Sitafloxacin [DU 6859, DU 6859A, sitafloxacin hydrate, Gracevit™] is a novel N1-fluorocyclopropyl quinolone with very potent bactericidal activity against methicillin-resistantStaphylococcus aureus,Pseudomonas aeruginosaandBacteroidesspp.1The compound is characterised by a cis-oriented (1R,2S)-2-fluorocyclopropylamine moiety that is indispensable for its reduced side effects and superior pharmacokinetic profile.Figure. Sitafloxacin [DU 6859, DU 6859A, sitafloxacin hydrate, Gracevit™]Oral and injectable formulations of sitafloxacin have undergone phase III trials with Daiichi Seiyaku in Japan for the treatment of bacterial infections. A New Drug Application (NDA) has been filed with favourable results from phase III trials in Japan.Phase II trials with the injectable formulations have been conducted in Europe and the US, and Daiichi is preparing for phase III trials of this formulation in these regions. The tablet formulation is in phase III development in the US and phase III trials are being prepared in Europe. Sitafloxacin is expected to be launched in the US and Europe during 2006.Regarding the safety of sitafloxacin, Daiichi has stated that it is believed to be inferior to its levofloxacin product, Cravit®, for which overseas data show the occurrence of photosensitivity adverse effects. Therefore, Daiichi is planning for an IV formulation to be indicated only in patients with severe infection or drug-resistant diseases in markets outside Japan. No adverse effects have been reported in Japanese studies, believed to be most likely due to racial and dosage differences between patients overseas and in Japan.Although sitafloxacin has no antifungal properties on its own, it is known to enhance the activity of currently available antifungal agents and may be useful in the treatment ofCandida albicansinfections.