To investigate the safety, pharmacokinetics and pharmacodynamics of TS-143 when administered 3 times a day for 10 days to healthy Japanese adult males using placebo-controlled, double-blind, dose escalation study design.

Inclusion Criteria:

• Subjects with a BMI of 18.5 to less than 25.0 at the time of the screening tests
• Subjects judged by the principal investigator or a subinvestigator to be appropriate for participation in the study based on the results of the screening tests and the tests conducted before the investigational drug treatment on Day 1
• Subjects capable of receiving an explanation of this study before participation, understanding the details, and providing written informed consent themselves

Exclusion Criteria:

1. Subjects meeting any of the following criteria in the results of screening tests, tests conducted on the day before the first investigational treatment (Day -1), and tests conducted before the investigational drug treatment on the morning of Day 1:

   • Red blood cell count: ≥535 × 10^4 /μL
   • Hemoglobin: ≥16.2 g/dL
   • Hematocrit: ≥47.5%
   • Reticulocyte rate: Outside of the reference value range

2. Subjects meeting any of the following criteria in the screening tests:

   • Serum EPO concentration: Outside of the reference value range
   • Ferritin: ≤30 ng/mL or >upper limit of the reference value

3. Subjects meeting any of the following criteria in the vital signs in the screening tests and the tests conducted before the investigational drug treatment on the morning of Day 1:

   • Blood pressure: Systolic blood pressure ≥140 mmHg, or diastolic blood pressure ≥90 mmHg
   • Pulse rate: <40 bpm, or ≥100 bpm
   • Body temperature: ≥37.5°C