The United States Food and Drug Administration issued Monday warnings to doctors and patients as well regarding the recent victims of Amylin Pharmaceuticals' Byetta. The FDA posted the warning on its Web site mentioning that patients suffering from type 2 diabetes were hospitalized due to the symptoms caused by treatment with Byetta.

Since October 2007, the treatment with Amylin’s best-selling drug caused six patients hemorrhagic pancreatitis and necrotizing pancreatitis forcing them to check into hospitals. Two of them died.

The FDA warnings caused Amylin shares to plunge 14.5%, or $4.92, to $29.29, in late-afternoon trading, the company’s biggest stock fall in seven years. Byetta is the San Diego-based company’s leading product. Byetta year-to-year sales climbed 17% for the second quarter, Amylin said.

Both Amylin and its collaborator, Indianapolis-based drug company Eli Lilly & Co., agreed to warn possible and current patients of the high risk of pancreatitis the drug poses after learning of the 30 mild cases reported so far to the FDA.

Eli Lilly & Co. shares also dropped 1.7%, to $47.95.

Byetta, which is administered through injection twice a day in order to lower blood sugar in people suffering from type 2 diabetes, was released on the market in 2005. Amylin also plans to come up with the long-acting release formula which is scheduled to hit the market in 2010. Although the drug company released positive info on Byetta Longer-Acting Release at the American Diabetes Association Meeting after studying it for 52 weeks, industry experts expressed fears that the drug might cause complications which would be very difficult to treat.

Pancreatitis (pancreas inflammation) can cause bleeding and can release toxins in the blood which eventually damages other organs. However, the death risk isn’t very high.

“The proportion of cases reporting complications or fatal outcome is similar to that observed in the general population with pancreatitis,” Amylin’s statement wrote.

Although Byetta isn’t very popular among patients because it has to be injected twice a day, Amylin said about 1 million people have been prescribed the drug. The new version of the Byetta that will be injected once a week is under development.