Treating primary-progressive multiple sclerosis: potential of ocrelizumab and review of B-cell therapies.

Multiple sclerosis (MS) therapy has evolved rapidly with an increased availability of several immunomodulating therapies over the past two decades. Disease-modifying therapies have proven to be effective in treating relapse-remitting MS (RRMS). However, clinical trials involving some of the same agents for secondary-progressive and primary-progressive MS (SPMS and PPMS) have been largely negative.