Randomized study of once-weekly interferon β-la therapy in relapsing multiple sclerosis: Three-year data from the OWIMS study

Mark S. Freedman*, G. S. Francis, E. A.C.M. Sanders, G. P.A. Rice, P. O'Connor, G. Comi, P. Duquette, L. Metz, T. J. Murray, J. P. Bouchard, O. Abramsky, J. Pelletier, F. O'Brien, J. de Rijk van Andel, J. P. Story, M. de Milliano, G. Ebers, J. Lesaux, K. Kennedy, P. HoustonJ. Hall, V. Martinelli, G. Santuccio, A. Poggi, M. Gironi, L. Moiola, G. Pepin, J. Poirer, G. Bernier, R. Dubois, R. Bell, D. McGowan, A. Demchuk, E. Harris, M. Yeung, A. Murphy, V. Bhan, C. Maxner, P. Weldon, L. Armstrong, F. Gosselin, M. Thibaut, L. Korouac, A. Morin, D. Karussis, A. Karni, M. Mor, R. Nelson, S. Christie, H. Rabonivitch, C. Freedman, M. Benavente, P. Bensa, A. Dalesky, D. Paty, D. Li, B. Rhodes, A. Riddehough, G. Zhao, X. Wang, Y. Chang, N. Ammoury, A. Galazka, R. Hyde, S. Shah, G. Francis, S. Shahid

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Background: Once weekly interferon β-1a for multiple sclerosis (OWIMS) demonstrated modest, but significant, magnetic resonance imaging (MRI) benefit of once-weekly (qw) interferon (IFN) β-1a at 48 weeks, but no significant effect on relapses. Objective: An OWIMS extension permitted assessment of longer-term efficacy/safety of qw IFN β-1a in relapsing-remitting multiple sclerosis (RRMS). Methods: Placebo patients were rerandomized to IFN β-1a, 22 or 44 mcg qw, for two additional 48-week intervals. Primary outcome was MRI lesion activity. Relapse rate and other MRI measures were secondary outcomes. Results: After three years, median (mean) T2 lesion count/patient/scan was 1.3 (2.6) for 44 mcg, 1.7 (3.3) for 22 mcg, 1.7 (3.4) for placebo/22 mcg, 2.0 (3.6) for placebo/44 mcg (all differences not significant). Annualized relapse rates were lowest for 44 mcg (0.77) versus other groups (0.83-0.86, not significant). Persistent neutralizing antibodies did not affect relapse rates, but MRI active lesions were increased in antibody-positive patients receiving 44 mcg compared to antibody negative patients. Conclusions: In RRMS, once weekly IFN β-1a, particularly 44 mcg, can induce a significant MRI, but not relapse, effect, compared with placebo. No significant dose effect was seen. In contrast to the significant effect observed with three-times-weekly dosing of subcutaneous IFN β-1a compared with placebo, this study confirms the lack of meaningful clinical benefit with once-weekly dosing.

Original languageEnglish
Pages (from-to)41-45
Number of pages5
JournalMultiple Sclerosis Journal
Issue number1
StatePublished - Feb 2005
Externally publishedYes


  • Controlled clinical trial
  • Interferon β-Ia
  • MRI
  • OWIMS study
  • Once-weekly dosing
  • Randomized
  • Relapse-related outcomes
  • Relapsing multiple sclerosis


Dive into the research topics of 'Randomized study of once-weekly interferon β-la therapy in relapsing multiple sclerosis: Three-year data from the OWIMS study'. Together they form a unique fingerprint.

Cite this