medwireNews: Results from the phase III ESTABLISH-1 study show that the new antibiotic tedizolid phosphate is noninferior to linezolid for the treatment of acute bacterial and skin structure infections (ABSSSIs).
The investigators hope that tedizolid phosphate may become a new option for treating infections such as methicillin-resistant Staphylococcus aureus (MRSA), because while linezolid is effective against this infection, it is the only oral drug currently approved for ABSSSIs caused by MRSA and linezolid-resistant MRSA strains have already been reported. There have also been concerns about the safety profile of linezolid.
Philippe Prokocimer (Trius Therapeutics Inc, San Diego, California, USA) and colleagues recruited 667 adults (aged 18 years or older) with ABSSSIs, mostly S. aureus infections, to take part in the trial.
The participants were randomly assigned to take oral tedizolid phosphate 200 mg/day for 6 days (n=332) or oral linezolid 600 mg every 12 hours for 10 days (n=335).
As reported in JAMA, the two groups had very similar 48- to 72-hour response rates (no increase in lesion size and normal oral temperature), at 79.5% and 79.4% of patients in the tedizolid phosphate and linezolid groups, respectively.
Sustained clinical response rates at day 11 were also similar, at 69.3% and 71.9% in the corresponding groups. And investigator-assessed clinical treatment success rates, measured 1-2 weeks following the end of treatment, were 85.5% with tedizolid phosphate and 86.0% with linezolid.
The team notes that when the subgroup of 178 patients with MRSA was assessed separately, similar efficacy rates for the two drugs were observed.
Treatment-associated adverse events were mostly mild or moderate and occurred in 40.8% of the tedizolid phosphate group compared with 43.3% of the linezolid group.
"Tedizolid is a new oral antibiotic that appears efficacious using a short course and may have a better safety profile than linezolid," say Shira Doron and Helen Boucher (Tufts University School of Medicine, Boston, Massachusetts, USA), authors of an accompanying editorial.
"The current study brings the Infectious Diseases Society of America's 10 x 20 initiative 1 step closer to its goal of regulatory approval of 10 new antibacterial drugs with activity against drug-resistant bacteria by 2020. If approved, tedizolid will be the first oral drug in this initiative."
Doron and Boucher conclude: "Future studies should add to the understanding of which patients may be treated safely with shorter-course therapy and further explore the correlation between early and sustained response in ABSSSI."
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