BUZZ-Medivation: Cancer therapy not as safe as AstraZeneca's
** Drug developer's shares down 2 pct at $108.97 premarket
** Says its prostate cancer therapy Xtandi was not as safe as AstraZeneca Plc (NYSE: AZN - news) 's treatment Casodex in a mid-stage study
** Says 31 pct patients given Xtandi had serious adverse reactions compared with 23.3 pct patients who were given Casodex
** Says Xtandi increased the time patients survived without progression of the disease to 15.7 months, compared to 5.8 months among Casodex patients
** Up to Wednesday's close, the stock more than doubled since Xtandi was approved on Aug. 31 2012