The FDA granted Fast Track designation to Autobahn Therapeutics’ elunetirom (ABX-002) for adjunctive treatment of depressive episodes associated with bipolar I or bipolar II disorder in adults. Autobahn said the program is designed to penetrate the central nervous system and activate CNS thyroid hormone receptors, aiming to avoid peripheral thyroid hormone effects. The designation follows ongoing evaluation in the phase 2 AMPLIFY-BD trial (NCT06869187), with Autobahn expecting topline data in Q2 2026. The company emphasized that Fast Track does not confirm efficacy or safety, but may enable more frequent FDA interactions and potential eligibility for expedited review pathways if later criteria are met. For biotech developers working in difficult-to-treat CNS indications, Fast Track can accelerate engagement—particularly when safety and tolerability requirements are high.