The move comes as GSK faces pressure to replenish its pipeline, with some of its top-selling drugs nearing the end of their exclusivity periods.

Under the agreement, GSK will acquire BP Asset IX, a subsidiary of Boston Pharmaceuticals, for up to $2 billion in total cash consideration, including $1.2 billion upfront and up to $800 million in milestone payments.

With its purchase of Boston Pharmaceuticals' drug, GSK extends a streak of dealmaking it's undertaken to build a liver disease franchise.