Dipeptidyl peptidase-4 inhibitors and cardiovascular and renal disease in type 2 diabetes: What have we learned from the CARMELINA trial?

Dipeptidyl peptidase-4 inhibitors are a relatively new class of oral anti-hyperglycaemic drugs to treat type 2 diabetes through prevention of degradation of incretins by the dipeptidyl peptidase-4 enzyme. The large trials evaluating the dipeptidyl peptidase-4 inhibitors sitagliptin, alogliptin and saxagliptin demonstrated safety for cardiovascular disease. Post hoc analyses on renal endpoints yielded similar findings. Linagliptin is the latest dipeptidyl peptidase-4 inhibitor evaluated in the CARMELINA trial. CARMELINA included individuals with type 2 diabetes and high cardiovascular and renal risk. Even in this setting, linagliptin displayed cardiovascular safety. CARMELINA also removed initial concerns for heart failure as a class-specific side-effect of dipeptidyl peptidase-4 inhibitors, as no signal for heart failure was found. Although numerically low, CARMELINA did confirm increased rates of pancreatitis in the linagliptin group, suggesting that pancreatitis is a class-specific side-effect of dipeptidyl peptidase-4 inhibitors. Linagliptin reduced progression of albuminuria, but had no effect on other hard renal endpoints. Overall, dipeptidyl peptidase-4 inhibitors are safe but do not confer significant reductions in complications observed for some of the other new glucose-lowering drugs. However, linagliptin is a safe alternative in renal impairment, without dose adjustment. Furthermore, dipeptidyl peptidase-4 inhibitors may hold value as alternatives to sulfonyl-urea derivatives or as an add-on therapy to delay insulin prescription given their favourable safety profile.