US FDA revises Byetta label to reflect possible kidney problems

The US Food and Drug Administration yesterday acted on new safety information about possible kidney function problems, including kidney failure, in patients taking Byetta (exenatide), a drug used to treat type 2 diabetes marketed by Eli Lilly and manufactured by Amylin.

'The current label reflects our understanding of post-marketing reports of renal events and provides physicians with updated guidance about appropriate use in patients with renal conditions. There is no evidence from preclinical and clinical studies that Byetta has any direct toxic effect on the kidney," said Orville Kolterman, senior vice president of R&D at Amylin Pharmaceuticals.

Last week, the FDA approved Byetta as a standalone drug that can be used to control blood sugar in type 2 diabetes patients. Worldwide turnover of the drug totaled $205.7 million in the third quarter. The two companies share revenue from US sales, and Lilly gets all the revenue generated internationally.

Two years ago(The Pharma Letter October 22, 2007), the FDA issued a letter warning about Byetta's pancreatitis risk, after it received 30 reports of patients developing acute cases of inflammation of the pancreas, 27 of whom were hospitalized.

From April 2005 through October 2008, the FDA received 78 reports of problems with kidney function in patients using Byetta. Some cases occurred in patients with pre-existing kidney disease or in patients with one or more risk factors for developing kidney problems. Nearly seven million prescriptions for Byetta were dispensed between April 2005 and September 2008. The 78 cases represent a small percentage of the total number of patients using the drug to control blood sugar (glucose) levels, the FDA noted.

he most common side effects associated with Byetta include nausea, vomiting and diarrhea. These side effects may have contributed to the development of altered kidney function. Kidney malfunction can result in a build-up of waste products in the blood, leading to serious illness or life-threatening conditions.

'Health care professionals and patients taking Byetta should pay close attention to any signs or symptoms of kidney problems,' said Amy Egan of the Division of Metabolism and Endocrinology Products at the FDA's Center for Drug Evaluation and Research. 'Patients also should be aware that problems with kidney function could lead to changes in urine color, frequency of urination or the amount of urine, unexplained swelling of the hands or feet, fatigue, changes in appetite or digestion, or dull ache in mid to lower back,' she noted.