Background and importance Aztreonam lysine inhalation solution (AZLI) is approved for nebulised treatment (nebT) of pulmonary Pseudomonas aeruginosa infections in patients with cystic fibrosis (CF). The clinical benefit of nebulised AZLI in non-CF, such as bronchiectasis (BC) or lung transplant (LT) patients with chronic gram negative infection, has not been clearly established.

Aim and objectives To assess the safety and effectiveness of AZLI for nebT in patients with non-CF BC or LT colonised by gram negative chronic bacteria.

Material and methods This was an observational retrospective study in patients with non-CF BC or LT affected by chronic gram negative bacterial infection who started AZLI in 2013–2019. Clinical data were collected from the hospital medical records: hospital admissions, infective bacteria, previous nebT, safety and effectiveness date of AZLI. Mean (SD) respiratory function tests (FVC, FEV₁, FEF25–75) were analysed for each patient, along with AZLI treatment.

To evaluate treatment effects (time=0 vs follow-up data), variance analysis (ANOVA) was applied (SPSS).

Results The study included 15 patients (aged >18 years) previously treated with alternative nebT. Reasons for stopping previous treatment were: tobramycin/colistin intolerance (n=6, 40%), tobramycin/colistin resistance (n=7, 46.7%) and no clinical improvement (n=2, 13.3%). Patients were classified by diagnosis: BC (n=7; 28.6% men) and LT (n=8; 50.0% men). AZLI was administered in ‘on/off’ cycles in combination with other nebT or in monotherapy (BC, n=1 (14.3%); LT, n=3 (37.5%)). Bacteria causing chronic infection was P aeruginosa in BC (n=7;100%), and in LT, P aeruginosa (n=6; 75%) and Proteus mirabilis (n=2; 25%).

AZLI treatment duration was 20.6±14.2 months (BC) and 10.1±9.7 months (LT). Respiratory function tests during AZLI (mean values of the population) are shown in table 1.

Comparing BC with LT, a statistically significant improvement was observed in FVC (p=0.011) and FEF25–75 (p=0.005) but this was not clinically relevant. BC annual emergency admissions were 0.07 before and 0.42 during AZLI; annual rates of hospital admissions were 0.44 and 0.55, respectively. Remission data (negative results in sputum burdens) were: BC (n=2, 28.6%) and LT (n=1, 12.5%). The most commonly reported treatment emergent adverse effects (AE) were dyspnoea, bronchospasm and arthralgias in BC (n=3; 42,9%). There were no AE in LT and no deaths in either group.

Conclusion and relevance The results suggest that off-label use of AZLI in complicated chronic infected patients could control gram negative infection and neutralise sputum burdens in some cases, while maintaining lung function and decreasing accelerated clinical deterioration.

References and/or acknowledgements No conflict of interest.