Previous research by UCLA Hillblom Center researchers suggested there might be a link between drugs that enhance the actions of GLP-1 and pancreatitis, possibly resulting from an increase in the rate of formation of cells that line the pancreatic ducts. That research, based on studies in rats, was published in 2009 in the journal Diabetes.
In addition to the six-fold increase in reported cases of pancreatitis, the researchers also found a 2.9-fold greater rate of pancreatic cancer in patients using exenatide and a 2.7-fold higher rate of pancreatic cancer in patients on sitagliptin, compared with the other therapies. Additionally, they found a statistically significant increase in the risk of thyroid cancer among the exenatide group, but not among the sitagliptin group.
The FDA data did not indicate links between the two diabetes drugs and any other form of cancer.
The researchers caution that the FDA's adverse events database "is not the ideal mechanism to compare adverse event rates between drugs," given its known limitations, such as incomplete data and reporting biases. They stress that more study is needed.
"Randomized, controlled clinical trials remain the gold standard for such assessment," the researchers wrote.
Source UCLA's Jonsson Comprehensive Cancer Center