A Study of Single and Multiple Ascending Doses of H021 in Healthy Participants

Inclusion Criteria:

1. Male or female, non-smoker (no use of tobacco or nicotine products within 3 monthsprior to screening), greater than and equal to (>=) 18 and less than and equal to (<=) 55 years of age, with body mass index (BMI) greater than (>)18.5 and less than (<) 32.0 kilograms per square meter (kg/m^2).

2. Healthy as defined by:

3. the absence of clinically significant illness and surgery within 4 weeks priorto study drug administration.

4. the absence of clinically significant history of neurological, endocrine,cardiovascular, respiratory, hematological, immunological, psychiatric,gastrointestinal, renal, hepatic, and metabolic disease.

5. Female participants of non-childbearing potential must be:

6. post-menopausal (spontaneous amenorrhea for at least 12 months prior to dosing)with confirmation by documented follicle-stimulating hormone (FSH) levels >=40milli-international units per milliliter (mIU/mL); or

7. surgically sterile (bilateral oophorectomy, bilateral salpingectomy,hysterectomy, or bilateral tubal occlusion) at least 3 months prior to dosing.

8. Participants must be willing not to donate sperm for 90 days or ova (egg) for 6months after the last dose.

9. Sexually active females of childbearing potential and non-sterile males must bewilling to use an acceptable contraceptive method throughout the study.

10. Able to understand the study procedures and provide signed informed consent toparticipate in the study.

Exclusion Criteria:

1. Any clinically significant abnormal finding at physical examination.

2. Clinically significant abnormal laboratory test results including biochemistry,hematology, urinalysis, and coagulation results, or positive serology test resultsfor hepatitis B surface antigen (HBsAg), hepatitis C virus (HCV) antibody, or humanimmunodeficiency virus (HIV) antigen and antibody, or QuantiFERON®-TB test atscreening.

3. Positive pregnancy test or lactating female participant.

4. Positive urine drug screen, urine cotinine test, or alcohol breath test at screeningor Day -1.

5. History of significant allergic reactions (example, anaphylactic reaction,hypersensitivity, angioedema) to any drug.

6. Clinically significant ECG abnormalities or vital signs abnormalities (systolicblood pressure lower than 90 or over 140 millimetres of mercury (mmHg), diastolicblood pressure lower than 40 or over 90 mmHg, heart rate less than 40 or over 100beats per minute (bpm), respiratory rate less than 10 or over 22 bpm), or oxygensaturation less than 95 percent (%) oxygen at screening.

7. History of drug abuse within 1 year prior to screening as determined by theinvestigator.

8. History of alcohol abuse within 1 year prior to screening or regular use of alcoholwithin 1 month prior to screening that exceeds 10 units of alcohol per week forwomen and men (1 unit = 375 [milliliter] mL of beer 3.5%, 100 mL of wine 13.5%, or 30 mL of distilled alcohol 40%).

9. History of active tuberculosis or presence of active or latent tuberculosis.Previous latent tuberculosis that has been treated and is no longer active is notexclusionary.

10. History of clinically significant opportunistic infection (example, invasivecandidiasis or pneumocystis pneumonia).

11. History of serious local infection (example, cellulitis, abscess) or systemicinfection (example, septicemia) within 3 months prior to screening.

12. Presence of fever (body temperature greater than (>) 37.5 degrees Celsius (°C) (example, a fever associated with a symptomatic viral or bacterial infection) within 2 weeks prior to dosing.

13. Use of medications within the timeframes specified.

14. Participation in a clinical research study involving the administration of aninvestigational or marketed drug or device within 30 days prior to the first dosing,administration of a biological product in the context of a clinical research studywithin 90 days prior to the first dosing, or simultaneous participation in aninvestigational study involving no drug or device administration.

15. Donation of plasma within 7 days prior to dosing or donation or loss of 500 mL ormore of whole blood within 8 weeks prior to dosing.

16. Any reason which, in the opinion of the Investigator, would prevent the participantfrom participating in the study.