Atacicept in Multiple Glomerular Diseases

Inclusion Criteria:

• Weight of at least 40 kg

• On a stable prescribed standard of care (SoC) treatment regimen according to local guidelines and the specific requirements for each disease

• Systolic blood pressure ≤160 mmHg and diastolic blood pressure ≤90 mmHg at Screening. For participants aged ≥10 to <18 years, the average of 3 separate systolic and/or diastolic blood pressures <95th percentile for age, gender, and height

Diagnosis of IgAN, IgAVN, pMN, MCD, FSGS, or primary nephrotic syndrome

For patients enrolling in IgAN cohorts (eligibility varies by cohort):

• Age ≥ 10 years

• Biopsy proven IgAN or IgAVN,

• UPCR ≥ 0.5 g/g

• eGFR≥ 20 mL/min/1.73m2

For patients enrolling in pMN cohorts (eligibility varies by cohort):

• Age ≥ 18 years

• Biopsy-proven pMN

• Anti PLA2R antibodies ≥ 25 RU/mL

• UPCR ≥ 1.5 g/g

• At low risk for spontaneous remission (based on severity or duration of disease)

For patients enrolling in Nephrotic Syndrome cohorts (MCD, FSGS, or pediatric idiopathic nephrotic syndrome):

• Age ≥ 10 years

• eGFR≥30 mL/min/1.73m2

• Biopsy diagnosis of primary MCD or FSGS (adults) or challenging clinical course with steroids in children (frequenlty relapsing, steroid-dependent, or steroid-resistant)

• UPCR ≥ 1.0 g/g at Screening,

• Evidence of anti-nephrin antibodies

Key Exclusion Criteria

• Evidence of rapidly progressive glomerulonephritis (loss of ≥50% of eGFR) within 3 months prior to and at Screening)

• Active viral or bacterial infections

• Existing conditions or clinically significant laboratory abnormalities that may interfere with participation in this study

• Administration of live and live-attenuated vaccinations within 30 days prior to enrollment

• Known hypersensitivity to atacicept or any component of the formulated atacicept

• Additional criteria apply to each cohort/disease.