Don't bring out the champagne bottles yet. Bloomberg is reporting that Amgen is having second thoughts about that $130 a share offer it reportedly made to Onyx ($ONXX) recently. Quoting sources, the business news service says that Amgen ($AMGN) is now pushing for a lower price after Onyx refused to hand over data from an ongoing study of the blood-cancer drug Kyprolis needed for European approval--countering an piece from Reuters Wednesday evening claiming that the issue had been defused. Meanwhile, at least one other potential bidder--AstraZeneca ($AZN)--is doing due diligence, though no other company has made an offer following Amgen's public $120 per share bid. At this point it's hard to say exactly what's happening behind the scenes related to the trial data, though clearly Onyx is still in play. Onyx obtained early FDA approval for Kyprolis based on mid-stage data from a single-arm study and needs positive pivotal data to expand and secure its market. Handing over data from a blinded, ongoing study is no simple matter, though. Story