GSK to buy Sierra Oncology for $1.9 billion

- Britain's GlaxoSmithKline has agreed to buy California-based biopharmaceutical company Sierra Oncology in a deal valued at $1.9 billion, the companies said on Wednesday.

Shareholders in Sierra, which focuses on targeted therapies for the treatment of rare forms of cancer, will receive $55 per share of common stock in cash, GSK said.