Psoriasis is a chronic, inflammatory skin disease that usually needs long-term treatment. Tumour necrosis factor alpha (TNF alpha) – a protein in the body involved in inflammation - is thought to play a part in the development of psoriasis. Scientists know that a drug called infliximab can neutralise the activity of TNF alpha. Infliximab is already approved for other inflammatory diseases triggered by TNF alpha, such as rheumatoid arthritis and Crohn's disease, but its safety and effectiveness against psoriasis has been unclear until now.
Professor Christopher Griffiths (University of Manchester, UK) and colleagues recruited 378 patients with moderate to severe psoriasis to intravenously receive infliximab or placebo at 0, 2, and 6 weeks, then every 8 weeks until week 46. The researchers assessed signs of psoriasis using the psoriasis area and severity index (PASI) and nail psoriasis severity index (NAPSI). They found that at week 10, 80% of patients treated with infliximab achieved at least a 75% improvement from their baseline PASI, and 57% achieved at least a 90% improvement, compared with 1% and 3% in the placebo group. The investigators also found that the positive effect of the drug was sustained through to week 24 and up to week 50 for most patients. A quarter of the patients taking the drug had complete clearing of skin psoriasis (PASI of 0) compared with none in the placebo group.
Patients receiving infliximab also experienced a good response in nail psoriasis, which is present in 20 – 50% of psoriasis patients and is often thought of as sign of treatment-resistant disease. By week 24 of the trial, those receiving the drug were experiencing a 56% average decrease in this condition, and this response was maintained throughout the trial.
There were more severe adverse events in the drug group compared with placebo but overall the drug was well tolerated. The authors note that the results for infliximab compare favourably with other approved drug treatments for psoriasis.
Professor Griffiths states: "Infliximab monotherapy is highly effective in the treatment of skin and nail disease in patients with moderate to severe psoriasis, with rapid onset of action and a sustained effect in most patients."
See also accompanying comment.
Contact: The University of Manchester press office Jo Nightingale on 0161 275 8156 joanne.nightingale@manchester.ac.uk (Mon - Weds am and Fri am), or Mikaela Sitford on 0161 275 2111 mikaela.sitford@manchester.ac.uk (Weds - Fri)
Journal
The Lancet