The randomised Phase III trial included 546 adults who had glycated haemoglobin (HbA1c) levels of 7-10% despite receiving at least 1500mg metformin daily. Participants were given-in addition to their metformin dose-once-daily tablets containing 2.5mg, 5mg or 10mg of dapagliflozin, or placebo.
The results, presented at the annual meeting of the European Association for the Study of Diabetes (EASD) in Vienna, showed that dapagliflozin significantly reduced both HbA1c and blood glucose levels.
At the lowest dose of 2.5mg, dapagliflozin reduced HbA1c and fasting blood glucose by a mean of 0.67% and 17.8mg/dl (1.0mmol/l), respectively, over 24 weeks. The corresponding reductions for placebo were 0.3% and 6.0mg/dl (0.3mmol/l).
Furthermore, patients on dapagliflozin lost around 3% (approximately 2.5kg) of their body weight.
However, genital infections occurred at higher rates in the dapagliflozin groups, affecting 8.0% of people who received the 2.5mg dose compared with 5.1% of placebo-treated patients. This effect could be linked to an increased flow of glucose through the kidneys.
"Doctors will be very excited about this [drug], one because it's a tablet and also because of its association with weight loss," said Marc Evans, an endocrinologist at the University of Wales, based at Llandough hospital in Cardiff. "The infection rates, along with other potential side effects, are the questions everyone will be looking at."
The trial data were followed by the release of figures showing that the number of people diagnosed with diabetes in the UK has increased by more than 145,000 in the last year. The condition now affects one in twenty people.
AstraZeneca and BMS could file for approval of dapagliflozin in late 2010 or early 2011.
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