Safety and Efficacy Study of ELND005 as an Adjunctive Maintenance Treatment in Bipolar I Disorder

Inclusion Criteria:

- Meets the DSM-IV-TR criteria for BPD I by the SCID, prior to the Screening Visit.

- Has a history in the last 3 years of ≥ 1 manic or mixed episodes of sufficient
severity that required hospitalization and/or treatment with a mood stabilizer or
antipsychotic, or confirmed by a family member or medical records to ensure the
episode fulfills the DSM-IV-TR criteria.

- Has experienced a mood episode of any polarity within 4 months prior to the Screening
Visit and responded to StOC therapy.

- Is euthymic at the Screening Visit (ie, score of ≤ 12 on the MADRS and a score of ≤
12 on the Y-MRS).

- Is receiving maintenance treatment for his or her BPD I with either LTG or VPA; on
stable doses for past 4 weeks and therapeutic drug levels (total VPA 50--125 µg/mL
and LTG 10-50 µmol/L or as deemed appropriate by the investigator). Dose adjustments
made for tolerability reasons will be acceptable.

A study patient must meet the following additional criteria to be eligible for
randomization in the Double-blind Randomization Phase of this study:

- Maintained in a stable euthymic state during Phase 1, defined as Y-MRS and MADRS scores
of ≤ 12, with the following exceptions: a maximum of 2 nonconsecutive excursions will be
allowed throughout Phase 1. Excursions are defined as Y-MRS or MADRS scores >12 but ≤ 16.

Exclusion Criteria:

- Woman of childbearing potential who is unwilling or unable to use an acceptable
method of birth control or is using a prohibited contraceptive method.

- Is found to be actively suicidal on the C-SSRS (answer of "yes" to question 4 or 5
[current or over the last 30 days]) or a score of ≥4 on the MADRS item 10 at the
Screening Visit.

- Has suboptimally treated thyroid disease as evidenced by thyroid-stimulating hormone
(TSH) >3 mIU/L at the Screening Visit.

- Has received electroconvulsive therapy (ECT) during the current episode or within 6
months prior to the Screening Visit.

- Has an estimated glomerular filtration rate <40 mL/min/1.73 m2 according to the
Modification of Diet in Renal Disease formula.

A study patient who meets ANY of the above and ANY of the criteria below will not be
eligible for enrollment in the Double-blind Randomization Phase of this study:

- Has current signs or symptoms of psychosis.

- Has become actively suicidal as defined by C-SSRS answer of "yes" to question 4 or 5
(current or over the last 30 days) and/or has a score of ≥4 on MADRS item 10.