A Study to Evaluate the Efficacy, Safety and Pharmacokinetics (PK) of a Higher Dose of Ocrelizumab in Adults With Primary Progressive Multiple Sclerosis (PPMS)

To join this study, you must be an adult between 18 and 55 years old and have been diagnosed with primary progressive multiple sclerosis (PPMS). Your doctors will need to review your medical history and imaging scans, like MRI, to confirm your diagnosis and ensure your MS fits the study's requirements. You also need to be generally stable in your health and any MS treatments you're already taking.

There are also some important things that would prevent you from joining. For example, if you have other types of MS like relapsing-remitting MS or secondary progressive MS, you would not be able to participate. Also, if you have any active infections, a history of certain serious brain conditions, or past cancers, this study might not be right for you. Your study doctor will discuss all these details with you.

If you're a woman who could become pregnant, you'll need to agree to use effective birth control throughout the study. Women who are past menopause or have had certain surgeries would not need to use birth control.

If you decide to join this study, you'll be involved for quite a long time. You'll receive the study medicine, either the approved dose of ocrelizumab or the higher dose, through an intravenous (IV) drip every 24 weeks. You'll have regular visits to the study clinic for check-ups, where doctors will monitor your MS symptoms, take blood tests, and perform physical examinations. You'll also likely have MRI scans to see how your brain is responding to the treatment.

The main part of the study where you receive the treatment will last for at least 120 weeks, which is about two and a half years. After this, if the initial results are positive, there might be an option to continue receiving the higher dose in an 'open-label' phase, where everyone knows they are getting the higher dose. This extension would last for about 96 weeks (almost two more years). Once treatment stops, you'll be followed for safety for another 48 weeks. Some people might have even longer follow-up to check their immune cells return to normal levels. Throughout all these stages, the total time you're involved could be several years.