A Study to Investigate Safety, Tolerability, and Pharmacokinetics of JNJ-63623872 in Healthy Japanese Adult Participants

The purpose of this study is to evaluate the safety, tolerability, and pharmacokinetics of JNJ-63623872 following oral administration of single ascending dose of JNJ-63623872 in healthy Japanese adult participants.

This is a double-blind (test or experiment in which neither the person giving the treatment nor the patient knows which treatment the patient is receiving), placebo-controlled, randomized (study medication assigned to participants by chance) and single-center study of JNJ-63623872. The duration of study will be approximately 5.5 weeks for each ISO per participant. The study consists of 3 parts: Screening Phase (28 days before study commences on Day 1); double-blind Treatment Phase (single oral dose of JNJ-63623872 or placebo on Day 1 under fasted condition); and Follow up Phase (up to 7-10 days after study drug administration). All the eligible participants will be randomly assigned to 1 of 3 groups. The planned doses will be escalated in a stepwise fashion if the safety and tolerability in the preceding dose is found acceptable. Participants in Group 1 will receive JNJ-63623872 300 milligram (mg) or placebo, Group 2 will receive JNJ-63623872 600 mg or placebo and Group 3 will receive JNJ-63623872 1200 mg or placebo. Study drug will be administered following a 10-hour overnight fast. Blood samples will be collected for evaluation of pharmacokinetics at pre-dose and post-dose of study treatment. Pharmacokinetics of JNJ-63623872 will be evaluated primarily. Participants' safety will be monitored throughout the study.

Eligibility Criteria:
Inclusion Criteria:

* Be a Japanese participant who has resided outside Japan for no more than 5 years and whose parents and grandparents are Japanese as determined by participant's verbal report
* Each participant must sign an Informed Consent Form (ICF) indicating that he or she understands the purpose of and procedures required for the study and are willing to participate in the study
* Participant must be willing and able to adhere to the prohibitions and restrictions specified in this protocol
* A female participant must be either:

  1. Not of childbearing potential: postmenopausal \[greater than (\>) 45 years of age with amenorrhea for at least 2 years, or any age with amenorrhea for at least 6 months and a serum follicle stimulating hormone (FSH) level \>40 International Units (IU)/ liter (L) (to be confirmed at Screening for all postmonopausal women)\] OR
  2. Permanently sterilized (eg, bilateral tubal occlusion \[which includes tubal ligation procedures as consistent with local regulations\], hysterectomy, bilateral salpingectomy, bilateral oophorectomy) or otherwise incapable of becoming pregnant, OR c. If of childbearing potential and heterosexually active, practicing an effective method of birth control before entry and agree to continue to use two effective methods of contraception throughout the study and for at least 30 days after receiving the study drug
* A male participant who is sexually active with a woman of childbearing potential must agree to use two effective methods of birth control for 30 days after receiving the study drug, and a male participant must also not donate sperm during the study and for 3 months after receiving the study drug

Exclusion Criteria:

* Participant has a history of current clinically significant medical illness including (but not limited to) cardiac arrhythmias or other cardiac disease, hematologic disease, coagulation disorders (including any abnormal bleeding or blood dyscrasias), lipid abnormalities, significant pulmonary disease, including bronchospastic respiratory disease, diabetes mellitus, hepatic or renal insufficiency, thyroid disease, neurologic or psychiatric disease, infection, or any other illness that the Investigator considers should exclude the participant or that could interfere with the interpretation of the study results
* Participant with a past history of heart arrhythmias (extrasystoli, tachycardia at rest), history of risk factors for Torsade de Pointes syndrome (eg, hypokalemia, family history of long QT Syndrome)
* Participants with any history of clinically significant skin disease such as, but not limited to, dermatitis, eczema, drug rash, psoriasis, food allergy, or urticaria
* Participants with a history of clinically significant drug allergy such as, but not limited to, sulfonamides and penicillins, or drug allergy diagnosed in previous studies with experimental drugs
* Participant has taken any disallowed therapies as noted in protocol, Pre-study and Concomitant Therapy before the planned study drug