Abbott Laboratories has filed its anti-inflammatory blockbuster Humira with US and European regulators for psoriasis in a bid to get approval for a fifth indication of the drug.

The company says it has simultaneously submitted a supplemental Biologics License Application with the US Food and Drug Administration and a Type II Variation to the European Medicines Agency to get approval for Humira (adalimumab) as a treatment for moderate to severe chronic plaque psoriasis, which affects 125 million people worldwide

The company based its submissions on clinical trial data on two studies, REVEAL and CHAMPION. In the first, pivotal 52-week trial, the short-term and sustained clinical efficacy and safety of Humira were evaluated in more than 1,200 patients with moderate to severe chronic plaque psoriasis. Patients experienced a significant reduction in the signs of their disease at 16 weeks when treated with the drug and Abbott noted that almost three out of four patients (71%) receiving Humira achieved PASI (the Psoriasis Area and Severity Index which measures the severity of the condition) 75 or better, compared to only 6.5% of patients receiving placebo. One in five achieved PASI 100, or complete clearance, compared to less than 1% in the placebo group.

In CHAMPION, a 16-week study evaluating 271 patients, 80% of those treated with Humira achieved PASI 75 compared to those on methotrexate (36%), a standard treatment for psoriasis, and four times more than patients treated with placebo (19%). Nearly 17% treated with Humira achieved PASI 100 at week 16, compared to 7% methotrexate and 2% placebo. The most commonly reported adverse events in the trials were upper respiratory tract infection, nasopharyngitis (inflammation of the nose and pharynx) and headache.

The bid to get the green light for psiorasis comes just two months after Abbott gained FDA approval to sell Humira for Crohn's disease. It is also approved to treat rheumatoid arthritis, psoriatic arthritis and ankylosing spondylitis, an inflammatory disease of the spine and spinal joints. Sales of the drug edged over $2 billion last year and Abbott said at the time that this figure should rise to around $2.7 billion in 2007, though these extra indications suggest that the estimate is somewhat conservative.

If approved, Humira will compete in psoriasis with the likes of Johnson & Johnson's Remicade (infliximab), Biogen Idec's Amevive (alefacept), Genentech's Raptiva (efalizumab) and Wyeth and Amgen's Enbrel (etanercept)