indication

For the treatment of testicular cancer, as well as hypercalcemia and hypercalciuria associated with a variety of advanced forms of cancer.

pharmacology

Plicamycin is lethal to Hela cells in 48 hours at concentrations as low as 0.5 micrograms per milliliter of tissue culture medium. Plicamycin has shown significant anti-tumor activity against experimental leukemia in mice when administered intraperitoneally.

mechanism of action

Plicamycin is presumed to inhibit cellular and enzymic RNA synthesis by forming a complex with DNA. Plicamycin may also lower calcium serum levels by inhibiting the effect of parathyroid hormone upon osteoclasts or by blocking the hypercalcemic action of pharmacologic doses of vitamin D.

toxicity

The most important form of toxicity associated with the use of plicamycin consists of a dose-related bleeding syndrome which usually begins with an episode of epistaxis. Plicamycin crosses the blood-brain barrier; the concentration found in brain tissue is low but it persists longer than in other tissues.

route of elimination

Radioautography studies with 3H-labeled plicamycin in mice show that the greatest concentrations of the isotope are in the Kupffer cells of the liver and cells of the renal tubules. Plicamycin is rapidly cleared from the blood within the first 2 hours and excretion is also rapid. 67% percent of measured excretion occurs within 4 hours, 75% within 8 hours, and 90% is recovered in the first 24 hours after injection.