Plazomicin: an investigational therapy for the treatment of urinary tract infections.

INTRODUCTION: Living in the ever-expanding era of multidrug-resistant (MDR), extensively drug-resistant (XDR), and even pandrug-resistant Gram-negative microorganisms, the medical community is facing the approaching fear of the "End of Antibiotics." Plazomicin is a next-generation aminoglycoside designed to evade all clinically relevant aminoglycoside-modifying enzymes, the main mechanism of aminoglycoside resistance. A newer aminoglycoside active against several MDR-XDR microorganisms is herein presented and discussed. AREAS COVERED: Herein, the authors present the currently available information on plazomicin. This includes the current knowledge concerning plazomicin's: mechanisms of action, in vitro activity and interactions, its pharmacokinetics, its clinical efficacy in complicated urinary tract infections (cUTIs) and acute pyelonephritis, and its toxicity issues. EXPERT OPINION: Plazomicin was developed to evade all clinically relevant aminoglycoside-modifying enzymes. Unfortunately, ribosomal enzymatic modification by ribosomal 16S-rRNA methyltransferases confers broad-spectrum high-level aminoglycoside resistance. Still, plazomicin demonstrates high activity against the Enterobacteriaceae including extended spectrum beta lactamase and most carbapenemase producers, as well as several of the non-fermenters. When compared to levofloxacin, the in vivo activity of plazomicin in complicated urinary tract infections (cUTIs) and in acute pyelonephritis in humans was very promising. Furthermore, regarding safety, no clinically significant effects on renal, vestibular, or cochlear function have been observed both at Phase I and II studies in humans, with mild to moderate adverse events being dose related. However, the authors believe that the real position of plazomicin in the MDR-XDR world will be revealed once pending Phase III studies are completed.