Leflunomide: new indication. In psoriatic rheumatism: too many risks, too little efficacy.

(1) The severity of joint involvement in psoriatic rheumatism varies greatly and its outcome is difficult to predict; some patients have long-term spontaneous remissions. The best-evaluated slow-acting treatments are sulfasalazine and methotrexate; adding etanercept can help some patients who do not respond to these drugs. (2) Leflunomide, an immunosuppressant drug, is already marketed for the treatment of rheumatoid arthritis, a condition for which it shows a less favourable risk-benefit balance than methotrexate. (3) Leflunomide is now licensed in France for "active psoriatic rheumatism". (4) The only available clinical data come from a double-blind placebo-controlled trial in 190 patients. On the basis of a combined outcome measure, significantly more patients responded to leflunomide than to placebo (59% versus 29.7%). However, the patients' global assessment was less positive: 15.8% of patients felt their condition had deteriorated during leflunomide therapy, compared to 24.2% of patients in the placebo group. The study population was too heterogeneous to show which types of patients might benefit most from leflunomide therapy. (5) Pharmacovigilance studies have confirmed some severe adverse effects (hepatic, cutaneous and haematological) and have uncovered other previously unrecognised effects such as interstitial pneumonia, hypertension, weight loss, and peripheral neuropathies. (6) In France, leflunomide treatment costs nearly 10 times more than methotrexate. (7) We conclude that leflunomide should not be used to treat psoriatic rheumatism.