ALTO-100-211

The purpose of this study is to assess antidepressant efficacy differences between ALTO-100 and placebo during the Double-Blind period in patients with bipolar disorder I or II with current major depressive episode, when used adjunctively to a mood stabilizer and/or atypical antipsychotic, related to patient characteristics. Additionally, safety, tolerability, and efficacy will be assessed in a subsequent open label treatment period.

You may be eligible to participate if

• You have a diagnosis of Bipolar
• At baseline, taking a mood stabilizer, lithium (LI) or lamotrigine (LMG) or valproic acid (VPA, any form) or combination of Li + LMG or Li + VPA and/or taking an approved atypical antipsychotic medication (olanzapine, quetiapine, lurasidone, risperidone, ziprasidone, cariprazine, aripiprazole, lumateperone, and asenapine) for at least 6 weeks with no dose modifications in the past 2 weeks
• You are willing to comply with all study assessments and procedures
• You are not pregnant or breastfeeding at time of enrolment or throughout study