FDA Approved New Fluoroquinolone for ABSSSI

The US Food and Drug Administration (FDA) has just approved Melinta Therapeutics’ delafloxacin (Baxdela), a new fluoroquinolone drug designed to treat acute bacterial skin and skin structure infections in adults.

The Baxdela New Drug Application (NDA) approvals were supported by two phase 3 studies in patients with skin and skin structure infections, demonstrating that IV and oral Baxdela monotherapy was statistically non-inferior to the combination of vancomycin plus aztreonam at the FDA primary endpoint of early clinical response at 48-72 hours, according to a statement from Melinta.

Baxdela was well tolerated with a 0.9% discontinuation rate in the phase 3 studies due to adverse events. In addition, Baxdela has not shown any potential for QT prolongation or phototoxicity in definitive clinical studies. There have been no signals of adverse effects on liver function, kidney function, or glucose regulation in controlled clinical studies.

According to the statement from Melinta, The drug is available for intravenous and oral use, and the 450 mg tablet is bioequivalent (area under the curve) to, and interchangeable with the 300 mg IV dose, and can be dosed without regard to food.

Melinta reports that “The most common adverse reactions in patients treated with Baxdela were nausea (8%), diarrhea (8%), headache (3%), transaminase elevations (3%), and vomiting (2%).” Like all fluoroquinolones, delafloxacin has a Boxed Warning to alert healthcare professionals and patients that it can increase risk of “disabling and potentially irreversible serious adverse reactions that have occurred together including tendinitis and tendon rupture, peripheral neuropathy, and central nervous system effects.” In addition, delafloxacin is contraindicated for patients with known hypersensitivity to fluoroquinolones.

In contrast to most FDA-approved fluoroquinolones, which are zwitterionic, delafloxacin has an anionic character. This results in a 10-fold increase in delafloxacin accumulation in both bacteria and cells at acidic pH, which is believed to give the drug an advantage for the eradication of some bacteria in acidic environments.

The drug received the FDA’s fast track designation — a process designed to facilitate the development and expedite the review of drugs to treat serious conditions that fill an unmet medical need. “The purpose is to get important new drugs to the patient earlier,” according to the FDA. It was also given priority review status, which sped the review process from 10 months to 6 months.

Commenting on the approval of the drug, David Hooper, MD, professor of medicine, Harvard University, and chief of Infection Control, associate chief, Division of Infectious Diseases, Massachusetts General Hospital said in a statement, “Antibiotic resistance is a growing concern, and physicians need more tools in the fight against this threat to modern medicine. Approval of new therapies like Baxdela, which is effective against methicillin-resistant Staphylococcus aureus (MRSA) and other serious pathogens, provides physicians another option in addressing the challenges of ABSSSI patients.”