Rituxan Not Effective in Primary Progressive MS

Four courses of the monoclonal antibody Rituxan (rituximab) did not delay the time to confirmed disease progression in primary progressive multiple sclerosis, according to a 96-week, placebo-controlled phase 2/3 study. The results were announced yesterday by the drug's US marketers, Genentech and Biogen Idec. A senior scientist at Genetech, however, indicated that the drug exhibited "some evidence of biologic activity" in this uncommon and difficult-to-treat form of MS.

The results are not scheduled for presentation at the ongoing annual meeting of the American Academy of Neurology in Chicago, but safety and pharmacologic data from a 72-week phase 1 study (Bar-Or et al. S12.004) and pharmacologic data from a 48-week phase 2 study (Bar-Or et al. S22.002) of rituximab in relapsing-remitting MS will be presented today and tomorrow at the meeting. Phase 3 development of the drug in relapsing-remitting MS is stalled, because of a protracted dispute between Genentech and Biogen. The development dispute is currently in arbitration.