Pfizer has entered into an agreement to acquire Serenex, Inc., a privately-held biotechnology company with a Phase I clinical candidate and an extensive compound library that targets Heat Shock Protein 90 (Hsp90), an anti-cancer target.     Under the agreement, Pfizer will acquire the rights to SNX-5422, an oral Hsp90 inhibitor currently in Phase I trials for the potential treatment of solid tumors and hematological malignancies. Pfizer will also acquire Serenex’s drug discovery technology an...