The FDA granted Fast Track status to elunetirom (ABX-002) as an adjunctive treatment for depressive episodes associated with bipolar I or bipolar II disorder in adults, according to a May 26 announcement from Autobahn Therapeutics. The designation is not an approval decision, but it can enable more frequent FDA interactions and, if milestones are met later, eligibility for expedited review pathways. Elunetirom is an investigational once-daily oral prodrug designed to penetrate the central nervous system and activate CNS thyroid hormone receptors, while limiting peripheral thyroid hormone receptor effects tied to systemic thyroid exposure. The company is advancing the AMPLIFY-BD Phase 2 trial (NCT06869187), with Autobahn stating topline results are expected in the second quarter of 2026. The regulatory step arrives amid high unmet need for bipolar depression therapies that balance efficacy with tolerability and safety considerations, including the risk profile associated with antidepressant exposure in bipolar patients.