However, rituximab has not been adequately evaluated in cases of immediately life-threatening disease, while cyclophosphamide in this setting has both avoided organ damage and been lifesaving, he said.
Other areas that require further study are the effective dose and dosing intervals for rituximab maintenance, although some data suggest that both 500-mg and 1,000-mg doses every 6 months are effective, he noted.
Data are needed with respect to the long-term risks, as well. Some longer-term data in patients with rheumatoid arthritis suggest that serious infusion reactions are rare, and mortality is not increased, but GPA and MPA are very different diseases from RA, and additional study is needed. GPA and MPA, as well as other types of ANCA-associated vasculitis, are also very different from each other, and should be studied separately, he said.
Dr. Hoffman is a member of the data safety monitoring board for Roche and sanofi-aventis and is a consultant for Genentech and sanofi-aventis.