The in vitro cytotoxicity observed for Etoposide phosphate is significantly less than that seen with Etoposide which is believed due to the necessity for conversion in vivo to the active moiety, Etoposide, by dephosphorylation. The mechanism of action is believed to be the same as that of Etoposide. Etoposide has been shown to cause metaphase arrest in chick fibroblasts. Its main effect, however, appears to be at the G2 portion of the cell cycle in mammalian cells. Two different dose-dependent responses are seen. At high concentrations (10 µg/mL or more), lysis of cells entering mitosis is observed. At low concentrations (0.3 to 10 µg/mL), cells are inhibited from entering prophase. It does not interfere with microtubular assembly. The predominant macromolecular effect of Etoposide appears to be the induction of DNA strand breaks by an interaction with DNA-topoisomerase II or the formation of free radicals.
INDICATION
Etoposide (Etoposide phosphate) for Injection is indicated in the management of the following neoplasms:
Refractory Testicular Tumors – Etoposide (Etoposide phosphate) for Injection in combination therapy with other approved chemotherapeutic agents in patients with refractory testicular tumors who have already received appropriate surgical, chemotherapeutic, and radiotherapeutic therapy.
Small Cell Lung Cancer – Etoposide (Etoposide phosphate) for Injection in combination with other approved chemotherapeutic agents as first-line treatment in patients with small cell lung cancer.