Background Immunomodulatory drugs represent the best therapeutic option in first-line treatment of relapsing-remitting multiple sclerosis (RRMS). This group includes glatiramer acetate (GA) and three formulations of Interferon β (IFNβ): subcutaneous IFNβ1a (scIFNβ1a), intramuscular IFNβ1a (imIFNβ1a) and subcutaneous IFNβ1b (scIFNβ1b). Several studies have reported similar efficacy among IFNβ and GA preparations, while other have concluded that some differences exist between them.

Purpose To compare the effectiveness of first-line disease modifying drugs (FL-DMD) in patients with RRMS.

Materials and Methods In this retrospective and observational study we included treatment-naive patients with RRMS who had started treatment with FL-DMD between 1996 and 2011. Patients receiving other immunosuppressant drugs were excluded. Data were collected from medical records and pharmacy computer applications. Patients were classified in four groups: those treated with imIFNβ1a, scIFNβ1a, scIFNβ1b or GA. The annualised relapse rate (ARR) and degree of disability for each group were determined in the pre-treatment and treatment periods. The time to first relapse (TFR), proportion of relapse-free patients (RFP) and proportion of patients without progression of disability (DPFP) in each group were compared.

Results We identified 72 patients who had started treatment with DMD: 22 with imIFNβ1a, 13 with scIFNβ1a, 26 with scIFNβ1b and 11 with AG.

Mean ARR in the pre-treatment and treatment periods were the following (mean±SD): 0.73 ± 0.40 and 0.10 ± 0.16 for imIFNβ1a. 0.81 ± 0.43 and 0.21 ± 0.32 for scIFNβ1a. 0.56 ± 0.33 and 0.11 ± 0.20 for scIFNβ1b and 0.73 ± 0.34 and 0.17 ± 0.28 for GA. TFR in each group were respectively 5.8 ± 4.2. 3.8 ± 2.8. 5.3 ± 3.8 and 2.4 ± 1.6 years. We found 59.1%, 61.5%, 61.5% and 63.6% RFP in each group and 90.9%, 92.3%, 88.5% and 81.8% DPFP respectively. No statistical differences were found in TFR, RFP or DPFP among groups.

Conclusions No differences were found among the different first-line treatment options in terms of reduction of disease activity or progression of disability.

No conflict of interest.