Arcturus' Investigational Inhaled Therapy Lacks Meaningful Lung Function Improvement, Analyst Notes Mixed Picture

Core Insights - Arcturus Therapeutics Holdings Inc. reported interim results from its Phase 2 trial of ARCT-032, an inhaled mRNA therapy for cystic fibrosis, leading to a decline in stock price by 56.30% to $10.12 [8] Group 1: Trial Results - The second cohort of the Phase 2 trial involved six Class I CF adults receiving daily doses of 10 mg ARCT-032 for 28 days, with the treatment being generally safe and well-tolerated [1] - Initial analysis of FEV₁ values from Day 1 to Day 28 did not show meaningful improvement [4] - A post hoc exploratory analysis indicated improvements in lung function for four out of six participants, with an average absolute increase of 3.8% and a relative increase of 5.1% in percent predicted FEV₁ (ppFEV₁) [5] Group 2: Safety and Efficacy - Treatment-related adverse events (AEs) were observed in the Phase 1 study but ceased with continued dosing, and a serious adverse event (SAE) was not deemed related to ARCT-032 [2] - High-resolution computed tomography (HRCT) scans showed reductions in mucus burden in four Class I CF participants, indicating therapeutic activity of ARCT-032 [6] - The ongoing third cohort aims to assess dose escalation at 15 mg and further evaluate safety and tolerability [3] Group 3: Future Directions - Data from the second cohort and ongoing third cohort will inform future studies, including a planned 12-week safety and preliminary efficacy trial set to begin in the first half of 2026 [7] - Analysts suggest that the efficacy of ARCT-032 may improve with longer treatment duration or higher doses, aiming to reduce data variability [8]