ATOR-1015 is a bispecific immune activating antibody, developed for tumor-directed immunotherapy

The drug candidate binds to two different immunomodulating target proteins: the inhibitory checkpoint receptor CTLA-4, and the co-stimulatory receptor OX40. The OX40 binding part originates from ALLIGATOR-GOLD®, and the CTLA-4 binding part was generated by FIND® optimization of CD86, which is a natural binder to CTLA-4.

ATOR-1015 is a bispecific immunostimulating antibody simultaneously binding two different target molecules, CTLA-4 and OX40. Both targets are overexpressed by regulatory T-cells in the tumor environment. ATOR-1015 reduces the number of regulatory T-cells and activates effector T-cells, resulting in an immune-mediated anti-tumor effect. ATOR-1015 has also been shown to mediate interactions between CTLA-4 and OX40 expressing cells, which may further improve the anti-tumor effect.


ATOR-1015 is capable of binding individual T-cells simultaneously, thereby bringing those cells in close proximity, which may support the immune activating effect. It reduces the number of regulatory T-cells and activates effector T-cells. A strong immune activation is expected to be achieved primarily in environments where both target molecules are expressed at high levels, such as inside a tumor. Taken together, this results in an effective immune activation as well as localization of the effect to the tumor environment, the latter being expected to minimize immune-related side effects. The objective of ATOR-1015 is to be the first CTLA-4 and OX40-binding bispecific antibody to achieve a strong anti-tumor effect, either as a monotherapy or in combination with currently established immunotherapies such as PD-1 and PD-L1 blockers. ATOR-1015 is expected to be suitable for treating a large number of different forms of cancer.