Arcturus Therapeutics (ARCT) Citigroup’s Biopharma Back to School Summit 2026 summary

Key program updates

• Advanced self-amplifying mRNA technology supports both vaccine and therapeutics divisions, with vaccines approved in 32 countries and used to fund the therapeutics pipeline.

• Lead liver platform asset targets ornithine transcarbamylase (OTC) deficiency, with a phase II data readout and regulatory update expected later this month.

• Inhaled mRNA platform for cystic fibrosis (CF) is in a 12-week open-label study, with a go/no-go phase III decision guided for Q4, triggering up to $40M in funding from Thermo Fisher.

• Regulatory feedback for OTC program has been positive, with distinct metrics for pediatric (ammonia) and adult (glutamine) populations.

• Comprehensive update on intravenously dosed mRNA therapeutics platform for the liver is planned alongside OTC data.

Biomarker and regulatory insights

• OTC program focuses on ammonia and glutamine as key biomarkers, with orotic acid and 15N-ureagenesis assay as supportive measures.

• Pediatric patients emphasize ammonia control due to severe disease, while adults focus on glutamine reduction for symptom relief.

• Regulatory path and detailed feedback from Type C meetings will be disclosed with the upcoming data readout.

• 15N-ureagenesis assay is considered exploratory and supportive, not a primary endpoint.

• Patient-reported outcomes, such as feeling less foggy and improved protein intake, will be included in future updates.

Cystic fibrosis program details

• Inhaled mRNA therapy has overcome historical safety and tolerability challenges through proprietary lipid nanoparticle and purification technologies.

• Current study doses 10mg daily for 12 weeks in up to 20 patients, focusing on those with null mutations and high unmet need.

• Five clinical endpoints: FEV1, lung clearance index (LCI), high-resolution CT, and two quality-of-life measures (CFQ-R, EQ-5D).

• Phase III decision is based on collective improvement or stabilization across endpoints, with no fixed threshold due to first-mover status.

• Thermo Fisher's funding is in exchange for commercial manufacturing exclusivity, not royalties or equity.