Prior to the 1970s, severe cases of
antineutrophil cytoplasmic antibody associated
vasculitis (AAV) were thought to be invariably fatal. However, the use of
cyclophosphamide-based treatment regimens fundamentally altered disease outcomes, transforming AAV into a manageable,
chronic illness. Despite the tremendous success of
cyclophosphamide in the treatment of AAV, there remained a need for
alternative therapies, due to high rates of treatment failures and significant toxicities. In recent years, with the introduction of targeted
biologic response modifiers into clinical practice, many have hoped that the treatment options for AAV could be expanded.
Rituximab, a chimeric
monoclonal antibody directed against the B-lymphocyte
protein CD20, has been the most successful
biologic response modifier to be used in AAV. Following the first report of its use in AAV in 2001, experience with
rituximab for treatment of AAV has rapidly expanded.
Rituximab, in combination with glucocorticosteroids, is now well established as a safe and effective alternative to
cyclophosphamide for
remission induction for severe manifestations of
granulomatosis with polyangiitis and
microscopic polyangiitis. In addition, initial experiences with
rituximab for remission maintenance in these diseases have been favorable, as have experiences for
remission induction in
eosinophilic granulomatosis with polyangiitis.