Efficacy of iptacopan in idiopathic immune complex–mediated membranoproliferative glomerulonephritis refractory to conventional treatment

Membranoproliferative glomerulonephritis due to immune complexes (MPGN-IC) idiopathic is a diagnosis of exclusion, made after ruling out the most common etiological processes associated with this pattern of glomerular injury (infectious, autoimmune diseases, gammopathies, among others). Idiopathic MPGN-IC shares with C3 glomerulopathy the activation of the alternative complement pathway, often evidenced by decreased serum C3 levels. Currently, there is no specific treatment for this type of glomerulonephritis; however, various immunosuppressive agents (such as prednisone, mycophenolate, cyclophosphamide, rituximab) have been used depending on the severity of the case. We present a clinical case diagnosed with idiopathic MPGN-IC presenting as an aggressive nephritic-nephrotic syndrome with rapidly progressive renal deterioration unresponsive to conventional therapy, requiring hemodialysis. Complete remission was achieved after initiating treatment with iptacopan, an oral inhibitor of factor B of the alternative complement pathway, and we demonstrate the patient's evolution over 12 months of treatment.