ARCT-810 - (LUNAR-OTC)

September 23, 2026: Arcturus Therapeutics Holdings (NASDAQ: ARCT) reported interim Phase 2 data for ARCT-810 in ornithine transcarbamylase deficiency, saying the investigational mRNA therapy was generally safe and well tolerated. In the study to date, ARCT-810 reduced and/or maintained first-morning fasting ammonia within the normal range, including during increased protein intake, reduced glutamine, and at the 0.5 mg/kg dose produced mean glutamine values within the normal range during treatment; weight gain was observed in all participants.

The company also introduced its next-generation LUNAR 2.0 mRNA delivery platform. In non-human primates, LUNAR 2.0 showed a 40-fold improvement versus LUNAR 1.0 for human erythropoietin expression and 38-fold greater potency than ATX-95 for human OTC expression.

For ARCT-2601, a next-generation OTC deficiency candidate using LUNAR 2.0, Arcturus said FDA provided favorable feedback and regulatory path clarity after a Type C meeting in June. The company plans to begin dosing near year-end in OTCD patients aged 12 and older under an amended Phase 2 protocol integrating ARCT-2601 into the ongoing ARCT-810 study.

Separately, Arcturus said it entered a definitive agreement to acquire AI discovery company myNEO, with closing expected in October.