Study to Investigate Efficacy, Safety and Pharmacokinetics of BT595 in Subjects With PID

Criteria for inclusion:

• Written informed consent/assent obtained from subjects/subjects' parent(s) or legally acceptable representative indicating that they understood the purpose of, and procedures required for the study and are willing to participate in it.
• Male or female, aged 2 through 75 years, inclusive.
• Diagnosis of PID with impaired antibody production, ie:
• Diagnosis of common variable immunodeficiency (CVID) as defined by the European Society for Immunodeficiencies (ESID)/Pan American Group for Immunodeficiency (PAGID) diagnostic criteria.

Or

• X-linked agammaglobulinaemia (XLA) as defined by ESID/PAGID diagnostic criteria.
• Established replacement therapy with any immunoglobulin for intravenous administration (IVIg) reference preparation during the previous 6 months, including documentation of IgG trough levels.
• Established replacement therapy with a single IVIg reference preparation for ≥3 months prior to treatment start with BT595 at a 3 week (Q3W) or 4 week (Q4W) schedule with a constant IVIg dose that did not change by ±20% of the mean dose, regular dosage intervals, and at least 1 IgG trough level of ≥5 g/L during the previous 3 months.

Criteria for exclusion:

• Pregnancy or unreliable contraceptive measures or lactation period (females only).
• Known intolerance to immunoglobulins or comparable substances (eg, vaccination reaction).
• Known intolerance to proteins of human origin or known allergic reactions to components of the study product.
• Participation in another clinical study within 30 days before entering the study or during the study and/or previous participation in this study.
• Employee or direct relative of an employee of the contract research organization, the study site, or Biotest.
• Acquired medical conditions known to cause secondary immune deficiency, such as chronic lymphatic leukemia, lymphoma, multiple myeloma, as well as protein losing enteropathies and hypoalbuminemia.
• Other medical condition, laboratory finding, or physical examination finding that precludes participation.
• Recent febrile illness that precludes or delays participation.
• Active infection and receiving antibiotic therapy for the treatment of this infection at the time of screening. Note: if the subject was deemed to be a screen failure due to a nonserious active infection requiring antibiotic therapy, the subject may have been rescreened after the initial screening.
• Therapy with systemic steroids or other immunosuppressant drugs at the time of enrollment (current daily use of corticosteroids, ie, >10 mg prednisone equivalent/day for >30 days. Intermittent corticosteroid use during the study was allowable, if medically necessary).
• History of thrombotic events (including myocardial infarction, cerebral vascular accident [including stroke], pulmonary embolism, and deep vein thrombosis) within the 6 months before treatment start with BT595 or the presence of significant risk factors for thrombotic events.
• Therapy with live-attenuated virus vaccines within 3 months before start of the study.
• Selective, absolute immunoglobulin A (IgA) deficiency or known antibodies to IgA.
• Positive diagnosis of hepatitis B or hepatitis C.
• Positive human immunodeficiency virus (HIV) test.
• History of drug or alcohol abuse within the 12 months before treatment start with BT595.
• Inability or lacking motivation to participate in the study.