In the wake of disputed criticism of Lantus, Sanofi-Aventis has unveiled the results of a long-term study which show that the link between the diabetes drug and retinopathy showed the risk for patients was not greater than with human insulin.

The French drugmaker said that the results of a 1,024-patient five-year study of Lantus (insulin glargine) versus human neutral protamine Hagedorn (NPH) insulin looking at the progression of retinopathy, a major cause of blindness in people with type 2 diabetes, showed similar effects on the disease and overall safety in the two treatment groups. The findings indicate that Lantus does not have mitogenic effects different from the human NPH insulin within the eye, Sanofi said.

The Paris-headquartered group added that “there was no observable trend for a difference in the incidence of serious adverse events including cancer, as well as adverse events leading to study withdrawal”. The most common adverse events in the study were upper respiratory tract infection, peripheral oedema and arthraralgia.

The results were published in Diabetologia, the journal which last week published studies which suggest an increased risk for cancer associated with use of Lantus. However, the US Food and Drug Administration then noted that “inconsistencies” in the findings “raise concerns as to whether an association between the use of insulin glargine and cancer truly exists”.

Lantus is a major earner for Sanofi and sales rose 27.1% to 747 million euros in the first quarter.