ATOR-1015 is a bispecific antibody targeting CTLA-4 and OX40 designed to direct the effect to the tumor microenvironment and thereby improve the response rate and reduce TRAEs.<h4>Materials and methods</h4>We conducted a phase I, first-in-human, multicenter study to determine the safety and tolerability of intravenously administered ATOR-1015 every second week. Here, CTLA4 is linked to neoplasm.