Which is the best treatment strategy before autologous peripheral blood stem cell transplantation in POEMS syndrome?

Autologous peripheral blood stem cell transplantation (aPBSCT) provides optimal outcomes in POEMS syndrome but the definition of the best treatment before aPBSCT remains to be defined, because of the disease rarity and the heterogeneity of published case series. We collected clinical and laboratory data of patients with POEMS syndrome undergoing aPBSCT from 1998 to 2020 in 10 Italian centres. The primary endpoint of the study was to evaluate the impact of prior therapies and mobilizing regimen on outcome. We divided patients in three groups: patients who did not receive any treatment before transplant (15 patients, group A: front-line), pre-treated patients with other agents (14 patients, group B) and patients treated with cyclophosphamide as mobilizing regimen (16 patients, group C). The three groups did not show differences in terms of demographic and clinical characteristics. All 45 patients underwent aPBSCT after high dose melphalan conditioning regimen, with a median follow-up of 77 months (37-169 months). The responses were not statistically different between the 3 groups (p 0.38). PFS and OS rates at 6 years were 65% (49-85) and 92% (84-100), respectively and did not differ in the 3 groups. The cumulative incidence of transplant related mortality and relapse was respectively 4% and 36%. In conclusion, in a relatively large number of patients with POEMS syndrome, undergoing an autologous transplant, pre-treatment and disease status at transplant did not appear to have an impact on major transplant outcomes.