Spero Therapeutics (NASDAQ:SPRO) shares climbed 16% on Thursday after the U.S. Food and Drug Administration approved Utebzi, a novel oral carbapenem antibiotic developed through a collaboration between GSK (NYSE:GSK) and Spero, for the treatment of complicated urinary tract infections (cUTIs), including pyelonephritis, in adults with limited or no suitable oral treatment alternatives.
Landmark Approval Opens New Treatment Option
Utebzi becomes the first oral carbapenem antibiotic to receive approval in the United States, marking a significant development in the treatment of serious urinary tract infections caused by drug-resistant bacteria.
The product was developed under GSK’s exclusive global licensing agreement with Spero Therapeutics, excluding certain Asian markets.
Addressing a Growing Medical Need
Complicated urinary tract infections affect more than three million people annually in the United States, with treatment failures reported in up to one-third of cases.
Many of these infections are linked to multidrug-resistant pathogens, creating a substantial burden on healthcare systems and generating more than $6 billion in annual medical costs.
Until now, carbapenem antibiotics—often considered a key treatment option for severe resistant infections—have generally required intravenous administration, limiting their use outside hospital settings.
Phase III Trial Supports Approval
The FDA’s decision was supported by findings from the Phase III PIVOT-PO study, which evaluated tebipenem pivoxil against intravenous imipenem-cilastatin in hospitalized patients suffering from cUTIs, including kidney infections.
Results showed tebipenem pivoxil achieved an overall success rate of 58.5% (261 of 446 patients), compared with 60.2% (291 of 483 patients) for imipenem-cilastatin. The adjusted treatment difference was -1.3% (95% CI: -7.5%, 4.8%), demonstrating non-inferiority to the intravenous standard of care.
Safety Profile Remains Consistent
The treatment’s safety profile was broadly comparable to that observed with imipenem-cilastatin and other carbapenem antibiotics.
The most commonly reported side effects were diarrhoea and headache, with reported adverse events generally classified as mild to moderate and non-serious.
Commercial Launch Expected by Year-End
Utebzi is expected to become available to patients in the United States before the end of 2026.
Development of tebipenem pivoxil received support from the U.S. Department of Health and Human Services through funding provided by the Biomedical Advanced Research and Development Authority (BARDA), helping advance the programme through late-stage clinical development.