Patients with primary immunodeficiency disorders (PID) on intravenous immunoglobulin (IVIG) treatment may experience adverse events (AEs). Patients who experience AEs on any 10% IVIG solution will be changed to octagam 5% for six infusions to evaluate the potential benefit for reduction of AEs on a lower concentration IVIG product.

Patients with PID require life long immunoglobulin (Ig) replacement therapy with IVIG being the most common form. As more 10% IVIG products are FDA approved, the older and well characterized 5% IVIG products are becoming less used. Currently, the standard of care for patients who experience AEs on IVIG is to move to a subcutaneous (SCIG) delivery and product. This study will evaluate the AEs on a 10% product and octagam 5%. The study will enroll 15 patients after an AE on any 10% product who will then be infused with octagam 5% for six infusions. AEs will be documented and compared to the 10% product along with changes in biomarkers. The study data may document another therapeutic option for patients who experience AEs - SCIG and octagam 5%.

Inclusion Criteria:

• Participants, or legal guardians with assent by underage children, will sign informed consent/assent and are willing to comply with all aspects of the study
• Diagnosis of CVID according IUIS Expert Committee
• Participants on a 10% product who experience AEs
• Ages between 10 and 75 years of age
• Participants on 10% IVIG therapy every 21±3 days or 28±3 days between 300 - 800 mg/Kg body weight

Exclusion Criteria:

• Acute infection requiring antibiotic therapy within 7 days prior to visit 1
• Presence of any condition that is likely to interfere with the evaluation of the study medication or satisfactory conduct of the trial
• History of anaphylactic or severe systemic reactions to human immunoglobulin
• IgA deficient patients with antibodies against IgA and a history of hypersensitivity
• Females who are pregnant or lactating

Diagnosis of PID - specifically common variable immunodeficiency (CVID)