AAN: Early MS Treatment with Interferon Beta-1b Delays Progression

BOSTON, May 2 -- The risk of multiple sclerosis (MS) progression can be significantly reduced by starting patients on interferon beta-1b (Betaseron) before a diagnosis is even confirmed, investigators reported here.

For patients with a first demyelinating event suggestive of MS, two years of subcutaneous interferon beta-1b reduced the risk of disability progression at three years of additional follow-up by 40%, compared with patients who received placebo, reported Mark S. Freedman, M.D., of the University of Ottawa (Ontario).

The disability progression was measured by the Expanded Disability Scale Score (EDSS), Dr. Freedman reported at the American Academy of Neurology meeting.

Also, after three years of follow-up, patients who had received interferon beta-1b at the outset had a 41% lower risk of progression to clinically definite MS compared with patients who were started on the drug later.

The results, from an open-label follow-up study of the BENEFIT (Betaseron in Newly Emerging Multiple Sclerosis for Initial Treatment) trial, confirmed earlier results of a placebo-controlled study, which found that interferon beta-1b reduced the risk of progression to MS at two years by 50%, and the risk of MRI-defined MS by 46% compared to placebo.

In the double-blind study, 468 patients with a clinically isolated syndrome -- a clinical demyelinating event suggestive of MS -- were randomly assigned to placebo or interferon beta-1b at 250 mcg every other day in subcutaneous injection. The placebo-controlled treatment period lasted for up to 24 months or until a diagnosis of clinically definite MS.

The patients were then invited to be part of a pre-planned prospective open-label follow-up study designed to assess the efficacy of immediate versus delayed treatment with the drug over five years.

"We agreed that one of the things we'd really like to get at is the long-term outcome, and what we really want to know is disease progression," Dr. Freedman said in an interview. "Does it mean there's going to be a meaningful change in EDSS progression?"

If it does neab that, he added, that means "you've given me a very good reason to start therapy early."

In the current report, the authors described three-year interim results of the follow-up study, which enrolled 418 of the 437 eligible patients. The cohort comprised 261 patients previously treated with interferon beta-1b, and 157 originally treated with placebo, but switched to interferon beta-1b when they were diagnosed with MS.

The authors reported that 24% of patients in the original placebo group had confirmed EDSS progression, compared with 16% of those in the immediate therapy group at three years of follow-up. The risk of EDSS progression was 40% lower among patients in the immediate treatment group compared with controls (P=0.0218).

"What makes it even more meaningful is the fact those patients [in the placebo group] were on at least a year of treatment, so they never caught up," Dr. Freedman said. "So the extra protection added by starting the drug early continues to span three years."

The only significant adverse events were injection site reactions, flu-like reactions, and similar events, Dr. Freedman said.