August 10, 2019

Johann Motsch, Cláudia Murta De Oliveira, Viktor Stus, Iftihar Köksal, Olexiy Lyulko, Helen W. Boucher, Keith S. Kaye, Thomas M. File Jr, Michelle L. Brown, Ireen Khan, Jiejun Du, Hee-Koung Joeng, Robert W. Tipping, Angela Aggrey, Katherine Young, Nicholas A. Kartsonis, Joan R. Butterton, and Amanda Paschke9
Clin Infect Dis. 2019 Aug 10. pii: ciz530.
DOI: 10.1093/cid/ciz530 | PMID: 31400759

Abstract

BACKGROUND: The β-lactamase inhibitor relebactam can restore imipenem activity against imipenem-nonsusceptible gram-negative pathogens. We evaluated imipenem/relebactam for treating imipenem-nonsusceptible infections.

METHODS: Randomized, controlled, double-blind, phase 3 trial. Hospitalized patients with hospital-acquired/ventilator-associated pneumonia, complicated intraabdominal infection, or complicated urinary tract infection caused by imipenem-nonsusceptible (but colistin- and imipenem/relebactam-susceptible) pathogens were randomized 2:1 to 5-21 days imipenem/relebactam or colistin+imipenem. Primary endpoint: favorable overall response (defined by relevant endpoints for each infection type) in the modified microbiologic intent-to-treat (mMITT) population (qualifying baseline pathogen and ≥1 dose study treatment). Secondary endpoints: clinical response, all-cause mortality, and treatment-emergent nephrotoxicity. Safety analyses included patients with ≥1 dose study treatment.

RESULTS: Thirty-one patients received imipenem/relebactam and 16 colistin+imipenem. Among mITT patients (n = 21 imipenem/relebactam, n = 10 colistin+imipenem), 29% had Acute Physiology and Chronic Health Evaluation II scores >15, 23% had creatinine clearance <60 mL/min, and 35% were aged ≥65 years. Qualifying baseline pathogens: Pseudomonas aeruginosa (77%), Klebsiella spp. (16%), other Enterobacteriaceae (6%). Favorable overall response was observed in 71% imipenem/relebactam and 70% colistin+imipenem patients (90% confidence interval [CI] for difference, -27.5, 21.4), day 28 favorable clinical response in 71% and 40% (90% CI, 1.3, 51.5), and 28-day mortality in 10% and 30% (90% CI, -46.4, 6.7), respectively. Serious adverse events (AEs) occurred in 10% of imipenem/relebactam and 31% of colistin+imipenem patients, drug-related AEs in 16% and 31% (no drug-related deaths), and treatment-emergent nephrotoxicity in 10% and 56% (P = .002), respectively.

CONCLUSIONS: Imipenem/relebactam is an efficacious and well-tolerated treatment option for carbapenem-nonsusceptible infections.

CLINICAL TRIALS REGISTRATION: NCT02452047.

Source (Full Text): https://academic.oup.com/cid/advance-article/doi/10.1093/cid/ciz530/5546004