Sanofi says new data inconclusive on Lantus risk

PARIS (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.

It noted that clinical studies, which represent the gold standard of evidence, did not indicate an association between Lantus and cancer.

"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," Lehner said.

Sanofi said it would continue to vigorously monitor the safety of Lantus in close collaboration with regulatory agencies and scientific experts.

Tim Anderson, an analyst with Sanford Bernstein, said his initial assessment of the data in the medical journal Diabetologia shows they raise questions about Lantus and the possibility that it causes cancer but "is far from conclusive."