The gold rush for obesity medications just got a bit more intense.With some promising clinical trial results in hand and more that could be on the way relatively soon, Amgen's (AMGN -0.21%) latest attempt to develop a therapy for obesity is looking like it could be a contender for the crown that's currently jointly held by the likes of Eli Lilly (LLY -0.13%) and Novo Nordisk (NVO 0.35%). Though it won't be competing with those two heavyweights directly until it finishes the clinical trials process, which co ...