Initial experience with routine administration of etanercept in psoriasis

Background Etanercept and efalizumab recently became available and reimbursed for routine use in severe psoriasis in the Netherlands. The criteria for reimbursement are Psoriasis Area and Severity Index (PASI) >= 10 (or Skindex-29 >= 35 if PASI >= 8 and < 10) and ineffectiveness of ultraviolet (UV) B/psoralen plus UVA, methotrexate and ciclosporin, or a contraindication to or serious side-effect(s) during these treatments. Objectives We hypothesized: (i) that efficacy would be lower than that obtained in published phase II and III studies because (a) resistance to all conventional therapies as a reimbursement condition would select for more resistant cases and (b) inclusion would be more restricted to severe cases (higher PASI), and (ii) that efficacy would be lower in obese patients due to the possible role of adipose tissue in tumour necrosis factor (TNF)-alpha homeostasis. Methods We treated 50 patients (38 men, 12 women; mean PASI 15.8) with etanercept 25 mg or 50 mg twice weekly and evaluated in a retrospective analysis the efficacy and safety in comparison with data from published trials. Additionally, we related the clinical effect to the body mass index (BMI), for adipose tissue is thought to have a possible role in TNF-alpha homeostasis. Results Based on the literature, 30% and 49% of the patients treated with etanercept 25 mg and 50 mg twice weekly, respectively, should have achieved 75% or more improvement in PASI compared with baseline (PASI 75), and 10% and 21%, respectively, should have achieved 90% or more improvement (PASI 90). Our data showed that 21% in the 2 x 25 mg group and 23% in the 2 x 50 mg group achieved PASI 75. PASI 90 was only attained in 7% of patients treated with 2 x 25 mg and 6% of those treated with 2 x 50 mg. Contrary to our hypothesis, the mean initial PASI was comparable with the mean PASI mentioned in the phase II and III clinical trials. Although fatigue is not identified as a side-effect of etanercept, 10% of our patients reported fatigue as an adverse event during etanercept treatment. High BMI, indicating overweight or obesity, was found both in patients with little efficacy and in patients achieving PASI 75 or better. Conclusions Use of etanercept in real practice gives impressive results, but these are generally less favourable than those published in clinical trial reports. This is probably due to the stringent conditions for reimbursement, which select for more treatment-resistant patients. Fatigue as a possible side-effect of etanercept should also be an issue for further investigation. Finally, the BMI does not seem to influence the patients' response to etanercept, although further investigations would be needed to confirm this.