Saxagliptin (Onglyza) for DM2 - Not first line.

The Buzz: Saxagliptin is not as efficacious or cost-effective as metformin
Citation: "STEPS: New Drug Reviews" AFP June 15, 2010 81:12 1483-84
Summary: Saxaglipatin (Onglyza) is an oral dipeptidyl peptidase-4 inhibitor that works by slowing degradation of incretin hormones in the gut. Incretins contribute to post-meal insulin secretion, inhibit glucagon release, improve satiety and slow gastric emptying. Few side effects have been reported with saxagliptin and it does not seem to increase the risk of hypoglycemia or cause weight gain. On average, monotherapy with saxagliptin lowers A1C levels by 0.4-0.9 % and adding it to metformin or glyburide will lower A1C levels by an additional 0.6-0.9%. Of note, efficacy trials with saxagliptin were no longer than 6 months and long-term safety and effectiveness studies are currently ongoing. Morbidity and mortality effects are still unknown. No studies have evaluated the effects of combining saxagliptin with insulin. 
Commentary: At $200/month (vs $32/month for metformin), saxagliptin use should be limited to patients who are intolerant or refractory to other treatments.  
By: Spencer Blackman MD