Abbott Laboratories says that US regulators have approved use of its blockbuster Humira to treat the new indication of juvenile rheumatoid arthritis.

The US Food and Drug Administration has approved Humira (adalimumab) as a treatment to reduce signs and symptoms of moderately to severely active polyarticular juvenile idiopathic arthritis in patients four years of age and older. It is the first biologic treatment to receive FDA approval for this condition since 1999, and the first to be administered by injection in these patients once every two weeks.

JIA is the most common chronic rheumatic disease in children with onset before age 16, said Abbott. Typical symptoms include stiffness when awakening, limping, and joint swelling and while it was once believed that most children eventually outgrow JIA, it is now known that between 25%-70% of sufferers will still have active disease into adulthood.

Humira, which generated more than $3 billion in sales last year, has already has been approved to treat adult arthritis, spinal arthritis, Crohn's disease, psoriasis and psoriatic arthritis.