Overview

The purpose of this study is to evaluate the safety and tolerability of atacicept in adult and adolescent participants and to measure the effect in reducing proteinuria and preserving renal function.

Eligibility

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
• 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.