DPP-IV inhibitors

GLP-1 in the body is broken down by an enzyme called DPP IV. Logically, you can either make a synthetic GLP-1 that is not broken down by this enzyme (for example, Byetta) OR you could try to stop the enzyme that breaks down the GLP-1 your body already makes. Hence, the new class of drugs called DPP IV inhibitors. They do just that, that is, they inhibit this enzyme from breaking down GLP-1. This allows GLP-1 already in the blood to circulate longer. There are a number of companies working on this class of drug and the FDA just approved the first drug in this class made by Merck and called Januvia. Januvia can be used in combination with certain other medications and must be dose adjusted in patients with poor kidney function. For more, please read the Januvia pamplet.
These drugs have essentially the same side effect profile as Byetta; however, they are in pill form. While Byetta has a significant weight loss profile, DPP-IV inhibitors so far have had no effect on weight.