FDA Approves Enmetazobactam for Complicated UTIs: A Breakthrough in Antimicrobial Therapy


Enmetazobactam (Exblifep; Orchid Pharma) has received FDA approval for treating complicated urinary tract infections (cUTIs), offering a promising solution in the battle against antimicrobial resistance.

Testing for a complicated urinary tract infection  (Adobe Stock 477609989 by Dancing Man)

Testing for a complicated urinary tract infection

(Adobe Stock 477609989 by Dancing Man)

This article first appeared on our sister site, Contemporary OB/GYN.

Enmetazobactam (Exblifep; Orchid Pharma) has received a New Drug Approval (NDA) from the FDA for use in patients aged 18 years or older with complicated urinary tract infections (cUTIs) such as pyelonephritis.1

Top Takeaways

  • Enmetazobactam (Exblifep) has received FDA approval for treating complicated urinary tract infections (cUTIs) in patients aged 18 years and older.
  • The drug underwent rigorous testing in a global phase 3 trial, where it demonstrated non-inferiority and even superiority in clinical cure and microbiological eradication compared to piperacillin-tazobactam.
  • Enmetazobactam is a fourth-generation cephalosporin combined with a proprietary beta-lactamase inhibitor, developed specifically to combat antimicrobial resistance in gram-negative bacteria.
  • The symptoms of cUTIs, such as chills, fever, and back pain, highlight the significant impact these infections have on patients' quality of life.
  • With a comparable safety profile to existing treatments and a high success rate in combating cUTIs, enmetazobactam's FDA approval marks a significant milestone in the fight against antibiotic-resistant infections.

The approval follows a randomized, controlled, double-blind, global phase 3 trial of enmetazobactam for managing cUTI.2 It received Qualified Infectious Disease Product status, granting the drug priority FDA review.

The fourth-generation cephalosporin cefepime and proprietary beta-lactamase inhibitor combination were developed to fight anti-microbial resistance in gram-negative bacteria. Non-inferiority and superiority criteria for clinical cure and microbiological eradication were observed when comparing enmetazobactam to piperacillin-tazobactam.

CUTIs requiring therapy are reported in approximately 3.6 US patients.3 Symptoms of cUTIs include chills, fever, back pain, flank pain, costo-vertebral angle pain or tenderness, and malaise. Intravenous treatment is often employed to manage cUTIs.

Acute pyelonephritis is reported in 15 to 17 female patients per year in the United States. It is caused by an ascending UTI from the bladder to the kidneys, leading to inflammation. Pyelonephritis was included among the cUTIs evaluated in the phase 3 trial.

In the phase 3 trial, 1034 participants were randomized to receive cefepime 2 g and enmetazobactam 0.5 g or piperacillin 4 g and tazobactam 0.5 g through 2 hours of continuous intravenous infusion every 8 hours. Clinical cure was defined as symptom resolution and microbiological eradication under 103 CFU/mL in urine culture.

Efficacy was evaluated in patients with a Gram-negative pathogen infection deemed non-resistant to cefepime-enmetazobactam and piperacillin-tazobactam. Cefepime-enmetazobactam had a success rate of 79.1%, while piperacillin-tazobactam had a success rate of 58.9%.

Treatment discontinuation was observed in 5.2% and 4% of patients taking cefepime-enmetazobactam and piperacillin-tazobactam, respectively. This indicated a similar safety profile between the 2 drugs.

The FDA approval will allow enmetazobactam to be introduced in the United States.1 It is expected to launch in the US market within the next few quarters.


  1. Orchid Pharma gets USFDA approval for Exblifep. Express Pharma. February 23, 2024. Accessed February 23, 2024. https://www.expresspharma.in/orchid-pharma-gets-usfda-approval-for-exblifep/
  2. Allecra Therapeutics submits New Drug Application to the US FDA for EXBLIFEP for the treatment of complicated urinary tract infections. Business Wire. June 27, 2023. Accessed February 23, 2024. https://www.businesswire.com/news/home/20230627361506/en/Allecra-Therapeutics-Submits-New-Drug-Application-to-the-U.S.-FDA-for-EXBLIFEP%C2%AE-for-the-Treatment-of-Complicated-Urinary-Tract-Infections
  3. Allecra Therapeutics announces positive top-line results for phase 3 ALLIUM clinical trial of EXBLIFEP for complicated Urinary Tract Infections. Allecra Therapeutics. February 25, 2020. Accessed February 23, 2024. https://www.globenewswire.com/news-release/2020/02/25/1989893/0/en/Allecra-Therapeutics-Announces-Positive-Top-Line-Results-for-Phase-3-ALLIUM-Clinical-Trial-of-EXBLIFEP-for-Complicated-Urinary-Tract-Infections.html

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