A Randomized, Double-Blind, Multi-Center Phase 2 Trial of Exemestane (Aromasin®) plus Dasatinib versus Exemestane plus Placebo in Advanced Estrogen Receptor-Positive Breast Cancer after Disease Progression on a Non-steroidal Aromatase Inhibitor (NSAI). + Administrative Letter 1 dated 18-Aug-2008; Revised Protocol 02 incorporating Administrative Letter 02 (dated 30-Nov-2009) and Protocol Amendment 02 (dated 06-Apr-2010)