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# FDA Complete Response Letter for Spero NDA
- URL: https://www.fdaweb.com/fda-complete-response-letter-for-spero-nda/
- Published: 2022-06-28T12:00:00.000Z
- Updated: 2026-09-14T17:50:17.000Z
- Author: David McFarland
- Tags: Drugs, #legacy-id-D5152182

FDA has issued a complete response letter for a Spero Therapeutics NDA for tebipenem HBr oral tablets to treat adult patients with complicated urinary tract infections, including pyelonephritis. The agency had previously set 6/27 as the PDUFA action date for the NDA.

The company [says](https://investors.sperotherapeutics.com/news-releases/news-release-details/spero-therapeutics-receives-complete-response-letter-us-food-and?ref=fdaweb.com) FDA found that the NDA could not be approved in its present form because the company’s ADAPT-PO Phase 3 study was insufficient to support approval and further clinical study will be required.

Spero says it will request a meeting with FDA officials “to gain further insights as to the pathway towards a potential regulatory approval for tebipenem HBr.”