Infliximab in Psoriasis and Psoriatic Arthritis

Psoriasis is a chronic inflammatory disorder of the skin and joints. Although rarely life threatening, psoriasis can significantly impair quality of life (QOL) and cause considerable physical and psychological distress. Between 6 and 42% of patients with psoriasis develop psoriatic arthritis, which is characterized by stiffness, pain, swelling and tenderness of the joints. Nail psoriasis is highly prevalent in both plaque-type psoriasis and psoriatic arthritis and is found in approximately 50% of patients with psoriasis and in 80% of patients with psoriatic arthritis. Infliximab, a chimeric human murine monoclonal antibody directed against tumour necrosis factor a, is approved in the USA and EU for the treatment of plaque psoriasis and psoriatic arthritis at a recommended dosage of 5 mg/kg administered by intravenous infusion at 0, 2 and 6 weeks, then every 8 weeks thereafter. The EXPRESS and EXPRESS II trials demonstrated that infliximab is efficacious as induction and maintenance therapy in the treatment of moderate to severe plaque psoriasis and also improved health-related QOL. Infliximab is also efficacious in the treatment of psoriatic arthritis, as shown in the IMPACT and IMPACT II studies. Infliximab is generally well tolerated, with a similar adverse event profile in both psoriasis and psoriatic arthritis. The use of infliximab in three case reports is presented. The patients are similar to those normally seen by clinicians, and include a male patient with plaque psoriasis and a history of severe psoriatic arthritis who was corticosteroid dependent and in whom other systemic treatments were not effective or were not able to be used. This patient showed a rapid response to infliximab with no skin lesions or arthritis after 7 weeks' treatment. Infliximab was also safe and effective in the treatment of a female patient with plaque and nail psoriasis and a history of psoriatic arthritis. Importantly, this case report supports the efficacy of infliximab in psoriatic nail disease in the context of severe skin and joint involvement. Case 3 describes a young male patient with moderate plaque-type psoriasis associated with severe nail involvement and early signs of psoriatic arthritis. Treatment with infliximab improved nail psoriasis and appears to be an effective biological treatment for nail psoriasis. Importantly, ultrasound was able to diagnose joint involvement, as seen from the proliferative synovitis in the distal interphalangeal joint and mild enthesitis, despite there being no clinical evidence of psoriatic arthritis. This case report highlights the importance of early screening. If such abnormalities are detected early on in the course of psoriasis, clinicians may be able to predict which patients are more likely to develop psoriatic arthritis, and therefore offer effective and long-term treatment that may reduce the disability and impairment of daily activities that can be associated with psoriatic arthritis.