Business Decision; no human safety concern; evaluating preclinical toxicology finding

The purpose of this study is to characterize safety and tolerability of TAK-418 in non-Japanese and Japanese healthy female participants when administered at single or multiple (once daily [QD]) oral doses.

The drug being tested in this study is called TAK-418. This study will assess the safety, tolerability, PK and PD of single and multiple rising doses of TAK-418 in healthy Japanese or non-Japanese females.

The study will enroll approximately 48 participants in 6 cohorts and each cohort will have 8 participants. The study will include 2 parts: single rising dose (SRD) in Cohort 1 and multiple rising dose (MRD) in Cohorts 2 to 6. Cohort 3 will include cerebrospinal fluid (CSF) collection. Participants will be randomly assigned (by chance, like flipping a coin) to one of the 6 cohorts.

This two-center trial will be conducted in the United States. The overall time to participate in Cohort 1 of this study is approximately 105 days and 98 days in Cohort 2. Participants will be contacted by telephone 14 days after last dose of study drug for a follow-up assessment.

Inclusion Criteria:

1. Has a body mass index (BMI) greater than or equal to (>=) 18.5 and less than or equal to (<=) 30.0 kilogram per square meter (kg/m^2) at the Screening Visit. (Cohorts 1 to 4 only).
2. Is a nonsmoker who has not used tobacco- or nicotine-containing products (example, nicotine patch) for at least 6 months before administration of the first dose of trial drug or invasive procedure.
3. The participant either is of nonchildbearing potential, OR, if of childbearing potential, is using a highly effective method of contraception with low user dependency during the entire duration of the study.

For Cohorts 5 and 6 (Japanese participants) only:

1. Has a BMI >=18.0 and <= 26.0 kg/m^2, at the Screening Visit.

Exclusion Criteria:

1. Has a positive test result for hepatitis B surface antigen (HBsAg), hepatitis C antibody (HCV), or human immunodeficiency virus (HIV) antibody/antigen, at Screening.
2. Had major surgery, donated or lost 1 unit of blood (approximately 500 milliliter [mL]) within 4 weeks before the Screening Visit.
3. Has a history of alcohol consumption exceeding 2 standard drinks per day on average (1 glass is approximately equivalent to beer [354 mL/12 ounces], wine [118 mL/4 ounces], or distilled spirits [29.5 mL/1 ounce] per day).
4. Consumes excessive amounts, defined as greater than 6 servings (1 serving is approximately equivalent to 120 mg of caffeine) of coffee, tea, cola, energy drinks, or other caffeinated beverages per day.
5. Has a substance abuse disorder.
6. Has risk of suicide according to the investigator's clinical judgment per Columbia-Suicide Severity Rating Scale (C-SSRS) at Screening or has made a suicide attempt in the 6 months before Screening.
7. Has luteinizing hormone (LH), follicle-stimulating hormone (FSH), or estradiol levels that are clinically abnormal.
8. Has a resting heart rate outside of the range of 50 to 100 beats per minute, confirmed on repeat testing within a maximum of 30 minutes, at the Screening Visit or Check-in (Day -1).

For Cohort 3 only (includes CSF sample collection):

1. Has had CSF collection performed within 30 days before Check-in (Day -1).
2. Has significant vertebral deformities (scoliosis or kyphosis) that, in the opinion of the investigator, may interfere with the lumbar puncture procedure.
3. Has a local infection at the puncture site.
4. Has thrombocytopenia or other suspected bleeding tendencies noted before the procedure.
5. Has developed signs and symptoms of spinal radiculopathy, including lower extremity pain and paresthesia.
6. Has any focal neurological deficit that might suggest an increase in intracranial pressure.
7. Has any abnormal finding on ophthalmological assessment/fundoscopy indicative of raised intracranial pressure (that is, optic disc swelling/edema; or [uncontrolled] hypertensive retinopathy).
8. Regularly has moderate-to-severe headaches requiring analgesics.
9. Has any bleeding abnormality or history of bleeding abnormalities.
10. Has abnormal coagulation tests (prothrombin time [PT]/international normalized ratio [INR], partial thromboplastin time [PTT]) at Screening.

Takeda makes patient-level, de-identified data sets and associated documents available for all interventional studies after applicable marketing approvals and commercial availability have been received (or program is completely terminated), an opportunity for the primary publication of the research and final report development has been allowed, and other criteria have been met as set forth in Takeda's Data Sharing Policy (see www.TakedaClinicalTrials.com for details). To obtain access, researchers must submit a legitimate academic research proposal for adjudication by an independent review panel, who will review the scientific merit of the research and the requestor's qualifications and conflict of interest that can result in potential bias. Once approved, qualified researchers who sign a data sharing agreement are provided access to these data in a secure research environment.