Bristol-Myers Squibb will acquire Kosan Biosciences, a cancer therapeutics company, for approximately $190 million in cash. The acquisition adds two classes of anticancer agents to BMS’s pipeline, novel Hsp90 (heat shock protein 90) inhibitors and epothilones.     “Helping patients prevail against serious disease is paramount at Bristol-Myers Squibb,” said Jim Cornelius, BMS’ chairman and chief executive officer. “We pursue innovative science, both internally and externally, that ...