Bristol-Myers Squibb is to acquire privately-held Flexus Biosciences in a deal worth up to $1.25 billion.

That includes an $800 million upfront payment which will give B-MS full rights to Flexus’ IDO/TDO discovery programmes, including F001287, a preclinical “potentially best-in-class IDO1 inhibitor”. IDO/TDO inhibitors reduce kynurenine production enabling the immune system to attack tumours more effectively, B-MS noted, and “strong scientific rationale supports exploring combination regimens with immunotherapies where synergistic activity may enhance long-term survival benefits”.

Francis Cuss, chief scientific officer, said B-MS is “committed to leading scientific advances in immuno-oncology and our acquisition of Flexus will expand our innovative pipeline with an important approach to enhancing immune responses in cancer”. The Flexus assets will help the firm “explore numerous immunotherapeutic approaches across tumor types, including combinations with our biologic checkpoint and co-stimulatory agents that target different and complementary pathways”, he added.

Rigel deal

B-MS also unveiled a pact with Rigel Pharmaceuticals using the latter’s TGF beta receptor kinase inhibitors to develop “a new class of therapeutics aimed at increasing the immune system’s activity against various cancers” either as monotherapy or in combination with checkpoint inhibitors, including B-MS’ Opdivo (nivolumab) and Yervoy (ipilimumab).

B-MS will pay Rigel $30 million upfront and development and regulatory milestones that could total more than $309 million, plus tiered milestones.