In May 2021, Calithera and Antengene announced a worldwide license agreement for the development and commercialization of CB-708, Calithera’s oral small-molecule CD-73 inhibitor being developed for oncology indications. CB-708 was well tolerated in preclinical studies. It demonstrated immune-mediated, single-agent activity in syngenic mouse tumor models, as well as enhanced anti-tumor activity when combined with either an anti-PD-L1 or chemotherapy.