Dalbavancin an effective treatment option for serious gram-positive infections

In a real-world study presented at IDWeek 2023, dalbavancin has been shown to be an effective treatment alternative for patients with invasive gram-positive infections.

Despite higher rates of patient-directed discharge (27.3 percent vs 3.1 percent) and loss to follow up (21.8 percent vs 6.1 percent), the rates of clinical cure at 90 days were similar between people who use drugs (PWUD; 71.8 percent) and those who do not (non-PWUD; 75.5 percent). [IDWeek 2023, abstract 964]

“Even when we assumed that patients lost to follow-up did not achieve clinical cure, our findings suggest that clinical cure may be even higher, and there was no statistically significant difference between the two arms (p=0.577),” said presenting author Dr Sarah Zambrano from Brigham and Women’s Hospital, Boston, Massachusetts, US.

Zambrano and her team evaluated patients with more serious non-skin and soft tissue infections (non-SSTI), with special focus on PWUD. “Serious [non-SSTI] are hard to treat, often require long-term IV access, prolonged antibiotic course, and extended hospitalization. For vulnerable populations including PWUD, this can be challenging for both personal and systemic reasons,” she said.

When a patient is not able to complete a more typical standard course for serious infections, dalbavancin is sometimes brought up as a potential option owing to its broad gram-positive coverage, long half-life, and dosage (can be given weekly), she continued. It also often precludes the need for long-term IV access and prolonged hospital stays.

“Dalbavancin is a particularly useful option for PWUD, who face unique challenges with long-term IV antibiotics. However, currently, dalbavancin is only approved for SSTI, is expensive, and there is usually a wide variation in its use,” stressed Zambrano.

As such, the team sought to evaluate the characteristics and outcomes of patients who received off-label, unique dalbavancin courses for serious infections* between 2016 and 2022. A total of 176 patients (average age 49.2 years, 56 percent male) met the eligibility criteria of having been initially treated with a different antibiotic and having their first dalbavancin dose during hospital admission.

Of the 78 PWUD, 58 had used drugs within the last 6 months leading to hospitalization; within this group, 37 had IV drug use within 2 weeks prior to admission. The remaining 20 PWUD had a history of drug use >6 months prior to admission.

In both PWUD and non-PWUD groups, isolated bacteraemia was the most common serious infection, more so in the non-PWUD group. All patients received standard of care antibiotics before switching to dalbavancin.

Compared with the non-PWUD group, the PWUD group had longer antibiotic usage prior to dalbavancin (14.6 vs 10.1 days) and had more patients who had additional antibiotic prescription while on dalbavancin (50.0 percent vs 35.7 percent) and had received >1 dalbavancin dose (44.9 percent vs 37.8 percent). More than 80 percent of patients in both groups completed the intended dalbavancin course.

The PWUD group had younger patients (average age 40.4 vs 56.2 years) and more people experiencing homelessness (24.4 percent vs 2.0 percent) and who had a history of hepatitis C (65.4 percent vs 2.0 percent).

“This is the first study comparing outcomes between PWUD and non-PWUD for serious non-SSTI,” said Zambrano. It is also the largest study of real-world dalbavancin use to date. However, the variable clinical scenarios (eg, different infections and severity of infection) and non-standardized treatment regimens may have limited the findings.

“[Nonetheless,] our study showed that dalbavancin was an effective treatment option for serious non-SSTI regardless of PWUD status. Prospective clinical trials of dalbavancin for different serious infections are needed,” said Zambrano.