Pfizer Inc. has entered into a definitive merger agreement to acquire Seagen Inc., a global biotechnology company developing and commercializing cancer medicines, for a total value of $43 billion. The Boards of Directors of both companies have unanimously approved the transaction.   Seagen expects to generate approximately $2.2 billion of revenue in 2023, representing 12% year-over-year growth, from its four in-line medicines, royalties and collaboration and license agreements. Pfizer anticipa...