Inhaled therapy ARCT-032 wins FDA orphan drug status for CF

Phase 1, 2 trials now testing medicine in patients and healthy volunteers

Patricia Inácio, PhD avatar

by Patricia Inácio, PhD |

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The U.S. Food and Drug Administration (FDA) has granted orphan drug status to ARCT-032, Arcturus Therapeutics’ inhaled experimental treatment for cystic fibrosis (CF).

The designation is intended to encourage the development of therapies for rare diseases, or those affecting fewer than 200,000 people in the U.S. It provides incentives, including exemption from FDA application fees and assistance in drug development design, as well as seven years of market exclusivity if the treatment ultimately is approved.

ARCT-032 is now being tested in two separate Phase 1 clinical trials that are assessing the therapy’s safety and tolerability in healthy people and those with CF.

“Orphan drug designation is a very important regulatory milestone in our development plan for ARCT-032,” Joseph Payne, Arcturus’ president and CEO, said in a company press release.

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

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Mutations in the CFTR gene, leading to the impairment or absence of a protein of the same name, are the root cause of CF. They result in a thick and sticky mucus accumulating in several organs, particularly including the lungs.

ARCT-032 contains a type of molecule called messenger RNA, or mRNA — a template for protein production derived from DNA — that carries the information to make the CFTR protein. That protein controls the movement of chloride across the cell membrane.

The therapy is designed using a platform called LUNAR. It is inhaled in tiny, fat-like particles that unload their cargo into lung cells so that a functional CFTR protein can be produced.

Dosing has been completed in a Phase 1a clinical study (NCT05712538) designed to assess the safety and tolerability of ARCT-032 versus a placebo in healthy adults. An estimated 32 people are enrolled.

The trial also is evaluating the treatment’s pharmacokinetics, or its movement into, through, and out of the body.

Participants were randomly assigned to receive single ascending doses of inhaled ARCT-032 or the placebo. Follow-up assessments will be conducted over four weeks.

According to Arcturus, a Phase 1b trial also is underway to test ARCT-032 in up to eight adults with CF.

Its goal is to assess the safety, tolerability, and pharmacokinetics of the treatment in CF patients. Exploratory measures also will include ARCT-032’s impact on lung function and mucus clearance after two inhaled doses.

Enrollment started in October. The first patient has received two doses of ARCT-032. Interim data is expected by June 2924.

The clinical development of ARCT-032 is being supported by funding from the Cystic Fibrosis Foundation. The investment is part of the foundation’s Path to a Cure, a $500 million initiative that aims to boost the development of therapies that target the cause of CF.

ARCT-032 in October also was granted the FDA’s rare pediatric disease designation, meant to boost the development of medicines for conditions mainly affecting children. If the treatment is approved, Arcturus may receive a voucher to be used for shortened review of another product.