Dalbavancin shows promise for Staphylococcus aureus bloodstream infections
Researchers report that treating complicated Staphylococcus aureus bloodstream infections with two intravenous (IV) doses of the antibiotic dalbavancin seven days apart is as effective as treatment with daily IV doses of conventional antibiotics for four to six weeks.
The findings appeared on August 13, 2025 in JAMA/ Journal of the American Medical Association.
As background, the authors noted that about 120,000 S. aureus bloodstream infections and 20,000 associated deaths occurred in the United States in 2017.
“Given the small number of antimicrobial drugs available to treat Staphylococcus aureus bloodstream infections and the bacteria’s growing drug resistance, establishing dalbavancin as a beneficial therapy for these severe infections gives us a vital new alternative to treat them,” said John Beigel, M.D., the acting director of the Division of Microbiology and Infectious Diseases at NIH’s (USA) National Institute of Allergy and Infectious Diseases (NIAID), which sponsored and funded the trial.
Treatment for complicated S. aureus bloodstream infections, or bacteremia, typically requires the insertion of a long IV line, known as a peripherally inserted central catheter (PICC), into a vein, most often in the arm, through which antibiotics are delivered for many weeks.
The PICC line must stay in place for the complete course of treatment, which can cause serious limitations on movement. It can also lead to blood clots and more infections.
Notably, delivery of dalbavancin therapy requires only temporary insertion of a short catheter into a vein in the hand or arm twice for only an hour at a time.
Investigators from the USA and Canada enrolled 200 hospitalized adults in the phase 2b study. All subjects were diagnosed with complicated S. aureus bacteremia
The researchers randomized the subjects to treatment with either dalbavancin 1500 mg intravenously on days one and eight, or standard therapy administered for four to eight weeks.
The antibiotics used as standard therapy were cefazolin or an anti-Staphylococcal penicillin for methicillin-susceptible S. aureus and vancomycin or daptomycin for methicillin-resistant S. aureus (MRSA).
Overall outcome was measured by clinical success (survival with resolution of bacteremia), infectious complications, safety complications, death, and health-related quality of life.
A committee of four infectious disease experts ranked subjects according to overall treatment outcome after 70 days of therapy.
While dalbavancin therapy did not show superiority to standard treatment, components of overall outcome, such as clinical success, were similar for the two groups, suggesting that dalbavancin therapy and standard therapy were equally effective.
“Our findings give patients and healthcare providers the data to support an extra choice when deciding on treatment for complicated S. aureus bacteremia,” said Nicholas A. Turner, M.D., assistant professor of medicine at Duke University School of Medicine in Durham, North Carolina, and first author of the study.
