Lantus Insulin May Be Linked to Cancer

Just heard about this on Twitter, and it worries me, because I take Lantus (generic name: glargine) insulin as one of the medications for my newly diagnosed type 2 diabetes:

"Studies Show Diabetes Drug Might Have Cancer Link," says the headline of a story in the Wall Street Journal; the drug in question is Lantus. I couldn't read the full story because it's behind a subscription firewall; if you have a subscription, you should be able to read it. I found a version from the news service Reuters:

Sanofi-Aventis (SASY.PA) said on Friday that new data on the safety of its blockbuster diabetes drug Lantus had not reached any definitive conclusions on a possible link to cancer.

The French drugmaker has been rocked in the past two days by a safety scare over Lantus, following rumours that a damaging analysis of the product's safety was shortly to be published in a major medical journal. Its stock fell 8 percent on Friday.

Sanofi said it had just been made aware of data associated with a retrospective follow-up of four patient registries but said no firm conclusions could be drawn on any possible causal link to the occurrence of malignancies.

It added that the authors of the study had also pointed this out.

"We consider that the results of these patient registries are not conclusive," Jean-Pierre Lehner, the company's chief medical officer, said in a statement. ...

And here's a story from Science Daily with more info on the science:

The risk of cancer possibly increases if patients with diabetes use the long-acting insulin analogue glargine instead of human insulin. The Institute for Quality and Efficiency in Health Care (IQWiG), in collaboration with the "Wissenschaftliches Institut der AOK" (WIdO), the research institute of the German Local Health Care Fund, analysed the data of almost 130,000 patients with diabetes in Germany who had been treated with either human insulin or the insulin analogues lispro (trade name: Humalog), aspart (Novorapid) or glargine (Lantus) between January 2001 and June 2005.

The analysis has now been published together with further studies in the scientific journal Diabetologia.

The disturbing result is that malignancies were found more frequently in patients treated with glargine than in those prescribed a comparable dose of human insulin. "Our analysis does not provide absolute proof that glargine promotes cancer," says Peter T. Sawicki, IQWiG's Director and co-author of the study. "Our study does, however, arouse an urgent suspicion which should have consequences for the treatment of patients." ...

Ironically, when I viewed the page, there was a Lantus banner ad at the top.

Here are PDFs of the uncorrected author page proofs of soon-to-be-in-print studies that initially raised alarms, made freely available by the medical journal Diabetologia because lots of people are concerned about Lantus now:

• First study


• Second study


• Third study


• Fourth study

Two of the studies found a possible risk; the other two had inconclusive results.

If you take Lantus, please have a chat with your physician—as I plan to do with mine as soon as I can get an appointment—about the advisability of switching to another kind of injectable insulin. Do not stop taking Lantus without consulting your physician. Yes, I know, lots of substances are carcinogenic, but if you can avoid injecting a potential carcinogen into your body, that's probably a good thing.

By the way, because Sarnoff-Aventis is the maker of Lantus, its stocks' values are dropping because of the news.


Updated at 12:03 a.m., June 28, 2009: The Reuters story has been updated.


Updated at 11:13 p.m., June 28, 2009: Here is a very balanced discussion of the issues from a diabetes expert who has type 2 diabetes herself.


Updated at 8:45 a.m., June 29, 2009: Here is a Q&A from Reuters.


Updated at 5:11 p.m., June 29, 2009: And now, Sanofi weighs in, trying to make the Lantus studies out to be much ado about nothing.


Lantus glargine insulin cancer Sanofi-Aventis EditorMom