In vitro and in vivo cytotoxicity of alkyl lysophospholipid ET-18-OCH3 and thioether lipid BM 41.440.

Screening for cytotoxicity in the clonogenic assay in human tumor xenografts and L1210 mouse leukemia revealed comparable dose-dependent effects of the alkyl lysophospholipid ET-18-OCH3 and the thioether lipid BM 41.440. The efficacy in human tumors only was marginal at low doses. In vivo tests of both agents were carried out in nude mice bearing two of the tumors that proved most sensitive in vitro and in mice inoculated with L1210 leukemia. Only small effects on the growth of the human tumors and no effects on L1210 leukemia were observed. In view of clinical rules for definition of remission, no convincing antitumor effects were obtained.