UPDATE 2-Sanofi says new data inconclusive on Lantus risk

* No definitive conclusions on possible cancer link

* Company says just been made aware of new data

* Sanofi stands by safety profile of Lantus (Adds analyst comments)

PARIS, June 26 (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."

"On balance, this is not horrific and importantly, it is not alarmist," Anderson said in a research note.

"That said, Lantus is still likely to see contraction to an uncertain degree," Anderson said. "As the core driver of Sanofi-Aventis' earnings going forward, this will probably continue to weigh on the stock."

Sanofi is relying on Lantus, which many analysts expect to be its second-biggest seller this year, to offset a fall in sales of other products, such as Plavix and Lovenox, that could soon face generic competition.

Investors, however, fear any suggestion of a safety issue -- particularly a possible link to cancer -- will inevitably undermine sales.

Some analysts have suggested Sanofi might suffer the same fate as GlaxoSmithKline (GSK.L) did in 2007, when safety concerns over its diabetes drug Avandia saw prescriptions tumble almost 50 percent in the United States within six months.

Lantus, also known as insulin glargine, is a modern form of insulin. Rival products are made by Denmark's Novo Nordisk (NOVOb.CO), shares in which fell 4 percent on Friday.

For an earlier analysis on Lantus, click on [ID:nLQ157683] (Reporting by Helen Massy-Beresford and Ben Hirschler; editing by Carol Bishopric and Richard Chang)