Results of an Immune Tolerance Network (ITN) clinical trial may provide doctors with another weapon in the treatment of ANCA-associated vasculitis, which has seen no new approved treatments in 40 years. The study, published in the New England Journal of Medicine, showed that the drug rituximab provides the same treatment benefits as the existing standard of care, and appears to offer additional benefits to those suffering relapses.

ANCA-associated vasculitis comprises a group of autoimmune diseases in which affected individuals make antibodies that attack their own cells – called neutrophils – causing inflammation in small- to medium sized blood vessels. This leads to subsequent organ damage, particularly in the airways, lungs and kidneys. Wegener’s granulomatosis and microscopic polyangitis are the most common forms of the disease, the former affecting 3 of every 100,000 people in the United States and accounting for approximately 1500 hospitalizations each year.

The current standard of care for these conditions is a cyclophosphamide-based regimen that has been used since the 1970s. Although this regimen has been successful in inducing remission in the majority of cases, its immunosuppressive nature puts patients at risk of serious infection and cancer. Furthermore, many patients experience relapses after the therapy is discontinued.

The current study, led by Dr. John Stone of Massachusetts General Hospital and Dr. Ulrich Specks of the Mayo Clinic aimed to establish whether rituximab, a manmade antibody currently approved for the treatment of non-hodgkins lymphoma and moderate-to-severe rheumatoid arthritis (marketed under the trade name ‘Rituxan’ by Genentech, Inc) could be just as effective.

The ITN study concludes that rituximab is not inferior to standard therapy for ANCA-associated vasculitis. However, in patients with relapsing disease, who were previously treated with cyclophosphamide at the start of the study (as opposed to those newly diagnosed), 67 percent of those in the rituximab group had no disease activity were able to discontinue all steroid use after therapy, compared with only 42 percent in the cyclophosphamide group.

“Although the two therapy regimens were equally effective in reducing patients’ disease activity, our results indicate that rituximab is superior to cyclophosphamide in inducing remission for patients experiencing a disease flare,” comments Dr. Specks.

Coupled with the fact that participants in the rituximab group received intravenous therapy once a week for 1 month–compared with 3 to 6 months of daily cyclophosphamide therapy followed by daily AZA—the observation that rituximab offers similar benefits, if not greater, for patients with ANCA-associated vasculitis is a significant advance in treatment. Investigators also did not observe any major differences in the side effects in patients from the two treatment groups.

According to Drs. Stone and Specks, ITN investigators plan to follow the participants until 18 months post treatment to determine if patients who received rituximab will relapse and to evaluate the long-term safety of this regimen.

The study was conducted by the Immune Tolerance Network and was sponsored by the National Institute of Allergy and Infectious Diseases.

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