A common rheumatoid arthritis drug may be an effective new therapy for lowering blood glucose levels in patients with type-2 diabetes, according to a study.

Rheumatoid arthritis, affecting approximately one per cent of the worldwide population, is a chronic autoimmune condition that causes pain and swelling in the joints. The anti-inflammatory drug, lefluonamide, lowered blood glucose levels and reversed insulin resistance in mouse models of Type 2 diabetes, which suggests that this therapy could be repurposed as an effective antidiabetic treatment, particularly suitable for patients with both diabetes and rheumatoid arthritis.

"We found that lefluonomide targets a protein involved in desensitising the insulin receptor, which is responsible for instructing the cells to start absorbing sugar from the bloodstream", said Xiulong Xu, Professor at the Institute of Comparative Medicine at Yangzhou University in China. Lefluonamide has long been approved to treat rheumatoid arthritis and previous clinical studies have noted that patients taking the drug tended to have lower blood glucose levels and that obese patients lost weight.

However, lefluonomide also acts on other molecular targets in the body. This suggests that more studies are needed to confirm that the anti-diabetic effects observed are solely caused by lefluonamide's effect on the insulin receptor. "We know some inflammatory factors can also desensitise the insulin receptor, and lefluonamide is an anti-inflammatory, so it may be that it controls blood sugar partly by its anti-inflammatory effect," Xu said, in a paper published in the Journal of Endocrinology. The next step for Xu is to conduct clinical trials to test if the antidiabetic effect of lefluonamide also occurs in humans as well as mice.