Rituximab, a drug that is FDA approved to treat B cell lymphoma and rheumatoid arthritis, can also treat severe vasculitis as well as the current standard therapy, researchers have said.
Infertility and the development of cancers have been associated with the traditionally used medication, cyclophosphamide, and the risk of these complications is expected to be much lower with Rituximab. The news will be published in the July 14 issue of the New England Journal of Medicine
"The reason this is a big deal is that this is a disease where people would come in and be told 'listen, we are probably going to be able to get on top of your life-threatening disease by using cyclophosphamide, but you are going to have major side effects down the road from this drug,'" said Robert Spiera, M.D., an associate attending rheumatologist at Hospital for Special Surgery in New York. "This study provides strong evidence that Rituxan works as well as cyclophosphamide, at least in terms of getting patients over that acute hump of being very ill. And, we can treat patients without the likelihood of causing infertility or cancers."
Hospital for Special Surgery was one of nine centers involved in the Phase III trial, which was led by Ulrich Specks, M.D., a professor of medicine in the Department of Pulmonary and Critical Care Medicine at the Mayo Clinic, and John Stone, M.D., at the Massachussetts General Hospital.
Vasculitis, an inflammation of the blood vessels, can damage tissues and organs and, in severe cases, lead to death. Specifically, the study examined something known as ANCA-associated vasculitis that includes Granulomatosis with Polyangiitis. "The reason this is such a significant study is that this is an uncommon but devastating group of diseases," said Dr. Spiera. Prior to the use of cyclophosphamide treatment, 90 percent of patients who were diagnosed with ANCA-associated vasculitis could be expected to be dead within three years. In the 1970s, doctors discovered that cyclophosphamide was extremely effective at combating the disease and could put people into remission. In the ensuing decades, however, doctors recognized that these drugs came with a price.
"If you followed patients long enough, you found they had a higher risk of leukemias, lymphomas and solid tumors," said Dr. Spiera, who is also an associate professor at Weill Cornell Medical College. "People would sometimes develop terrible infections. Women, almost reliably, would become infertile, as did many men. So, although it was a dramatically effective drug at reducing remissions in these patients, it came at a price."
In the current study, nine centers enrolled a total of 197 patients with severe Granulomatosis with Polyangiitis or microscopic polyangiitis, two of the more common types of ANCA-associated vasculitis. Patients were given steroids and randomized to receive either the standard treatment of cyclophosphamide or Rituxan given at a dose of 375 mg/m2 weekly for four weeks. Investigators used the standard tools to assess disease status and remission. The study was rigorously designed and was double-blinded, meaning that neither patient nor doctor knew which drug individuals were getting.
Eight-four of the 99 (85%) patients in the Rituxan arm and 81 of the 98 patients (83%) in the cyclophosphamide arm had completed six months of treatment. Investigators found that the treatments were equally effective in putting patients into remission and that, in fact, the treatment outcomes looked slightly better in patients receiving Rituxan (64% vs. 53%). This difference, however, was not considered statistically significant (P=0.09). In patients suffering with severe relapses of their disease, Rituxan appeared to be even more effective than cyclophosphamide in inducing remission.
"These results show that the Rituxan worked at least as well as cyclophosphamide," Dr. Spiera said. "If anything, there was almost a hint of it maybe looking a little better, and even in the short term, it looked safer. This study shows that there is strong evidence that Rituxan may be an alternative to cyclophosphamide in this disease. It might help manage flares in patients who have gone into remission, and it should be a consideration as first-line therapy, especially in women of child bearing potential who have a good chance of losing their fertility."Until this study, there was only anecdotal evidence that Rituxan would be beneficial in patients with vasculitis. ANCA-associated vasculitis is one of the few rheumatic diseases that is equally represented in men and women. It can occur in people of all ages. Rituxan, manufactured by Genentech, is currently approved in the U.S. to treat non-Hodgkin's lymphoma and rheumatoid arthritis.