Efficacy and safety of bortezomib in refractory lupus nephritis: a single-center experience

Abstract

Background and objectives: Resistant lupus nephritis (LN) has been associated with the persistence of long-lived plasma cells. Preliminary studies identified bortezomib as a potential treatment option for patients with refractory LN. The aim of this study was to analyze the efficacy and safety of bortezomib in the treatment of severe refractory LN.

Methods: This retrospective study included 12 female patients diagnosed for the first time with class IV or IV/V LN with acute or rapidly progressive kidney injury (n = 11) and/or severe nephrotic syndrome (n = 1) who showed resistance to induction therapy with cyclophosphamide, steroids, mycophenolate, and rituximab, and were treated with either intravenous or subcutaneous bortezomib plus intravenous dexamethasone.

Results: All patients with acute or rapidly progressive kidney injury showed a significant reduction in both biochemical and immunological activity after a mean of 6 (minimum 5, maximum 7) weekly cycles of bortezomib regimen, with a significant increase in C3 levels and a significant decrease of anti-ds DNA antibody titers, Systemic Lupus Erythematosus Disease Activity Index score, serum creatinine, and proteinuria. One patient (8.3%) achieved a complete response, and 10 patients (83.4%) achieved a partial response. During follow-up, all these patients maintained partial responses under treatment with mycophenolate and low-dose glucocorticoids. The patient with refractory nephrotic syndrome showed a partial response but relapsed 11 months after the end of bortezomib treatment and was resistant to treatment. A significant decrease in serum IgG levels after initiation of bortezomib treatment was observed in all patients, five of them (41.6%) showed hypogammaglobulinemia (<500 mg/dl), but no patient suffered from opportunistic infections; in only two patients (16.6%) hypogammaglobulinemia persisted at the end of follow-up. Two patients (16.6%) suffered from sensory neuropathy, which led to bortezomib treatment discontinuation.

Conclusions: Bortezomib may be an effective option for refractory LN, but close monitoring must be performed for possible adverse events such as peripheral neuropathy and hypogammaglobulinemia.

Keywords: Lupus nephritis; bortezomib; proteasome inhibitor; refractory lupus nephritis.