Insulin Glargine Potentially Associated With Increased Cancer Risk

Emma Hitt, PhD

July 01, 2009

July 1, 2009 — Three of 4 observational studies suggest an increased risk for cancer associated with use of insulin glargine (Lantus, sanofi-aventis), although these findings warrant further follow-up studies to confirm an association, according to the US Food and Drug Administration (FDA).

The FDA is currently reviewing many sources of safety data for insulin glargine, including these newly published observational studies, according to an alert sent today from MedWatch, the FDA's safety information and adverse event reporting program.

The FDA currently is recommending that patients not stop taking insulin glargine without consulting a healthcare professional. No guidance regarding action to be taken by healthcare professionals has been issued.

Insulin glargine is approved to control blood glucose in patients with type 1 and type 2 diabetes.

The observational studies were published in the June 30 issue of Diabetologia,, the journal of the European Association for the Study of Diabetes (EASD). According to an EASD press release, one data analysis of 127,000 insulin-treated patients reported a statistically significant link between cancer and insulin glargine use compared with those using similar doses of human insulin. Among those receiving insulin glargine, there was an increase of 1 person with cancer for every 100 people receiving human insulin.

This study, conducted in Germany, also indicated a dose-dependent increase in cancer risk; 10 U of insulin glargine increased the risk by 9% whereas 50 U increased the risk by 31%.

As a result of these findings, studies were also conducted in databases from Sweden, Scotland, and the United Kingdom. The Swedish study found that compared with patients on other forms of insulin, patients receiving insulin glargine alone had a 2-fold increased risk for breast cancer. The Scottish study found a nonsignificant increased risk for breast cancer, whereas the UK study found no link between insulin glargine and any type of cancer.

According to the FDA, further studies are underway “to better understand the risk, if any, for cancer associated with use of [insulin glargine].”

More information is available on the FDA's MedWatch Web site.

Adverse events related to use of insulin glargine therapy should be communicated to the FDA's MedWatch reporting program by telephone at 1-800-FDA-1088, by fax at 1-800-FDA-0178, online at, or by mail to 5600 Fishers Lane, Rockville, Maryland 20852-9787.


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