Arcturus Therapeutics Holdings Inc. Q2 FY2025 earnings call

ARCT-032 Program: Advancing enrollment in adult CF Phase II study. Completed enrollment/dosing in 5-mg cohort, proceeding to 10-mg cohort. Expecting Phase II interim data in September, plan to complete enrollment by year-end, and FDA meetings in 2026 for pivotal trials. ### ARCT-810 Program: Positive interim data from Phase II studies, showing glutamine normalization and improved urea cycle function. Preparing for FDA meetings on Phase III trial design. ### CoStave: CSL filed marketing authorization to UK MHRA, expected approval next month. Meiji Seika filed NDA to PMDA for Japan, US BLA filing on track for September 2025. ### ARCT-2138: Phase I study in young and older adults showed immunogenicity against all influenza strains. ### ARCT-2304: Received FDA Fast Track designation, completed recruitment in Phase I trial, results expected later in 2025. Restructuring to focus on CF and OTC programs, extending cash runway to 2028.

Revenue for the 3 months ended June 30, 2025, was $28 million, and $58 million for the 6 months ended June 30, 2025, representing decreases compared to the prior year. Total operating expenses for the 3 months ended June 30, 2025, were $40 million vs. $71 million in 2024, and $86 million vs. $139 million for the 6 months. R&D expenses decreased due to lower manufacturing and clinical costs, but increased for CF. G&A expenses decreased due to reduced share-based compensation and headcount.

CF: Expect to share Phase II data for 2 cohorts in September. Plan to meet with FDA in 2026 for Phase II data and pivotal trial plans. ### OTC: Prepare for FDA meetings on Phase III trial design alignment in 2026. ### Vaccines: CoStave approvals expected in UK (next month), Japan (fall), US (2026). ARCT-2138 and ARCT-2304 clinical data expected later in 2025.

Forward-looking statements involve known and unknown risks, uncertainties, and assumptions that may cause actual results to differ. Regulatory uncertainties and potential issues with toxicology/tolerability in inhaled RNA therapeutics are areas of concern.

Q: Maybe 2 CF-related questions. As we get closer to the readout, how to think about the bar for success and ratio of modulator eligible to noneligible patients?

A: Lili, historical precedent for CF is a 3% threshold. Strong majority of enrolled CF subjects are Class I (modulator nonresponders).

Q: Talk about safety/efficacy of ARCT-032 and OTC pivotal design alignment.

A: Toxicology/tolerability issues in inhaled RNA therapeutics are addressed by Arcturus' delivery system and purification IP. For OTC, FDA is aware of biomarker data and strategy for Phase III trial alignment.

Q: Confirm highest dose data for CF and definition of clinically meaningful.

A: Yes, 28-day data for 10-mg cohort. 3% is reasonable, considering CF population's FEV degradation.

Q: Interest in patient enrollment after Vertex/Moderna trial pause and OTC higher dose thoughts.

A: Limited overlap with competitors in CF recruitment. For OTC, conservative expectation to consider 0.7 mg per kg but no definitive decision yet.

Q: CF data analysis without placebo arm and OTC full data timeline.

A: Placebo strategy for Phase III. OTC full data depends on whether 0.7 mg per kg cohort is included, with parallel FDA discussions ongoing.