*Updated on 11/02/2017 at 11:54 AM EST
This week, Melinta Therapeutics announced that the US Food and Drug Administration (FDA) has cleared 3 antimicrobial susceptibility tests (ASTs) that will help health care practitioners use its new fluoroquinolone Baxdela, appropriately.
Baxdela (delafloxacin) was recently approved by the FDA for the treatment of acute bacterial skin and skin structure infections (ABSSSI) in adults, and is available in both tablet, 450 mg, and intravenous, 300 mg, formulations; it can be dosed for 5 to 14 days, twice daily.
The 3 cleared ASTs are: Hardy Diagnostics’ Delafloxacin Antimicrobial Susceptibility Disk (HardyDisk), Liofilchem Delafloxacin MIC Test Strip (MTS), and Thermo Scientific Sensititre MIC System.
"Due to the rise in antibiotic resistance, it is important for physicians to perform testing to ensure that an appropriate antibiotic is chosen to treat an infection. These tests will tell the physician which antibiotics will treat the identified bug. Susceptibility testing is also important to monitor resistance development at the local, regional, national and global level,"Melinta's chief medical officer Sue Cammarata, MD, told Contagion®.
ASTs are used to establish just how effective a specific antibiotic is against harmful bacterial pathogens; they are essential for helping health care practitioners understand how to use a drug correctly. “The value that antimicrobial susceptibility testing provides to clinicians to inform antimicrobial selection in support of antimicrobial stewardship efforts cannot be overstated,” said Jason C. Gallagher, PharmD, FCCP, FIDSA, BCPS, Contagion’s new editor in chief in a recent article.
As for how these three tests in particular can help physicians use Baxdela appropriately? "Antibiotics are typically started before the infecting bacteria is known. Once a
pathogen is isolated, these tests can confirm that Baxdela will effectively treat it. The availability of these tests will allow the physician to use Baxdela in a manner that will more likely ensure positive clinical outcome for the patient," Dr. Cammarata said.
However, oftentimes, the role of ASTs is undermined by delays—that could last for years—between the approval of a drug by the FDA and FDA-approved inclusion of susceptibilities to the drug. “When facing a critically ill patient with a suspected Gram-negative bacterial infection, delayed appropriate therapy can be lethal,” according to Dr. Gallagher.
Therefore, Melinta Therapeutics has been working with manufacturers to develop these ASTs in accordance with their phase 3 PROCEED studies. "For the speed of the approvals, it all came down to good communication on behalf of all of the parties (Melinta, Manufacturers, and FDA DAIP and CDRH at FDA) to expedite the review process as much as possible," Dr. Cammarata shared with us. "Two of the three devices are considered “manual methods” (Liofilchem gradient strip and Hardy disk) and are not commercial automated AST panels while the third device (ThermoFisher Sensititre) is a considered an automated AST method. It will still be several years before delafloxacin is on the other automated systems such as the Microscan, Phoenix and Vitek II."
In a recent press release, Melinta’s president and chief operating officer John Temperato added, “The FDA was supportive of our plans to coordinate our New Drug Application approval with AST clearance. It was clear to us that they understood the importance of the tests.” He noted that having both the antibiotic and the diagnostic tools receive approval at the same time is extremely beneficial for health care providers. “Because these tools will be available with Baxdela at launch, doctors will have the full set of clinical tools they need in order to make a clinical decision on how to treat patients appropriately.”
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