Limited Role of Plasma Exchange in Multiple Myeloma-Associated Acute Kidney Injury: Chemotherapy as the Cornerstone of Renal Recovery

Acute kidney injury (AKI) is a common and serious complication in newly diagnosed multiple myeloma (MM), often causing dialysis and impairing treatment. Although modern chemotherapy improves renal function and survival, the benefit of adding prophylactic plasma exchange (PE) remains uncertain. This study investigates its effect on renal recovery and treatment response. A total of 47 MM patients with AKI were retrospectively analyzed. Seventeen patients received prophylactic PE alongside chemotherapy, while thirty received chemotherapy alone. Renal function, dialysis status, and treatment response were assessed over two chemotherapy cycles.In the PE group, median serum creatinine decreased significantly from 3.1 to 1.7 mg/dL (p= 0.002). Median reductions were also observed in free light chain (–202 mg/dL, p= 0.009) and heavy chain levels (–2959 mg/dL, p= 0.013). Dialysis independence was achieved in 50% of PE-treated patients compared to 16.7% in the non-PE group (p= 0.545). A strong positive correlation was identified between the number of PE sessions and creatinine improvement (r = 0.795, p= 0.006). Although bortezomib-based regimens yielded greater early reductions in creatinine (p= 0.021), this difference was no longer significant after the second cycle. Prophylactic PE was associated with rapid biochemical improvement and higher dialysis independence rates, particularly in patients with a high circulating light chain burden. However, its long-term benefit appears limited. Chemotherapy – particularly proteasome inhibitors and anti-CD38 monoclonal antibodies – remains the primary driver of renal recovery in MM-associated AKI, supporting a selective rather than routine use of PE. Keywords: Multiple myeloma, Acute kidney injury, Plasma exchange, Bortezomib-based therapy; Dialysis dependency