In the last decades of the 20th century, the progress being made in the field of cancer research began to stagnate. While many forms of cancer had experienced dramatic reductions in overall mortality throughout the middle years of the twentieth century, towards the end of the 1980s, that lightning-quick pace of development had began to slacken noticeably. The industry needed some shaking up. As it happened, a few researchers were up to the task.
One of those researchers was a man by the name of Clay Siegall. Armed with a an MS from the University of Maryland in biology and a PhD in genetics from George Washington University, Clay Siegall was hired out of graduate school by the world-renowned cancer research organization, the National Cancer Institute. During his stint at the National Cancer Institute, Dr. Siegall began working on an entirely new class of drugs, called targeted cancer therapies. These were a category of drugs that contained a wide array of agents, using disparate principles in order to target the site of the malignancy directly.
One category of targeted cancer therapy drugs can be described as cytostatic. These are drugs that, simply put, seek to limit any further growth of the tumor or malignancy. They do this through a wide variety of means, but all of them have in common the complete interference with the mechanisms by which the cancer cells multiply. At the time, the majority of targeted cancer therapies were of the cytostatic variety. These were considered the easiest to engineer and had the most robust body of knowledge to which current researchers could refer.
However, there was a second type of targeted cancer therapies, much less well understood and hardly researched at all, up to that point. These drugs can be termed cytotoxic. The goal behind cytotoxic drugs is to completely kill all malignant cells in the organism. Dr. Siegall decided to focus on this area, which had been largely neglected.
Eventually, this work would lead Dr. Siegall to invent a new class of cytotoxic targeted therapy drugs, known as antibody drug conjugates. Today, antibody drug conjugates are employed as first-line treatment and save thousands of lives.