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ARTHRITIS DRUG LINKED TO RARE LUPUS SIDE EFFECTReuters Health -Researchers in Chicago report that four women with rheumatoid arthritis developed symptoms of the autoimmune disease systemic lupus erythematosus (SLE) after taking the drug etanercept (Enbrel). The patients developed symptoms, including face reddening and body rash, while taking the drug, but the symptoms disappeared when the drug was halted, according to a research letter in the February 16th issue of The Lancet. Such very rare side effects are not unexpected, said Kris Greco, spokeswoman for Immunex, the manufacturer of Enbrel. "In regard to the letter and commentary, what is indicated there is nothing outside of our label. These reports are part of information that was provided to the (US Food and Drug Administration (news - web sites)) as part of a comprehensive overview in August. Based on that assessment there were no new concerns expressed. "Enbrel has demonstrated an outstanding safety profile supported by 5 years of clinical information," Greco said. "That's important for the public and, in particular, patients to understand." Enbrel inhibits an immune system protein--called tumor necrosis factor (TNF)--that is produced in excess in the joints of rheumatoid arthritis patients. It has been prescribed to an estimated 80,000 patients worldwide since its launch in the US in 1998 and in Europe in 2000. Rheumatoid arthritis is an autoimmune disease in which the immune system attacks the lining of joints, causing pain, stiffness and inflammation. According to the letter, Dr. Najia Shakoor and colleagues at Rush Medical College in Chicago, Illinois found the lupus-like symptoms occurred between 6 weeks and 14 months after the start of treatment with Enbrel. Lupus is a disease that can occur in several forms and the condition can vary widely in severity, manifesting as skin rash and arthritis or leading to damage to the kidneys, heart, lungs and brain to varying degrees. In two of the patients, the SLE diagnosis was deemed "probable" because of incomplete data. "Nevertheless," Shakoor and colleagues write, "in all cases, compelling evidence for an SLE-like syndrome developed subsequent to etanercept introduction and resolved rapidly after drug withdrawal." The researchers suggest that Enbrel's blocking action of TNF may be to blame--noting that studies in mice have shown that TNF may have a "protective role" in SLE. Such drug-induced lupus symptoms are known to be a rare side effect of another drug on the market that blocks TNF. However, the authors also note that "identification of drug-induced SLE among patients with rheumatoid arthritis is difficult owing to extensive overlap between the two diseases." While Shakoor and co-authors point out that they have come across no other reports of an Enbrel and SLE connection, "these cases suggest that etanercept might be associated with true drug-induced SLE," they write. "Further investigation is necessary to clarify its prevalence and pathogenesis," they conclude. |
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