AbbVie Inc. (NYSE: ABBV) announced today that it has agreed to acquire ImmunoGen, Inc. (NASDAQ: IMGN), a biotechnology company focused on developing antibody-drug conjugates (ADCs) for the treatment of cancer. The deal values ImmunoGen at $31.26 per share in cash, or about $10.1 billion in total. The acquisition will give AbbVie access to ImmunoGen’s flagship…