Pharmaceutical giants Johnson & Johnson and Sanofi have stopped a late-stage clinical trial for their experimental E.coli vaccine after results failed to demonstrate sufficient efficacy.
The companies announced on Thursday that while the vaccine showed no safety concerns, it did not meet the necessary effectiveness thresholds to continue development.
The experimental vaccine, known as ExPEC9V, was designed to protect against bloodstream infections and sepsis caused by E.coli bacteria, a major contributor to urinary tract infections and other serious health complications.
The trial, which began in June 2021, recruited older adults aged 60 and above who had a recent history of urinary tract infections and were otherwise in stable health.
It was conducted across more than 250 sites spanning five continents.
Despite rigorous testing and monitoring, the vaccine did not produce the desired immune response to move forward.
J&J confirmed that an independent review of the data found no safety issues, and the company is now conducting follow-ups with participants who had already received the vaccine.
Shares of J&J were unchanged in pre-market trading on Thursday.
Sanofi, which partnered with J&J’s Janssen unit in the development of the vaccine, disclosed that it had recorded a $250 million charge related to the halted trial in its fourth-quarter earnings report.
However, the company reassured investors that the financial setback would not affect its 2025 revenue forecast, which was issued in January.
Jean-François Toussaint, head of vaccine research and development at Sanofi, stated that the companies would analyze the trial results to understand why the vaccine failed to achieve its intended efficacy.
“We will share further insights once we complete a comprehensive review of the data,” he added.
The failure of ExPEC9V represents a setback in the ongoing battle against E.coli infections, which pose significant public health risks.
While most strains of the bacteria are harmless and commonly found in the intestines of humans and animals, some can cause severe illnesses.
The more dangerous strains of E.coli can lead to foodborne outbreaks, resulting in symptoms such as diarrhea, abdominal cramps, and, in severe cases, kidney failure.
One recent example of the risks posed by E.coli occurred last year when an outbreak linked to McDonald’s Quarter Pounder hamburgers sickened 104 people and hospitalized 34.
That outbreak was caused by the O157:H7 strain, which is known for producing a dangerous toxin that can lead to severe complications.
The setback in vaccine development underscores the challenges scientists face in creating effective immunizations against bacterial infections.
Unlike viral diseases, which often have more predictable immune responses, bacterial infections can be more complex, requiring a deeper understanding of how to stimulate long-lasting immunity.
While the discontinuation of the ExPEC9V trial is a disappointment, experts believe the insights gained from this study could inform future vaccine development efforts.
Both J&J and Sanofi said they remain committed to advancing research in infectious disease prevention and will continue to explore alternative solutions to combat E.coli-related illnesses.
For now, healthcare professionals emphasize the importance of preventive measures, including proper food handling, hygiene, and early treatment of urinary tract infections, to reduce the risks associated with E.coli infections.
