New diabetes pills' link to pancreatic cancer risk needs further probe

Two new drugs used to treat Type 2 diabetes could significantly increase the risk of developing pancreatitis and pancreatic and thyroid cancer, a new study has warned.

Researchers from the Larry L Hillblom Islet Research Center at UCLA examined the US Food and Drug Administrations database for adverse events reported between 2004 and 2009 among patients using the drugs sitagliptin and exenatide.

They found a six-fold increase in the odds ratio for reported cases of pancreatitis with these drugs, compared with four other diabetes therapies they used as controls.

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 researchers, however, cautioned that more studies were needed to conclusively establish the link.

We undertook these studies because several studies in animal models by several investigators had suggested that this form of therapy may have unintended actions to promote growth of the ducts (tubes) in the pancreatic gland that convey digestive juices from the pancreas to the gut, said Dr Peter Butler, director of the Hillblom Center and a study co-author.

This is a concern if it happens in humans since it might be expected to increase the risk for pancreatitis and pancreatic cancer. While the FDA data base has limitations, it does have advantages in being very large, openly accessible and independent from companies that market the drugs.

Taken together the animals studies and the FDA data base analysis suggest that further work needs to be undertaken to at least rule out that this now widely available new drug class for diabetes does not increase the risk of pancreatic cancer, Butler added.

The study has been published in the journal Gastroenterology.