Anticancer activity of isomers of 6-phenyl-2,3,5,6-tetrahydroimidazo[2,1-b]thiazole

Three phenylimidazothiazole isomers, L-(-)-form (levamisole), D-(+)-form (dexamisole), and DL-(+/-)-form (tetramisole), modulate mouse and rat immune responsiveness. They depress the relapse of urinary bladder cancer, BC-47, when they are used with 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) for treatment of rats bearing BC-47. Levamisole was the most effective isomer. Effectiveness of the isomers is expressed by their ability to enhance the number of plaque-forming cells to sheep red blood cells. They also stimulate the DNA synthesis of murine lymphocytes in vitro.