WESTPORT, CT (Reuters Health) Oct 10 - Final results of the first independent prospective trial comparing interferon beta-1b (Betaseron; Schering AG) with interferon beta-1a (Avonex; Biogen Inc.) for relapsing-remitting MS indicate that interferon beta-1b is considerably more effective than interferon beta-1a.
The 2-year results from the Independent Comparison of Interferon (INCOMIN) trial, presented this week during the Italian Neurological Society Meeting in Turin, Italy, confirm interim, 1-year results reported earlier this year.
The clinical benefits of interferon beta-1b seen at 1 year continue and become more pronounced over time when compared with interferon beta-1a, Dr. Luca Durelli, of the University MS Center, Torino, and the INCOMIN investigators say.
In the trial, 188 patients with relapsing-remitting MS were randomized to either interferon beta-1a, at 30 µg intramuscularly once weekly, or interferon beta-1b, at 0.25 mg subcutaneously on alternate days.
At 2-year follow-up, there were significantly more relapse-free patients, which was the primary clinical endpoint, in the interferon beta-1b group than the interferon beta-1a group, 51% versus 36% (p = 0.036).
The treatment benefit of interferon beta-1b over interferon beta-1a was particularly pronounced in the second year of the study, according to the team, with 72% of interferon beta-1b-treated subjects free of relapse compared with just 49% of interferon beta-1a-treated subjects.
Furthermore, the research team noted that MS progressed significantly more slowly (p = 0.005) and fewer new T2 lesions developed (p = 0.0003) in patients treated with interferon beta-1b than in those treated with interferon beta-1a. There was also evidence of reduced activity of existing MS lesions in the interferon beta-1b arm.
The 2-year data "clearly [show] that all beta interferon regimens are not the same," Dr. Durelli said in a university press release.
In an interview with Reuters Health, Dr. Douglas R. Jeffery, director of the MS Clinic at Wake Forest University in Winston-Salem, North Carolina, said he is not at all surprised that "virtually all of the clinical and MRI parameters are much more positively affected with Betaseron as opposed to Avonex. The interferon beta-1b preparation is really a much higher dose and that really provides greater efficacy."
"We are talking of clinically relevant differences of between 42% and 56% in the benefit of interferon beta-1b. The superiority of interferon beta-1b is self-evident," Dr. Durelli told Reuters Health. "This confirms the importance of a long-term study in the context of a chronic disease that may have a 20-to-25 year course," she added.
The trial was supported by research grants from the MS Association of Italy and the Italian Ministry of Health, without aid from the pharmaceutical industry.
"We will submit our study to The
Lancet. These are important data that clearly discriminate between the
beta interferon agents," Dr. Durelli told Reuters Health.
Copyright © 2001 Reuters Ltd
Copyright © 2001 Reuters Ltd