Randomized Open Label Trial Evaluating Efficacy and Safety of Intravenous Immunoglobulin (IVIg, Privigen) as Add-on to SoC Versus SoC Alone for Coronavirus Disease 2019 (COVID-19) in Patients with Severely Impaired B-cell Function

INTERVENTION: Product Name: Privigen 100 mg/ml solution for infusion, Product Code:PRD7946772, Pharmaceutical Form: SOLUTION FOR INFUSION, Other descriptive name: , Strength: , Product Name: Veklury 100 mg powder for concentrate for solution for infusion, Product Code:PRD8099279, Pharmaceutical Form: SOLUTION FOR INFUSION, Other descriptive name: , Strength: , Product Name: Paxlovid 150 mg + 100 mg film‐coated tablets, Product Code:PRD12437510, Pharmaceutical Form: FILM‐COATED TABLET, Other descriptive name: Ritonavir , Strength: , Product Name: Paxlovid 150 mg + 100 mg film‐coated tablets, Product Code:PRD12437511, Pharmaceutical Form: FILM‐COATED TABLET, Other descriptive name: , Strength: CONDITION: COVID‐19 and Severely Impaired B‐cell Function Therapeutic area: Diseases [C] ‐ Immune System Diseases [C20] Therapeutic area: Diseases [C] ‐ Virus Diseases [C02] PRIMARY OUTCOME: Main Objective: To evaluate the efficacy of intravenous immunoglobulin as an add‐on to SoC versus SoC alone in vaccine nonresponding severely immunocompromised patients with COVID‐19 on clinical recovery and clearance of RNAemia by Day 28 after randomization Primary end point(s): Proportion of participants with clinical recovery (defined as a score of 0 or 1 according to the WHO Clinical Progression Scale) and no detectable SARS‐CoV‐2 RNA in blood plasma at Day 28, without receiving additional SARS‐CoV‐2 directed treatment (direct acting antivirals and/or IVIg) beyond SoC after randomization. Secondary Objective: To evaluate the efficacy of IVIg as an add‐on to SoC versus SoC alone on clinical improvement and clearance of RNAemia at Day 10 after randomization, To evaluate the efficacy of IVIg as an add‐on to SoC versus SoC alone on sustained recovery and clearing of the viral infection, To evaluate the efficacy of IVIg as an add‐on to SoC versus SoC alone on improved clinical status at days 10 and 28, To evaluate the efficacy of IVIg as an add‐on to SoC versus SoC alone in preventing progression to severe COVID‐19 up to and by Day 28 after randomization., To assess the safety of IVIg as add‐on to SoC versus SoC alone SECONDARY OUTCOME: Secondary end point(s):AEs/SAEs. Assessments related to AEs include: Occurrence/frequency, Relationship to the Investigational Medicinal Product (IMP) as assessed by the investigator, Intensity, Seriousness, Death, AEs leading to withdrawal from the study, Other significant AEs Secondary end point(s):Proportion of participants with clinical improvement (defined as a reduced score of =1 according to the WHO clinical progression scale) and no detectable SARS‐CoV‐2 RNA in blood plasma at Day 10 after randomization Secondary end point(s):Proportion of participants with severe COVID‐19 (defined as a score of =6 according to the WHO clinical progression scale) up to and by Day 28 after randomization. Secondary end point(s):Proportion of participants with sustained clinical recovery (defined as a score of 0 or 1 according to the WHO Clinical Progression Scale) and no baseline SARS‐CoV‐2 straina RNA in blood plasma and nasopharyngeal sample at days 90 and 180, without additional SARS‐CoV‐2 directed treatment (direct acting antivirals and/or IVIg) beyond SoC after randomization. Secondary end point(s):Ranked‐based comparison of 10‐category ordinal WHO Clinical Progression Scale score as assessed by the Investigator at days 10 and 28 AR INCLUSION CRITERIA: Age =18 years, Signed informed consent to participate in the trial and being available for follow‐up for the duration of the trial, Symptomatic COVID‐19 of any severity with a duration of =7 days, Presence of SARS‐CoV‐2 RNA in blood plasma as detected by RT‐PCR within 96 hours from randomization., Having received full initial COVID‐19 vaccination (at least two doses) with any COVID‐19 vaccine at least four weeks prior, Severely impaired B‐cell function due to either disease or treatment according to the Investigator, including hematological malignancy, rejection therapy following solid organ transplantation, and current or previous anti‐CD20 monoclonal antibody treatment., Anti‐SARS‐CoV‐2 Spike IgG level below the detection limit for seropositivity for the available serological instrument within one week from randomization, Signed informed consent to participate in the trial and being available for follow‐up for the duration of the trial, Negative pregnancy test for