In by far the largest deal to date in the immuno-oncology sector in terms of upfront consideration, Bristol-Myers Squibb (BMS) has agreed to acquire start-up Flexus Biosciences for US$800 M plus up to US$450 M in development milestones that could be achieved within 3 years. The deal adds a preclinical-stage IDO1 (indoleamine 2,3-dioxygenase 1)inhibitor programme to BMS’ burgeoning cancer immunotherapy pipeline. On the same day, the company also announced a collaboration with Rigel Pharmaceuticals that is focused on another immunotherapeutic approach, namely TGF beta inhibition.