New Drug for Multiple Sclerosis Shows Promise in Trials
In what has been called a “remarkable finding” by Stephen Hauser, MD, at the University of California, San Francisco, a research team has reported on the findings of a Phase II trial of an experimental drug called ocrelizumab, which shows promise in treating multiple sclerosis. Hauser noted that the study results are “extremely exciting, both in terms of the prospect of improved therapy for people with multiple sclerosis but also for the lessons that it teaches us about the fundamental cause of the disease.”
Multiple sclerosis drug shows fewer disease signs
Multiple sclerosis is a chronic, often debilitating disease that affects the central nervous system of approximately 400,000 people in the United States, and more than 2.1 million people around the world. Women are affected 2 to 3 times more often than men, and the disease usually presents between the ages of 20 and 50.
Multiple sclerosis symptoms can include fatigue, numbness, coordination and balance problems, bladder and bowel dysfunction, vision problems dizziness, pain, cognitive dysfunction, depression, and spasticity. An accumulation of lesions of the brain and spinal cord is characteristic of the disease, which leads to the various impairments.
The new study evaluated ocrelizumab in 220 individuals with multiple sclerosis who were divided into four groups: two received injections of the experimental drug at two different doses, one received the standard multiple sclerosis drug interferon-beta, and one was given a placebo.
Using magnetic resonance imaging (MRI), the investigators followed the progression of the treatment by evaluating the number of lesions observed in the brain scans and the severity and frequency of the symptoms. Overall, the patients who received ocrelizumab had an 89% reduction in the development of brain lesions as well as the number of new multiple sclerosis attacks during a 24-week period.
Another finding was that interferon was no better than placebo during the trial evaluated. When it comes to side effects, 4% of patients who took placebo or interferon experienced them compared with 2% of patients who took 600 mg of ocrelizumab, and 6% of those who took 2,000 mg of the drug.
The importance of this study is that the researchers found that targeting the B cells could help individuals with the disease, while researchers had previously focused on the T cells, which were believed to be the “smoking gun” of multiple sclerosis. Ocrelizumab, however, focuses on CD20, a molecule on the surface of B cells.
Hauser noted that their study indicated that the B cells trigger the T cells to attack. He explained that “this is a great example of lessons learned at the bench bringing us to an experiment at the bedside that completely transformed our understanding of what we needed to do to develop more selective and more effective therapy for MS.”
Causes of multiple sclerosis are unknown, although scientists have a number of theories that involve environmental, genetic, immunologic, and infectious factors. Generally, it is accepted that multiple sclerosis is an autoimmune process that involves an abnormal response of the body’s immune system against the fatty sheath (myelin) that protects the nerve fibers.
Other causative factors may be environmental, including a deficiency of vitamin D, as people who live closer to the equator (and thus likely to have more exposure to the sun) are less likely to develop the disease. Genetics may have a role, as having a first-degree relative with the disease increases a person’s risk of developing the disease. Exposure to viruses, bacteria, or other microbes also may have a part in the development of multiple sclerosis.
At this point, researchers need to explore whether the drug will continue to produce positive effects and safety over a longer time, questions that will be addressed in two Phase 3 trials. Hopefully the additional trials of the new drug for multiple sclerosis will result in even more promising results.
National Multiple Sclerosis Society
University of California, San Francisco