Insulin glargine ( Lantus ) is a long-acting insulin analogue, an Insulin molecule that has been modified for more sustained effects after injection. It contains arginine residues at positions B31 and B32, together with a glycine substitution at A21.
Insulin glargine is licensed for the treatment of adults, adolescents, or children age 6 years or older who have diabetes mellitus, where treatment with Insulin is required. In type 1 diabetes, glargine is usually given once daily as part of a basal bolus regimen.

The National Institute for Health and Clinical Excellence ( NICE ) recommends neutral protamine Hagedorn ( NPH ) Insulin as first-line therapy for type 2 diabetes, but glargine may be indicated for those who require assistance to administer injections, or who cannot cope with twice-daily injections for other reasons, or who experience troublesome hypoglycaemia.

Diabetes and cancer

Type 2 diabetes is associated with an increased risk of certain types of cancer, including cancer of the breast, colon, and pancreas. These tumours are insulinresponsive in vitro, raising the possibility that Insulin might act as a tumour growth factor. Three studies found that Metformin was associated with a lower risk of cancer than Insulin or sulfonylureas. Cancer diagnosis or mortality are increased in Insulin or sulfonylurea users compared with those on Metformin, suggesting that Metformin may have an antitumour effect; however, this remains to be confirmed.

Data for cancer risk with Insulin glargine

Epidemiological studies - After an initial observational study suggesting a possible association between Insulin glargine and an increased risk of cancer, further findings have been published. These studies assessed the overall risk of cancer in addition to the risk of breast cancer with Insulin glargine, compared with risk in other treatment groups ( some Insulin and some oral therapy ). The results of these retrospective observational studies are not entirely consistent, and can neither confirm nor exclude a relationship between insulin glargine and cancer.

The four studies were relatively short in duration of exposure and observation period to study drug-induced or drug-modified malignances. The mean follow-up for glargine varied from 1.31 years to 2.74 years, whereas the mean follow-up for comparator groups varied from 1.68 years to 3.36 years.
A positive association between Insulin glargine and any malignancy was found in the study by Hemkens and colleagues only after re-analysis of the data for dose-related effects.
Jonasson and colleagues investigated the incidence of in situ tumours, breast cancer, gastrointestinal cancer, and prostate cancer and found a positive association with use of Insulin glargine alone and breast cancer.
Methodological problems identified in these studies included potential exposure misclassification, selection bias, differing choice of comparator group, adjustment for confounding factors, and incomplete information on risk factors. Although the studies controlled for some confounding factors such as age and smoking, most known risk factors for breast cancer (ie, age at menopause, parity, exogenous hormone use, genetic predisposition or family history, body-mass index, and socioeconomic status) were not taken into account in most of the analyses.

Randomised controlled trials - A post-hoc analysis of data from a randomised controlled trial is more reassuring. This relatively small 5-year trial compared the risk of diabetic retinopathy in patients receiving Insulin glargine or NPH Insulin; cancer risk was a secondary outcome. 514 patients received Insulin glargine and 503 patients received NPH. Three (0.6%) patients in the Insulin glargine group developed breast cancer versus five ( 1% ) patients in the NPH group.

Source: Safety Drug Update – MHRA, 2009

XagenaMedicine2009


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