To evaluate the safety and tolerability of three dose regimens of budoprutug in subjects with PMN

Budoprutug is a humanized, immunoglobulin (Ig) G1 monoclonal antibody that selectively binds to CD19 and is projected to deplete targeted cells through antibody-dependent cellular cytotoxicity (ADCC). This Phase 2, open-label, multicenter study evaluates the safety, pharmacodynamics, and preliminary efficacy of three intravenous dose regimens of budoprutug in adult subjects with primary membranous nephropathy (PMN) who are anti-PLA2R antibody positive and have persistent proteinuria despite optimized RAAS inhibition. Approximately 45 subjects will be enrolled across three sequential dose cohorts, each receiving a single IV dose of budoprutug on Day 1, Day 15, Day 169 and Day 183. Subjects will be followed through Week 48, with extended follow-up for B-cell recovery as needed.

Inclusion Criteria:

• Confirmed diagnosis of PMN with positive anti-PLA2R antibodies
• CD19+ B cell count ≥40 cells/μL
• UPCR ≥2.0 g/g
• eGFR ≥35 mL/min/1.73 m²
• Stable RAAS inhibitor therapy
• Blood pressure <150/90 mmHg at baseline
• Adequate hematologic, hepatic, and renal function
• Willing to use effective contraception (both sexes)
• Other inclusion criteria may apply

Exclusion Criteria:

• Secondary Membranous Nephropathy
• Rapidly progressive glomerulonephritis or other glomerulopathies
• Prior B cell-depleting therapy within 24 weeks
• Recent use of immunosuppressants
• Active or high-risk infections
• History of malignancy
• Pregnancy or breastfeeding
• Recent major surgery or hospitalization
• Other exclusion criteria may apply