This article is written live from ID Week 2017 Annual Meeting in San Diego, CA. MPR will be reporting news on the latest findings from leading experts in infectious diseases. Check back for more news from IDWeek 2017.

SAN DIEGO—Fosfomycin for injection (ZTI-01) is well-tolerated in patients with complicated urinary tract infections (cUTI) and acute pyelonephritis (AP), according to safety and efficacy findings from the multicenter, randomized, double-blind Phase 2/3 ZEUS clinical trial, reported at IDWeek 2017.

“IV fosfomycin (total 18g/day) was well tolerated,” reported Paul B Eckburg, MD, of Zavante Therapeutics, Inc., in San Diego, CA, and coauthors. “Most TEAEs [treatment-emergent adverse events] were mild and transient; severe or serious TEAEs were rare. Premature discontinuation or interruption of the study drug was uncommon.”

ZTI-01 is an injected, broad in vitro spectrum epoxide antibiotic that is active against multidrug-resistant pathogens, Dr. Eckburg and coauthors reported. ZTI-01 is being developed for the treatment of cUTI and AP in the United States.

Study participants included 464 hospitalized adults with cUTI or AP diagnosis, randomly assigned to be administered either ZTI-01 (6g as 1-hour IV infusions every 8 hours, for a total daily dose of 18g; n=233) or piperacillin/tazobactam (P-T; 4.5g IV as 1-hour IV infusions every 8 hours, for a total daily dose of 13.5g; n=231) for a fixed 7 days, or up to 14 days if patients had concurrent bacteremia. Oral step-down therapy was not allowed.

A total of 42.5% of patients receiving ZTI-01 experienced any adverse reaction, compared to 32% of patients on P-T. But drug-related TEAEs affected 20.6% of patients in the ZTI-01 group and 13.9% of the P-T group. Serious adverse events (SAEs) were uncommon overall, affecting 2.1% and 2.6% of the ZTI-01 and P-T group patients, respectively. One patient from each study group experienced a drug-related SAE, the team reported. No patient deaths were reported during the study. TEAEs leading to study drug discontinuation occurred in 7 (3%) patients in the ZTI-01 group and 6 (2.6%) in the P-T group.

The most common TEAEs were gastrointestinal (GI), affecting 10.7% of patients in the ZTI-01 group and 17.4% of patients in the P-T group. Lab abnormalities were noted for 20 (8.6%) and 8 (3.5%) of patients, respectively. Metabolic and nutrition disorders affected 17 (7.3%) patients on ZTI-01and 4 (1.7%) on P-T.

For continuous infectious disease news coverage from the IDWeek 2017, check back to MPR’s IDWeek page for the latest updates.


Rice LB, Kaye KS, Dane A, Skarinsky D, Das A, Ellis-Grosse E, Eckburg PB. Safety Results from the ZEUS Study: Multi-center, Randomized, Double-Blind Phase 2/3 Study in Hospitalized Adults with Complicated Urinary Tract Infections Including Acute Pyelonephritis who Received Intravenous Fosfomycin. Poster presented at IDWeek; October 4–8, 2017; San Diego, CA.