> ## Content Index
> Fetch the complete content index at: https://www.fdaweb.com/llms.txt
> Use this file to discover other available public pages before exploring further.

# FDA Lifts Hold on Spero Antibacterial Trial
- URL: https://www.fdaweb.com/fda-lifts-hold-on-spero-antibacterial-trial/
- Published: 2022-01-05T12:00:00.000Z
- Updated: 2026-09-14T17:27:33.000Z
- Author: David McFarland
- Tags: Drugs, #legacy-id-D5150864

FDA has lifted a clinical hold on a Spero Therapeutics Phase 2 trial of SPR720, an investigational oral product being developed for nontuberculous mycobacterial disease. Spero describes SPR720 as a novel class of antibacterial agents that target enzymes essential for bacterial DNA replication.

The hold was placed after FDA reviewed data from a non-human primate toxicology study in which “mortalities with inconclusive causality to treatment were observed,” the company says. Its removal follows Spero’s submission of a comprehensive study report with detailed analyses from the toxicology study, it says. The company plans to meet with FDA this quarter to discuss the re-initiation of the SPR720 trial, with an expected study start date commencing in the second half of the year.