Membranoproliferative glomerulonephritis and acute renal failure in a patient with chronic lymphocytic leukemia: Response to obinutuzumab

Objective/background Membranoproliferative glomerulonephritis (MPGN) is a common extramedullary renal presentation in chronic lymphocytic leukemia (CLL) and can present with either a frank renal failure or proteinuria. One of its etiologies has been attributed to a paraneoplastic, immune complex phenomenon occurring in CLL. Although there is no standard of care in such patients, use of anti-CD20 monoclonal antibodies like rituximab have been used before in such patients with variable responses. Obinutuzumab is a novel, type II, immunoglobulin-G1 monoclonal antibody with a higher efficacy than rituximab and has an established safely profile in patients with comorbidities and poor renal functions. There are no such reported cases of MPGN in CLL being treated with obinutuzumab. Methods We used the standard doses of obinutuzumab in our elderly patient (78-year-old woman) with high-risk CLL due to an underlying TP53 mutation, along with a MPGN-related acute renal failure. Results The patient achieved complete remission after six cycles of obinutuzumab; however, she remained positive for minimal residual disease on flow cytometry. Her renal function improved completely, suggesting a complete response of her underlying MPGN. Conclusion Obinutuzumab has an established safety profile in patients with CLL, but our case is the first reported case of a paraneoplastic, immune complex-mediated MPGN in CLL being treated with obinutuzumab. Obinutuzumab should be explored as a potential option in patients with CLL and MPGN.