The purpose of this study is to evaluate the efficacy and safety of high-dose human Immunoglobulin G Intravenous (IGIV) 10% in subjects with Kawasaki diseases (KD).

This is a multicenter, single-arm, and open-label clinical trial to evaluate the coronary artery lesions (CALs) at 2 and 7 weeks after single dose of IGIV 10% (2 g/kg) administration for at least 12 hours to evaluate the efficacy and safety of IGIV 10%.

Inclusion Criteria:

1. Infants and children aged 3 months to 7 years inclusive, at the time of signing the informed consent, however, patients with complete KD are eligible up to 12 years (applies to 2A)

2. Subjects with fever 4-10 days meeting one of following criteria (A, B or C)

   A. Subjects with at least 4 of the following principal clinical findings:

   i) Bilateral bulbar conjunctival injection without exudate

   ii) Erythema and cracking of lips, strawberry tongue, and/or erythema of oral and pharyngeal mucosa

   iii) Erythema and edema of the hands and feet in acute phase and/or periungual desquamation in subacute phase

   iv) Cervical lymphadenopathy (≥1.5 cm diameter), usually unilateral

   v) Rash: maculopapular, diffuse erythroderma, or erythema multiforme-like

   B. Subjects with at least 3 of the principal clinical findings and coronary artery abnormalities detected by 2-dimensional echocardiography: Z score of left anterior descending coronary artery or right coronary artery ≥2.5

   C. Subjects without coronary artery abnormalities, but with fever ≥5 days, 2 or 3 of the principal clinical findings , CRP of ≥3.0 mg/dL and meeting 3 or more of the following laboratory findings:

   i) Albumin <3.0 g/dL

   ii) Anemia for age

   iii) Elevated alanine aminotransferase level

   iv) Platelet count of >450,000/mm3 after the 7th day of fever

   v) White blood cell count of >15,000/mm3

   vi) Urine >10 white blood cells/high-power field

3. Subjects whose subject's parents or legally authorized representative gave voluntary written consent to participate in the clinical trial

Exclusion Criteria:

1. Subjects with a history of KD

2. Subjects with following laboratory findings:

   A. Platelet count <100,000/mm3

   B. WBC count <3,000 cells/mm3

   C. hemoglobin, hematocrit or red blood cell count more than 30% above the upper limit or 30% below the lower limit of the normal range

3. Subjects who are currently receiving or who have received any investigational drug or device within 30 days prior to administration of the IP

4. Subjects who have received TNF alpha antagonist or systemic corticosteroids within 48 hours prior to administration of the IP

5. Subjects who are considered by the investigator to be an unsuitable candidate for the study due to a severe chronic disease (e.g. cardiovascular disease except controllable hypertension, respiratory disease with respiratory failure, metabolic disease, renal failure, hemoglobinopathy, etc.)

6. Subjects who have received immunosuppressive or immunomodulatory drugs within 3 months prior to administration of the IP

7. Subjects with immunodeficiency including known positive serology for human immunodeficiency virus (HIV)

8. Subjects with a history of hypersensitivity or shock to IVIG formulations

9. Subjects with underlying liver disease or liver dysfunction with known etiology

10. Subjects with renal impairment whose creatinine level is more than twice the upper limit of the normal range

11. Subjects with a history of malignant tumor

12. Subjects with a history of IgA deficiency

13. Subjects who are considered by the investigator to be an unsuitable candidate for the study for any reason