Rebif (interferon beta-1a) is an under-the-skin injection therapy for relapsing forms of multiple sclerosis (MS). It reduces the frequency of disease exacerbations, and delays the accumulation of physical disability caused by these flares.
Relapsing-remitting multiple sclerosis (RRMS) is the most common form of MS, representing about 85% of all cases. It is characterized by moments of crisis (exacerbation) followed by periods of symptom relief. These relapse phases may last hours or days.
How does Rebif work?
MS is an autoimmune disease that affects nerve cells in the brain and spinal cord. Increased inflammation damages the myelin sheath (the protective coating that surrounds nerve fibers) that allows rapid transmission of the electrical impulses nerves use to communicate. The loss of myelin slows, or stops, these impulses and damages nerve cells.
Interferon beta-1a is a signaling molecule that the immune system normally produces to help fight infections. Scientists don’t fully understand the precise mechanism by which Rebif works to treat MS. However, they know that it signals to different types of immune cells, changing how they respond to threats, to lessen inflammation.
By reducing inflammation, Rebif can decrease attacks on the myelin sheath, easing disease symptoms.
Rebif in clinical trials
A clinical trial, conducted in the 1990s in nine countries, randomized 560 patients with RRMS to either 22 micrograms (mcg) or 44 mcg of Rebif, or a placebo. Data from the study showed that Rebif treatment significantly reduced the number and severity of exacerbations over two years. It also delayed disability progression.