The editor of a respected diabetes journal has admitted he rushed an article on a Sanofi-Aventis drug into print in response to the company’s plunging share price.

Rumours about the results of the study on Lantus (insulin glargine) are perceived to be behind a 14% tumble in Sanofi shares last week.

“The market was falling and there were rumours about papers that we assumed were ours,” says Edwin Gale, editor of the Diabetologia journal and a researcher at the University of Bristol (Bloomberg).

“Because we were aware there were leaks, we felt there would be an alarmist, uncontrolled statement coming out in the press, so we did a rush job on it, coming out a week earlier than expected. We’ve never had to do that before.”

Bloomberg notes that Ralph DeFronzo, a diabetes researcher at the University of Texas Health Science Center, warned in an 11 June conference call that an “earthquake” might put doctors off Lantus.

Sanofi was in trouble after that and Tim Anderson, an analyst for Sanford Bernstein, was far from alone last week when he warned that, “Our information is that indeed a study is likely to be published soon raising the possibility of a link between Lantus use and a certain cancer type.” (Reuters.)

Shares responded negatively.

On Friday last week the European Association for the Study of Diabetes published four papers of patient data from Germany, Sweden, Scotland, and the UK (all papers here).

The Swedish and German data appear to show Lantus users have an increased risk of breast cancer compared with users of other types of insulin. The Scottish paper found an increase in risk but it was not statistically significant. The UK study found no increase.

The EASD issued “an urgent call for more research into a possible link between use of insulin glargine (an insulin analogue, brand name Lantus) and increased risk of cancer” but warned users to keep taking the drug. The European Medicines Agency issued similar advice.

Sanofi said it “stands behind the safety of Lantus”.

Jean-Pierre Lehner, the Chief Medical Officer of Sanofi, added, “It is important to remember that the authors stress in conclusion that their analyses are inconclusive and show no evidence of an overall increase in the rate of cancer development in patients taking Lantus. The findings of these registry studies are not confirmed by any of sanofi-aventis’ own data for Lantus, neither the data from our extensive clinical studies nor from our post-marketing surveillance.”

After the papers came out, Sanofi’s share price began to rise.