Rebif], or SC IFN beta-1b 250 microg 3.5x/week [Betaferon/Betaseron]) for >or= 2 years. Pre-planned outcomes at 1 and 2 years included change from baseline Expanded Disability Status Scale (EDSS) score, percentage of progression-free patients (< 1.0 EDSS point), annualised relapse rate (RR), percentage of relapse-free patients, and reasons for therapy change. Of 4754 evaluable patients, 3991 (84%) received IFN beta as initial therapy. There were no significant differences among IFN betas when used as initial or follow-up therapy on almost all outcome variables. Relapse rate was consistently higher and percentage of relapse-free patients consistently lower for all products used as follow-up versus initial therapy. Results of QUASIMS showed similar effectiveness among IFN beta products. Benefits were consistently superior when IFN beta was used as initial rather than follow-up therapy. Our results suggest that patients do not benefit in terms of disease outcome from switching between IFN beta preparations/dosing regimens.