Biogen BIIB initiated dosing in a global, late-stage study of its investigational candidate, felzartamab, for treating adult patients with primary membranous nephropathy (PMN). Top-line data readout is expected in 2029.
Felzartamab is an anti-CD38 antibody with a unique mechanism of action that is particularly relevant in PMN treatment. Currently, no approved therapies exist for PMN, and treatment typically relies on immunosuppressants or chemotherapy.
Felzartamab was added to Biogen’s pipeline with the acquisition of Human Immunology Biosciences (HI-Bio) last year. The candidate was originally developed by MorphoSys AG (acquired by Novartis), which out-licensed exclusive rights to develop and commercialize felzartamab to HI-Bio across all indications in all countries and territories, excluding China and certain other geographies.
Biogen’s global phase III PROMINENT study will evaluate the efficacy and safety of felzartamab compared to an immunosuppressive drug, tacrolimus, in moderate-to-high-risk PMN patients in achieving complete remission of proteinuria (high levels of protein in the urine). The patient pool will include both newly diagnosed and relapsed cases.
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Biogen expects to enroll approximately 180 PMN patients in the PROMINENT study who will be randomized to receive either felzartamab or tacrolimus, with the primary endpoint being the percentage of patients who achieve complete remissions at week 104. The study will evaluate patients with and without a certain antibody (called anti-PLA2R) linked to PMN. Patients will be grouped based on how much of this antibody they have. As secondary endpoints, BIIB will also evaluate the effect of felzartamab on serum aPLA2R antibodies and patient-reported outcomes.
PMN is a serious kidney disease that can lead to kidney failure and affects about 36,000 people in the United States. It causes severe swelling, fatigue and infection risk. There are no approved treatments, and current options like immunosuppressants or chemotherapy fail in about one-third of patients, representing a serious unmet medical need.
In 2025, Biogen has also initiated dosing patients with felzartamab in two other phase III studies, TRANSCEND for late antibody-mediated rejection in adult kidney transplant recipients and PREVAIL for IgA nephropathy.
Biogen previously evaluated felzartamab in two phase II studies, M-PLACE and NewPLACE, focusing on patients with aPLA2R-positive PMN. In M-PLACE, most patients showed a significant drop in aPLA2R antibody levels within a week (median reduction of 45%), with most achieving more than 50% reduction by six months. The treatment also led to improvements in protein levels in urine and blood.
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