Is exenatide (Byetta) so much more effective than sitagliptin (Januvia) that exenatide is worth the discomfort of subcutaneous injections?
—Kashif Memon, MD, Vernal, Utah
Clinical trials conducted by Amylin Pharmaceuticals, Inc., and Eli Lilly and Company showed that Byetta provided a mean 2.1% reduction in hemoglobin A1c (HbA1c) in poorly controlled patients (HbA1c >9.0%) over the course of 2.5 years, and a 0.7% mean reduction in HbA1c in patients whose initial level was <9.0 (www.byettahcp.com /hcp/hcp210_a1c_reductions.jsp. Accessed June 11, 2008). In contrast, Merck conducted 18- and 24-week trials on the efficacy of Januvia as measured by HbA1c reduction. Their pooled data show a mean HbA1c reduction of 1.4% in patients with an initial HbA1c >9.0 and an approximately 0.7% HbA1c reduction in patients with less severe diabetes (www.januvia.com/sitagliptin/januvia/hcp/efficacy/. Accessed June 11, 2008). Since Januvia is dosed only once daily (Byetta is dosed twice a day), does not require refrigeration or injection, and is less expensive, I hypothesize that many patients and providers may exhibit a preference for this medication, particularly when smaller reductions in HbA1c are required.
—Daniel G. Tobin, MD (117-2)