Climb Bio announces CLYM116 preclinical data

Climb Bio (CLYM) announced results from a completed nonhuman primate study comparing CLYM116 to sibeprenlimab, a first-generation anti-APRIL monoclonal antibody. The company is hosting a virtual investor event focused on CLYM116 today, Monday, September 29, 2025, at 8:00 a.m. ET. Climb Bio’s management team will be joined by leading nephrologist Craig E. Gordon, MD, MS, who has over 20 years of experience treating patients with IgA nephropathy and was a co-director of the Evidence Review Team for the recently issued 2025 KDIGO Clinical Practice Guideline for IgAN. New CLYM116 NHP data demonstrate improvement versus sibeprenlimab: Subcutaneous formulation demonstrated high bioavailability, with a favorable tolerability profile; Prolonged exposure observed compared to sibeprenlimab, with a ~2-3 times longer half-life across doses; Deeper and more prolonged IgA reduction observed compared to sibeprenlimab after a single subcutaneous administration at equivalent doses, with greater than70% maximal reduction in IgA observed with CLYM116; Additional in vivo studies in mice showed enhanced APRIL elimination and antibody recycling relative to sibeprenlimab. CLYM116 advancing towards planned Phase 1 trial in healthy volunteers: Phase 1 trial expected to initiate in Q4 2025, subject to regulatory clearance, with initial data, including biomarkers and projected dosing interval, anticipated mid-year 2026; Parallel execution by Mabworks in China expected to provide a complementary Phase 1 dataset; IgAN represents a high unmet need indication, with a well-defined development path. Progressive autoantibody-mediated renal disease, caused by APRIL-mediated production of pathogenic IgA and deposition of immune complexes in the glomeruli: Damage to glomeruli leads to proteinuria, kidney injury and loss of kidney function, with 30-40% of patients developing kidney failure within 10 years of diagnosis; Prior product approvals in IgAN provide precedent regarding study design and registrational endpoints, including use of proteinuria for accelerated approval and estimated glomerular filtration rate for full approval; Biomarkers enable rapid assessment of clinical profile during early development.