Study of ABX-002 for the Adjunctive Treatment of Depressive Episodes Associated With Bipolar Depression in Adults

The goal of this clinical trial is to learn if ABX-002 added to participants' existing treatment shows effects on brain chemistry that may relate to anti depressive effects

This is a single treatment arm, open-label, Phase 2 study of ABX-002 in 30 adults with bipolar disorder and 5 healthy volunteers. Healthy volunteer participants will receive no drug treatment and will undergo 2 imaging sessions to confirm instrument and test - retest method reliability control. For bipolar disorder participants with depression, the study will include 3 study periods:

1. Screening Period of up to 4 weeks
2. 6-week Treatment Period
3. 2-week post dose Safety Follow-up Period.

For healthy volunteers, the study will include 2 study periods:

1. Screening Period of up to 3 weeks
2. Imaging Period of up to 3 weeks.


Eligibility Criteria:
Inclusion Criteria (For Bipolar Disorder Patients):

* Current diagnosis of bipolar disease for at least 2 years
* DSM-5-TR criteria for bipolar disorder based on Structured Clinical Interview for the DSM-5 - Clinical Trials Version (SCID-5-CT) at Screening
* Has a current depressive episode with or without mixed features, but not psychotic features, with duration ≤ 24 months
* 17-item Hamilton Rating Scale for Depression total score ≥ 22 at Screening and Baseline
* Young Mania Rating Scale total score ≤ 12 at Screening and Baseline
* Able to undergo imaging sessions using Magnetic Resonance Spectroscopy/Imaging with no history of aborted scanning due to anxiety, claustrophobia, or an incompatible implant/device
* Taking a single mood stabilizer (e.g., lithium, valproate, lamotrigine) with or without a single second-generation antipsychotic (SGA, atypical antipsychotic) approved for the treatment of depression in bipolar disorder (e.g., cariprazine, lumateperone, lurasidone, olanzapine/fluoxetine, quetiapine). In addition, antidepressants (i.e., selective serotonin reuptake inhibitors \[SSRI\], serotonin norepinephrine reuptake inhibitors \[SNRI\]) and atypical antipsychotics not approved for depression in bipolar disorder (e.g., aripiprazole, asenapine, olanzapine, risperidone) are permissible. All medications intended to treat the current episode of depression should be at an adequate and stable dose for ≥ 6 weeks prior to screening.

Exclusion Criteria (For Bipolar Disorder Patients):

* History of \> 4 manic, hypomanic, or depressive episodes within a one-year period (rapid cycler; DSM-5-TR) in the last 2 years
* History of schizophrenia or schizoaffective disorder (DSM-5-TR) or a psychotic disorder unrelated to bipolar disorder
* History of obsessive-compulsive disorder, or posttraumatic stress disorder, according to DSM-5-TR criteria
* Diagnosis of a personality disorder (DSM-5-TR)
* Evident risk of suicide at Screening or Baseline
* History of an inadequate response to more than 2 second-generation antipsychotic treatments (including their current treatment) in their current episode of depression in bipolar disorder despite an adequate dose and duration (\> 6 weeks at approved or standard of care doses)
* Received any course of deep brain stimulation in participant's lifetime or plans to receive deep brain stimulation during the study
* Treatment with electroconvulsive therapy (for psychiatric/therapeutic purposes) or repetitive transcranial magnetic stimulation, or treatment with ketamine or esketamine for the current episode and received any of those treatments within 12 months prior to Screening
* Started new psychotherapy or had a change in the intensity of psychotherapy within 6 weeks before Screening
* Prior use of psychedelics for the treatment of depression
* Refusal to abstain from consumption of excessive amounts of alcohol during the study
* History of uncontrolled, clinically significant neurological (including prior cerebrovascular accident \[stroke\] or chronic seizures), cardiovascular, gastrointestinal, respiratory, renal, hepatic, immunological, hematological, endocrine (including uncontrolled diabetes), or other medical disorder, including cancer
* History of cardiovascular disease
* Current use of high dose (\> 4 mg/day lorazepam equivalents) anxiolytic and/or hypnotic medication
* Cannabinoids (marijuana, cannabis, tetrahydrocannabinol \[THC\], cannabidiol \[CBD\]) in any form or use frequency are not allowed.

Inclusion Criteria (For Health Volunteers):

* In good health, based on medical history, physical examination (including neurological examination), vital sign measurements, and laboratory safety tests obtained at the Screening Visit
* Able to undergo imaging sessions using Magnetic Resonance Spectroscopy/Imaging, with no history of aborted scanning due to anxiety, claustrophobia, or an incompatible implant/device

Exclusion Criteria (Healthy Volunteers):

* Mentally or legally incapacitated, has significant emotional problems at the time of the Screening Visit, or is expected to have potential for mental incapacitation during the conduct of the study
* History of any illness (including psychiatric illness)
* Participation in an investigational drug or device study where last dosing of previous drug is within 30 days
* Prior use of psychedelics within the past year
* Refusal to abstain from consumption of excessive amounts of alcohol during the study
* Cannabinoids (marijuana, cannabis, tetrahydrocannabinol \[THC\], cannabidiol \[CBD\]) in any form or use frequency are not allowed.