The Efficacy and Safety of Meropenem and Tobramycin vs Ceftazidime and Tobramycin in the Treatment of Acute Pulmonary Exacerbations in Patients With Cystic Fibrosis

BackgroundCystic fibrosis (CF) is characterized by chronic pulmonary infection with acute pulmonary exacerbations (APEs) requiring IV antibiotic treatment. We report on a blinded comparative trial of IV meropenem (40 mg/kg to 2 g q8h) or ceftazidime (5 mg/kg to 2 g q8h), each of which was administered with IV tobramycin (at a serum peak of ≥ 8 μg/mL and a trough of < 2 μg/mL), as treatment for CF patients with APEs.MethodsPatients who were ≥ 5 years of age who were infected with ceftazidime-susceptible Pseudomonas aeruginosa were stratified by lung function and randomized to treatment with meropenem/tobramycin or ceftazidime/tobramycin. Patients infected with Burkholderia cepacia complex or ceftazidime-resistant P aeruginosa were assigned to receive open-label meropenem/tobramycin. Clinical response was assessed by spirometry to determine the change in percent predicted FEV1 and by a clinical acute change score (ACS).ResultsOne hundred two patients were randomized to meropenem/tobramycin (n = 50) or ceftazidime/tobramycin (n = 52). Nineteen patients received open-label meropenem/tobramycin. FEV1 was improved at the end of treatment (EOT) with meropenem/tobramycin (mean [± SD] increase, 38.8 ± 52.3%) and with ceftazidime/tobramycin (mean increase, 29.4 ± 35.1%; p < 0.0001 vs baseline values). The proportion of patients with ≥ 15% relative increase from baseline FEV1 (satisfactory response) at day 7 was 62% for the meropenem/tobramycin group and 44% for the ceftazidime/tobramycin group (p = 0.04). The median time to FEV1 response was 4 days for meropenem/tobramycin therapy vs 6 days for ceftazidime/tobramycin therapy. Similarly, FEV1 improved in the open-label group (mean increase, 12.5 ± 25.7%; p = 0.05). ACS improved in all three groups at EOT (p < 0.0001 vs baseline values).ConclusionsTherapy with both meropenem/tobramycin and ceftazidime/tobramycin improved pulmonary and clinical status and reduced sputum bacterial burden in CF patients with APEs. A larger proportion of patients receiving meropenem/tobramycin therapy demonstrated a satisfactory FEV1 response at day 7. Resistant P aeruginosa emerged infrequently during treatment with both regimens.