by David Douglas

Last Updated: 2008-03-26 16:46:19 -0400 (Reuters Health)

NEW YORK (Reuters Health) – Patients with systemic-onset juvenile idiopathic arthritis (JIA) or adult-onset Still’s disease who are resistant to conventional treatment, may benefit from therapy with the interleukin-1 (IL-1) receptor antagonist anakinra, French researchers report in the March issue of the Annals of the Rheumatic Diseases.

Dr. Pierre Quartier told Reuters Health that "anti-IL-1 treatment is worth considering as a first line anti-cytokine treatment … in patients with an active, corticosteroid-dependent disease. Controlled trials are needed, however, both to assess efficacy and safety. We need to better understand why some patients are good responders and others not."

Dr. Quartier of Hopital Necker-Enfants Malades, Paris and colleagues studied 20 patients (mean age, 12.4 years) who had had JIA for a mean of 7.0 years and 15 (mean age, 38.1 years) who had had Still’s disease for a mean of 7.8 years.

Children were treated with 1-2 mg/kg/day of anakinra and adults were given 100 mg/day.

The investigators note that although most Still’s patients responded, less than half of the JIA patients achieved a marked and sustained improvement.

Specifically, five of the patients with JIA (25%) had a 50% improvement by ACR criteria at 6 months. Steroid use was reduced by 15% to 78% from baseline in 10 of the JIA patients.

However, 11 (73%) of the Still’s disease patients had "a prompt and dramatic improvement in all disease markers." At a mean follow-up of 17.5 months, two of these patients had stopped corticosteroids and eight had reduced steroid use by as much as 95%.

The team concludes that one issue to be addressed "is whether the anakinra dose or the number of injections per day should have been increased in patients that did not respond." Little is known, they add, "about the pharmacokinetics of anakinra in children."

The author of an accompanying editorial, Dr. Patricia Woo of University College, London, told Reuters Health that "this study confirms that blocking the action of IL-1 works well in only a proportion of systemic-onset JIA patients, and the available evidence suggests there are different disease mechanisms that produce the clinical picture of systemic-onset JIA."

Ann Rheum Dis 2008;67:302-308.

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