This study is to compare the pharmacokinetics of FK949E low dose tablets and FK949E high dose tablets in non-elderly patients with major depressive disorder. The safety of FK949E in the population was also evaluated.

The objective of the study is to compare the pharmacokinetics of FK949E low dose tablets and FK949E high dose tablets in non-elderly patients with major depressive disorder in a 2 × 2 crossover design. The safety of FK949E in the population is also evaluated.

Inclusion Criteria:

• Patients considered to be able to understand and follow subject requirements, as judged by the investigator/sub-investigator.
• Patients diagnosed with major depressive disorder according to the DSM-IV-TR by means of M.I.N.I.
• BMI: 17.6 (inclusive) to 26.4 (exclusive).

Exclusion Criteria:

• Current or past history of DSM-IV-TR Axis I disorder, except major depressive disorder, within the past 6 months before informed consent.
• Concurrent DSM-IV-TR Axis II disorder that is considered to greatly affect patient's current mental status.
• Current or past history of dependence of substances (other than caffeine and nicotine) or history of abuse or dependence of alcohol.
• Unable to suspend treatment with inducers or inhibitors of the drug-metabolizing enzyme, cytochrome P450 3A4 (CYP3A4), for 14 days before the screening assessment and throughout the study.
• Patients who could not use an appropriate contraception (condoms) during the study. Patients who were pregnant or lactating.
• Patients (carriers) with documented or suspected renal failure, hepatic failure, serious cardiac disease,

hepatitis B, hepatitis C, or acquired immunodeficiency syndrome (AIDS).

• Patients receiving treatment for hypertension, or patients with concurrent hypertension or unstable angina that may worsen with the study or may affect the study results based on the clinical judgment of the investigator/sub-investigator.
• Patients with concurrent hypotension (criterion for hypotension: a systolic blood pressure of less than 100 mmHg), or orthostatic hypotension
• Patients with a mean QTcF interval of ≥450 ms on a 12-lead ECG at the screening assessment
• Patients with the risk of torsades de pointe (e.g., those with a history of QT prolongation, those with familial long QT syndrome).
• Concurrent malabsorption syndrome, hepatic disease, or other conditions that may affect the absorption and/or metabolism of the study drug.
• Concurrent malignancy or history of cured malignancy within 5 years
• Current or past history of cerebrovascular disease or transient ischemic attack (TIA).
• Received electroconvulsive therapy within 90 days before the screening assessment

Access to anonymized individual participant level data will not be provided for this trial. Further details on Astellas' data sharing policy can be found at https://www.clinicaltrials.astellas.com/transparency/.