Arcturus Therapeutics is trading 12.6% higher at $14.97 after its September 23, 2026, announcement of encouraging interim Phase 2 results for ARCT-810. - The treatment was generally safe and reduced or maintained fasting ammonia within the normal range. - LUNAR 2.0 mRNA delivery platform showed substantially higher protein-expression potency in non-human-primate studies; the company also signed a definitive agreement to acquire AI discovery company myNEO. - Biotech was up 2.61% pre-market while major U.S. indices were lower.