Fosfomycin does not inhibit the tumoricidal efficacy of cisplatinum.

Abstract

This study investigates the effect of fosfomycin on the tumoricidal efficacy of cisplatinum. Prospective study utilizing the FaDu squamous cell carcinoma cell line and a nude mouse tumor xenograft model. Tumor cell growth was assessed in vitro in the presence of cisplatinum and/or fosfomycin utilizing the MTT assay. An optimal cisplatinum dose and dosing schedule was established in a nude mouse tumor xenograft model of squamous cell carcinoma. Using this model, fosfomycin was tested at three dosages and tumor growth monitored over 4 weeks. Mice treated with cisplatinum and fosfomycin had smaller tumors than those treated with cisplatinum alone (P<.01). This study is the first demonstration that fosfomycin does not inhibit the tumoricidal efficacy of cisplatinum in vivo. This suggests that fosfomycin may be useful in preventing cisplatinum-induced ototoxicity and nephrotoxicity in humans without altering the tumor response rate.