Durable Responses with Autologous Hematopoietic Stem Cell Transplantation in Patients with POEMS Syndrome

Abstract 4522 Introduction: POEMS syndrome (polyradiculoneuropathy, organomegaly, endocrinopathy, monoclonal plasma cell disorder, and skin changes) is a rare plasma cell disorder often associated with papilledema, extravascular volume overload, sclerotic bone lesions, Castleman disease, and high vascular endothelial growth factor (VEGF) levels. High-dose chemotherapy and autologous hematopoietic stem cell transplant (auto-HCT) can be used with good clinical response, but has significant post-transplant morbidity. Here we present our experience in 5 patients with POEMS syndrome who underwent auto-HCT at the MD Anderson Cancer Center (MDACC). Method: Between January 1999 and October 2010, 5 patients (4 males, 1 female) with POEMS syndrome received auto-HCT at MDACC. Diagnosis of POEMS was based on criteria of Dispenzieri et. al.1 All 5 patients had received systemic therapy prior to auto-HCT as follows: bortezomib+dexamethasone (dex) in 2, lenalidomide+dex in 1, cyclophosphamide+dex in 1, and pulse dex in 1. Two patients also received localized radiation for bone disease. Peripheral blood stem cells were collected with granulocyte colony-stimulating factor (G-CSF) in 4 patients and with cyclophosphamide+G-CSF in 1. The preparative regimen was melphalan 200 mg/m2 in 4 patients, while 1 patient received 180 mg/m2 due to renal insufficiency. We evaluated the response rate, toxicity, transplant-related mortality, progression-free survival (PFS) and overall survival (OS). Hematologic response was defined by the International Myeloma Working Group (IMWG) criteria2. Result: Median age at auto-HCT was 48 years (range: 39–58) and median time from diagnosis to auto-HCT was 16.6 months (6.4 – 89 months). All 5 patients had osteosclerotic bone lesions and monoclonal gammopathy: IgA lambda in 3, IgG lambda in 1, and IgG kappa in 1. Two patients had biopsy proven Castleman disease. Four patients had debilitating polyneuropathy. Other features were: skin involvement in 3, endocrinopathy in 2, ascites in 1, anasarca in 2, pulmonary hypertension in 1, and papilledema in 1. Median follow up after auto-HCT was 11.6 months (8.6 – 83.5 months). Median Karnofsky performance status was 80% (70–100) at the time of transplant and 90% (80–100) by the one year follow up visit. Two patients (40%) had complete response, 2 (40%) had a very good partial response, and 1 (20%) had a partial response by IMWG criteria. Engraftment syndrome was not seen in any of the 5 patients. Significant post auto-HCT complications were fungal pneumonia in 2 patients and pulmonary embolism in one. Patients fully recovered from these complications. One-year transplant-related mortality was 0%. All 5 patients had complete or significant resolution of their clinical symptoms after auto-HCT. Median PFS and OS have not yet been reached. With a median follow up of 11.6 months, 1-year PFS and OS were 100%. Four patients are alive and in remission, while one patient died 6 years after his auto-HCT secondary to gastrointestinal bleeding unrelated to his underlying disease. Conclusion: High-dose therapy followed by auto-HCT is safe and effective in selected patients with POEMS syndrome and is associated with durable responses and survival. Disclosures: No relevant conflicts of interest to declare.