Safety and Pharmacokinetics of IGSC 20% in Subjects With Primary Immunodeficiency

This is a prospective, multi-center, open-label, single-sequence, 6-month, pharmacokinetic,
safety and tolerability study of IGSC 20% in subjects with primary immunodeficiency.
Approximately 50 subjects will be enrolled in order to have approximately 30 adult subjects
and 12 to 15 pediatric subjects (age 2-16 years) completing treatment with subcutaneously
administered IGSC 20%.

This study will include 3 treatment phases: Run-In Phase, IV Phase (IV administration of
IGIV-C 10% treatment), and SC Phase (SC administration of IGSC 20%).

Subjects, depending on their current IgG treatment regimen, may be required to enter the
Run-In Phase to receive IV IGIV-C 10% treatment (Sponsor provided) to achieve an
approximately steady-state condition prior to entering the IV Phase. They will then enter the
IV Phase to determine the AUC profiles of IV infusions of IGIV-C 10%.

Subjects with a qualifying IV IGIV-C 10% treatment regimen (on stable IGIV-C 10% doses of
300-800 mg/kg) can enter the IV Phase directly where they will receive IGIV-C 10%. In the IV
Phase, steady-state IV PK assessments, including AUC, will be performed.

After completing the IV Phase, subjects will enter the SC Phase to receive weekly SC doses of
IGSC 20% for at least 24 weeks.

The PK profiles of total IgG following administration of both IV (IGIV-C 10%) administration
and SC (IGSC 20%) administration will be determined and compared after reaching approximate
steady-state conditions.

Inclusion Criteria:

- Pre-existing diagnosis of primary immunodeficiency with features of
hypogammaglobulinemia requiring IgG replacement therapy

- No serious bacterial infection within the last 3 months prior to Screening

- Currently on IgG replacement therapy (via IV or SC infusion) for ≥3 consecutive
months. Subjects receiving IGIV must be receiving a dosage of 300 to 800 mg/kg per
infusion

- Documented (at least once within previous 3 months) IgG trough level of ≥500 mg/dL on
current IgG replacement therapy regimen

Exclusion Criteria:

- Known serious adverse reaction to immunoglobulin or any severe anaphylactic reaction
to blood or any blood-derived product

- History of blistering skin disease, clinically significant thrombocytopenia, bleeding
disorder, diffuse rash, recurrent skin infections or other disorders where SC therapy
would be contraindicated during the study

- Isolated IgG subclass deficiency, isolated specific antibody deficiency disorder, or
transient hypogammaglobulinemia of infancy

- Nephrotic syndrome, and/or a history of acute renal failure and/or severe renal
impairment, and/or on dialysis

- History (year prior to Screening or 2 episodes in lifetime ) of or current diagnosis
of deep venous thrombosis or thromboembolism (eg, deep vein thrombosis, myocardial
infarction, cerebrovascular accident or transient ischemic attack)

- Acquired medical condition known to cause secondary immune deficiency, such as chronic
lymphocytic leukemia, lymphoma, multiple myeloma, chronic or recurrent neutropenia
(absolute neutrophil count less than 1000/μL [1.0 x 10^9/L]), or human
immunodeficiency virus infection/acquired immune deficiency syndrome

- Known previous infection with or clinical signs and symptoms consistent with current
hepatitis B virus or hepatitis C virus infection

- Non-controlled arterial hypertension (systolic blood pressure >160 mmHg and/or
diastolic blood pressure >100 mmHg in adult subjects)

- Receiving any of the following medications: (a) immunosuppressants including
chemotherapeutic agents, (b) immunomodulators, (c) long-term systemic corticosteroids
defined as daily dose >1 mg of prednisone equivalent/kg/day for>30 days Note:
Intermittent courses of corticosteroids of not more than 10 days would not exclude a
subject. Inhaled or topical corticosteroids are allowed.