The Comparison of Unmanipulated Bone Marrow Versus Peripheral Blood Haploidentical Stem Cell Transplantation in Adult Acute Leukemia: A Systematic Review and Meta-Analysis
Authors: Durer Seren , Durer Ceren , Jamil Faiza , Selene Insija Ilyas , Malik Mustafa Nadeem , Rafae Abdul , Abu Zar Muhammad , Kamal Ahmad , Ijaz Awais , Usman Muhammad , Khan Ali Younas , Jose Jemin Aby , Tariq Muhammad Junaid , Katsanis Emmanuel , Anwer Faiz 
Published: October 2019

Abstract
Background:
The use of peripheral blood stem cell source (PBSC) continues to grow in the setting of haploidentical hematopoietic stem cell transplantation (haplo-SCT), mainly due to the ease of collection and rapid peripheral blood count recovery. We conducted a systematic review and meta-analysis of the published literature to evaluate the outcomes of unmanipulated bone marrow (BM) and PB haplo-SCT for adult leukemia patients.
Method:
A comprehensive literature search of electronic databases (Medline, Embase, and Cochrane library) for studies published between 1 January 2004 to 24 June 2018 was conducted. We included the studies of unmanipulated BM and/or PB haplo-SCT in adult acute myeloid leukemia (AML) and acute lymphoblastic leukemia ( ALL) . We excluded the studies which combined PB and BM stem cell sources and the studies which did not report the results of BM and PB haplo-SCT for ALL and AML separately. CMA software v.3 was used for the analysis. Heterogeneity among studies was assessed using the I2 test. Random-effect model was applied. Publication bias was assessed using funnel plots. Primary endpoints were engraftment, 2-year overall survival (OS), disease-free survival (DFS), relapse incidence (RI); grade II-IV, III-IV acute and chronic GVHD.
Results: Out of 1548 publications, 3 studies (n = 672 patients; retrospective; multi-center) met our inclusion criteria. The sample size of the studies varied between 71 and 451 patients. The median follow-up ranged from 18 to 46 months. PB haplo-SCT was used in 191 patients (Ruggeri, A. et al. 2018) and BM haplo-SCT was used in 481 patients (Arcese, W. et al. 2015; Ruggeri, A. et al. 2018; Chiusolo, P. et al. 2018). Myeloablative (MA) conditioning was used in majority of patients. The pooled (95%CI) engraftment rate was 93% (88-95) in BM group and 95% (91-97) in PBSC group. The pooled estimates (95%CI) of BM studies showed a 2-year OS rate of 56.1% (51.6-60.4), 2-year DFS of 48.9% (43.5-54.2) and 2-year cumulative RI of 24.6%(20.7-29).There was no heterogeneity in BM group (I2=0%) for 2-year OS, DFS and RI. For PBSC group, the pooled estimates (95%CI) for 2-year OS, DFS and RI were 56 % (48.9-62.9; I2=0%), 54% (46.9-60.9; I2=0%) and 22% (16.7-28.4; I2=0%), respectively. Incidences of grade II-IV, grade III-IV aGVHD and cGVHD from a pooled analysis (95%CI) were 23.1% (17.2-30.3; I2=55%), 5.4% (3.4-8.3; I2=16%) and 19.5% (9.7-35.3; I2=88%) for BM group in comparison to 38% (31.4-45.1; I2=0%), 14% (9.8-19.7; I2=0%) and 32% (25.8-38.9; I2=0%) for PBSC group. Pooled estimates were shown in figure 1.
Conclusions:
In this analysis, higher pooled rates of grade II-IV aGVHD (38% vs 23.1%), III-IV aGVHD (14% vs 5.4%) and cGVHD (32% vs 19.5%) were observed in PBSC group vs BM group, respectively. Based on comparable OS, DFS and RI, PB haplo-SCT appears to be a good alternative option for adult AML and ALL patients. Large prospective randomized controlled trials are required to confirm these results.
Figure 1. Figure 1.

Disclosures
No relevant conflicts of interest to declare.