Number of participants with AEs and SAEs, including significant changes from baseline in physical findings, vital signs, electrocardiograms and laboratory values qualifying and reported as AEs. The number of participants in each category (AEs and SAEs) is reported per dose level: CDZ173 10 mg from Day 1 to Day 28, CDZ173 30 mg from day 29 to day 56 and CDZ173 70 mg from day 57 to day 84.

Venous whole blood samples were collected for the assessment of the dose-PD and the PK/PD relationship of CDZ173 in participants with APDS/PASLI for dose selection in Part II. CDZ173 was determined by a validated Liquid chromatography - Mass spectometry (LC-MS) method; anticipated Lower Limit of Quantification (LLOQ) was 3 ng/mL. Concentrations below the LLOQ were reported as "zero" and no methods for imputation of missing data were used.

Phosphorylation of Akt in ex vivo stimulated and unstimulated B cells was quantified at baseline and at the end of the 4-week treatment period for each of the three dose levels. Determination of the percentage (%) of CD20B+ phospho-Akt positive cells after ex vivo stimulation of whole blood was performed by flow cytometry analysis. The percentage of inhibition of pAkt was defined as (-1) \* percent change from baseline pAkt value. Unstimulated cells served as controls at each time point. Baseline was defined as the mean of the day -1 value and the pre-dose value on Day 1 when both were available (if one was missing, then baseline was defined as the existing value). A higher percentage of inhibition of stimulated B cells indicates improvement. No methods for imputation of missing data were used.

For the assessment of the impact of CDZ173 on lymphadenopathy, participants were scanned in a magnetic resonance imaging (MRI) or a computed tomography (CT) scanner as based on clinical practice and local regulation. MRI or CT imaging of the neck, chest, abdomen and pelvis was performed. Index lesions were selected from measurable nodal and extranodal lesions as per the Cheson methodology. A maximum of six of the largest dominant lesions were selected and documented at baseline and assessed again at the end of treatment. The change in lymph node size was measured using the log10 transformed sum of product of diameters (SPD), the sum of the longest lesion diameter (mm)" and "longest perpendicular diameter (mm)". A lower score indicates index lesions SPD reduction. A negative change from baseline indicates improvement.

APDS/PASLI patients suffer from dysregulation in B cell function and differentiation with low numbers of naive B cells. Change from baseline in percentage of naïve B cells out of total B cells at the end of treatment was assessed by flow cytometry to evaluate the pharmacodynamic effect of CDZ173 on B cell immunophenotyping. A higher percentage in naïve B out of total B cells is a positive outcome. A positive change from baseline indicates improvement.