GSK and Spero Therapeutics have scored an FDA approval for Utebzi as the first oral carbapenem antibiotic for complicated urinary tract infections (cUTI). With the nod, patients in the United States will soon have an at-home option for the infection, which is otherwise treated with infused carbapenem antibiotics.
The FDA endorsement also covers patients with pyelonephritis, which is a type of kidney inflammation. GSK, which inked a licensing agreement with Spero in 2022, expects to launch Utebzi stateside by the end of the year. The British pharma holds marketing rights to the drug everywhere around the world except Japan and select other Asian regions.
The green light marks a significant addition to the GSK portfolio, as there are more than 3 million cases of cUTI in the U.S. each year. The condition is estimated to account for more than $6 billion annually in healthcare costs, the company said. Additionally, treatment failure occurs in up 34% of patients.
“With antibiotic resistance continuing to rise, patients and healthcare professionals need new treatment options,” Tony Wood, GSK’s chief scientific officer, said in a release Wednesday. “The approval of Utebzi provides the first and only oral carbapenem antibiotic for appropriate adults with complicated UTIs, a solution that could help reduce reliance on hospital-based intravenous care and support efforts to address resistant infections.”
The approval is based on results from a phase 3 trial that showed Utebzi’s non-inferiority to the intravenous carbapenem antibiotic Primaxin in 1,690 patients hospitalized with cUTI. Over a span of 7 to 10 days, patients on Utebzi were given a 600 mg oral dose every six hours, while those on Primaxin received a 500 mg infusion every six hours.
With the primary endpoint defined as clinical cure and microbiological eradication, Utebzi achieved a 58.5% success rate compared to a 60.2% figure for those on intravenous Primaxin. The difference was within the trial’s 10% margin for non-inferiority and the interim results were convincing enough to halt the study.
As for secondary endpoints, 93.5% of those on Utebzi were free of symptoms versus 95.2% of those on the standard of care treatment. Microbiological response rates were 60.3% in the Utebzi group and 61.3% in the Primaxin cohort.
It’s been a long road to approval for Spero, which received a complete response letter (CRL) from the FDA in 2022 as the agency requested another trial. Three months later, Spero signed a licensing deal with GSK, which paid $66 million up front and committed to $525 million in milestones for access to the asset.
GSK tied a $150 million milestone to the delivery of the phase 3 program and put up another $150 million tied to the first sales of the antibiotic. The remaining $225 million in milestones comes into play if sales rise above a series of thresholds, starting at $200 million and topping out at $1 billion.
Spero CEO Esther Rajavelu called the approval “the culmination of more than a decade of dedication from our team, partners, and, most importantly, the patients who placed their trust in this program.”
Also putting trust in the program by way of funding were the U.S. Department of Health and Human Services (HHS) and the Biomedical Advanced Research and Development Authority (BARDA).
The approval adds Utebzi to GSK’s portfolio of first-in-class oral antibiotics, which includes Blujepa, approved last year for uncomplicated UTIs and gonorrhea, and Brexafemme, which was approved in 2021 for vaginal yeast infections and sustained a 19-month clinical hold which ended in May of last year.
Earlier this year, two former Spero CEOs agreed to settle with the Securities and Exchange Commission (SEC) for allegedly misleading investors about the efficacy of Utebzi, paying a total fine of $187,500.