Sanofi's Lantus linked to cancer risk

The rumors came true: European studies released over the weekend suggest a link between cancer and Sanofi-Aventis' diabetes treatment Lantus. Word of a possible safety problem with Lantus [1] leaked out last week, spurring some stock analysts to downgrade the company and investors to sell off their Sanofi stock.

The data is far from conclusive, as their publisher, the European Association for the Study of Diabetes, points out. Two of the bigger database analyses found an increase in cancer risk--especially breast cancer--among Lantus patients compared with those using other forms of insulin. One of the smaller studies found no statistically significant link, while the smallest found no link at all. "Our study does, however, arouse an urgent suspicion," one of the authors told Reuters, "which should have consequences for the treatment of patients."

Sanofi defended Lantus's safety, saying that clinical trials found no cancer link--and pointed out that clinical trials do remain the "gold standard" of drug research. The company plans a conference call later today at 1 p.m. Eastern, which will be aired as an audio webcast at its site (see below for the link). "Given the extensive clinical evidence covering over 70,000 patients and the results of post-marketing surveillance arising from 24 million patient-years of experience, Sanofi-Aventis stands behind the safety of Lantus," Sanofi CMO Jean-Pierre Lehner said in a statement. "We consider that the results of these patient registries are not conclusive."

But a lack of ironclad evidence doesn't mean Lantus sales won't suffer. (Need we remind you about the infamous Avandia meta-analysis?) A Societe Generale analyst has already churned out numbers: Marietta Miemietz predicts that Lantus sales may only reach $4.78 billion by 2012 now, compared with a previously expected $7 billion or more, Bloomberg reports. "We expect Lantus to remain commercially available, but expect controversies to ensue, with a likely negative impact on the franchise," Miemietz said in a note to investors. And with Lantus expected to be a key driver of Sanofi revenue as patents expire on its other big drugs, the company has plenty to worry about. How can it fight back? Tune in this afternoon to see what Sanofi is planning.

- read the Sanofi release [2]
- find the link [3] to the company webcast
- read the Wall Street Journal story [4]
- see Bloomberg's coverage [5]
- get more [6] from Reuters

ALSO: Shares in Novo Nordisk rose over 5 percent Monday after the drugmaker said it hasn't seen any cancer risks for any of the three insulin analogues it markets, distancing itself from the worries surrounding a diabetes treatment from French rival Sanofi-Aventis. Report [7]

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Lantus worries drag on Sanofi stock [1]
Sanofi-Aventis - Biotech Market Share Report [8]
Sanofi profits leap; Wyeth results flatten [9]