William Coley

Coley's toxins were a mixture of killed bacteria, primarily Streptococcus pyogenes and Serratia marcescens, developed by William Coley to treat bone cancer. He created this early form of immunotherapy in the late 19th century after observing tumor regressions in patients who developed severe infections like erysipelas.

He was the first physician to deliberately use the immune system to attack cancer cells by injecting bacterial toxins directly into inoperable tumors. Although his methods were controversial and largely abandoned after his death in 1936, his foundational theories paved the way for modern immunotherapy treatments like CAR-T cell therapy and checkpoint inhibitors.

Coley spent the majority of his career as a bone surgeon and oncologist at Memorial Hospital in New York City. That institution eventually became Memorial Sloan Kettering Cancer Center, which is now one of the world's leading cancer research and treatment facilities.

While Coley documented hundreds of cases where patients experienced complete or partial tumor regression, his medical records lacked the rigorous control groups required by modern scientific standards. Today, researchers recognize that his toxins successfully stimulated an immune response that shrank tumors in some patients, though the results were highly unpredictable.