CLYM116 & IgAN Opportunity - Climb Bio's mission is to deliver high impact, disease-modifying medicines for individuals living with immune-mediated diseases[5] - CLYM116 is an anti-APRIL monoclonal antibody being developed for IgA Nephropathy (IgAN)[8, 48] - Climb Bio has worldwide rights to CLYM116 outside Greater China, partnering with Beijing Mabworks Biotech Co, Ltd[9, 11] - Phase 1 initiation of CLYM116 is expected in Q4 2025, with initial data anticipated mid-year 2026[8, 15, 16, 106] IgAN Market & Treatment Landscape - IgAN represents a significant market opportunity estimated at ~$10-20 billion in the US, with most patients requiring lifelong treatment[12, 105] - KDIGO 2025 guidelines recommend treatment initiation for patients with proteinuria >=05 g/day, representing approximately 60-75% of patients[13] - The FDA recognizes the need for surrogate outcomes, such as improvement in proteinuria, in IgAN studies for accelerated approval[29] CLYM116 Differentiated Profile - CLYM116 is the only known "sweeper" anti-APRIL mAb in development, designed for improved activity, less frequent dosing, and a favorable safety profile[10, 57, 103, 106] - Preclinical NHP data demonstrated potential for deep and durable IgA suppression, with >70% maximal reduction after a single 6 mg/kg SC dose, and a ~2-3x longer half-life compared to sibeprenlimab[16, 74, 84, 89, 90, 104] - In NHPs, CLYM116 SC demonstrated high bioavailability of ~85% and favorable tolerability, supporting potential for convenient, at-home dosing[81]