In patients with left-sided infective endocarditis a clinical response-tailored antibiotic strategy shortened antibiotic duration by two weeks compared with standard therapy, with no major safety concerns, based on findings from the POET-II study presented at ESC Congress 2026 and simultaneously published in NEJM.

Researchers randomized approximately 500 patients to either response-tailored therapy or standard-duration antibiotic therapy. All patients received a minimum of two to four weeks of therapy and met criteria for clinical stabilization prior to randomization. Following randomization, patients in the tailored-therapy cohort discontinued antibiotics, while those receiving standard therapy continued treatment for four to six weeks.

The primary efficacy endpoint was days alive without antibiotic treatment for infective endocarditis or bacteremia within six months after randomization. The primary safety endpoint was a composite of death from any cause, unplanned cardiac surgery, or symptomatic embolic events within the same period. Researchers also tracked relapse of bacteremia or infective endocarditis.

Overall results showed the median time alive without antibiotic treatment was 183 days with tailored therapy vs. 169 days with standard therapy. A primary safety endpoint event occurred in 21 patients (8.2%) receiving tailored therapy compared with 27 patients (10.7%) receiving standard therapy, indicating non-inferiority.

Researchers also noted that relapse rates, while low overall, occurred in more patients (n=13) in the tailored therapy group compared with the standard therapy group (n=4). However, most relapse events were managed with reinitiation of antibiotics, they said.

"The results from our landmark trial have the potential to change clinical practice," said Henning Bundgaard, MD, DMSc, the study's principal investigator from Rigshospitalet - Copenhagen University Hospital, Denmark. "We estimate that around half of the patients that we see in our clinics with left-sided infective endocarditis could be eligible for tailored reduced-duration antibiotic therapy. Shorter courses of antibiotics may also improve patients' quality of life by reducing the physical and psychological toll associated with prolonged antibiotic treatment and hospitalisations."

Keywords: ESC Congress, ESC26, Endocarditis