While some diabetes patients worry about the possibility of Onglyza cancer, critics say that not enough has been done to research the issue or to warn the public.

Onglyza is a brand name for the diabetes medication saxagliptin. Saxagliptin is also a component in the brand-name medication Kombiglyze XR, which combines saxagliptin with metformin. Onglyza itself is a relatively new diabetes medication, having been initially approved by the FDA in 2009.

Onglyza is one of a relatively new class of diabetes medications known as incretin mimetics. These drugs help keep blood sugar levels from getting too high by doing the work of incretin hormones.

These naturally-occurring hormones, which the body releases after eating a meal, travel to the pancreas where they stimulate insulin production. That insulin in turn stimulates the body’s cells to absorb sugar from the blood, keeping blood sugar levels from getting above normal.

Onglyza in particular works by suppressing the action of an enzyme that stops incretin hormones from doing their job. With that enzyme out of the way, incretins remain in the bloodstream, stimulating more insulin production.

Part of Onglyza’s appeal comes from its potential to manage blood sugar levels without contributing to weight gain. That popularity is reflected in Onglyza sales figures. Sales in 2014 reached $820 million, and some projections predict sales to exceed $2 billion by 2018.

Onglyza, Diabetes and Pancreatic Cancer

However, despite its widespread use, some recent research suggests that Onglyza could be a diabetes drug linked to pancreatic cancer. In 2009, one researcher from UCLA found pancreatic abnormalities in lab rats that had been given sitagliptin, an incretin mimetic with a mechanism of action similar to Onglyza’s.

Later, the same researcher found precancerous lesions and other changes in the pancreases of eight organ donors who had taken other types of incretin mimetics.

In March 2013, the FDA published a Drug Safety Communication addressing a possible link between incretin mimetics used to treat diabetes and pancreatic cancer. While the agency did not have enough evidence of Onglyza cancer to take immediate regulatory action, it said it would begin reviewing scientific literature suggesting that Onglyza could be a diabetes drug linked to pancreatic cancer.

The FDA’s communication cited a study published online by JAMA Internal Medicine in February 2013. This study had found a higher risk of pancreatitis and pre-cancerous cellular changes in diabetes patients who had taken incretin mimetics.

A more recent review found a significantly higher risk of pancreatic cancer associated with two types of incretin mimetics, as reported in the FDA’s adverse events reporting system. The review was published in 2015 in the Journal of Environmental Science and Health Part C Environmental Carcinogenesis & Ecotoxicology Reviews.

An investigation by the journal BMJ concluded that not enough has been done to warn patients and doctors about the possibility of Onglyza cancer. Documents acquired through the Freedom of Information Act revealed previously unpublished data suggesting “unwanted proliferative or inflammatory pancreatic effects” related to incretin mimetics, the BMJ says.

The BMJ also alleges that pharmaceutical companies have also failed to conduct essential safety studies related to these drugs. Investigations editor Dr. Deborah Cohen says the findings pose serious questions about the safety of incretin mimetics. And editor-in-chief Dr. Fiona Godlee believes that patients and doctors “have not been kept properly informed about the uncertainties surrounding these drugs.”