Clinical, microbiological, and laboratory predictors of on- and off-label dalbavancin treatment failure.

OBJECTIVES

Data about risk factors for treatment failure (TF) to dalbavancin are lacking. Our aim was to investigate the clinical, microbiological, and laboratory predictors of TF in both on- and off-label dalbavancin treatments.

METHODS

We included all patients who received at least one dose of dalbavancin at our centre from January 2018 to June 2024 and with available data on follow-up, collecting all clinical and laboratory parameters. TF was defined as the need for readmission, emergency department access, or death within 90 d after treatment. Factors correlating with TF and mortality rate were assessed using multivariable analyses and Kaplan-Meier curves.

RESULTS

Three hundred fifty-one patients were included, mostly men (60.9 %), median age of 64 years (interquartile range [IQR] = 49.5-75.5), 55.3 % receiving dalbavancin in the emergency department/outpatient setting, and 44.7 % for early discharge, in 54.9 % cases as off-label. The main off-label indications were osteomyelitis, prosthetic infections, and endocarditis (17.1 %, 8.3 %, and 7.7 %). In 53.3 % of the cases, a microbiological isolate was available (Methicillin-resistant Staphylococcus aureus [MRSA] in 49.2 % of cases). Overall, the TF rate was 19.4 %. Overall, multivariable analysis showed that intravenous (IV) drug use (hazard ratio [HR] = 7.99, P < 0.001), diabetes (HR = 6.1, P < 0.001), obesity (HR = 4.5, P < 0.001), cancer (HR = 5.3, P < 0.001), HIV (HR = 4.88, P < 0.001), levels of CRP at dalbavancin treatment initiation (HR = 1.01, P < 0.001, and HR = 0.72, P = 0.02) were associated with TF. Additionally, the duration of IV antibiotic therapy before being discharged influenced outcomes in the off-label group (HR = 0.52, P = 0.02).

CONCLUSIONS

The observed TF rate was high, particularly in off-label uses and among individuals with multiple comorbidities or IV drug use. More evidence is needed to better define the optimal patient profile for effective dalbavancin treatment.