Bristol-Myers Squibb said it would buy drugmaker Flexus Biosciences for up to $1.25 billion to add an emerging class of cancer-fighting drugs to its pipeline. The deal includes $800 million in an up front payment and up to $450 million in milestone payments.

Bristol-Myers also signed a deal with Rigel Pharmaceuticals to develop a line of cancer therapies that can be used with Bristol-Myers's immunotherapy cancer drugs. Bristol-Myers will pay Rigel $339 million, bringing its investment in cancer treatments on Monday to $1.59 billion.

Buying Flexus will give Bristol-Myers rights to an experimental cancer compound belonging to a class of drugs called IDO1-inhibitors, which work by disrupting mechanisms through which cancer cells hide from the body’s immune cells. – (Reuters)