Biogen Idec announced that the experimental oral therapy BG-12 significantly reduced the proportion of people with MS who experienced relapses in a two-year study of more than 1200 people with relapsing-remitting MS. Although its exact mode of action is not known, BG-12 is thought to inhibit immune cells and molecules involved in MS attacks on the brain and spinal cord. The results were announced in an April 11 press release. Data analysis is ongoing and the company expects to provide a full report at an upcoming medical meeting. Another trial of BG-12 is currently underway.
Background: Multiple sclerosis involves immune system attacks against brain and spinal cord tissues. Although its exact mechanism of action is not known, BG-12, an oral drug, is thought to inhibit immune cells and molecules and may be protective against damage to the brain and spinal cord. In an earlier phase 2 study, compared to inactive placebo, the highest tested BG-12 dose led to a 69% reduction in active inflammation on MRI scans from weeks 12 to 24. Side effects (formally known as adverse events) included abdominal pain, flushing, headache, fatigue, and feeling hot. (The Lancet 2008;372:1463-1472).
This Study: The primary goal of the DEFINE study was to determine whether BG-12 could decrease the proportion of participants experiencing relapses and whether the agent was safe and well tolerated. Secondary objectives included assessing BG-12’s effects on the frequency of relapses, disability progression, and disease activity detected by MRI.
Participants were randomly assigned to one of two treatment groups receiving different doses, or a group receiving placebo. According to the press release, in both groups taking BG-12, the primary endpoint was met, meaning a significant reduction in the proportion of people experiencing relapses at 2 years. All secondary endpoints were met as well in these groups, with significant reductions in relapse rate, disease activity on MRI scans, and in disability progression as detected by the EDSS, a standard scale that measures disability. According to the press release, adverse events were similar to those experienced during the Phase 2 study (those included abdominal pain, flushing, headache, fatigue, and feeling hot):
Comment: These positive results are the first reported from this large, Phase 3 study of BG-12. Full details and evaluation of this study, and from another Phase 3 study now underway, should help define the safety and promise of BG-12 as a potential therapy for relapsing MS.