Street talk about Big Pharma bidders for Onyx Pharmaceuticals ($ONXX) puts Pfizer ($PFE) and Bristol-Myers Squibb ($BMY) in the hunt, with biotech giant Amgen ($AMGN) still leading the charge. Novartis ($NVS), Sanofi ($SNY), GlaxoSmithKline ($GSK) and Biogen Idec ($BIIB) are said to have bowed out. Report