Finally, new agents are becoming available, but for patients who are able to tolerate the standard treatments, unproven therapies should not be used except in the context of clinical trials. ANCA-associated vasculitis and microscopic polyangiitis are potentially life-threatening diseases. “If the agent is not effective, the disease could worsen or unexpected toxicities could be seen,” Dr. Langford said.
For example, in a trial that evaluated adding etanercept or placebo to standard therapy with cyclophosphamide or methotrexate, there were no differences between the groups in the rates of sustained remission or severe adverse events, but six patients in the etanercept group developed solid tumors, compared with no patients in the placebo group (N. Engl. J. Med. 2005;352:351-61).