FDA fast tracks delafloxacin

FDA has granted delafloxacin (Rib-X) as a Qualified Infectious Disease Product (QIDP) for the indications of acute bacterial skin and skin structure infections (ABSSSI) and community-acquired bacterial pneumonia (CABP).

The QIDP designation will enable Rib-X to benefit from certain incentives for the development of new antibiotics, including an additional 5 years of market exclusivity, priority review and eligibility for fast-track status, provided under the new Generating Antibiotic Incentives Now (GAIN) program. GAIN was included in the FDA Safety and Innovation Act (FDASIA), formerly known as PDUFA V, which received bipartisan Congressional support and was signed into law by President Obama in July 2012.

Delafloxacin has the potential to offer broad spectrum coverage as a monotherapy, including for methicillin-resistant Staphylococcus aureus (MRSA), with both intravenous (IV) and oral formulations. With the exception of linezolid (Zyvox, Pfizer), all other currently approved treatments for MRSA offer only IV delivery. In addition to strong Gram-positive potency, delafloxacin has shown excellent in vitro activity against susceptible Gram-negative bacteria, according to a company press release.

"The intent of the GAIN program, which part of FDASIA and includes benefits like priority review status and fast track designation, is to encourage the industry's development of new drugs that will be effective against resistant pathogens, like the superbug MRSA," Mark Leuchtenberger, Rib-X president and chief executive officer, told Formulary.

"This means that we will be able to have more frequent interactions with the FDA around the development and review of our candidate delafloxacin, and if our phase 3 trials are ultimately successful, the FDA review time once an NDA filing has been accepted is shortened to 6 months," Leuchtenberger said.

According to Leuchtenberger, delafloxacin is being developed for use as a first-line antibiotic primarily in hospitals prior to the availability of a specific diagnosis.

"Studies have shown that it has potential to offer broad spectrum coverage as a monotherapy, including MRSA, and it is expected to offer the convenience of both intravenous and oral formulations," he said.

"Delafloxacin is a fluoroquinolone antibiotic," Formulary advisor James M. Wooten, PharmD, associate professor, department of medicine, section of clinical pharmacology, University of Missouri-Kansas City, said. "The reason for the fast-track designation is due to delafloxacin's potential to treat resistant organisms. More studies need to be conducted to determine delafloxacin's effectiveness and ultimate place in the antibiotic armamentarium."