SPRO News & Events

Spero Therapeutics (SPRO) announced that its development partner, GSK (GSK), filed a New Drug Application, NDA, resubmission to the U.S. Food and Drug Administration, FDA, for tebipenem HBr, an investigational oral carbapenem antibiotic being developed for the treatment of complicated urinary tract infections, cUTI, including pyelonephritis. The NDA submission triggers a $25 million milestone payment to Spero, expected to be received in Q1 2026.

Spero Therapeutics announced that on November 3, 2025, the Compensation Committee of Spero's Board of Directors approved the grant of an aggregate of 90,000 restricted stock unit awards to one new employee under the Spero Therapeutics, Inc. 2019 Inducement Equity Incentive Plan, as amended. The RSUs are being granted as an inducement material to Spero's new employee in accordance with Nasdaq Listing Rule 5635(c)(4). The 2019 Inducement Plan is used exclusively for the grant of equity awards to individuals who were not previously employees of Spero, as a material inducement for such individuals entering into employment with Spero, pursuant to Rule 5635(c)(4) of the Nasdaq Listing Rules. The RSUs will vest in four equal annual installments beginning on December 1, 2025, subject to the employees' continued employment with Spero on such vesting dates. The RSUs are subject to the terms and conditions of the 2019 Inducement Plan and an RSU agreement covering the grant.

Spero Therapeutics (SPRO) and GSK plc (GSK) announced efficacy and safety results of the phase 3 PIVOT-PO trial evaluating tebipenem HBr, an investigational oral treatment for complicated urinary tract infections, including pyelonephritis. These results were presented on October 20 in a late-breaking oral abstract session at IDWeek 2025 in Atlanta, Georgia. The trial, which was stopped early for efficacy in May this year, demonstrated non-inferiority of tebipenem HBr compared to intravenous imipenem-cilastatin in hospitalized patients with cUTI, including pyelonephritis, based on the overall response at the test of cure visit. Tebipenem HBr achieved a 58.5% overall success rate compared to 60.2% overall success rate for imipenem-cilastatin. The safety profile of tebipenem HBr was generally similar to that of other carbapenem antibiotics. The most frequently reported adverse events were diarrhea and headache; these events were all mild or moderate and non-serious. Secondary endpoints also show: clinical cure rates at test of cure visit were 93.5% in the tebipenem HBr group compared to 95.2% in the imipenem-cilastatin group with adjusted treatment difference: -1.6%. Microbiological response rates at test of cure visit were 60.3% in the tebipenem HBr group compared to 61.3% in the imipenem-cilastatin group with adjusted treatment difference: -0.8%. Overall, clinical and microbiological response rates at test of cure in participants with infections caused by antimicrobial-resistant Enterobacterales were consistent with the respective response rates in the primary analysis population. Spero has licensed tebipenem HBr to GSK for development and commercialization in all markets except certain Asian territories. GSK plans to work with US regulatory authorities to include the data as part of a filing in Q4. If approved, tebipenem HBr would be the first oral carbapenem antibiotic in the US for patients who suffer from cUTIs, adding to GSK's growing anti-infectives portfolio and helping address the challenges of antimicrobial resistance. The development of tebipenem HBr is supported in part with federal funds from the U.S. Department of Health and Human Services; Administration for Strategic Preparedness and Response; Biomedical Advanced Research and Development Authority.