Coley's toxins

Coley's toxins (also called Coley's toxin, Coley's vaccine, Coley vaccine, Coley's fluid or mixed bacterial vaccine) is a mixture containing toxins filtered from killed bacteria of species Streptococcus pyogenes and Serratia marcescens, named after William Coley, a surgical oncologist at the Hospital for Special Surgery who developed the mixture in the late 19th century as a treatment for cancer. Their use in the late nineteenth and early 20th centuries represented a precursor to modern cancer immunotherapy, although at that time their mechanism of action was not completely understood.

While there are many case studies of patients with severe cancer recovering after severe bacterial infection, including a long series of case studies of patients with inoperable sarcomas published by Coley himself, such infections carried risks of harming the patient, for which reason they were only offered to patients with advanced disease and poor prognosis. The formulation of the toxins and techniques used varied from patient to patient, leading to a lack of statistical evidence about their efficacy. Modern treatments that say they use Coley's toxins rely on a different formulation than the one Coley originally used.