Daratumumab (anti-CD38)- and elotuzumab (anti-SLAMF7)-based treatments for refractory POEMS syndrome: a single-center case series.

The survival and neurological prognosis of polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy, and skin changes (POEMS) syndrome have been substantially improved by peripheral blood stem cell transplantation and immunomodulating agents since the 2000s. However, some patients with POEMS syndrome are refractory to these treatments. This study aimed to evaluate the efficacy and safety of monoclonal antibody therapy with daratumumab (anti-cluster of differentiation 38) and elotuzumab (anti signaling lymphocytic activation molecule family member 7) for POEMS syndrome. We reviewed patients with refractory POEMS syndrome who received daratumumab- or elotuzumab-based treatment between January 2019 and July 2024. We studied the hematologic, vascular endothelial growth factor (VEGF), and clinical responses; time to the next treatment; and adverse events. Eight patients received 13 regimens of daratumumab, elotuzumab, or both. All patients were recurrent/refractory to immunomodulatory drugs, proteasome inhibitors, and/or autologous stem cell transplantation. After a median of six cycles of treatment (range, 3-32 cycles), one hematologic (8%), seven VEGF (54%), two neurologic (15%) and eight generalized clinical responses (62%) were observed. Six patients received subsequent treatment, and the median time to the next treatment was 11 months (range, 4-33 months). Grade 3 hematologic toxicity occurred in four regimens and grade 2 infusion-related reactions occurred in five. None of the patients died during the median follow-up period of 39 months (range, 3-66 months). Daratumumab- and elotuzumab-based regimens may be treatment options for refractory POEMS syndrome.