FRIDAY, Feb. 22 (HealthDay News) -- The U.S. Food and Drug Administration has approved Humira (adalimumab) to treat moderate-to-severe juvenile idiopathic arthritis (JIA) in children aged four years and older, maker Abbott Laboratories said Friday.

JIA -- often called juvenile rheumatoid arthritis -- can cause pain and permanent joint damage, making it difficult for children to engage in common activities like running, playing sports and writing.

Humira is the first biologic treatment for JIA to be approved since 1999, the company said in a statement. The drug is injected once every two weeks.

JIA is the most common chronic rheumatic disease in children, with symptoms including limping, joint swelling, and stiffness when waking. In clinical testing, 171 patients aged 4 to 17 had fewer "flares" than those who took a non-medicinal placebo, Abbott said. Common side effects included pain and/or reaction at the injection site.

Humira is already FDA-approved to treat adults with several conditions, including rheumatoid arthritis, the intestinal disorder Crohn's disease, and the skin disorder plaque psoriasis.

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