Procter & Gamble's proposed launch of an over-the-counter version of AstraZeneca's blockbuster Prilosec will be delayed after the FDA requested changes to its label design.

Prilosec (Losec in the UK) was the second biggest-selling drug in the US in 2001, with sales of more than $ 3.7 billion, and remains AstraZeneca's biggest selling drug.

The FDA told P&G that the product needed to have a label which consumers could understand, pushing back the expected launch date six months to Autumn 2003.

A label-comprehension study is expected to last about eight weeks, but the FDA has said it will take six months to review the study, company treasurer Juan Pedro Hernandez told analysts in a conference call.

The delay will not have a material effect on P&G expected results, he said.

Meanwhile shares in AstraZeneca fell nearly 3% after reports in the Wall Street Journal said Schwarz Pharma AG, Andrx. and Merck KGaA are expected to collaborate on the launch of generic versions of Prilosec. The partnership is likely to centre Schwarz Pharma 's version of the product, the only one not ruled to infringe AstraZeneca's patents.

pharmafocus@pharmafile.co.uk