James McKinnell, MD: Outcomes of Delafloxacin Treatment for Skin Structure Infections

James McKinnell, MD, David Geffen School of Medicine, UCLA: I think it's really important for doctors in all branches of care to pay attention to novel antibiotics. I think as we learn about antibiotics, we see the weaknesses of old agents and the benefits of new agents and when you're looking at delafloxacin, there's some significant differences compared to other fluoroquinolones. It simply has anti-MRSA activity, it means you can use it for your skin, and the safety profile is different. There's no QT prolongation for delafloxacin that's been observed, and that's a huge advantage for traditional agents particularly in the elderly patient population.

So the safety data being presented at this meeting talks about delafloxacin verses vancomycin and aztreonam, and the overall summary is that the delafloxacin was noninferior to vancomycin aztreonam. There were some differences in discontinuation where delafloxacin was discontinued less frequently than vancomycin, and the side effects are characterized as relatively mild. So, it's encouraging to see what may be a more tolerable agent there.

So this is a very different change from old fluoroquinolones. Again, the idea of that safety factor of no QT prolongation, when especially if you're looking in the elderly patient population where your number needed to harm for a fluoroquinolone from just simply QT prolongation could be 1 in 30 to have an arrhythmia event, to 1 in 500 to have potentially torsades de pointes — to be able to get rid of that, is a major step forward, so that's an encouraging development for fluoroquinolones. And you have to understand the use of this drug, fluoroquinolones are drugs that traditionally been ones that we've tried to avoid for a whole host of reasons, yet there were 3 million fluoroquinolone prescriptions written last year. So here's potentially a safer, different option, that may be tolerable for skin and skin structure infections.