FDA Needs More Data on Sulopenem for Uncomplicated UTI

The NDA submission was supported by data from the phase 3 SURE1 clinical trial.

The Food and Drug Administration has issued a Complete Response Letter to Iterum Therapeutics regarding the New Drug Application (NDA) for oral sulopenem etzadroxil/probenecid for the treatment of uncomplicated urinary tract infection (UTI) in women.

The NDA submission was supported by data from the phase 3 SURE1 clinical trial (ClinicalTrials.gov Identifier: NCT03354598), which evaluated sulopenem etzadroxil/probenecid, a novel oral penem anti-infective compound, in women with uncomplicated UTI. Results from the study showed that among patients with baseline pathogens resistant to quinolones, sulopenem was found to be superior to ciprofloxacin (P <.001). However, the trial failed to show noninferiority of sulopenem to ciprofloxacin among those with organisms susceptible to quinolones.

In the letter, the Agency noted that additional data would be needed from the Company to support the approval of oral sulopenem in the treatment of adult women with uncomplicated UTI caused by designated susceptible microorganisms proven or strongly suspected to be nonsusceptible to quinolone antibiotics. An additional study potentially using a different comparator was recommended, as was a nonclinical investigation into an optimal dosing regimen.

“We are disappointed in this outcome and believe that the data package submitted was adequate for the approval of oral sulopenem,” said Corey Fishman, Chief Executive Officer. “Regardless, we will evaluate the points raised in the CRL for discussion with the FDA to determine an expeditious path forward.”

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The sulopenem clinical development program includes over 1800 participants treated with the investigational antibiotic. No safety issues were cited in the letter.


  1. Iterum Therapeutics receives complete response letter from US Food and Drug Administration for oral sulopenem. News release. Accessed July 26, 2021. https://www.globenewswire.com/news-release/2021/07/26/2268441/0/en/Iterum-Therapeutics-Receives-Complete-Response-Letter-from-U-S-Food-and-Drug-Administration-for-Oral-Sulopenem.html.
  2. Iterum Therapeutics announces topline results from its phase 3 clinical trial of oral sulopenem for the treatment of uncomplicated urinary tract infections. News release. Accessed July 26, 2021. https://www.globenewswire.com/news-release/2020/06/29/2054608/0/en/Iterum-Therapeutics-Announces-Topline-Results-from-its-Phase-3-Clinical-Trial-of-Oral-Sulopenem-for-the-Treatment-of-Uncomplicated-Urinary-Tract-Infections.html.

This article originally appeared on MPR