San Diego-based Autobahn Therapeutics reported positive topline results from its Phase II AMPLIFY-BD trial of elunetirom (ABX-002) in bipolar depression, with the oral CNS thyroid hormone receptor (CNS-TR) agonist delivering a statistically significant 16.8-point reduction in the Hamilton Depression Rating Scale (HAMD-17) and a 75% response rate at six weeks. Elunetirom represents the first clinical evidence for CNS-targeted thyroid hormone receptor agonism as an antidepressant strategy — a mechanism distinct from atypical antipsychotics and serotonergic agents that currently dominate the bipolar depression treatment landscape. The readout now positions the company for a regulatory dialogue with the US FDA ahead of a potential pivotal program.
Trial data
AMPLIFY-BD is an open-label Phase II trial that enrolled 21 adults with bipolar I or bipolar II disorder experiencing a moderate-to-severe major depressive episode. Patients received once-daily oral elunetirom for six weeks as adjunctive therapy on top of existing mood stabilizers and/or atypical antipsychotics. The primary endpoint — change in HAMD-17 total score from baseline to Week 6 — showed a mean 16.8-point reduction (p < 0.001). At Week 6, 75% of patients met the response threshold ( ≥ 50% HAMD-17 reduction) and 50% achieved remission (HAMD-17 ≤ 7). Improvements were statistically significant across all secondary assessments, including clinician- and patient-reported measures of functional impairment. Notably, neuroimaging in a patient subset showed statistically significant changes in functional connectivity in brain regions implicated in depression, providing an objective correlate of the clinical signal.
Safety was favorable: all treatment-related adverse events were mild to moderate, with no severe or serious treatment-related adverse events reported.
Competitive context