A class of drugs is emerging that can attack cancer cells in the body without damaging surrounding healthy ones. They have the potential to replace chemotherapy and its disruptive side effects, reshaping the future of cancer care. 

The concept behind ADCs was envisioned in 1900 by German Nobel laureate Paul Ehrlich, who formed the idea of a “magic bullet” in which a single toxic molecule would be delivered to attack a diseased cell without damaging surrounding healthy cells. 

ADCs are complex molecules composed of an antibody linked to a biologically active cytotoxic (anticancer) payload or drug. Antibody-drug conjugates are examples of bioconjugates and immunoconjugates.

ADCs combine the targeting capabilities of monoclonal antibodies with the cancer-killing ability of cytotoxic drugs.The antibodies target the antigens on the specific cell and deliver the anti cancer drug specifically to it. They can be designed to discriminate between healthy and diseased tissue.

The complex biological medicines, called antibody drug conjugates (ADCs), have been in development for decades, and are now generating renewed excitement because of the success of one ADC in late-stage testing, a breast cancer treatment called DS-8201. 

DS-8201, which will be filed for U.S. approval by the end of September, is so well-regarded that some analysts already predict it will surpass the $7 billion in annual sales for Roche Holding AG’s breast cancer drug Herceptin, which it aims to replace. 

Drugs like Herceptin only target high levels of HER2, and women with lower levels must rely on hormone therapy or chemotherapy. That’s where DS-8201 has the potential to serve far more patients, treating those with both higher and lower levels of HER2.