High-Dose Melphalan in 1 Day Versus over 2 Days Followed By Autologous Stem Cell Transplantation As Consolidation Treatment in Patients with Multiple Myeloma

• Published in: Blood 2021-11, Vol.138 (Supplement 1), p.3944-3944
• Main Authors: Aydin, Mesire, Tang, Man Wai, Wondergem, Marielle, de Leeuw, David C., Wegman, Jurgen J., Biemond, Bart J., van de Donk, Niels W.C.J., Zweegman, Sonja, Meijer, Ellen, Nur, Erfan
• Format: Article
• Language: English
• ISSN: 0006-4971; 1528-0020
• DOI: 10.1182/blood-2021-147860

Background High-dose melphalan (HDM) at 200 mg/m2 is a myeloablative consolidation treatment prior to autologous stem cell transplantation (ASCT) in patients with multiple myeloma (MM) and is administered in 1-day or divided over 2-days. Although the 1-day regimen (lower AUC) has been shown to result in significantly less gastro-intestinal toxicity, it is not completely clear whether this administration strategy has any deleterious effects on efficacy, compared to the 2-day regimen. In this retrospective cohort study, we aimed to evaluate the effects of 1- or 2-day dosing of HDM on disease remission, progression-free survival (PFS) and overall survival (OS) in patients with MM. Methods Data from two academic centers in Amsterdam that have recently merged were used for the analysis, with one of the centers using the 1-day regimen and the other the 2-days regimen. A total of 265 patients with MM divided over the 1-day group (n=174) and 2-day group (n=91) treated between July 2017 and February 2020, were included in the study. The primary endpoint was the proportion of patients with at least very good partial remission (≥VGPR) at day ±90 post-ASCT. Secondary endpoints were overall survival (OS), progression-free survival (PFS), duration of hospitalization post-ASCT, engraftment period of neutrophils and platelets, and complications (other than mucositis) during hospitalization. Results Patient characteristics are summarized in Table 1. Remission status of ≥VGPR was comparable between the 1-day and 2-day groups (84% vs. 80% respectively). After a median follow-up of 21 months, OS (92% vs. 91%) and PFS (80% vs. 81%) were comparable in the 1-day and 2-day group respectively. There were no differences in the incidence of hematologic adverse events between the 1-day and 2-day groups (neutropenia; 98% vs. 100%, thrombocytopenia; 90% vs. 96% respectively). Median time to neutrophil engraftment (ANC >0.5 x10 9 L -1) was significantly shorter in the 2-day group than in the 1-day group (14 days vs. 18 days, p = 0.002). Median time to platelet engraftment (platelets >20 x10 9 L -1) was comparable between the groups. Lower CD34+ cell counts were administered in the 1-day group compared to the 2-day group (2.6 vs. 3.4 x10 6/kg, p