In the middle part of the twentieth century, the advent of three types of cancer treatment dramatically increased the survivability of that disease. These treatments were radiation therapy, chemotherapy and innovations in surgical excision techniques. Combined, these three novel treatment modalities enabled tens of thousands of people to go on to live highly productive and healthy lives, who otherwise would have been certainly consigned to death by the ravages of cancer.

However, for all of the progress that these new forms of treatment brought, they also came with extreme costs. In many cases, the side effects of these treatments were horrific. Even though the net benefit was indisputable and enormous, still, many patients who underwent chemotherapy often ended up with permanent disabilities, such as neuropathy, dementia – also known as chemo brain – and other neurological and cardiovascular deficits, such as heart failure. Even worse, in many cases, patients were outright killed by the administration of these highly lethal agents, which rely on their own cytotoxicity to destroy the cancer cells.

The main biological problem with these drugs is that they had no means of differentiating between cancer cells and healthy cells that the treatment regimen sought to preserve. Therefore, using crude methods, such as the targeting of all fast-reproducing cell types, those patients undergoing chemotherapy often endured the side effects associated with the destruction of all of the body’s fast-reproducing cells. This is why so many patients undergoing chemotherapy have famously lost all of their hair, have run into liver dysfunction and had other digestive problems. All of these body systems are predicated upon fast-dividing cell types.

One man, Clay Siegall, had a novel solution to this terrible problem of unintended side effects caused by chemotherapy. He devised a new class of drugs, called antibody drug conjugates, which are able to directly target the site of the malignancy, leading to no systemic release of the highly lethal cytotoxic agents that are designed to kill the cancer cells.

Today, antibody drug conjugates are used as first-line treatments in thousands of cases of cancer per year.