Arcturus Therapeutics Holdings Inc. announced it is providing mid-year updates for ARCT-810, an investigational mRNA therapeutic to treat ornithine transcarbamylase (OTC) deficiency, and ARCT-032, an investigational inhaled mRNA therapeutic to treat cystic fibrosis (CF). ARCT-810 (OTC Deficiency) Update: The double blind ARCT-810 Phase 2 study in the EU and UK has completed enrollment of eight (8) subjects, including adolescents and adults, at the 0.3 mg/kg dose level. The participants in this group are randomized 3:1 and receive 6 doses of ARCT-810 or placebo administered every 14 days.

Treatment and follow-up are ongoing with the safety and complete set of biomarker data expected later this year. ARCT-810 is expanding the Company?s clinical program in the U.S. by enrolling patients with more severe disease. Patient screening has been initiated and the Company expects the Phase 2 clinical program to be completed in the United States.

More details pertaining to the U.S. trial expansion and interim data will be provided later this year. ARCT-032 (CF) Update: The Company plans to submit an IND application in the next 60 days for an ARCT-032 Phase 2 multiple ascending dose study designed to identify a safe and effective dose in Class I (null) and other CF participants who do not benefit from CFTR modulators. This study is supported by safety and tolerability data collected in healthy volunteers (N = 32) and the ongoing two-administration Phase 1b study.

No serious adverse events (SAEs) have been observed in any clinical trial participants to date. No febrile reactions have been observed within the target dose range of the planned Phase 2 study. The Phase 1b study is ongoing with the seventh and final participant scheduled to be dosed soon.

Of the seven total CF participants in Phase 1b, six are receiving CFTR modulator treatment while one subject has Class I mutations and therefore does not benefit from modulator therapy. The Class I CF subject had low lung function at baseline (ppFEV1 below 50%) and showed an improvement of 4% in ppFEV1 on Day 8, after receiving two well-tolerated administrations, with no febrile reactions.