FP59

FP59 is a **fusion protein** drug used in experimental cancer therapy research. It is a genetically engineered **chimeric protein** combining domains from the **Bacillus anthracis lethal factor** and **Pseudomonas exotoxin A**. FP59 acts as the cytotoxic payload within modified anthrax toxin systems, designed to selectively kill tumor cells by exploiting aberrant protease activity in the tumor microenvironment. When paired with engineered variants of anthrax protective antigen (PrAg), which are selectively activated by tumor cell-surface proteases (such as testisin or urokinase-type plasminogen activator), FP59 is delivered into tumor cells. Once internalized, it disrupts cell signaling and induces cell death by targeting key cellular processes, leveraging the enzymatic activity of its exotoxin A domain[4]. This selectivity is engineered to reduce toxicity in non-tumor tissues. FP59 has shown efficacy in preclinical models against various cancers, including non-small cell lung cancer, and has been used as the payload in several protease-activated prodrug systems under investigation for targeted anti-tumor therapy[4].

Other names

FP59FP-59FP 59