A case report describes rituximab controlling severe PR3-ANCA pulmonary-renal syndrome in a dialysis-dependent patient after conventional induction therapy failed. The report highlights a rescue-use scenario where rituximab appears to restore disease control when first-line approaches do not achieve remission. While limited by single-patient design, the clinical narrative reinforces rituximab’s role as a potent B-cell targeting strategy in ANCA-associated vasculitis, including high-acuity settings. The key contribution is the sequencing decision under refractory disease. For clinicians and biotech teams watching translational trends, it adds real-world context for rescue regimens and patient selection considerations when standard protocols fall short. The report is best read as hypothesis-generating evidence supporting continued evaluation of rituximab rescue strategies in difficult disease courses.