Atacicept in Multiple Glomerular Diseases

The purpose of this study is to evaluate the safety and efficacy of Atacicept in multiple autoimmune glomerular diseasing including:

• IgAN (IgA Nephropathy)
• pMN (Primary Membranous Nephropathy)
• MCD/FSGS (Minimal Change Disease/Focal Segmental Glomerulosclerosis)

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.

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

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

• Age ≥ 18 years
• Biopsy proven IgAN, IgAVN, or recurrent IgAN in kidney transplant
• UPCR ≥ 0.5 g/g or UPE ≥ 0.5 g/day on 24h urine
• eGFR≥ 20 mL/min/1.73m2

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

• Age ≥ 2 years and < 18 years
• Biopsy proven IgAN or IgAVN
• On stable prescribed regimen of RAASi (or SoC) for at least 8 weeks
• UPCR ≥ 1.0 g/g or UPE ≥ 1.0 g/d on 24h urine
• eGFR≥ 30 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 or UPE ≥ 1.5 g/d on 24h urine
• 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
• Adults with biopsy diagnosis of primary MCD or FSGS (adults) or children with challenging clinical course with steroids (frequenlty relapsing, steroid-dependent, or steroid-resistant)
• UPCR ≥ 1.0 g/g or UPE ≥ 1.0 g/d on 24h urine
• Evidence of anti-nephrin antibodies

Key Exclusion Criteria:

• Evidence of rapidly progressive glomerulonephritis (loss of ≥50% of eGFR) within 12 weeks 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
• Immunosuppressant medications within 4 weeks prior to dosing with atacicept (except transplant maintenance immunosuppression).
• Known hypersensitivity to atacicept or any component of the formulated atacicept
• Additional criteria apply to each cohort/disease.