Therapeutic potential of targeting LAG-3 in cancer

Immune checkpoint inhibitors targeting negative regulatory checkpoints including programmed death-1 (PD-1) and cytotoxic T-lymphocyte-associated protein 4 have produced significant improvements in progression-free survival (PFS) and overall survival in multiple solid tumors. Lymphocyte activation gene 3 (LAG-3) is an inhibitory receptor that is highly expressed by exhausted T cells. Dual blockade of LAG-3 and PD-1 with monoclonal antibodies relatlimab and nivolumab has improved PFS in advanced melanoma, leading to Food and Drug Administration approval for this indication. Concurrently, enthusiasm for targeting LAG-3 has been tempered by negative results in multiple indications, although novel approaches including LAG-3-directed bispecifics tebotelimab continue to demonstrate promise. In this review, we discuss the current understanding of LAG-3 in regulating antitumor immunity and the ongoing state of clinical development of LAG-3-directed agents in cancer.