GSK’s decision to swoop in and save Spero Therapeutics’ antibiotic three years ago appears to have paid off based on a fresh phase 3 readout.
The trial of 1,690 hospitalized patients with complicated urinary tract infections (cUTIs) has been halted early after it looked certain that the candidate, called tebipenem HBr, would hit the study’s primary endpoint of showing its non-inferiority to intravenous treatment with the antibiotic imipenem/cilastatin.
Armed with the new phase 3 data, GSK is planning its own push for a potential FDA review this year. If it gets the nod from the regulator, tebipenem HBr would become the first oral carbapenem antibiotic available for U.S. patients with cUTIs, GSK pointed out in a May 28 release.
“Complicated UTIs can have a profound impact on patients and carry a high risk of clinical complications, including sepsis and septic shock,” GSK Chief Scientific Officer Tony Wood, Ph.D., said in the release.
“Currently, many need hospital-based intravenous treatment due to limited oral options for drug-resistant infections, contributing to over $6 billion per year in U.S. healthcare costs,” Wood added. “These positive results add to our growing anti-infectives portfolio and reinforce the potential of tebipenem HBr as an effective oral alternative taken at home.”
GSK recently scored a regulatory success against uncomplicated UTIs when the FDA approved its antibiotic Blujepa, also known as gepotidacin, in March.
The Big Pharma saw similar promise in tebipenem HBr back in 2022, despite the FDA having at the time recently rejected Spero’s approval application. The biotech used the $66 million upfront payment it received from GSK as part of the licensing deal to fund the phase 3 trial that read out today.
“Achieving the primary endpoint in the PIVOT-PO trial marks a significant milestone for tebipenem HBr,” Spero’s CEO Esther Rajavelu said in this morning’s release. “If approved, we believe tebipenem HBr is well-positioned to change the treatment landscape for patients diagnosed with cUTI, including pyelonephritis.”
The late-stage win for tebipenem HBr is a welcome boost for Spero, which has spent the past year navigating layoffs and stripping back its pipeline. This included halting work on the oral antibiotic SPR720 after it failed to beat placebo and showed signs of liver toxicity in a phase 2 trial for non-tuberculous mycobacterial pulmonary disease.
The low return on investment means many of the biggest biopharmas have given up working on new antifungals or antibiotics in recent years—although GSK in particular has continued to sign deals and post encouraging clinical results against infections like gonorrhea.