suptavumab suptavumab suptavumab (inn; development code (regn2222) is a humanized monoclonal antibody designed for the prevention of medically attended lower respiratory tract disease due to respiratory syncytial virus. suptavumabmonoclonal antibodytype?sourcehumantargetrespiratory syncytial virus fusion proteinclinical dataother namesregn2222atc codenoneidentifierscas number1629615-23-1chemspidernoneuniia0ze931055keggd10991chemical and physical dataformulac6502h10038n1726o2020s42molar mass146054.41 g·mol−1 this experimental drug candidate was being developed by regeneron pharmaceuticals inc until it was discontinued after unsuccessful phase iii clinical trials.