Arthritis drug (Enbrel) linked to rare lupus side effect

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Arthritis drug linked to rare lupus side effect

NEW YORK, Feb 15 (Reuters 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) 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.

Despite such rare side effects, the authors explain that TNF-blocking drugs

have " been an important advance in treatment " for rheumatoid arthritis.

Such drugs are " a powerful addition to our therapeutic armamentarium " and

are " generally well tolerated " by patients, they add.

SOURCE: The Lancet 2002;359:579-580.