Omadacycline noninferior to Zyvox in treating ABSSSIs, including MRSA
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Treatment of skin infections with the antibiotic omadacycline was noninferior to Zyvox in a phase 3 study, researchers said at the European Congress of Clinical Microbiology and Infectious Diseases in Vienna.
Paratek Pharmaceuticals’ investigational drug was safe and effective in treating several acute bacterial skin and skin structure infections (ABSSSIs), including MRSA, they said.
“With this new microbiology analysis, we further increase the body of evidence regarding the utility of omadacycline against serious community-acquired infections and pathogens with known resistance patterns, including MRSA,” study researcher Evan Loh, MD, Paratek’s chief operating officer and chief medical officer, said in a news release.
The trial — named the Omadacycline Acute Skin and Skin Structure Infections Study (OASIS) — tested the efficacy of once-daily doses of omadacycline in IV and oral form compared with that of twice-daily Zyvox (linezolid, Pfizer). The randomized, double blind, multicenter study included two populations of adult patients with ABSSSIs. One was a modified intent-to-treat (mITT) population without a sole gram-negative pathogen at screening, and the other was a clinically evaluable (CE) population of those with at least one gram-positive pathogen.
Patients started with IV doses of either drug but could be switched to oral doses after at least 3 days of treatment. Early clinical response — defined as a reduction in lesion size of at least 20% — was measured at 48 to 72 hours after the first dose. Post-therapy clinical success was measured at 7 to 14 days after the final dose.
In the mITT population, 316 patients received omadacycline and 311 received Zyvox. Early clinical response for omadacycline was 84.8%, compared with 85.5% for Zyvox, the researchers said. Post-therapy clinical success rates were 86.1% and 83.6%, respectively.
In the CE population, 269 patients received omadacycline and 260 received Zyvox. Post-therapy clinical success rates were 96.3% and 93.5%, respectively.
Treatment-emergent adverse events (TEAEs) occurred in 48.3% of patients receiving omadacycline and 45.7% of those taking Zyvox, the researchers said. Serious TEAEs occurred in 3.4% and 2.5%, respectively. Of those receiving omadacycline, 1.9% stopped therapy because of TEAEs, compared with 2.2% of those receiving Zyvox.
Paratek officials announced that they expect data from a phase 3 study of once-daily, oral-only omadacycline for ABSSSIs as early as the end of June. – by Joe Green
Reference:
O’Riordan WA, et al. Abstract OS0606. Presented at: European Congress of Clinical Microbiology and Infectious Diseases; April 22-25, 2017; Vienna.
Disclosure: Loh is employed by Paratek.