A Study to Investigate the Safety, Tolerability and Pharmacokinetics of JNJ-64991524 in Healthy Participants

A Phase 1, Randomized, Double-Blind, Placebo-Controlled, Single and Multiple Ascending Dose Study to Assess the Safety, Tolerability and Pharmacokinetics of JNJ-64991524 in Healthy Participants

The purpose of this study is to evaluate safety and tolerability of JNJ-64991524 compared with placebo after administration of single ascending oral doses of JNJ-64991524 (Part 1) and multiple ascending oral doses of JNJ-64991524 (Part 2) in healthy participants.

Inclusion Criteria:

• Weigh at least 50 kilogram (kg), and have a body mass index (BMI) of 18 kg/ meter (m)^2 to 30 kg/m^2, inclusive, at screening
• Be otherwise healthy on the basis of physical examination, medical history, vital signs, and 12-lead ECG performed at screening and Day-1. This determination must be recorded in the participant's source documents and initialed by the investigator
• Be otherwise healthy on the basis of clinical laboratory tests performed at screening and Day -1. If the results of the serum chemistry panel, including liver enzymes, white blood cell count and hematocrit, coagulation, or urinalysis are outside the normal reference ranges, the participant may be included only if the investigator judges the abnormalities or deviations from normal to be not clinically significant or to be appropriate and reasonable for the population under study. This determination must be recorded in the participant's source documents and confirmed initialed by the investigator
• Have the platelet count pretreatment clinical laboratory values not below the normal range during Screening and Day -1
• A woman must have a negative serum pregnancy test (beta-human chorionic gonadotropin [beta-hCG]) at screening and a negative urine pregnancy test on Day -2

Exclusion Criteria:

• History of liver or renal insufficiency; significant cardiac, vascular, pulmonary, gastrointestinal, endocrine, neurologic, hematologic, rheumatologic, psychiatric, or metabolic disturbances
• Known allergies, hypersensitivity, or intolerance to JNJ-64991524 or its excipients
• History of severe allergic reaction, angioedema, or anaphylaxis to drugs or food
• Has a history of malignancy before screening. Exceptions are squamous and basal cell carcinomas of the skin and carcinoma in situ of the cervix, or a malignancy which is considered cured with minimal risk of recurrence
• Has a history of or is infected with human immunodeficiency virus (HIV [positive serology for HIV antibody]); tests positive for hepatitis B virus (HBV) infection; has antibodies to hepatitis C virus (HCV) at screening