Paratek: Phase 3 Data Show Omadacycline Effective Against Common Skin Pathogens, Including MRSA

Analysis of microbiology data from a Phase 3 study of omadacycline in acute skin infections shows that once-daily treatment with IV-to-oral omadacycline is effective in treating the most frequently isolated bacterial pathogens associated with skin infections, including methicillin-resistant Staphylococcus aureus (MRSA), developer Paratek reports. These findings were presented for the first time at the annual meeting of the European Congress of Clinical Microbiology and Infectious Diseases (ECCMID 2017) in Vienna, Austria. 

The Omadacycline Acute Skin and Skin Structure Infections Study (OASIS) was a global Phase 3 randomized, double-blind, multi-center study comparing the safety and efficacy of IV-to-oral once-daily omadacycline with twice-daily linezolid over a seven-to-14-day course of therapy in 645 treated adult patients with acute bacterial skin and skin structure infections (ABSSSI). The modified intent-to-treat (mITT) population included in analysis was comprised  of randomized subjects without a sole Gram-negative pathogen at screening (n=627). Among this population, infection type broke down as follows: 33% wound infection; 38% cellulitis/erysipelas; and 29% major abscess. At Post Therapy Evaluation (PTE, seven – 14 days after the last day of treatment), once-daily omadacycline was effective across all infection types studied. Compared to twice-daily linezolid, efficacy for once-daily omadacycline was comparable in wound infection (81% vs 81%), cellulitis/erysipelas (91% vs 85%), and major abscess (85% vs 85%). 

Further analysis of the micro-mITT population, which included patients with at least one Gram-positive pathogen at screening (n=455), showed that the most common pathogen was Staphylococcus aureus (68% overall, 61% MSSA and 39% MRSA) followed by Streptococcus anginosus (19%) with mixed Gram-positive and Gram-negative infections in 15% of the patients. Overall clinical success at PTE in this.

Additionally, economic studies conducted by Paratek suggest that treatment with omadacycline may reduce hospital stays and associated costs. Additionally, a decision-analytic, cost-minimization model was constructed from the hospital perspective to compare the costs of inpatient treatment with IV vancomycin (current standard of care) versus outpatient omadacycline for the treatment of ABSSSI patients with few or no comorbidities presenting to the emergency department. Conservatively assuming that treatment with inpatient treatment with vancomycin is ~$6500 U.S. dollars, switching an individual patient from vancomycin inpatient treatment to outpatient omadacycline was estimated to save $2,500 to $4,000 per patient, depending on use of observation unit and inputted daily cost of omadacycline. It was also estimated that up to 48% of omadacycline patients discharged home from the emergency department could be subsequently admitted to the hospital after 3 days of omadacycline oral while maintaining budget neutrality.