Arcturus Therapeutics (ARCT) Leerink Global Healthcare Conference 2026 summary

Cystic fibrosis (CF) program updates

• Completed three cohorts in phase II with 5 mg, 10 mg, and 15 mg dosing, all well-tolerated over 28 days.

• Early signals of biological proof of concept observed, including reduction in mucus plugging via high-res CT scans.

• Upcoming 12-week phase II study will use multiple baseline measures and a narrower FEV1 range to reduce variability and optimize patient selection.

• Study endpoints include FEV, LCI, two quality-of-life measures, and CT imaging, with data to inform regulatory discussions.

• Expansion to Europe and Middle East sites due to higher prevalence of Class 1 CF and equivalent standards of care.

Regulatory and clinical development plans

• FDA open to LCI as a pivotal endpoint in adults; natural history studies underway to support future filings.

• Conservative expectation is a phase III study after the 12-week phase II, with size and duration dependent on upcoming data.

• Open-label 12-week study to initiate soon, with data sharing after enrollment milestones; no specific timing guided yet.

Ornithine transcarbamylase deficiency (OTC) program

• Multiple phase I and II studies completed in adults and adolescents; focus shifting to pediatric population due to high unmet need.

• Ongoing Type C FDA meetings to clarify regulatory path for pediatric approval, with expected clarity in the next three months.

• Novel 15N ureagenesis assay introduced; ammonia control likely to be a key endpoint for severe pediatric cases.

• Aggressive prioritization of pediatric development, with adult/adolescent as potential extensions.