Investigational E coli Vaccine Does Not ‘Demonstrate Sufficient Efficacy’ in Phase 3 Study

An independent data monitoring committee (IDMC) determined that the Sanofi and Johnson & Johnson’s vaccine candidate for extraintestinal pathogenic E coli was not sufficiently effective at preventing invasive E coli disease (IED) compared to placebo. No safety signals related to the vaccine candidate were identified.¹ “We are disappointed to see that the vaccine was not associated with sufficient efficacy to support the trial continuation, and we will work tirelessly to understand the factors behind the IDMC’s finding and to share further analysis once available,” Jean-François Toussaint, MD, Global Head of Research and Development Vaccines, Sanofi, said in a statement. ¹

In October 2023, Sanofi entered into an agreement with Janssen Pharmaceuticals, a Johnson & Johnson company, to develop and commercialize the vaccine candidate. Under the terms of the agreement, both parties agreed to co-fund current and future research and development costs.¹

Study Specifics
The E.mbrace study is a randomized, double-blind, placebo-controlled, multicenter, interventional phase 3 study evaluating the efficacy, safety, and immunogenicity of a single dose of the vaccine candidate compared to a placebo in the prevention of IED, which includes sepsis and bacteremia (blood infections). ¹

The study was initiated in June 2021 enrolling adults aged 60 years or older in stable health with a history of urinary tract infection in the past two years. The study was conducted at over 250 sites across 5 continents. Janssen is the trial sponsor and responsible party and will continue appropriate safety follow up for the currently enrolled participants. ¹

E coli Presentation and Clinical Considerations

E coli is a bacterial infection that can cause dehydration, bloody diarrhea and abdominal cramps 2–8 days (3–4 days, on average) after exposure the organism. While most people recover within a week, some develop a type of kidney failure called hemolytic uremic syndrome (HUS).²

Symptoms can usually last between 5 to 10 days, and people with mild symptoms usually recover on their own without treatment.³

This condition can occur among persons of any age but is most common in children under 5-years old and older adults. It is marked by easy bruising, pallor, and decreased urine output. Persons who experience these symptoms should seek emergency medical care immediately.²

Antimicrobial therapy is not recommended for patients with suspected Shiga toxin-producing E coli (STEC) infections until complete diagnostic testing can be performed and STEC infection is ruled out. According to the Centers for Disease Control and Prevention, some studies have shown that administering antibiotics to patients with STEC infections might increase their risk of developing HUS, and a benefit of treatment has not been clearly demonstrated.⁴

References

1. Press Release: Update on extraintestinal pathogenic E. coli vaccine phase 3 clinical study. Sanofi press release. February 13, 2025. Accessed February 13, 2025.
2.FSIS Issues Public Health Alert for Ground Beef Products Due to Possible E coli O157:H7 Contamination. FSIS press release. April 20, 2024. Accessed February 13, 2025.
https://www.fsis.usda.gov/recalls-alerts/fsis-issues-public-health-alert-ground-beef-products-due-possible-e--coli-o157h7-0
3. E coli O157:H7 and HUS Fact Sheet. Minnesota Department of Health. Accessed February 13, 2025. https://www.health.state.mn.us/diseases/ecoli/ecoli.html
4. E coli. CDC. Last reviewed May 14, 2024. Accessed February 13, 2025..
https://www.cdc.gov/ecoli/index.html