Allergan (AGN) has announced the acquisition of Vitae Pharmaceuticals (VTAE) in an all cash transaction worth $639 million. The deal values Vitae Pharmaceuticals at $21 per share, which represents a premium of more than 150% over Vitae Pharma's closing price on Tuesday. The transaction will strengthen Allergan's dermatology pipeline with the addition of VTP-43742, a retinoic acid receptor-related orphan receptor gamma inhibitor for the treatment of psoriasis and other autoimmune disorders and VTP-38543.