According to a new study published in The New England Journal of Medicine, children and adolescents with moderate to severe plaque psoriasis who received treatment with Enbrel experienced significant improvements in the signs and symptoms of their disease.

Enbrel, a fully human soluble tumour necrosis factor (TNF) receptor, is manufactured by Immunex Corporation, a wholly owned subsidiary of Amgen.

While Enbrel is marketed in North America by Wyeth Pharmaceuticals, a division of Wyeth, and Amgen, the medicine is marketed outside North America by Wyeth.

The phase III study was designed to assess the safety and efficacy of ENBREL therapy in children and adolescents between 4 and 17 years old with moderate to severe plaque psoriasis whose disease had been inadequately controlled with topical therapy or who received systemic therapy or phototherapy. In this 48-week study, 211 paediatric psoriasis patients were initially randomised to receive 12 once-weekly weight-based doses of Enbrel (0.8 mg/kg up to the intended dose of 50 mg) or placebo. After this double-blind portion, 208 patients entered a 24-week period of open-label Enbrel treatment once-weekly. At week 36, 138 patients were re-randomised to receive either Enbrel or placebo, to investigate withdrawal and re-treatment.

Enbrel is not indicated for the treatment of paediatric psoriasis. Amgen has filed a supplemental Biologics License Application (sBLA) with the US Food and Drug Administration (FDA) for the use of Enbrel in treating paediatric patients with chronic moderate to severe plaque psoriasis who have tried another therapy. If approved by the FDA, Enbrel is expected to be the first biologic, as well as the first systemic medication, indicated to treat this disease in paediatric patients.

"Moderate to severe plaque psoriasis is a chronic disease of the immune system that can significantly impact many aspects of the daily lives of children and teens," said Amy Paller, M.D., study investigator and Professor and Chair of Dermatology, Northwestern University School of Medicine. "These etanercept data are encouraging and reinforce the importance of continuing to investigate treatment options that may help this particularly vulnerable patient population manage their disease."

During the 48-week study, the percentage of patients achieving 75 per cent or greater disease improvement from baseline, as measured by the standard Psoriasis Area and Severity Index (PASI 75), was used to evaluate the efficacy of Enbrel in patients between 4 and 17 years old. The primary efficacy endpoint was PASI 75 at week 12. There were 106 patients initially randomised to receive Enbrel and 105 patients randomised to receive placebo.

At week 12, which was the conclusion of the double-blind, placebo-controlled portion of the study, 57 per cent (n=60) of paediatric patients treated with Enbrel achieved PASI 75, compared with 11 per cent (n=12) of paediatric patients who received placebo (p less than 0.001).

At week 36, after 24 weeks of open-label treatment during which all patients in the study received Enbrel, PASI 75 was achieved by 68 per cent (n=71) of the patients initially treated with Enbrel from the start of the study and 65 per cent (n=67) of those who initially received placebo from the start of the study.

At the conclusion of the open-label treatment period (week 36), 138 patients were re-randomised to receive either Enbrel or placebo. During this period, patients who lost PASI 75 were re-treated and no patient had a rebound of psoriasis or a change in the type of their psoriasis.

There were no serious adverse events or serious infections during the 12-week placebo-controlled period and rates of adverse events were similar for Enbrel and placebo. During open-label treatment, three patients developed four serious adverse events. No deaths, cancers, opportunistic infections, tuberculosis or demyelination events were reported. The most common adverse events observed during the 48-week trial in patients treated with Enbrel were upper respiratory tract infection, headache, and nasopharyngitis.

Enbrel was first approved in 1998 for moderate to severe rheumatoid arthritis and has since been used in nearly 500,000 patients worldwide across indications.

It is also indicated for reducing signs and symptoms, keeping joint damage from getting worse, and improving physical function in patients with moderate to severe rheumatoid arthritis. Enbrel can be taken with methotrexate or used alone.

Enbrel is indicated for reducing signs and symptoms of moderately to severely active polyarticular-course juvenile rheumatoid arthritis in patients who have had an inadequate response to one or more disease-modifying anti-rheumatic drugs.

Enbrel is also indicated for reducing signs and symptoms, keeping joint damage from getting worse, and improving physical function in patients with psoriatic arthritis. Enbrel can be used in combination with methotrexate in patients who do not respond adequately to methotrexate alone.

Enbrel is indicated for reducing signs and symptoms in patients with active ankylosing spondylitis and for the treatment of adult patients (18 years or older) with chronic moderate to severe plaque psoriasis who are candidates for systemic therapy or phototherapy.

Enbrel is a type of protein called a tumour necrosis factor (TNF) blocker that blocks the action of a substance your body's immune system makes called TNF. People with an immune disease, such as rheumatoid arthritis, ankylosing spondylitis, psoriatic arthritis, and psoriasis, have too much TNF in their bodies. Enbrel can reduce the amount of TNF in the body to normal levels, helping to treat your disease. But, in doing so, Enbrel can also lower the ability of your immune system to fight infections.