BTN1A1 is an immune checkpoint protein that disrupts the normal immune activity of T cells in the human body. While it is not expressed or is expressed only at extremely limited levels in normal cells, it is strongly expressed in cancer cells. Therefore, treatment targeting BTN1A1 exhibits minimal toxicity, effectively suppressing cancer cells while minimizing side effects on normal cells.

We are developing an immune checkpoint inhibitor known as ‘Nelmastobart’, an anti-BTN1A1-antibody that activates the immune function of suppressed T cells. Through various preclinical and human clinical studies, we have consistently observed that Nelmastobart is safe and effective.

BTN1A1 is expressed in mutually exclusive manner to PD-L1, the most prominent anti-cancer target for existing immune checkpoint inhibitors. The two proteins show different expression patterns in terms of location and timing within tumor tissues. Notably, high expression of BTN1A1 is observed in most solid tumors where the expression of PD-L1 is low, which is a key research finding confirmed through our preclinical studies.

This characteristic suggests that the BTN1A1-targeted therapy could be an exciting new treatment option to address the unmet needs of patients who are resistant to PD-(L)1-targeted immune checkpoint inhibitors.