Amylin Says Byetta Side Effects Not Linked to Risk of Heart Problems

Amylin Pharmaceuticals, Inc. and Eli Lilly and Co. said this week that a new meta-analysis of clinical data for their diabetes drug Byetta indicates that the injection does not increase the risk of cardiovascular events. The drug makers will use the data to support a new once-weekly version of the medication amid closer scrutiny by the FDA for heart risks of diabetes drugs. However, other reports have raised concerns in the medical community that Byetta side effects may increase the risk of pancreatitis.

Byetta (exenatide) was approved in 2005 for treatment of type 2 diabetes. It is sold in a pre-filled injection pen, which is used to administer the drug twice daily to lower blood glucose levels.

Amylin and Eli Lilly have been seeking FDA approval for a new once-weekly version of Byetta, called Byetta LAR, that is longer acting than the daily version. In November 2008, the FDA requested additional safety data before considering the new drug.

In December 2008, the FDA began taking a closer look at the heart side effects for all new drug applications for medications used to treat diabetes. The increased scrutiny came in response to concerns over side effects of Avandia, a widely used diabetes drug which has been found to increase the risk of heart attacks, congestive heart failure and death.

According to a statement released March 26, 2009, an analysis of clinical studies conducted by Amylin, Eli Lilly and Alkermes, Inc. did not show an increased risk of cardiovascular events linked to Byetta use. The drug makers indicate that the findings will be used to support the heart safety of Byetta’s once-weekly version.

Byetta has been used by over 700,000 people in the United States and generates annual sales of around $650 million, which is expected to increase dramatically if a new longer-acting version of the drug is approved. However, sales growth has stalled over the past year after reports linked side effects of Byetta to a risk of pancreatitis.

The FDA issued an alert to healthcare providers in October 2007 after they identified at least 30 reports of acute pancreatitis associated with the use of Byetta. In August 2008, the alert was updated by the FDA to notify doctors about additional reports of pancreatitis involving six serious cases of necrotizing pancreatitis and hemorrhagic pancreatitis, two of which resulted in death.

Although Lilly and Amylin have denied that there is any established causal connection between Byetta and pancreatitis, they have disclosed that they are aware of at least four additional Byetta pancreatitis deaths.

Analysts have speculated that the FDA may require the drug makers to add a Byetta black box warning about the potential risk of pancreatitis, and it is unclear what, if any, impact this risk may have on the approval of the longer-acting version of the drug.