The US FDA has granted Orphan Drug Designation to KB407, currently in preclinical development for the treatment of cystic fibrosis (CF), according to manufacturer Krystal Biotech Inc.

KB407 is an inhaled, repeat-dose gene therapy product currently in the preclinical phase with plans to file an IND in 2021. In pre-clinical studies to date, KB407 has been able to successfully transduce human CF patient-derived epithelial cells and deliver functional cystic fibrosis transmembrane conductance regulator (“CFTR”) in vitro in 2D and 3D organotypic systems. Additional data has shown that the therapy is amendable to non-invasive inhaled administration in vivo, as indicated by successful delivery to the lungs through the use of a clinically relevant nebulizer in rodent healthy and diseased small animal models.

The FDA’s Office of Orphan Drug Products grants Orphan Drug Designation to support the development of medicines for underserved patient populations, or rare disorders, that affect fewer than 200,000 people in the United States. Orphan Drug Designation may allow Krystal Biotech to be eligible for a seven-year period of US marketing exclusivity upon approval of KB407, tax credits for certain clinical research costs and a waiver of the Prescription Drug User Fee Act (PDUFA) filing fees, subject to certain conditions.

“We are pleased to receive Orphan Drug Designation for KB407 to treat cystic fibrosis as this is an important step forward in our efforts to address the continued unmet need in this devastating disease,” said Suma M. Krishnan, founder and chief operating officer of Krystal Biotech. “We are excited by the results of the in vitro data thus far, as presented at ASGCT earlier this year, and we look forward to sharing in vivo animal data later this year.”