Fig. 3
From: Immune checkpoint inhibitors for multiple myeloma immunotherapy
Covering immune checkpoint with monoclonal antibodies. ICIs aim to block co-inhibitory pathway. The main targeted immune pathways include the PD-1/PD-L1, CTLA-4/B7, and CD47/SIRP-a signal pathways. From 2011 to date, there have been seven FDA-approved and marketed ICIs that can be used in clinical treatment, including one CTLA-4 mAb (ipilimumab), three PD-1 mAbs (nivolumab, pembrolizumab, and cemiplimab), and three PD-L1 mAbs (atezolizumab, avelumab, and durvalumab)