Novel Toxic Compound May Treat Prostate Cancer

Because PRX302 is activated by prostate-specific antigen, it spares neighboring tissue

FRIDAY, March 9 (HealthDay News) -- PRX302, a toxin activated by prostate-specific antigen, may be a safe and effective treatment for prostate cancer and other prostate conditions, according to the results of a study in animals published in the March 7 issue of the Journal of the National Cancer Institute.

Simon Williams, Ph.D., of The Johns Hopkins University School of Medicine in Baltimore, and colleagues modified proaerolysin, the inactive precursor of a bacterial cytolytic pore-forming protein, to produce PRX302, and tested its efficacy in a mouse model of prostate cancer and its safety in cynomolgus monkeys.

The researchers found that PRX302 caused shrinkage of the mouse tumors. They also found that PRX302 caused extensive but organ-confined damage in the monkeys without affecting neighboring organs.

Therapies for local recurrences include "salvage prostatectomy and cryosurgery, techniques that are associated with substantial morbidity, including increased rates of incontinence and impotence," the authors note. "The potential advantage of the PRX302 toxin approach over these therapies relates to the requirement for prostate-specific antigen activation of the toxin as this limits non-specific injury to normal structures associated with the prostate, such as the urethra and neurovascular bundles."

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