Studies on anti-Helicobacter pylori agents. Part 3: A novel, efficacious cephem derivative, FR193879

The synthesis, therapeutic efficacy against H. pylori, and preliminary safety of the novel cephem derivative, FR193879 (8a) are described. Compound 8a having a (4-carbamoylmethylthiazol-2-yl)thio moiety at the 3-position and a phenylacetamido at the 7-position was found to have good safety showing a nontoxic dose of >100 mg/kg in dogs in a 4-week repeat dose toxicity study and extremely potent therapeutic efficacy against H. pylori, showing 30 times superior activity compared to AMPC, and did not display cross-resistance with CAM or MNZ.