Lantus worries drag on Sanofi stock

Sanofi-Aventis has a public relations snafu on its hands. The company's shares dropped precipitously in Paris for the second day in a row as yet another analyst expressed worries about the safety of Sanofi's Lantus diabetes drug. On the heels of a downgrade by UBS, Morgan Stanley analysts downgraded Sanofi as well, saying that forthcoming meta-analysis of U.K. patient trials "may well identify an increased risk of cancer in Lantus-treated patients compared with matched controls treated with the older (and considerably cheaper) NPH insulin," the Financial Times reports.

Sanofi defended the drug, however, saying that data from studies of 70,000 patients and post-marketing surveillance data "confirms the safety profile of Lantus." Credit Suisse declared itself on the fence because of a "lack of any details" about the potential safety problem; Citigroup said that at this stage "the data is far from clear," so it retained the "buy" recommendation on Sanofi, despite the fact that its analysts think the company has staked much of its growth on the drug.

It was a Credit Suisse conference call, however, that apparently started the rumors flying. During that call, a University of Texas diabetes researcher mentioned an "earthquake" event that would raise questions about Lantus's safety, Bloomberg reports. When asked for details, the researcher would only say, “Can’t tell you anything. So keep your ears open. It won’t take too long.” We, like you, will be listening.

- read the article in the Financial Times
- see the MarketWatch story
- check out the coverage from Bloomberg