Review: Therapies for Psoriatic Arthritis

Treatments for psoriatic arthritis (PsA) range from high-cost agents like tumour necrosis factor (TNF) inhibitors evaluated in large randomised control trials (RCTs) and low-cost disease modifying anti-rheumatic drugs (DMARDs) studied in less detail. Researchers at the King’s College in London compared their efficacy and toxicity in a systematic review.

The researchers searched Medline, PubMed and EmBase (1966-2006) for RCTs in PsA. They included RCTs that were randomised, placebo-controlled, in English, involved current treatments and only enrolled PsA patients. Efficacy was assessed by the numbers of patients withdrawn for lack of effect; toxicity by withdrawals for adverse events. RCTs were compared using risk ratios (RR) with 95% confidence intervals (CI). 32 potentially relevant RCTs were identified; 14 were excluded because they involved unused agents, were unblinded, were not placebo-controlled and enrolled patients with other diseases. 18 studies were included in the meta-analysis assessing DMARD monotherapy (11), DMARD combinations (1), TNF inhibitors (5) and alefacept (1). Treatment was more effective than placebo (RR = 0.35; 95% CI 0.25, 0.49) but caused more toxicity (RR = 2.33; 95% CI 1.61, 3.37). There was evidence that gold, sulfasalazine, leflunomide and TNF inhibitors were effective; gold and TNF inhibitors showed the largest effect sizes; TNF inhibitors had the best efficacy/toxicity ratio (number needed to harm/number needed to treat=0.25); tolerability was least with gold and leflunomide. The researchers concluded that efficacy/toxicity ratios were highest with TNF inhibitors followed by leflunomide, gold and sulfasalazine. Gold, though effective, has excessive toxicity and sulfasalazine, though of low toxicity, was also relatively ineffective.(Source: Ravindran V, Scott DL, Choy EH. A systematic review and meta-analysis of efficacy and toxicity of disease modifying anti-rheumatic drugs and biologic agents for psoriatic arthritis. Ann Rheum Dis. 2007 Sep 7; [Epub ahead of print] : September 2007)