08:19 AM EDT, 10/22/2025 (MT Newswires) -- Arcturus Therapeutics ( ARCT ) said Wednesday its phase 2 clinical trial of ARCT-032, an investigational inhaled mRNA therapy for people with cystic fibrosis, showed "meaningful trends" of clinical activity based on high-resolution computed tomography scans.

In the second cohort of the trial, four out of six adults with class 1 cystic fibrosis exhibited reduction of mucus plug number and mucus volume after 10-milligram doses of the drug over 28 days, the company said. The treatment was generally safe and well tolerated, Arcturus added.

The trial's expanded third cohort is ongoing and aims to enroll up to six subjects to determine if there is a dose escalation response at 15 milligrams, the company said.

Arcturus said it plans to initiate a 12-week safety and preliminary efficacy study in up to 20 participants in H1 of 2026.

The company's shares plunged more than 61% in premarket activity on Wednesday.

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