I believe that you are referring to Rituxan, it has not proven to be effective, or approved for PPMS. They are trying to get it approved now under a new name, Ocrevus, but the effectiveness for PPMS is still very questionable, and was in a very small sub-group of younger PPMS patients, with active lesions in their MRI's. For more details look up Oratorio Trials.
For @A MyMSTeam Member - I have shared the following info many places, I hope that it helps.
Ocrelizumab is continuing to get a lot of press lately as a new MS wonder drug, especially for those of us with PPMS. When I first saw these headlines a few months ago I researched a little deeper only to discover that what they are really doing is simply rebranding an older drug, Rituximab/Rituxan before the patent runs out, which would be a cash flow killer for the owner Genetech. In reading all of the previous research and results, as a PPMS sufferer, I am not very encouraged or impressed with the results reported for PPMS specifically. We need myelin repair. Here is the most enlightening information that I found.
https://www.mscenter.org/education/patient-reso...
that trial says the meds used is not same as rituxan so disregard