The purpose of this study is to determine whether Intravenous Immunoglobulin (IVIG) is safe and effective in the acute treatment of pain crises in sickle cell disease.

Funding Source: Food and Drug Administration (FDA), Office of Orphan Products Development (OOPD)

Patients will be randomized to a single dose of IVIG versus normal saline placebo during an uncomplicated pain crisis. Length of vaso-occlusive crisis (VOC) and other secondary endpoints will be monitored.

Phase I: To determine the tolerability and obtain preliminary data on the clinical efficacy of IVIG treatment in a randomized, double-blind, placebo-controlled, dose escalation Phase I clinical study of sickle cell disease patients, ages 12-65, admitted for acute vaso-occlusive crisis.

Phase II: To evaluate the effect of a single dose of 400mg/kg of intravenous (IV) Gamunex on length of VOC in subjects 6-13.99 years of age (initially 8-65 years of age, see "NOTES/CLARIFICATION below) hospitalized for sickle cell VOC in a randomized, double blind placebo-controlled Phase II trial. To further evaluate safety of a single dose of 400mg/kg of IV Gamunex in subjects 6-65 years of age hospitalized for sickle cell VOC.

NOTES/CLARIFICATION:

The following is a timeline of the 'evolution' of the required Age Range as per eligibility criteria for this study:

Initial Age Range: 8-65 years of age Effective 1/2/2013: 12-65 years of age Effective 3/31/2015: 8-21 years of age Effective 6/22/2018: 8-13 years of age Effective 7/11/2019: 6-13.99 years of age

Each subject must fulfill each of the following Inclusion/Exclusion criteria at screening and continue to fulfill these criteria prior to dosing:

Inclusion Criteria:

• Documented Sickle Cell Disease (SS or S-β thalassemia genotype)
• Age 12-65 years for Phase 1 (Completed), 6-13.99 years for Phase 2 (Ongoing)
• Normal stroke risk as assessed by transcranial Doppler (TCD). A normal TCD in subjects 16 years of age and younger within the year prior to study drug administration are required
• Uncomplicated acute vaso-occlusive crisis requiring hospital admission and parenteral narcotic analgesics
• If prescribed Voxelotor: Consistent daily use of voxelotor in the past week AND able to continue Voxelotor inpatient OR no reported use in prior week

Exclusion Criteria:

• Concomitant acute process, including acute chest syndrome, potential serious infection, or clinically significant bleeding
• Fever > 38.5° C and clinical suspicion of infection
• Serum alanine aminotransferase >4x Upper Limit of Normal (ULN)
• Serum creatinine ≥1.3 mg/dL (or > than 95th percentile for age) or >300 mg/dL protein in spot urinalysis
• Known condition associated with renal dysfunction including but not limited to diabetes mellitus, uncontrolled hypertension, multiple myeloma, and congestive heart failure
• Any clinical evidence of prior stroke
• Prior thromboses or current estrogen use
• Current estrogen use
• Hb < 5 g/dL or > 10 g/dL
• Known Immunoglobulin A (IgA) deficiency or known allergy to gamma globulin
• Pregnancy or breastfeeding
• Current participation in another investigational drug study
• Current enrollment in a hypertransfusion program
• Previous participation in current study less than 3 months ago
• Current treatment with chronic transfusion
• Vaccination with a live attenuated virus in the preceding 6 weeks
• Documented history of illicit (e.g., heroin, cocaine) drug abuse
• Subject is otherwise not an appropriate study candidate, in the investigator's judgement, such as concern for opioid addiction or comorbid psychiatric diagnoses that may contribute to secondary gain in prolonged use of opioids or hospital stay
• Greater than 24 hours from time of presentation to the hospital for VOC
• Atrial fibrillation
• Right to left cardiac shunting due to patent foramen ovale or other anatomic cause
• Known magnetic resonance imaging/angiography (MRI/A) evidence of stroke or clinically significant central nervous system (CNS) vasculopathy at any age (Imaging done if clinically indicated)