Ovarian cancer remains unresponsive to immune checkpoint inhibitors due to its ability to suppress cytotoxicity from immune cells that are infiltrating the tumor, where the O-glycosylation pathway may be disrupted. Precision Biologics Inc. is developing PB-vcMMAE-5, an antibody-drug conjugate composed of the monoclonal antibody PB-223, which targets tumor-specific truncated core-2 O-glycans, conjugated to microtubule inhibitor MMAE and with a drug-to-antibody ratio of 3.92.