ATOR-1017 is an agonistic IgG4 antibody that activates the co-stimulatory receptor 4-1BB (CD137, TNFRSF9). It was developed from Alligator´s human antibody library, ALLIGATOR-GOLD®. In the development of ATOR-1017, Alligator has used their extensive expertise in the TNF receptor superfamily to develop a compound with a clear differentiation compared to other 4-1BB antibodies in development. Thus, ATOR-1017 has a unique target binding profile compared to the two 4-1BB antibodies currently in clinical development. In addition, its agonistic function is dependent on cross-linking by Fcγ receptors expressed by immune cells. The properties of the antibody directs the immune activation to the tumor area where 4-1BB as well as Fcγ receptors are highly expressed, resulting in a favorable safety-efficacy profile. ATOR-1017 therefore has the potential to be a best-in-class 4-1BB antibody in terms of risk-benefit profile.