Multiple sclerosis treatment options have expanded in recent years. There are over ten or probably more disease-modifying medications against multiple sclerosis. Most of our viewers are outside of the United States. Not all multiple sclerosis medications are available. But nevertheless it is an increasing family of potential options for multiple sclerosis treatment. Could you please discuss a roadmap of multiple sclerosis therapy. How to choose the best treatment for a given patient with multiple sclerosis? Dr. Anton Titov, MD. This is a big question. There are two stages of multiple sclerosis. There is a relapsing-remitting multiple sclerosis stage. Then there is the progressive multiple sclerosis stage. Dr. Howard Weiner, MD. We have many treatments for the relapsing-remitting multiple sclerosis stage. Dr. Howard Weiner, MD. We have few treatments for the progressive multiple sclerosis stage. Every patient who is diagnosed with multiple sclerosis and has relapsing disease should be treated. The question is which medication should they take? Dr. Anton Titov, MD. Dr. Howard Weiner, MD. I can't say that they should take medication A or B. The most important thing is for every patient to start multiple sclerosis therapy. What is important is, after they go on to therapy, they need to be monitored to make sure the therapy is working. If treatment is working, it is fine. Efficacy of treatment is determined by measuring multiple sclerosis relapses and MRI scans. Sometimes patients have side effects or they are still having multiple sclerosis symptoms. Then they should be changed to another medication. There are injectable multiple sclerosis medications, there are oral multiple sclerosis medications, and there are medications given by infusion. It depends on the patient and the doctor. The multiple sclerosis activity monitoring is done also by the serial MRI scans. Sometimes we start somebody on the multiple sclerosis medication. Then we start with an MRI every six months for a year or two, and then every year or if they have new symptoms. You have a vast multiple sclerosis practice. How often do you have to switch patients from one medication to another based on those monitoring results? Dr. Anton Titov, MD. It is hard to say because the multiple sclerosis medications keep changing. But Dr. Howard Weiner, MD. I would say virtually all of our multiple sclerosis patients have switched from one medication to another. But that is because new multiple sclerosis medications keep coming out. Dr. Howard Weiner, MD. I see, and those new multiple sclerosis medications presumably have a better risk to benefit ratio? Dr. Anton Titov, MD. New medications may be more effective, they may be easier to take. Maybe 25% of our patients don't do well on one medication. Dr. Howard Weiner, MD. We have to switch to another multiple sclerosis medication. Treatment of multiple sclerosis rapidly evolves. New medications appear. Precision medicine diagnostic tests match patients with most effective medications. Leading MS expert explains.