Alkermes Advances Narcolepsy Therapy with Promising Phase 2 Trial Results for Alixorexton on July 22, 2025 alixorexton Alkermes Cataplexy Daytime Somnolence Excessive (qualifier value) late-stage testing Narcolepsy Narcolepsy type 1 normative wakefulness Orexin Receptor Agonist Vibrance-1 study +