Abstract

"I'm not at all surprised at the time it's taken for monoclonal antibodies to move forward," says Patrick Scannon, president of Xoma Corp., a San Francisco-based biotechnology company that specializes in monoclonal antibody--or MAb--therapeutics. "I was always incredulous about the so-called magic bullet claims." The bold claims to which Scannon refers began springing up in 1975, the same year that the monoclonal antibody was first developed. Essentially bioengineered forms of antibodies--the natural proteins in animals and humans made by immune cells to fight against infection--MAbs were hailed by immunologists and biotech entrepreneurs as a great new component in the medical armamentarium because of their ability to find specific pathological targets in the body. MAbs could act therapeutically, said experts at the time, when linked to toxins to form immunotoxins--antibodies chemically joined to poisons--that would then search out and destroy disease-causing cells in the body. MAbs themselves, without toxins, could also bind to certain disease-causing cells in the body and prevent their pathology; or, it was pointed out, MAbs could soak up poisons from bacterial infections that may be present in a patient. What's more, it was argued, the precision with which MAbs could be targeted allowed them to