Amifostine: A Selective Cytoprotective Agent of Normal Tissues from Chemo-radiotherapy Induced Toxicity (Review)

Patients receiving systemic cancer chemotherapy must often have their dose intensity of therapeutic agents reduced, because a broad range of organs are adversely affected. Therefore, research and the development of agents protecting the normal tissues from the toxicity of antineoplastic therapy, without reducing the antitumour efficacy, are very important. Amifostine, a prodrug that forms an activated free thiol, when dephosphorylated by alkaline phosphatase, appears selective in its entry in non-malignant cells, and exerts a protective effect from toxicity induced by chemo- or radiotherapy on normal tissues, through free radical scavenging, hydrogen donation and inhibition of DNA damage. Studies in vitro and experimental models have confirmed the protective properties of amifostine in normal cells. In clinical trials pretreatment with amifostine reduced the frequency of cyclophosphamide induced neutropenia and nephro-, oto- and neurotoxicity of platinum compounds. In some cases the use of amifostine have also potentiated the effects of several drugs, such as alkylating agents and, in recent studies, taxanes. The main potentially dose-limiting adverse effect is hypotension, that is often asymptomatic. Amifostine is thus usefully employed in order to obtain a better quality of life in patients receiving oncologic treatments.