Fosfomycin Demonstrates In Vitro Activity Against Bacteria Resistant to Last-Resort Antibiotic

First-in-class injectable antibiotic wins fast track designation

A newly emerging bacterial pathogen resistant in vitro to the “last defense” antibiotic colistin has retained susceptibility to ZTI-01 (fosfomycin for injection, Zavante Therapeutics) as well as to certain other antibiotics, according to JMI Laboratories’ SENTRY surveillance report, published in Antimicrobial Agents and Chemotherapy.

ZTI-01 is a first-in-class injectable antibiotic that has demonstrated a broad spectrum of bactericidal gram-negative and gram-positive activity in vitro, including activity against most contemporary multidrug-resistant strains.

Confirmation of the presence in the United States of a multidrug-resistant pathogen with a resistance gene (mcr-1) represents a challenge for hospital-based physicians because of the limited therapeutic options that are currently available. 

The FDA has granted a fast track designation for the investigation of ZTI-01 for the following indications:

  • Complicated urinary tract infections (cUTIs)
  • Hospital-acquired bacterial pneumonia
  • Ventilator-associated bacterial pneumonia
  • Acute bacterial skin and skin-structure infections
  • Complicated intra-abdominal infections

An epoxide intravenous antibiotic, ZTI-01 is under development for the treatment of cUTIs, including those caused by multidrug-resistant pathogens. In April 2016, Zavante initiated the ZEUS study of ZTI-01 for the treatment of cUTIs in hospitalized patients.

ZEUS is a multinational, randomized, active-controlled, double-blind trial designed to provide data to support the use of ZTI-01 for the treatment of patients with cUTIs, including those with multidrug-resistant infections. It is anticipated that the study will enroll 460 hospitalized patients. ZEUS is the single pivotal study intended to support a new drug application for ZTI-01 in the U.S. The study is expected to be completed in the second half of 2017.

Sources: Zavante Therapeutics; July 12, 2016; and Zavante Therapeutics; April 14, 2016.