After being rejected in June 2022, GSK paid Spero Therapeutics $66 million for an exclusive worldwide license to develop and commercialize the drug. It’s the second oral antibiotic GSK has brought to market since the beginning of last year.
The FDA has given the go-ahead to GSK and Spero Therapeutics’ tebipenem pivoxil for the treatment of complicated urinary tract infections. The drug, which will be on U.S. shelves by year-end, will carry the brand name Utebzi.
The U.S. records more than 3 million cases of complicated urinary tract infections (cUTIs) annually, GSK said in a news release on Wednesday. These treatments are unsuccessful in more than a third of these patients, often due to drug-resistant pathogens. Carbapenem antibiotics form somewhat of a last-line of defense for resistant infections, but have so far only been available intravenously.
Utebzi is the first oral option of such an anti-infective, GSK said, and is indicated specifically for patients whose cUTI is caused by susceptible pathogens and who have limited or no alternative treatment options.
The drug was originally developed by Spero Therapeutics and was previously rejected by the FDA in June 2022. The agency contended that the Phase 3 study the biotech had used to back its application “was insufficient to support approval,” according to a news release at the time. The regulator asked for another study to establish the drug’s efficacy.
In December that year, GSK paid $66 million upfront and earmarked up to $750 million in milestones for an exclusive license to develop and commercialize the anti-infective globally except in Japan and certain Asian territories. GSK and Spero refiled their drug package for Utebzi in December 2025.
Data from the Phase 3 PIVOT-PO study supported the FDA’s approval. A readout in October 2025 showed that Utebzi was non-inferior to intravenous imipenem-cilastatin, a broad-spectrum antibiotic commonly used for infections caused by bacteria. Patients in the Utebzi group saw a 58.5% overall treatment success rate, versus 60.2% in those who received the intravenous therapy.
Ahead of this data drop, GSK in May 2025 announced that an independent data board recommended to stop PIVOT-PO ahead of schedule for efficacy.
With Utebzi’s clearance on Wednesday, GSK has now notched a trifecta of infectious disease approvals over the past year and a half. In March 2025, the pharma secured the FDA’s go-ahead for the oral antibiotic Blujepa for uncomplicated urinary tract infections in female patients 12 years of age and up. Then, in December that year, Blujepa cleared another regulatory hurdle and expanded into uncomplicated urogenital gonorrhea, becoming the first new class of antibiotics for this indication in more than 30 years.
GSK is the lone Big Pharma still involved in developing new antibiotics despite the threat of resistance.
