Omadacycline (OMC) is a novel aminomethylcycline antibiotic, available in once-daily intravenous and oral formulations, that has been studied in 1 phase 3 trial (OPTIC) for community-acquired bacterial pneumonia (CABP) and 2 phase 3 trials (OASIS-1 and OASIS-2) for acute bacterial skin and skin structure infections (ABSSSIs). Structural modifications at the C-7 and C-9 positions allow OMC to overcome the 2 main mechanisms of resistance to tetracyclines, efflux pumps and ribosomal protection. Forty-one clinical isolates (24 Gram-positive and 17 Gram-negative) were selected for characterization (26 from the OPTIC study, 10 from the OASIS-1 study, and 5 from the OASIS-2 study). Susceptibility testing and interpretation were performed by the Clinical & Laboratory Standards Institute methods. Gram-positive isolates were selected based on tetracycline and/or macrolide, lincosamide, streptogramin B MLSB phenotypes, and tetracycline nonsusceptible (NS) Gram-negative isolates were selected. The efficacy end point was the investigator’s assessment of clinical response at posttherapy evaluation (PTE).
Clinical success was noted in 14/16 (87.5%) OMC-treated subjects in OPTIC and 5/5 (100%) OMC-treated subjects in the combined OASIS studies.
These results indicate that OMC’s in vivo efficacy is not affected by tetracycline and/or MLSB resistance mechanisms, and expands the data on the efficacy of OMC among patients with tetracycline-NS pathogens.
Source: Mendes RE, et al. IDWeek 2018. Abstract 1364.