The FDA has approved dimethyl fumarate (Tecfidera, Biogen Idec) as a first-line treatment for adults with relapsing-remitting multiple sclerosis.
The drug, also known as BG-12, is the third oral medication available to treat MS. The other two are fingolimod (Gilenya) and teriflunomide (Aubagio).
“No drug provides a cure for multiple sclerosis so it is important to have a variety of treatment options available for patients,” said Russell Katz, MD, director of the Division of Neurology Products in the FDA’s Center for Drug Evaluation and Research, in a statement announcing the approval.
Dimethyl fumarate is a nicotinic acid receptor agonist that activates the nuclear factor-like2 (Nrf2) pathway, which is involved in the cellular response to oxidative stress.
It’s approval was based on results from two placebo-controlled phase III trials — DEFINE and CONFIRM — that showed patients assigned to dimethyl fumarate had fewer MS relapses and experienced worsening of disability less compared with those assigned to placebo.
In the DEFINE trail, twice-daily dimethyl fumarate reduced the proportion of patients who experienced relapses 49% (P<0.0001), the annualized relapse rate 53% (P<0.0001), and 12-week confirmed disability progression, as measured by the Expanded Disability Status Scale (EDSS), by 38% (P=0.0050) compared with placebo.
Results from the CONFIRM trial were similar, with twice-daily treatment significantly reducing the annualized relapse rate by 44% (P<0.0001) and the proportion of patients who relapsed by 34% (P=0.0020) compared with placebo at two year follow-up.
Both studies also showed that dimethyl fumarate significantly reduced lesions in the brain on MRI compared with placebo.
The most common adverse effects were gastrointestinal complaints and flushing. The FDA also noted that the drug carries a risk of lymphocytopenia, although infections did not appear to be increased as a result in the phase III studies.