Comparative therapeutic studies with Tilavist.

Comparative clinical trials which include known therapies as well as placebos are essential in constructing a solid basis from which to 'launch' any new drug. This applies especially to eye drops for treatment of seasonal allergic conjunctivitis, where the symptomatology, already dependent on the vagaries of the natural pollen challenge season, is further influenced by a positive washing action of the placebo eye drops. Tilavist (2% nedocromil sodium ophthalmic solution) has therefore been compared with sodium cromoglycate eye drops and non-sedating antihistamine tablets, both mainstays in the treatment of seasonal allergy, in a series of double-masked, placebo-controlled, mainly multicentre studies. Nedocromil sodium, twice or four times daily, proved as effective overall as sodium cromoglycate (2% or 4% four times daily) in three seasonal trials, and was the more effective treatment in a study of patients with vernal keratoconjunctivitis. Its efficacy was most evident during peak periods of pollen challenge, when neither placebo nor sodium cromoglycate eye drops controlled breakthrough symptoms. Three further seasonal studies showed nedocromil sodium eye drops to be as effective as standard oral doses of astemizole and terfenadine, whilst a faster onset of action than terfenadine was reported in one multicentre study.