IV antibiotics not superior to oral therapy for eradicating P. aeruginosa in cystic fibrosis

Treatment with IV antibiotics, compared with oral therapy, did not achieve sustained eradication of Pseudomonas aeruginosa in a greater proportion of patients with cystic fibrosis, according to results of the TORPEDO-CF trial.

“Current evidence supports starting antibiotic regimens that aim to eradicate P. aeruginosa as soon as the infection is diagnosed to disrupt nascent biofilms and prevent progression to chronic infection,” Simon C. Langton Hewer, MD, consultant pediatrician in the department of pediatric respiratory medicine at Bristol Royal Hospital for Children at the University of Bristol, U.K., and colleagues wrote. “However, evidence to suggest that any one regimen is better than another is absent.”

Researchers conducted a multicenter, parallel-group, open-label, randomized controlled trial of 286 patients older than 28 days with an isolate of P. aeruginosa. The study was conducted from October 2010 to January 2017. Patients were randomly assigned to 14 days of IV ceftazidime (Pfizer) and tobramycin (Pfizer; n = 137) or 12 weeks of oral ciprofloxacin (Pfizer; n = 149). Both groups also received inhaled colistimethate sodium.

The primary outcome, eradication of P. aeruginosa at 3 months and remaining free of infection out to 15 months, was achieved in 44% of the IV group compared with 52% of the oral group. Those randomly assigned IV ceftazidime and tobramycin were less likely to achieve sustained eradication of infection, but the researchers noted the between-group difference was not significant (RR = 0.84; 95% CI, 0.65-1.09).

In other results, at 1 year, fewer patients in the IV group were admitted to the hospital compared with the oral group. Both groups reported similar health-related quality of life, which the researchers said suggests that 2 weeks of IV antibiotics did not have a negative effect.

Researchers observed 11 serious adverse events that occurred in 10 (8%) patients in the IV group and 17 that occurred in 12 (8%) patients in the oral group. The most common adverse events in either group included cough, upper respiratory tract infection and productive cough.

In an economic evaluation, those in the oral antibiotic group had lower treatment costs compared with the IV group (incremental difference in mean costs, 5,939 British pounds; 95% CI, –7,107 to –4,666).

“Because there were no important clinical benefits to the use of intravenous over oral therapy, the large difference in cost suggests that oral therapy should usually be recommended for eradication of early infection with P. aeruginosa in cystic fibrosis,” the researchers wrote. “If the findings of this trial are implemented in routine clinical practice, most patients will receive oral eradication treatment as an outpatient and many hospital admissions will be avoided, which in turn will reduce both treatment burden and health care costs.”