Core Insights - Biogen has initiated dosing in a global, late-stage study of felzartamab for treating adult patients with primary membranous nephropathy (PMN), with top-line data expected in 2029 [1][4] - Felzartamab is an anti-CD38 antibody with a unique mechanism of action, and currently, there are no approved therapies for PMN, which typically relies on immunosuppressants or chemotherapy [1][6] - The PROMINENT study will evaluate the efficacy and safety of felzartamab compared to tacrolimus in moderate-to-high-risk PMN patients [3][5] Company Developments - Felzartamab was added to Biogen's pipeline through the acquisition of Human Immunology Biosciences last year, originally developed by MorphoSys AG [2] - The PROMINENT study will enroll approximately 180 PMN patients, with the primary endpoint being the percentage of patients achieving complete remissions at week 104 [5] - Biogen has also initiated dosing patients with felzartamab in two other phase III studies for late antibody-mediated rejection in kidney transplant recipients and IgA nephropathy [7] Clinical Study Details - The PROMINENT study will compare felzartamab to tacrolimus in 180 moderate-to-high-risk PMN patients, including newly diagnosed and relapsed cases [4][5] - Secondary endpoints will evaluate the effect of felzartamab on serum aPLA2R antibodies and patient-reported outcomes [5] - Previous phase II studies showed that felzartamab led to significant reductions in aPLA2R antibody levels and improvements in kidney markers [10] Market Context - PMN affects about 36,000 people in the United States and represents a serious unmet medical need, as current treatment options fail in about one-third of patients [6] - Year to date, Biogen's shares have declined by 17.9%, compared to the industry's decline of 3.6% [3]

Core Viewpoint - Biogen has initiated a Phase 3 clinical study, PROMINENT, to evaluate the efficacy and safety of felzartamab in treating primary membranous nephropathy (PMN), a severe kidney disease with no approved treatments [1][4]. Company Overview - Biogen is a leading biotechnology company founded in 1978, focused on innovative science to develop new medicines and create value for shareholders and communities [10]. - The company has a commitment to advancing treatment options for patients with kidney diseases, as evidenced by the launch of multiple Phase 3 trials for felzartamab in 2025 [3][5]. Drug Information - Felzartamab is an investigational anti-CD38 monoclonal antibody that selectively depletes CD38+ plasma cells, which are implicated in various immune-mediated diseases [2][6]. - The drug targets patients with PMN, where up to 80% have autoantibodies against PLA2R, and aims to provide a novel treatment option in a field lacking approved therapies [2][9]. Clinical Study Details - The PROMINENT study will enroll approximately 180 adults with PMN and is expected to read out in 2029 [1]. - The trial is designed as a 104-week, randomized, open-label study comparing felzartamab to tacrolimus, with the primary endpoint being the percentage of participants achieving complete remission of proteinuria at week 104 [3][4]. - Key secondary endpoints include the impact on serum anti-PLA2R antibodies and patient-reported outcomes [3]. Previous Research - Felzartamab has shown promising results in earlier Phase 2 studies, with significant reductions in aPLA2R titers and improvements in proteinuria and serum albumin levels observed [4][6]. - The majority of treatment-emergent adverse events reported were mild to moderate, primarily infusion-related reactions [4]. Market Context - PMN is a rare immune-mediated kidney disease with an estimated prevalence of approximately 36,000 patients in the U.S., highlighting the unmet medical need in this area [6][9].