Rheumatoid arthritis patients being treated with Humira or Remicade may have an increased risk of developing shingles, according to a new study released Tuesday.

Humira, marketed by Abbott Laboratories (ABT) and Remicade, by a unit of Johnson & Johnson (JNJ), are approved to treat rheumatoid arthritis, Crohn's disease, psoriasis and other inflammatory diseases. They both block a protein known as tumor necrosis factor-alpha. People with certain diseases have too much TNF-alpha in their bodies which causes the immune system to attack healthy parts of the body. The drugs can also lower the body's ability to fight infections and the drugs' labels warn of such risks.

According to a study by German researchers that will appear in the Feb. 18 edition of the Journal of the American Medical Association, patients on Remicade or Humira had a small increased risk of developing shingles, a painful infection characterized by blisters on the skin.

Researchers, led by those at the German Rheumatism Research Center, Berlin, looked at the association of various rheumatoid arthritis treatments, including TNF-blockers, and the risk of developing shingles, also known as herpes zoster, among 5,040 patients. The patients were enrolled in a German biologics register between May 2001 and December 2006 when they started treatment with a biologic agent such as Humira or Enbrel, another TNF-blocker by Amgen Inc. (AMGN) and Wyeth (WYE) that works in a different manner than Humira or Remicade. Most patients were followed for three years.

Of the 5,040 patients, researchers identified 86 cases of shingles in 82 people. Thirty nine of the cases were associated with patients on Remicade or Humira, while 23 cases were associated with patients on Enbrel and 24 with other rheumatoid arthritis treatments. In real terms, patients on Remicade or Humira had a shingles rate of 11.1 per 1,000 patient years.

According to an accompanying editorial written by two doctors at the University of Alabama in Birmingham, the shingles rate for the U.S. population as a whole is 3.5 per 1,000 patient years. They said the rate seen in the study for Remicade and Humira "appears to induce a risk similar to that observed in populations older than 80 years." They wrote that the drugs have "revolutionized" the treatment of rheumatoid arthritis and other conditions.

Brian Kenney, a spokesman for Centocor, the J&J unit that makes Remicade, said the company would keep an eye on post-marketing reports of shingles, but noted the drug's label already mentions reports of shingles. Humira also lists shingles as an adverse reaction that was seen in clinical trials.

Researchers said doctors should monitor patients on Humira or Remicade for "early signs and symptoms" of shingles. Doctors also said patients who hadn't yet started treatment with Remicade or Humira could consider being vaccinated against shingles.

Shingles is caused by the same virus that causes chicken pox, which afflicted most children in the U.S. until routine vaccination against chicken pox started in 1995.

After the chicken-pox infection has run its course, the virus remains dormant in people and can reactivate and turn into shingles. The condition is most common in people older than age 60, and the severity increases with age. People with rheumatoid arthritis also have an increased risk of developing shingles.

-By Jennifer Corbett Dooren, Dow Jones Newswires; 202-862-9294; jennifer.corbett@dowjones.com

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