Takeda presents interim data from Phase 1b study of mezagitamab

Takeda (TAK) announced new interim data from the Phase 1b, open-label, proof-of-concept study of subcutaneous mezagitamab, an anti-CD38 monoclonal antibody with disease-modifying potential, in primary immunoglobulin A nephropathy. Data from the study showed that kidney function remained stable in patients with IgA nephropathy through Week 96 – up to 18 months after the last mezagitamab dose. The results were presented at the American Society of Nephrology Kidney Week 2025 in Houston. IgA nephropathy is a lifelong progressive autoimmune disease often diagnosed in young people aged 10-30 years old that causes irreversible damage to the kidney function. It has no cure, and despite available treatments, approximately one in five patients experience renal failure within 10 years of diagnosis.3 By depleting cells that produce an abnormal protein called Gd-IgA1 implicated in the pathogenesis, mezagitamab targets early steps in the process leading to disease in IgA nephropathy. In the study, 17 patients with IgA nephropathy were treated with mezagitamab as an add-on to stable background therapy, and 13 patients continued into the long-term follow-up period. At Week 96 – 18 months after the last dose – kidney function remained stable and patients sustained a 55.2% mean reduction in proteinuria measured using a urine protein-creatinine ratio/ Sustained reductions of 50.1% in Gd-IgA1 and complete recovery toward baseline in IgG were observed by Week 96. Hematuria was resolved in 60% of patients by Week 96. In this study, mezagitamab was generally well tolerated with no new safety concerns identified. No serious adverse events, including no serious hypersensitivity or injection-related reactions, discontinuations due to AEs, opportunistic infections or grade greater than or equal to3 infections were reported.