The results of two recent studies of ocrelizumab show the drug holds significant promise for those with relapsing multiple sclerosis (MS).
The findings in the clinical trials, conducted by the Swiss pharmaceutical company Roche, highlighted the drug’s ability to significantly reduce relapses compared to standard therapy.
Both of the phase III studies looked at the safety and effectiveness of ocrelizumab, an antibody that targets B cells found in the immune system.
While other MS therapies address T cells, B cells are also suspected in playing a role in the autoimmune disorder.
How B Cells Function
B cells secrete proteins known as antibodies in response to exposure to an infection. When a future exposure occurs, these B cells remember the invader and bind to them using the specific protein. The B cells render the invader helpless, protecting us from the infection.
This process is commonly referred to as “building up immunity.” That is how vaccines work. Our immune systems are exposed to a tiny bit of the infectious agent causing our B cells to recognize it.
In the case of MS, the immune system mistakenly attacks the myelin covering of the nerves in the brain and spinal cord. During treatment, the monoclonal antibodies act as a switch to turn off the disease process.
The generic names for monoclonal antibody type drugs always end in “mab.” Other MS drugs that are monoclonal antibodies include natalizumab (Tysabri), and alemtuzumab (Lemtrada).
Rituximab (Rituxan), which is currently in clinical trials for treating MS, was approved by the Food and Drug Administration (FDA) in 2006 for treating rheumatoid arthritis. Since that time it has been prescribed “off-label” for some MS patients who were not responding to other therapies.
According to the Multiple Sclerosis Association of America, “Rituxan is a monoclonal antibody (CD20, from mouse tissue) that binds to a receptor on the surface of B cells. These cells are then destroyed and their levels in the circulation are decreased. It is approved for use in the treatment of lymphomas, leukemias, and autoimmune disorders.”
How Well Does Ocrelizumab Work?
Ocrelizumab may be a step up, researchers said.
“Ocrelizumab showed remarkable improvements over a standard-of-care medicine across clinical and imaging endpoints in two pivotal studies,” said Dr. Sandra Horning, Roche’s chief medical officer and head of global product development in a press release. “Ocrelizumab has the potential to make a meaningful difference for people with MS, a chronic and debilitating disease. Based on these compelling results, we plan to submit the data for review to U.S. and E.U. regulatory authorities in the first quarter of 2016.”
The medical community is also awaiting FDA-approval with anticipation.
“The OPERA trials press release is exciting because it means that we may soon have another powerful option for people with relapsing MS,” said neurologist Dr. Daniel Kantor, fellow of the American Academy of Neurology, in an interview with Healthline. “Instead of focusing on a part of the immune system called T cells, ocrelizumab focuses on B cells and the role that they play in MS.”
Kantor, immediate past president of the Florida Society of Neurology and chief medical correspondent for MS World, said that “Although the press release doesn't tell us any specifics about exactly how well ocrelizumab did in the trials, we do know that ocrelizumab was superior to standard MS therapies … and it only needs to be given every six months [by intravenous infusion].”
On the Horizon
This is encouraging news for people living with MS as some therapies require daily injections or remembering to take pills multiple times per day. Having only two infusions per year will remove the problem of remembering to take medication.
The full results of these studies will be presented later this year.
“We all look forward to seeing exactly how well ocrelizumab did at [The European Committee for Treatment and Research in Multiple Sclerosis] ECTRIMS meeting in Barcelona in October 2015,” said Kantor.
The most exciting news is perhaps yet to come, however, given that there are currently no approved therapies to treat progressive forms of MS.
“In 2016 we look forward to seeing the results of the trial of ocrelizumab in people with primary progressive MS (PPMS),” added Kantor, who is also the founder of the Medical Partnership 4 MS (MP4MS), “If ocrelizumab helps both relapsing MS and progressive MS, then it will surely play a central role in MS treatment.”