Study to Evaluate the Efficacy, Tolerability and Safety of Octanorm in Patients With Primary Immunodeficiency Diseases

Inclusion Criteria: 1. Age of ≥18 years and ≤70 years. 2. Confirmed diagnosis of PI requiring immunoglobulin replacement therapy due to hypogammaglobulinaemia or agammaglobulinaemia. The type of PI should be recorded. 3. Patients with at least 4 infusions on regular treatment with any Intravenous Immunoglobulin (IVIG) prior to entering the study. Constant IVIG dose between 200 and 800 mg/kg body weight (the individual doses of the last 4 infusions should not vary by more than ±25% of the mean dose for the last 4 infusions). 4. Availability of at least 2 IgG trough levels with an IgG level of ≥5.0 g/L from the period of the last 4 IVIG infusions. 5. Negative result on a pregnancy test (Human Chorionic Gonadotrophin \[HCG\]-based assay in urine) for women of childbearing potential and use of a reliable method of contraception for the duration of the study. Women of non-childbearing potential must be post-menopausal (amenorrhoeic for at least 12 months) or surgically sterile. Examples for medically acceptable methods of birth control for this study include: * Oral, implantable, transdermal or injectable contraceptives * Intrauterine device * Condoms; diaphragm or vaginal ring with spermicidal jellies or cream * Sexual abstinence * Vasectomised partner 6. Patient must freely give written informed consent. 7. Willingness to comply with all aspects of the protocol, including blood sampling, for the duration of the study. Exclusion Criteria: 1. Acute infection requiring intravenous (IV) antibiotic treatment within 2 weeks prior to and during the screening period. 2. Known history of adverse reactions to Immunoglobulin A in other products. 3. Patients with body mass index \>40 kg/m2 4. Exposure to blood or any blood product or plasma derivatives, other than IVIG treatment of PI, within the past 3 months prior to first infusion of octanorm. 5. Ongoing history of hypersensitivity or persistent reactions to blood or plasma derived products, or any component of the investigational medicinal product (IMP) (such as Polysorbate 80). 6. History of malignancies of lymphoid cells and immunodeficiency with lymphoma. 7. Severe liver function impairment (ALAT 3 times above upper limit of normal). 8. Known protein-losing enteropathies or proteinuria. 9. Presence of renal function impairment (creatinine \>120 µM/L or creatinine \>1.35 mg/dL), or predisposition for acute renal failure (e.g., any degree of pre-existing renal insufficiency or routine treatment with known nephritic drugs). 10. Treatment with enteral or parenteral steroids for ≥30 days or when given intermittently or as bolus, at daily doses ≥0.15 mg/kg. Inhaled corticosteroids are allowed. 11. Patients with chronic obstructive pulmonary disease (COPD) stage Global Initiative for Chronic Obstructive Lung Disease (GOLD) III or IV. 12. Treatment with immunosuppressive drugs. 13. Live viral vaccination (such as measles, rubella, mumps and varicella) within the last 2 months prior to first infusion of octanorm. 14. Treatment with any IMP within 3 months prior to first infusion of octanorm. 15. Presence of any condition that is likely to interfere with the evaluation of study medication or satisfactory conduct of the trial. 16. Known or suspected to abuse alcohol, drugs, psychotropic agents or other chemicals within the past 12 months prior to first infusion of octanorm. 17. Known or suspected human immunodeficiency virus (HIV), hepatitis C virus (HCV), or hepatitis B virus (HBV) infection. 18. Pregnant or nursing women; planned pregnancy during course of the study