AstraZeneca' has received some bad news after regulators in the USA requested more information on two filings the company has made to get more expanded approvals for its antiulcerant blockbuster Nexium.

The Anglo-Swedish drugmaker has received a complete response letter from the US Food and Drug Administration for Axanum, which combines aspirin and Nexium (esomeprazole) tablets. AstraZeneca was seeking approval for the combo for the risk reduction of low dose aspirin-associated gastric and/or duodenal ulcers.

The company also received a CRL for the supplemental new drug application for Nexium for the risk reduction of low-dose aspirin-associated peptic ulcers. AstraZeneca has given no details about the content of the letters but says it is currently evaluating the CRLs and will continue discussions with the FDA “to determine next steps…and will respond to the agency’s request for additional information”.

Nexium is still a big earner for AstraZeneca and first-quarter sales were up 3.9% to $1.24 billion. The antiulcerant is scheduled to go off-patent in May 2014 and the firm is hoping to extend the life cycle of the product through new formulations.

Last month, the FDA approved AstraZeneca and Pozen’s Vimovo (naproxen and esomeprazole) to alleviate the signs and symptoms of osteoarthritis, rheumatoid arthritis and ankylosing spondylitis, as well as decrease the risk of developing gastric ulcers in patients prone to NSAID-associated stomach problems. Meantime, an FDA advisory panel is scheduled to meet tomorrow to evaluate AstraZeneca’s new infant lung drug motavizumab.