A new and popular medication for diabetes is part of a class of medicines that may be linked to an increased risk of thyroid cancer.

The medicationOnglyza, also known by its generic name saxagliptin, is made by pharmaceutical manufacturer Bristol-Myers Squibb. The drug helps control levels of blood sugar and was approved by the FDA in July 2009 as a treatment for symptoms of type 2 diabetes.

What is Onglyza?

Onglyza is one of a class of relatively new diabetes medications called incretin mimetics. These diabetes medications work by promoting the action of incretin hormones, which in turn stimulate the pancreas to release insulin and lower concentrations of blood sugar.

Onglyza has been particularly popular as a diabetes medication because it does not promote weight gain like other medications do, leading to ample sales. Some experts predict annual Onglyza sales could exceed $2 billion by 2018.

Onglyza and Thyroid Cancer

Since Onglyza has only been on the market for a relatively short period of time, information about the long-term effects of its use is not complete. However, studies of other incretin mimetic drugs show a possible connection with thyroid cancer. The FDA has also received many reports of thyroid cancer that developed while a patient was taking other incretin memetics.

The FDA approved a Risk Evaluation and Mitigation Strategy (REMS) in 2009 for the incretin mimetic Byetta, also known by its generic name exenatide. With that REMS, the FDA required Amlyn Pharmaceuticals to conduct six post-marketing studies in part to “explore a potential signal of a serious risk of thyroid cancer.”

A study published in Gastroenterology in 2011, based on a review of the FDA’s Adverse Event Reporting System, found that patients treated with Byetta had a statistically significant increase in rates of thyroid cancer. The researchers noted these findings called for further investigation into the effect of drugs like Byetta on the thyroid gland.

In June 2011, the FDA required Novo Nordisk to issue a “Dear Healthcare Professional” letter, directing physicians to the risk of thyroid C-cell tumors caused by Victoza another incretin mimetic. The agency based its requirement on research showing a causal relationship between clinically relevant exposures of Victoza and the occurrence of such thyroid tumors in rats and mice. Based on these findings, the FDA approved a REMS for patients taking Victoza.

Thyroid Cancer Symptoms and Treatment

While these studies do not directly show a relationship between Onglyza and thyroid cancer, they raise the possibility that such a relationship could exist. The Mayo Clinic recommends that patients consult a doctor about the possibility of thyroid cancer if they experience any of the following signs or symptoms:

• Lumps that can be felt inside the neck
• Swelling of the lymph nodes in the neck
• Pain in the neck or throat
• Difficulty swallowing
• Changes to the sound of the voice

Treatment for thyroid cancer may surgical removal of most or all of the thyroid gland. Alternatives to surgery include chemotherapy, thyroid hormone therapy, external radiation therapy, or targeted drug therapy. Even after successful treatment, thyroid cancer may return, possibly affecting residual bits of thyroid tissue or other tissues elsewhere in the body.