Obesity and psoriasis: body weight and body mass index influence the response to biological treatment.

Patients with psoriasis, in particular those requiring systemic treatment, tend to be above normal weight. Obesity is associated with psoriasis and contributes significantly to the increased cardiovascular risk in these patients. Most biologics used to treat psoriasis in the European Union are fixed dosed treatments: etanercept, adalimumab and ustekinumab. Apart from infliximab, dosing regimens do not account for weight, with the exception of ustekinumab, the dose of which should be doubled in patients weighing more than 100 kg. The aim of this study was to review the available evidence on the association of obesity and psoriasis, and the effect of body weight or obesity on the efficacy of biologics as well as their practical implications in daily practice. A review was performed of the literature relating to obesity and psoriasis and weight effect, including subgroup analyses, on the efficacy of the biologicals available for treatment of psoriasis in the European Union, namely adalimumab, etanercept, infliximab and ustekinumab. Optimal responses with fixed dose biological agents are less frequent in patients with increasing weight, especially above 100 kg, who account for approximately 25% to 30% of patients in clinical trials. Body weight effect on drug clearance might partly account for this fact. The data are limited to subgroup analyses, often with no statistical significance reported. Further studies, including weight-based subanalysis of clinical trials and pharmacoeconomic evaluations, are required to assess the issue of body weight and response to therapy of the biologics. Infliximab response appears to be independent of body mass index. Possible weight-based dose adjustments and the impact of treatment on body weight changes also require additional study.