This study will test if a study drug (CS-3150) will affect the heart rate in healthy males and females. Two doses of the study drug will be tested. Heart rate is not expected to be different between the study groups.

This study will assess the effect of therapeutic and supratherapeutic plasma exposures of CS-3150 on the corrected QT (QTc) interval duration after administration of single oral 10-mg and 40-mg doses of CS-3150 in healthy male and female participants. This study will also determine the safety and tolerability of CS-3150 administration, assess the effect on electrocardiogram (ECG) parameters, detect QT interval (QT)/QTc prolongation with a positive control (moxifloxacin), characterize pharmacokinetics (PK) of CS-3150, and assess exposure-response relationship of CS-3150 on QTc.

Inclusion Criteria:

• Healthy males and/or females 18 years to 45 years of age with a body mass index of 19 kg/m2 to 32 kg/m2 (inclusive)
• Laboratory results (serum chemistry, hematology, and urinalysis [UA]), liver function, and serum K+ levels within normal range
• Written informed consent
• Female participants: Negative pregnancy test and must either be surgically sterile, postmenopausal, or agree to use acceptable nonhormonal contraception.

Exclusion Criteria:

• All prescription or over-the-counter (OTC) medication (systemic and topical) and herbal supplements will not be permitted for 14 days before the first dose and for the duration of the study.
• Oral, injected, or implanted hormonal contraception methods, or hormonal replacement therapy, should not have been received in the 3 months prior to the first dose, and for the duration of the study.
• Female participants: positive pregnancy test or are breast feeding.
• Supine systolic/diastolic blood pressure at screening, after resting for 10 min, higher than 140/90 mmHg or lower than 90/50 mmHg, confirmed after repeated testing at least approximately 1 h apart.
• Supine pulse at screening, after resting for 10 min, outside the range of 40 to 100 beats per minute (bpm).
• QTcF interval duration > 450 ms for male and female obtained as an average from the triplicate screening ECGs after at least 10 min in a fully supine quiet rest.
• Abnormal waveform morphology on any of the screening ECGs that would preclude accurate measurement of the QT interval duration.
• Family history of congenital Long QT syndrome (LQTS), a history of surviving an unexplained drowning episode, a history of any form of syncope or loss of consciousness, or known symptomatic cardiac arrhythmias.
• Known allergy to moxifloxacin.
• An estimated glomerular filtration rate (eGFR) using the Modification of Diet in Renal Disease (MDRD) equation lower than 90 mL/min.
• Previous participation in a CS-3150 study within 6 months prior to the single dose of CS-3150.
• History or current evidence of clinically significant cardiac, hepatic, renal, pulmonary, endocrine, neurologic, infectious, gastrointestinal, hematologic, or oncologic disease as determined by the PI after reviewing screening history, physical examination, laboratory test results, and 12-lead ECG
• Clinically significant illness (at the discretion of principal investigator) within 4 weeks of first dose, are carriers of Hepatitis B surface antigen (HBsAg), Hepatitis C antibody (HCV), or human immunodeficiency virus (HIV) antibody, and any other reason not deemed suitable for the study (at the discretion of the principal investigator).

De-identified individual participant data (IPD) and applicable supporting clinical trial documents may be available upon request at https://vivli.org/. In cases where clinical trial data and supporting documents are provided pursuant to our company policies and procedures, Daiichi Sankyo will continue to protect the privacy of our clinical trial participants. Details on data sharing criteria and the procedure for requesting access can be found at this web address: https://vivli.org/ourmember/daiichi-sankyo/

Studies for which the medicine and indication have received European Union (EU) and United States (US), and/or Japan (JP) marketing approval on or after 01 January 2014 or by the US or EU or JP Health Authorities when regulatory submissions in all regions are not planned and after the primary study results have been accepted for publication.

Formal request from qualified scientific and medical researchers on IPD and clinical study documents from clinical trials supporting products submitted and licensed in the United States, the European Union and/or Japan from 01 January 2014 and beyond for the purpose of conducting legitimate research. This must be consistent with the principle of safeguarding study participants' privacy and consistent with provision of informed consent.

The Investigator, participants, and all other clinical management and personnel will be blinded to treatment. CS-3150 and moxifloxacin (positive control) treatments will be blinded by matching placebos.