Rituxan (generic name rituximab) is a prescription medicine that targets a protein called CD20 in immune system B cells. It has been approved by the U.S. Food and Drug Administration (FDA) for treating diseases such as Non-Hodgkin's lymphoma and rheumatoid arthritis (RA).
Doctors sometimes prescribe Rituxan for treating multiple sclerosis (MS), although the FDA hasn’t approved it for this use. This is referred to as “off-label” drug use.
About off-label drug use
Off-label drug use means that a drug that’s been approved by the FDA for one purpose is used for a different purpose that hasn’t been approved.
However, a doctor can still use the drug for that purpose. This is because the FDA regulates the testing and approval of drugs, but not how doctors use drugs to treat their patients. So your doctor can prescribe a drug however they think is best for your care. Learn more about off-label prescription drug use.
If your doctor prescribes a drug for you for an off-label use, you should feel free to ask any questions you may have. You have a right to be involved in any decisions about your care.
Examples of questions you may ask include:
- Why did you prescribe an off-label use of this drug?
- Are there other approved drugs available that can do the same thing?
- Will my health insurance cover this off-label drug use?
- Do you know what side effects I may have from this drug?
There isn’t a consensus on exactly how safe and effective Rituxan is for treating MS, but studies suggest that it shows promise.
Is it effective?
Although there haven’t been enough comparative real-world effectiveness studies to conclusively judge Rituxan as an effective treatment for MS, positive signs suggest it might be.
A study of a Swedish MS registry compared Rituxan with traditional initial disease modifying treatment choices such as
- Tecfidera (dimethyl fumarate)
- Gilenya (fingolimod)
- Tysabri (natalizumab)
In terms of drug discontinuation and clinical efficacy in relapsing-remitting multiple sclerosis (RRMS), Rituxan not only was the leading choice for initial treatment, but also showed the best outcomes.
Is it safe?
Rituxan works as a B-cell depleting agent. According to research, long-term depletion of peripheral B cells via Rituxan appears safe, but more study is needed.
Side effects of Rituxan can include:
- infusion reactions such as rash, itching, and swelling
- heart problems such as irregular heartbeats
- kidney problems
- bleeding gums
- stomach pain
- body aches
- low white blood cells
- trouble sleeping
- swollen tongue
The safety profiles of other treatments such as Gilenya and Tysabri for people with MS have more extensive documentation than Rituxan.
Ocrevus (ocrelizumab) is an FDA-approved drug that is used for the treatment of RRMS and primary progressive multiple sclerosis (PPMS).
Some people believe that Ocrevus is just a rebranded version Rituxan. They both work by targeting B cells with CD20 molecules on their surface.
Genentech — the developer of both drugs — states that there are molecular differences and that the drugs each interact with the immune system differently.
One major difference is that more health insurance plans cover Ocrevus for MS treatment than Rituxan.