Psoriasis is an immune mediated genetically determined common dermatological disorder which affects skin, nails, joints and has various systemic associations. There is a growing number of population-based studies providing worldwide prevalence estimates of psoriasis. Prevalence of psoriasis varies in different parts of the world. According to published reports, prevalence in different populations varies from 0% to 11.8%. For most of the data given, the range extends from around 0.5% to close to 2.5%. In the USA, the prevalence of psoriasis was estimated to be around 4.6% while in Canada it was 4.7%. Data from Europe show little variation in countries with a range from 1.4% (Norway), 1.55% (Croatia) and 1.6% (UK). In East Africa, the figure was 0.7% and in the Henan district of China only 0.7% were found affected.

Adalimumab is the first fully human, high-affinity, recombinant immunoglobulin G1 (IgG1) anti-TNF monoclonal antibody. Adalimumab was created using phage display technology resulting in an antibody with human derived heavy and light chain variable regions and human IgG1:k constant regions. Adalimumab is produced by recombinant DNA technology in a mammalian cell expression system and is purified by a process that includes specific viral inactivation and removal steps. Because it is indistinguishable in structure and function from naturally occurring human IgG1, adalimumab has high selectivity and affinity for TNF; suitability for long-term chronic administration with a low degree of immunogenicity, with or without concomitant methotrexate (MTX) use; a low incidence of allergic reactions; and a half-life comparable to that of IgG1, allowing every-other-week dosing for patient convenience.