Sitagliptin ~(and vidagliptin) work in a way similar to Byetta. These drugs do not have the same weight loss associated with Byetta. They are taken once a day as an oral tablet.
Sitagliptin on its own is as effective as sulphonureas or metformin. But taken together it seems to be even more effective.
As I am on insulin I do no fit the SMC/NICE guidlines. But today I seem to brought my diabetologist a step closer to prescribing it (I want it as an insulin sparer). My HBA1c is 6.0% last week but I am on 160-170 units of insulin per day. There is little data on use with type 2s taking insulin.
sitagliptin is cheaper than byetta, and although may not have every benefit of byetta, it does not have all the drawbacks( injections, keeping it cool, reflux, nausea).