Quality Assessment in Multiple Sclerosis Therapy (QUASIMS)A comparison of interferon beta therapies for relapsing-remitting multiple sclerosis

Interferon beta (IFNβ) preparations are the most frequently prescribed therapies for patients with relapsing multiple sclerosis (MS). Several open-label observational studies report similar efficacy among IFNβ 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 IFNβ 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 IFNβ preparations/dosing regimens (intramuscular IFNβ-1a 30 µg 1×/week [Avonex®], subcutaneous (SC) IFNβ-1a 22 or 44 µg 3×/week [Rebif®], or SC IFNβ-1b 250 µg 3.5×/week [Betaferon/Betaseron®]) for ≥ 2 years. Preplanned 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 IFNβ as initial therapy. There were no significant differences among IFNβs 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 IFNβ products. Benefits were consistently superior when IFNβ 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 IFNβ preparations/dosing regimens.