A drug developed by Eli Lilly could provide a completely new way of tackling the damage to the retina that can occur in people with diabetes, according to clinical data reported at the American Diabetes Association conference in Washington DC.

Arxxant (ruboxistaurin) reduced the risk of moderate vision loss by around 40%, with 6.1% of patients suffering vision loss compared to 10.2% of those on placebo, according to combined results of two three-year Phase III trials.

Around 4.1 million US adults have some degree of retinopathy caused by diabetes, with around 900,000 at risk of losing their sight as a result. The drug could prevent 700,000 cases of vision loss if given routinely to eligible patients in the USA, said the reseachers.

Lilly has already included the data in a submission to the US Food and Drug Administration (FDA) for Arxxant, made back in February, but this was the first time the data were presented to diabetologists.

Arxxant “has the potential to be the first oral therapy to specifically reduce the risk of vision loss by diabetic retinopathy," said Lloyd Aiello, the lead investigator in the study and an associate professor of ophthalmology at Harvard Medical Center.

While encouraging, the results only apply to patients with non-proliferative forms of diabetic retinopathy. The proliferative form – an advanced stage of the disease characterised by the re-growth of blood vessels in the back of the eye that can rupture with severe sight-damaging consequences – can only be treated using laser surgery.

Ruboxistaurin limits protein kinase C beta (PKC beta) over-activation, and it is the first of a new class of compounds being investigated for the treatment of diabetic retinopathy, according to Lilly.

The drug was once tipped as a blockbuster medication for Lilly, but had had its sales forecasts scaled down after failing to demonstrate efficacy in peripheral neuropathy, another common complication of diabetes.