Dual treatment with the glucose-lowering drugs dapagliflozin and exenatide remains effective for patients with diabetes after two years of continual use, according to the results of a late-stage clinical trial. 

When used together, dapagliflozin (Farxiga) and exenatide (Byetta, Bydureon and others) originally were found to control diabetes progression better than either drug alone. But diabetes drugs are known for having short-lived efficacy.

Over time, type 2 diabetes in many patients no longer will respond to the first-line treatment metformin, for example. That’s why the results of the current study are encouraging, said senior author Serge Jabbour, M.D., of Thomas Jefferson University.

He and his colleagues assigned about 700 adults whose type 2 diabetes was not controlled with metformin to three study groups. Participants received either weekly exenatide injections in addition to metformin; daily dapagliflozin pills in addition to metformin; or exenatide and dapagliflozin together.

Participants who received both study drugs had better glycemic control than those who received just one. And the study for the first time demonstrated that this effect remained stable for the entire two-year study period.

“These two classes work synergistically to help control a type 2 diabetes patient’s glucose levels, and other measures associated with diabetes,” Jabbour said. “We can now feel more confident about prescribing these medications long term.”

The study was published in the journal Diabetes Care.