Belgium’s UCB and Franco-German partner Sanofi-Aventis are celebrating after US regulators gave the go-ahead for the antihistamine drug Xyzal, the follow-up to the blockbuster Zyrtec.

The US Food and Drug Administration has approved Xyzal (levocetirizine), a new once-daily antihistamine for the relief of symptoms associated with seasonal and perennial allergic rhinitis and uncomplicated skin manifestations of chronic idiopathic urticaria in adults and children six years of age and older. UCB filed a New Drug Application for Xyzal in July last year and signed up Sanofi as its US marketing partner last September, though most observers had expected that partner to be Pfizer which has a long-term licensing deal with the Belgian firm for Zyrtec.

The FDA’s approval is based on the results of eight randomised, placebo-controlled clinical trials involving over 2,000 allergic rhinitis patients which demonstrated that Xyzal considerably reduced the symptoms of sneezing, itchy and runny nose, plus itchy eyes. Studies in chronic idiopathic urticaria patients showed the drug significantly reduced the severity of itching and the number and size of wheals on the skin.

The firms quoted Michael Blaiss, clinical professor of paediatrics and medicine at the University of Tennessee Health Science Center, as saying that "with allergies on the rise and longer-lasting allergy seasons, patients desire a fast and long-acting treatment.” He added that Xyzal, which is expected to be available during the 2007 fall allergy season, “is a new treatment option in today's more challenging allergy environment".

Xyzal was launched in Europe in 2001 and is currently marketed in over 80 countries worldwide. Last year it had sales of 143 million euros, a 13% increase on the previous year.