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Mezagitamab Shows Promise for IgA Nephropathy in Phase 1b Trial, with Jonathan Barratt, MD, PhD
Jonathan Barratt, MD, PhD, discusses results from an open-label trial of mezagitamab from ERA 2025.
Positive data from a phase 1b trial presented at the 62nd European Renal Association (ERA 2025) Congress suggests another therapy in the pipeline for IgA nephropathy (IgAN) could be on the horizon.
Led by Jonathan Barratt, MD, PhD, the Mayer Professor of Renal Medicine at the University of Leicester, interim results from a phase 1b trial suggest mezagitamab, a CD38-targeting monoclonal antibody, was associated with meaningful biological and clinical responses, with no evidence of Grade 3 or greater infections, when added to standard care.
The open-label, single-arm study, which is sponsored by Takeda Pharmaceuticals, evaluated mezagitamab among 17 patients with biopsy-proven IgAN and persistent proteinuria despite stable renin–angiotensin system blockade. Per trial protocol, patients received subcutaneous mezagitamab 600 mg weekly for 8 weeks, followed by dosing every 2 weeks for an additional 16 weeks, with a total treatment duration of 24 weeks and a 24-week safety follow-up.
In the 48-week analysis from ERA 2025, mezagitamab demonstrated favorable tolerability. Sixteen of 17 participants (94.1%) experienced at least one adverse event, though none were serious or led to study discontinuation. No Grade 3 or higher infections or opportunistic infections were reported. The most common adverse events reported in the trial were upper respiratory tract infection (35%), pyrexia (24%), and oropharyngeal pain (24%).
Results of the interim analysis also indicated treatment led to meaningful biological and clinical responses. By week 48, serum IgA levels declined by 52.4%, Gd-IgA1 by 57.8%, and IgG by 18.9%. Mean proteinuria, measured by UPCR, was reduced by 54.1% (95% CI, –63.7 to –42.0). Renal function remained stable, with a mean change in eGFR of +1.1 mL/min/1.73 m² (95% CI, –2.6 to +4.8) from baseline.
For more on the evolving pipeline in IgAN and where mezagitamab may fit into future treatment algorithms, watch our full interview with Barratt from ERA 2025.
Relevant disclosures of interest for Barratt included Argenx, Calliditas Therapeutics, Chinook Therapeutics, Galapagos NV, GSK, Novartis, Travere Therapeutics, and others.
