Sanofi-Aventis, the French pharmaceutical company, on Monday moved to allay concerns in four new academic studies of a possible connection between its diabetes treatment Lantus and cancer, as EU regulators launched an investigation to further scrutinise the data.

The company, which saw its share price fall 10 per cent since analyst reports first drew attention to the studies in the middle of last week, said it was fully co-operating with scientists and regulators in a more detailed probe, but rejected any indications of a causative link.