Once-daily oral leflunomide is a safe and effective treatment for psoriatic arthritis (PsA) and plaque psoriasis, according to recently published results from the Treatment of Psoriatic Arthritis Study (TOPAS), which appear in the journal Dermatology.¹ In the 24-week study of 190 patients with plaque psoriasis (defined as at least 3% skin involvement) and active PsA, patients who received leflunomide at 100 mg/day loading dose for 3 days followed by 20 mg/day orally showed significant improvement compared with their counterparts, who received placebo; responses were measured according to the Psoriatic Arthritis Response Criteria (PsARC) and the Psoriasis Area and Severity Index (PASI) .

Specifically, patients treated with leflunomide had a higher PsARC response rate than patients given placebo (58.9% and  29.7%, respectively) (P < .0001). Moreover, 30.4% of patients who received leflunomide achieved PASI 50, compared with 18.9% of patients who received placebo (P = .05). Finally, more patients in the leflunomide group than in the placebo group achieved PASI 90 and showed improvement in three PASI severity subscore components, including infiltration, desquamation, and erythema.

In addition, target lesion response occurred in 46.4% of leflunomide-treated patients compared with 25.3% of the placebo-treated patients (P =.0048). Patients in the leflunomide group also showed a greater improvement than patients in the placebo group according to the combined skin and joint response scale (27.2% vs 8.9%, respectively); the Dermatology Life Quality Index (1.9 points vs 0.2 points, respectively); and some SF-36 sub-domains, including physical functioning, pain, general health, social functioning, and physical component summary. Moreover, dermatological responses were observed at the earliest examination (4 weeks) and increased throughout the 24-week study, the study showed. Finally, the most common adverse event was diarrhea, which was more prevalent among patients treated with leflunomide than patients given placebo (24% vs 13%, respectively). Furthermore, four patients in the leflunomide group had elevated alanine aminotransferase (ALT) levels, compared with one patient in the placebo group. No serious liver toxicity occurred and all elevated transaminase levels were reversible.

"Leflunomide offers several advantages in the treatment of PsA and psoriasis, including clinically significant improvements in skin and joint symptoms and patient quality of life, sustained efficacy, convenience of use and a favorable long term safety profile," write the TOPAS investigators, led by Peter Nash, MD, of the rheumatology research unit in the department of medicine at the University of Queensland in Queensland, Australia.

Leflunomide may be a welcome addition to treatment of psoriasis and PsA

"It is always good to have more therapeutic alternatives," Arthur Kavanaugh, MD, professor of medicine at the University of California, San Diego, tells CIAOMed. "While the extent of improvement in skin and joints is more modest than that typically seen with TNF blockers, many clinicians have pretty fair experience with leflunomide, so it might be an option, particularly for patients failing other options."

Mark G. Lebwohl, MD, a dermatologist at Mount Sinai Medical Center in New York City, agrees. "Leflunomide isn't used for PsA right now and this study indicates that it might be a reasonable use for it."

Reference

1. Nash P, Thaci D, Behrens F, et al. Leflunomide improves psoriasis in patients with psoriatic arthritis: an in-depth analysis of data from the TOPAS study. Dermatology. 2006;212:238-249.