ATOR-1015 (previously designated ADC-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 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.
Based on the promising results from concept validation and initial preclinical studies, cell line development, aimed at subsequent large-scale production for clinical trials, was initiated in January 2016. The program is currently in the second phase of production, process development, and is planned to be ready for clinical trials in early 2018.
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.