Omadacycline is noninferior to moxifloxacin in treating community acquired bacterial pneumonia

1. Intensive care unit (ICU) hospitalized adults with community acquired bacterial pneumonia had comparable clinical responses when taking antibiotic courses of omadacycline, a new trial antibiotic, versus moxifloxacin.

2. The observed safety profile of omadacycline was noted to be consistent with other known tetracyclines.

Evidence Rating Level: 1 (Excellent)

Study Rundown: Community acquired pneumonia is a common cause of hospitalization; it also has increasing rates of resistance to traditional antibiotics necessitating research for new antibiotic agents. Omadacycline is a new antibiotic from the tetracycline class, and it has in vitro activity against known pathogens commonly implicated in community acquired bacterial pneumonia. In this current study, researchers assessed the efficacy and safety profile of omadacycline versus a traditional antibiotic, moxifloxacin, among adult ICU patients with community acquired pneumonia. Overall, omadacycline was noninferior to moxifloxacin when early clinical response and overall clinical response rates were assessed, based on patient survival and symptoms. Researchers also noted that the safety profile of omadacycline was comparable to other tetracyclines.

Though results may not be generalizable to a larger patient population, this study still highlights that clinicians may be able to consider newer antibiotic agents to treat resistant bacterial community acquired pneumonia. A notable strength includes thorough microbial assessment which determined the causative pathogen in 50% of cases. This may also present a limitation as real world rates of pathogen identification are dramatically lower.

Click to read the study in NEJM

Relevant Reading: New antibiotics for community-acquired pneumonia

In-Depth [randomized controlled trial]: This multicenter, phase III, double-blind, noninferiority randomized control trial enrolled 774 participants across 86 sites between 2015 to 2017. Patients were randomized in a 1:1 ratio to either receive 7 to 14 days of 100 mg omadacycline or 400 mg moxifloxacin (both initially administered intravenously with option to switch to oral formulation after 3 days). The primary outcome of this study was evidence of an early clinical response, assessed between 72 to 120 hours after the initial dose of antibiotics were given. Investigators assessed for symptoms of community acquired pneumonia (cough, sputum production, pleuritic chest pain, dyspnea) and measured if there was improvement in symptoms to determine if there was adequate early clinical response. Secondary endpoints included investigator-assessed clinical response at the post-treatment evaluation period (5 to 10 days after the last dose of antibiotic was given) and evidence of adverse events. Results showed that the most frequently encountered identified pathogens that caused community acquired bacterial pneumonia were Mycoplasma pneumoniae (33%). Streptococcus pneunomiae (20%), Legionella pneumophila (19%), Chlamydia pneumoniae (15%) and Haemophilus influenza (12%). Omadacycline was shown to be noninferior to moxifloxacin when early clinical response rates were measured among an intention-to-treat population (81.1% vs 82.7% respectively; -1.6 percentage difference; 95% confidence interval [CI], -7.1 to 3.8). Clinical response rates were also similar when assessed at the end of the treatment course (87.6% vs 85.1%; 2.5 percentage difference; 95% CI, -2.4 to 7.4). Adverse events occurred in 41.1% of patients in the omadacycline group and 48.5% of patients in the moxifloxacin group. The most common adverse events included gastrointestinal events, such as constipation vomiting and nausea. Severe adverse events occurred in 6.0% of omadacycline patients and in 6.7% of moxifloxacin patients, including twelve total deaths (8 in omadacycline group and 4 in the moxifloxacin group).

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