Why isn't Victoza supposed to be used as a first nedication?

I was just diagnosed with type 2 on Tuesday and my doctor suggested Victoza. As I read through the info in my box of Victoza and read websites about Victoza it basically said that it is not supposed to be used first. Anyone have an idea why?

I’m guessing because it hasn’t been out long enough for studies of long term (20+ years) side effects? Or maybe because of it’s cost? All I know is, two year into my diagnosis and, thanks to Victoza, my numbers are under control. I just pray that this control outweighs any long term side effects.