Spero Therapeutics, Inc. announced that it has received a Complete Response Letter (CRL) from the U.S. Food and Drug Administration (FDA) for its New Drug Application (NDA) seeking approval for tebipenem HBr oral tablets for treatment of adult patients with complicated urinary tract infection (cUTI), including pyelonephritis. The FDA had set a Prescription Drug User Fee Act (PDUFA) target action date of June 27, 2022. In the CRL, the FDA communicated that it had completed its review of the NDA and determined that the NDA could not be approved in its present form.

As previously disclosed in Spero's May 3, 2022 press release, the CRL was anticipated based on feedback received at the late cycle meeting, in which the agency outlined potential deficiencies in the application. In the CRL, the FDA ultimately concluded that Spero's Phase 3 cUTI study of tebipenem HBr (ADAPT-PO) was insufficient to support approval and that additional clinical study would be required. Spero intends to promptly request a Type A meeting with the FDA, to gain further insights as to the pathway forward towards a potential regulatory approval for tebipenem HBr.

Tebipenem HBr Research Support: Select tebipenem HBr studies have been funded in part with federal funds from the Department of Health and Human Services; Office of the Assistant Secretary for Preparedness and Response; Biomedical Advanced Research and Development Authority, under contract number HHSO-100-2018-000-15C.