Clinical experience with eravacycline-based combination therapy for carbapenem-resistant Acinetobacter baumannii pneumonia: a prospective observational case series

Objective This study was conducted to investigate the clinical response, safety, and pharmacokinetic (PK) profile of eravacycline-based combination therapies in patients with pulmonary infections caused by carbapenem-resistant Acinetobacter baumannii (CRAB). Methods A prospective observational case series was conducted on patients with CRAB pneumonia treated at Fujian Medical University Union Hospital between February 2024 and August 2025. Prior to treatment, eravacycline minimum inhibitory concentration were determined. Patients received eravacycline-based combination therapy according to their susceptibility results. Data on clinical responses, microbiological clearance, adverse events, and 28-day all-cause mortality were collected. Eravacycline blood concentrations were measured in a subset of patients. Results Twenty-two patients with CRAB pneumonia (21 with ventilator-associated pneumonia) were enrolled; all had a Clinical Pulmonary Infection Score >6. The mean Acute Physiology and Chronic Health Evaluation II (APACHE II) scores and the Sequential Organ Failure Assessment (SOFA) scores were 13.77 and 6.23, respectively. All CRAB isolates were susceptible to eravacycline (ChiCAST breakpoint ≤1 mg/L). The clinical response rate, microbiological clearance rate, and 28-day mortality were 72.7%, 86.4%, and 13.6%, respectively. Two patients exhibited hypofibrinogenemia, considered an adverse drug reaction related to eravacycline. No associated bleeding events or other adverse events were observed. Nonresponders had significantly higher SOFA and APACHE II scores than clinical responders. Eravacycline PK was assessed in 14 patients and showed considerable interindividual variability. Among the PK parameters, C max correlated significantly with clinical response ( r = 0.729, p = 0.003). Conclusion The preliminary findings of this prospective observational case series indicate that individualized eravacycline-based combination regimens are associated with promising clinical outcomes and microbiological clearance, with good tolerability and a low incidence of adverse events. Additionally, initial blood concentration data provide a reference for future exploration of PK/PD targets in CRAB pneumonia. However, due to the small sample size and limited statistical power, these findings should be considered preliminary and require validation in larger prospective cohorts.