The Diabetes Therapy Utilization : Researching Changes in A1C , Weight and Other Factors Through Intervention with Exenatide Once Weekly ( DURATION-1 ) randomized clinical trial consisted of a 30-week controlled phase ( 2 mg of exenatide once weekly vs 10 g of exenatide twice daily ) with an open-ended uncontrolled extension ( once weekly exenatide only ) in patients with type 2 diabetes mellitus on background glucose-lowering therapies ( April 15 , 2006 , through February 21 , 2012 ) .