GlaxoSmithKline and Stiefel Laboratories, Inc. have signed an agreement to create a new specialist dermatology business. Under the terms of the agreement, GSK will acquire Stiefel for $2.9 billion in cash with a potential further $0.3 billion cash payment based on future performance. GSK’s existing prescription dermatological products will be combined with Stiefel’s and the new business will operate under the Stiefel identity within the GSK Group. Andrew Witty, chief executive off...