Dapagliflozin Added to Sitagliptin Reduces HbA1c

Philadelphia—After 48 weeks of treatment, patients with type 2 diabetes who took dapagliflozin had significant reductions in hemoglobin A1c l (HbA1c) compared with placebo as an add-on therapy to sitagliptin, according to a phase 3, multicenter, randomized, double-blind, placebo-controlled study.

Results were presented at the ADA meeting in a poster titled Dapagliflozin Is Effective as Add-On Therapy to Sitagliptin With or Without Metformin: A Randomized, Double-Blind, Placebo-Controlled Study.

Dapagliflozin is an oral selective sodium-glucose cotransporter 2 inhibitor. In January, the FDA told the drug’s manufacturers (Bristol-Myers Squibb and AstraZeneca) that it needed more data before making a decision on its approval. Last July, an FDA advisory committee recommended that the drug not be approved, citing potential risks of breast and bladder cancer.

In this study, 447 adults were randomized in a 1:1 ratio to receive 10 mg per day of dapagliflozin (n=223) or placebo (n=224) plus 100 mg per day of sitagliptin with or without metformin. The patients all had type 2 diabetes and were inadequately controlled by sitagliptin or sitagliptin plus placebo. They also had HbA1c between 7.0% and 10.0%. The study included a 24-week treatment period followed by a 24-week extension.

At 24 weeks, patients in the dapagliflozin plus sitagliptin with or without metformin group had a 0.48% decrease in HbA1c from baseline compared with patients who took placebo plus sitagliptin with or without metformin (P<.0001). There was a greater effect in dapagliflozin added to sitagliptin compared to placebo added to sitagliptin (HbA1c reduction of 0.56%; P<.0001). However, there was still a significant decrease of 0.40% when dapagliflozin was added to sitagliptin and metformin compared with placebo plus sitagliptin plus metformin (P<.0001).

The authors noted the results remained consistent during the 24-week extension period.

After 48 weeks, 66.2% of patients taking dapagliflozin and 61.1% of patients taking placebo had ≥1 adverse event (AE). The rates for ≥1 serious AE were also similar: 6.7% versus 8.0%, respectively. Hypoglycemia was found in 5.3% of dapagliflozin patients and 6.2% of placebo patients.

—Tim Casey