Phase 2/3 Study of IGSC, 20% in PIDD

Main Inclusion Criteria: * Documented diagnosis of a form of primary humoral immunodeficiency involving defective antibody formation and requiring gammaglobulin replacement as defined according to the IUIS Scientific Committee, 2011 and by diagnostic criteria according to Conley et al. (1999). The diagnosis must be confirmed by the Medical Director prior to first treatment with the investigational product (IP) in the study. * Participant is 2 years or older at the time of screening, and has a minimum body weight of 13 kg. * Written informed consent has been obtained from either the participant or the participant's legally authorized representative prior to any study-related procedures and study product administration * Participant has been receiving a stable monthly equivalent dose of IgG at an average minimum dose equivalent to 300 mg/kg bodyweight (BW)/4 weeks and a maximum dose equivalent to 1.0 gram/kg BW/4 weeks, for a minimum of 12 weeks prior to first treatment with the IP in the study. * Serum trough level of IgG \> 500 mg/dL at screening * Participant is willing and able to comply with the requirements of the protocol Main Exclusion Criteria: * Participant has known history of or is positive at screening for one or more of the following: hepatitis B surface antigen (HBsAg), polymerase chain reaction (PCR) for Hepatitis C virus(HCV), PCR for human immunodeficiency virus (HIV) Type 1/2 * Abnormal laboratory values at screening meeting any one of the following criter…