Efficacy of Autologous and Allogeneic Hematopoietic Cell Transplantation in Waldenström Macroglobulinemia: A Systematic Review and Meta-analysis

Introduction: Waldenström macroglobulinemia (WM) is an IgM-producing lymphoproliferative disorder that remains incurable. Patients with high-risk disease have an overall survival (OS) of less than 3 years. Both autologous (AHCT) and allogeneic (allo-HCT) hematopoietic cell transplantation (HCT) are prescribed for treatment of WM despite a lack of randomized controlled studies. Materials and Methods: We performed a comprehensive literature search using PubMed/Medline and EMBASE on September 10, 2019. Data on clinical outcomes related to benefits and harms was extracted independently by 3 authors. Fifteen studies (8 AHCT [n = 278 patients], 7 allo-HCT [n = 311 patients]) were included in this systematic review/meta-analysis. Results: Pooled OS, progression-free survival (PFS), and nonrelapse mortality (NRM) rates post AHCT were 76% (95% confidence interval [CI], 65%-86%), 55% (95% CI, 42%-68%), and 4% (95% CI, 1%-7%), respectively. Pooled OS, PFS, and NRM rates post allografting were 57% (95% CI, 50%-65%), 49% (95% CI, 42%-56%), and 29% (95% CI, 23%-34%), respectively. OS and PFS rates were reported at 3 to 5 years, and NRM was reported at 1 year in most studies. Pooled ORR (at day 100) post AHCT and allo-HCT were 85% (95% CI, 72%-94%) and 81% (95% CI, 69%-91%), respectively. Pooled complete response rates post AHCT and allo-HCT were 22% (95% CI, 17%-28%) and 26% (95% CI, 7%-50%), respectively. Relapse rates post AHCT and allo-HCT were 42% (95% CI, 30%-55%) and 23% (95% CI, 18%-28%), respectively. Conclusions: Our results show that both AHCT and allo-HCT are effective in the treatment of WM. A 2-fold lower relapse rate but a 7-fold higher NRM was noted for allo-HCT compared with AHCT. The role of transplant in WM needs to be addressed in the era of novel agents. We performed a systematic review and meta-analysis of all the available data to assess the efficacy of autologous (AHCT) and allogeneic (allo-HCT) hematopoietic cell transplantation for Waldenström macroglobulinemia. Both AHCT and allo-HCT are efficacious, resulting in complete response rates of around 20% with allo-HCT affording a 2-fold lower relapse rate, which is offset by a 7-fold higher non-relapse mortality compared with AHCT.