US-based Arcturus Therapeutics has secured orphan drug designation from the US Food and Drug Administration (FDA) for ARCT-032 for the treatment of cystic fibrosis (CF).

Arcturus Therapeutics is a late-stage clinical messenger RNA drug firm. It is engaged in the development of infectious disease vaccines with a focus on liver and respiratory rare diseases.

ARCT-032 has been designed to use the company’s LUNAR lipid-mediated aerosolised platform to provide CFTR messenger RNA to the lungs.

The expression of a functional copy of CFTR mRNA in the lungs can support the restoration of CFTR activity in cystic fibrosis patients and reduce the lung disease progression, Arcturus Therapeutics said.

The first cystic fibrosis patient in the company’s Phase 1b trial successfully completed two administrations of ARCT-032.

The US-based firm said that it is on track to release the interim Phase 1b results in H1 2024.

Arcturus Therapeutics president and CEO Joseph Payne said: “Orphan Drug Designation is a very important regulatory milestone in our development plan for ARCT-032.

“We are executing diligently to accelerate ARCT-032 as a potential new treatment option for people with cystic fibrosis.”

The FDA’s Office of Orphan Products Development gives orphan status to drugs being developed to treat, prevent, or detect a rare disease or condition affecting less than 200,000 people in the US.

The designation offers substantial incentives to advance the drug’s development, such as the possibility of seven years of market exclusivity following FDA approval and tax credits for qualifying clinical trials.

It also offers exemption from the Prescription Drug User Fee Act application fee, and the ability to obtain FDA regulatory guidance for creating a comprehensive drug development plan.

The ARCT-032 programme is assisted by preclinical data in rodents, ferrets and primates, along with evidence of restored CFTR expression and function in human bronchial epithelial cells.

In November last year, Arcturus Therapeutics and Australian vaccines maker CSL Seqirus entered into a licensing deal worth more than $4.5bn for the former’s late-stage self-amplifying mRNA vaccines.