Autobahn Therapeutics Presents Preclinical Data Supporting Elunetirom's Novel Neuroplasticity Mechanism for Depression Treatment
Key Insights
Autobahn Therapeutics (search) presented new preclinical data at the ACNP Annual Meeting demonstrating elunetirom (search)'s ability to enhance neuroplasticity and strengthen neuronal synapses for rapid antidepressant effects.
The first-in-class CNS thyroid hormone receptor agonist showed significant improvements in neuronal growth markers and cognitive function in preclinical studies, with effects comparable to BDNF.
Elunetirom (search) is currently in Phase 2 trials for adjunctive treatment of major depressive disorder (search) and bipolar depression (search), with topline results expected in 2Q26 and 3Q26 respectively.
Autobahn Therapeutics (search) announced new preclinical data for elunetirom (search) (ABX-002), its lead CNS thyroid hormone receptor agonist, at the 64th Annual American College of Neuropsychopharmacology (ACNP) Annual Meeting in Nassau, Bahamas. The data support the drug's novel mechanism of enhancing neuroplasticity to deliver rapid and enduring antidepressant effects in patients with major depressive disorder (search) (MDD) and bipolar depression (search).
Novel Mechanism Targets Brain-Specific Thyroid Receptors
Elunetirom (search) represents a first-in-class approach to treating depression through selective and potent activation of thyroid-beta hormone receptors in the brain (CNS-TRs). According to Jonathan Meyer, MD, Voluntary Clinical Professor of Psychiatry at the University of California, San Diego, this mechanism differs from other depression treatment strategies, including the nonselective TR agonist triiodothyronine.
"This new mechanism may address underlying neural dysfunction in patients who have not benefited from existing therapies," Meyer said. "Given that millions of patients living with MDD and bipolar depression (search) do not achieve adequate relief with their current treatment, novel pharmacological approaches like this are critically needed."
Preclinical Studies Demonstrate Robust Neuroplasticity Effects
The preclinical data presented at ACNP examined elunetirom (search)'s effects through a series of in vitro and in vivo assays relevant to neuroplasticity and depression treatment. In primary cultures of cortical neurons, the active metabolite showed significant increases in number of neurons, neurite length, number of roots, and number of neurite extremities.
Similarly, in primary cultures of mature hippocampal neurons, elunetirom (search) significantly increased markers of neuritogenesis and synaptogenesis, essential processes for building neuronal networks. In both experimental settings, the effects were comparable to those achieved with optimal concentrations of the positive control BDNF (brain-derived neurotrophic factor).
The compound also demonstrated cognitive benefits in animal models. Elunetirom (search) significantly improved spontaneous alternation in aged mice (12-month-old) and scopolamine-treated mice in a T-maze after seven days of treatment, indicating improvements in cognition potentially stemming from enhanced neuronal plasticity.
Clinical Development Program Advances
Elunetirom (search) is currently being evaluated as a potential adjunctive treatment in two ongoing Phase 2 studies: the AMPLIFY study for MDD and the AMPLIFY-BD study for bipolar depression (search). Autobahn anticipates reporting topline data from AMPLIFY-BD in the second quarter of 2026 and from AMPLIFY in the third quarter of 2026.
"These data provide strong mechanistic support for elunetirom (search)'s role in driving energy-dependent neuroplasticity, increasing our confidence in our ongoing Phase 2 studies," said Gudarz Davar, M.D., Executive Vice President, Head of Research and Development for Autobahn.
Drug Design and Safety Profile
Elunetirom (search) is formulated as an oral, once-daily, brain-penetrant small molecule prodrug that targets CNS thyroid hormone receptors (search). The drug is designed to enhance beneficial neurobiological activity at CNS-TRs while reducing the peripheral thyroid hormone receptor activity liabilities associated with synthetic thyroid hormone administration, such as triiodothyronine (T3).
CNS-TR agonism is believed to boost energy and plasticity in the brain through both increasing cellular energy production and driving neuroplastic changes. In nonclinical and clinical studies, elunetirom (search) has demonstrated optimized pharmacokinetic properties, target engagement in brain regions associated with depression, and an attractive safety and tolerability profile.
The therapeutic effects observed in preclinical studies are likely the result of direct actions on genes that drive restorative neuroplasticity in the brain, particularly BDNF, according to the research team.