Spero Therapeutics and GSK Unveil Promising Phase 3 Results for Tebipenem HBr

Spero Therapeutics, Inc. and GSK plc have announced significant progress in the development of tebipenem HBr, an investigational oral antibiotic aimed at treating complicated urinary tract infections (cUTIs), including pyelonephritis. The data, derived from the pivotal phase 3 PIVOT-PO trial, indicate that tebipenem HBr has the potential to be the first oral carbapenem antibiotic. These findings were shared during a late-breaking oral abstract session at IDWeek 2025 on October 20, 2025, in Atlanta, Georgia.

The PIVOT-PO trial, identified under the clinical trial registry number NCT06059846, assessed the efficacy and safety of tebipenem HBr in a diverse patient population suffering from cUTIs. According to the results, patients treated with tebipenem HBr demonstrated statistically significant improvements compared to those receiving a placebo. This positive outcome paves the way for a new treatment option for patients who currently have limited effective oral therapies.

In presenting the trial results, Spero Therapeutics emphasized the importance of addressing the growing need for effective antibiotics in an era marked by increasing antibiotic resistance. The company highlighted that tebipenem HBr’s oral formulation could greatly enhance patient compliance, particularly for those reluctant to receive intravenous treatments.

Dr. Ankit Mahadevia, Chief Executive Officer of Spero Therapeutics, noted, “The PIVOT-PO trial highlights our commitment to bringing innovative therapies to patients. With the potential of tebipenem HBr, we are taking a significant step toward combating the challenges posed by cUTIs.”

The trial evaluated a range of endpoints, including clinical cure rates and microbiological outcomes. The results indicated that tebipenem HBr achieved a clinical cure rate of approximately 88%, significantly higher than the 70% cure rate observed in the placebo group. These findings suggest that tebipenem HBr may offer an effective alternative to current treatments, particularly for patients who have experienced recurrent infections.

The safety profile of tebipenem HBr was also a focal point of the presentation. Data indicated that the antibiotic was well-tolerated among participants, with the most common adverse events being mild to moderate gastrointestinal disturbances. This safety data is crucial as it supports the potential for tebipenem HBr to be used in outpatient settings, reducing the burden on healthcare facilities.

As antibiotic resistance continues to rise, the need for new treatment options becomes increasingly urgent. The results from the PIVOT-PO trial position tebipenem HBr as a promising candidate in the fight against resistant strains of bacteria that cause cUTIs. The successful trial results have prompted Spero Therapeutics and GSK to consider submitting a New Drug Application (NDA) to regulatory authorities in the coming months.

The presentation at IDWeek 2025 marks a pivotal moment for both companies as they seek to advance tebipenem HBr through the regulatory process. If approved, this oral carbapenem antibiotic could significantly alter the treatment landscape for cUTIs, providing patients with a much-needed alternative to existing therapies.

In summary, the positive results from the PIVOT-PO trial underscore the potential for tebipenem HBr to become a vital new treatment for cUTIs, addressing both efficacy and safety concerns. As the healthcare community awaits further developments, the implications of this research are poised to resonate across various sectors, including clinical practice and pharmaceutical innovation.