Hwa, Yi

Abstract Extramedullary multiple myeloma (EMM) can present either at initial diagnosis (de novo) or at disease relapse (secondary) and confers an aggressive clinical course. Limited data exist for choosing the optimal therapy for EMM and this remains an area of unmet clinical need. After excluding paraskeletal multiple myeloma and primary plasma cell leukemia, we identified 204 (68%) patients with secondary EMM and 95 (32%) with de novo EMM between January 01, 2000 and 31 December, 2021. The median overall survival (OS) was 0.7 (95% CI: 0.6–0.9) years for secondary EMM and 3.6 (95%CI: 2.4–5.6) years for de novo EMM. The median progression‐free survival (PFS) with initial therapy was 2.9 months (95% CI: 2.4–3.2 months) for secondary EMM and 12.9 months (95% CI: 6.7–18 months) for de novo EMM. Patients with secondary EMM treated with CAR‐T therapy ( n = 20) achieved a partial response (PR) or better in 75% with a median PFS of 4.9 months (3.1 months‐not reached; NR). Patients with EMM treated with bispecific antibodies ( n = 12) achieved a ≥ PR in 33%, with a median PFS of 2.9 months (95%CI: 2.2 months‐NR). In a matched cohort, multivariate logistic regression analysis demonstrated younger age at diagnosis, 1q duplication, and t (4;14) at diagnosis of MM to be independent predictors of development of secondary EMM. Presence of EMM was independently associated with inferior OS in the matched cohorts for both de novo (HR 2.9 [95% CI: 1.6–5.4], p = .0007) and secondary EMM (HR 1.5 [95% CI: 1.1–2], p = .001).

Over the past decade, a number of changes have occurred in the diagnostic evaluation, management, and long‐term follow‐up of patients with POEMS syndrome at our institution. This study included 291 patients with POEMS syndrome diagnosed at the Mayo Clinic between 1974 and 2014. Patients diagnosed after 2003 had more features of the syndrome identified at diagnosis and were more likely to receive an autologous transplant (49% versus 8%, P < 0.0001) and to have achieved a hematologic complete response (CR) to treatment (41% vs 25%, P < 0.0001). With 2273 person‐years of follow‐up, 10‐year overall survival (OS) was 62% (95% C.I., 56%, 67%). On multivariate analysis, the three factors associated with superior OS were younger age (RR 0.98 [0.96–1.00]), albumin greater‐than 3.2 g/dL (RR 0.5 [0.32–0.89]) and attainment of complete hematologic response (RR 0.4 [0.2, 0.9]). This study confirms the very good long‐term outcomes of patients with POEMS syndrome and identifies two new prognostic risk factors: albumin at diagnosis and attainment of complete hematologic response. Am. J. Hematol. 91:585–589, 2016. © 2016 Wiley Periodicals, Inc.