Bristol-Myers agreed to buy Genetic Systems.

The drug and cosmetic giant said it will exchange stock worth as much as $294 million to purchase the outstanding shares of the Seattle-based biotechnology company. The proposal, one of the latest in a series of takeovers of biotech firms by established drug companies, leaves uncertain a recent agreement between Genetic Systems and Syntex, calling for the Palo Alto-based drug maker to pump $60 million into Genetic Systems.