Shares in Amylin Pharmaceuticals have taken a dip after the firm’s type 2 diabetes treatment Byetta, which is partnered with Eli Lilly, was the subject of a safety elert issued by US regulators concerning the possible risk of pancreatitis associated with taking the drug.

The US Food and Drug Administration said that it has reviewed 30 postmarketing reports of the disease in patients taking the treatment and concluded that “an association between Amylin's Byetta (exenatide) and acute pancreatitis is suspected in some of these cases”. Of the 30 cases, however, 27 patients had at least one other risk factor, the agency stated, such as gallstones, severe hypertriglyceridemia and alcohol use.

The FDA also noted that the data showed that in 22 of the 30 cases, patients improved after discontinuing treatment with the drug. Three reports indicated that the symptoms of acute pancreatitis returned when Byetta was restarted.

As a result of all this, the agency has issued a warning to healthcare professionals saying that they should instruct patients taking Byetta to seek prompt medical care if they experience “unexplained persistent severe abdominal pain which may or may not be accompanied by vomiting”. If pancreatitis is suspected, Byetta should be discontinued and if the condition is confirmed, it should not be restarted “unless an alternative etiology is identified”, the safety elert stated.

The FDA noted that it has asked Amylin to include information about acute pancreatitis in the precautions section of the product label and the firm has agreed. However, both Amylin and Lilly say that the pancreatitis problem has been part of their own postmarketing studies, so the label update was something they had already been working to. Nevertheless, investors in Amylin were worried about the elert and the firm’s stock fell over 5% to $45.51.