Unmanipulated haploidentical transplants compared with other alternative donors and matched sibling grafts

Clinical Features of Chronic Graft-Versus-Host Disease Following Haploidentical Transplantation Combined with Infusion of a Cord Blood

Our previous studies demonstrated promising outcomes after haploidentical donor transplant combined with unrelated umbilical cord blood (haplo-cord- hematopoietic stem cell transplantation [HSCT]) for hematological disorders. However, clinical profiling regarding chronic graft-versus-host disease (cGVHD) has not yet been fully described under this protocol. This study analyzed the clinical characteristics of cGVHD among 300 patients with hematological malignancies who received haplo-cord-HSCT between January 2012 and July 2016 at our center. During the follow-up, the 5-year cumulative incidence of cGVHD based on the National Institutes of Health (NIH) consensus criteria was 32.2% (95% confidence interval [CI], 28.7-35.7); the 5-year cumulative incidence of moderate to severe cGVHD was 11.4% (95% CI, 9.4-13.4). After the multivariate analysis, the GVHD overall survival (GOS) was associated with relapse, thrombocytopenia, bronchiolitis obliterans syndrome, and steroid-refractory cGVHD. The infused CD34⁺ cells (≥3.46 × 10⁶/kg) from haploidentical grafts were a protective factor affecting GOS. This study proposed a nomogram for predicting GOS using the aforementioned five variables. The concordance index was 0.877 (95% CI, 0.859-0.895) for the accuracy evaluation of the nomogram. Our results suggested that the 5-year cumulative incidence of NIH-defined cGVHD after haplo-cord-HSCT was 32.2%, and this nomogram may help clinicians select reasonable treatment strategies.

Increased risk of 100-day and 1-year infection-related mortality and complications in haploidentical stem cell transplantation

Background: While haploidentical transplantation has led to the near-universal availability of donors, several challenges for this form of transplant still exist. This study sought to investigate the rates of infection-related mortality and other complications following haploidentical vs nonhaploidentical transplant. Methods: We conducted a retrospective cohort study in adults with various malignant and benign hematological conditions who underwent allogeneic hematopoietic stem cell transplantation from 2011 to 2018. One hundred-day and 1-year overall survival were defined as survival from the time of transplant until 100 days or 1 year later. Results: A total of 187 patients were included in this study, with 45 (24.1%) receiving transplants from haploidentical donors and 142 (75.9%) from nonhaploidentical donors. There were similar rates of acute graft-versus-host disease (GVHD) (40% vs 38% in haploidentical vs nonhaploidentical recipients, P=0.86) and chronic GVHD (44.4% vs 43.7%, P=1). Rates of 100-day and 1-year infection-related mortality were significantly higher in the haploidentical group compared to the nonhaploidentical group (8.9% vs 1.4% at 100 days, P=0.03, and 15.9% vs 3.8% at 1 year, P=0.01). There were also higher rates of cytomegalovirus infections (59.1% vs 23.8%, P<0.01), BK virus-associated hemorrhagic cystitis (40.9% vs 8.4%, P<0.01), and BK viremia (15.9% vs 0.8%, P<0.01) in haploidentical recipients. Conclusions: Despite the use of identical antimicrobial prophylactic and treatment agents, haploidentical recipients were found to have significantly increased rates of 100-day and 1-year infection-related mortality as well as several other infectious complications.

Host and Graft Factors Impacting Infection Risk in Hematopoietic Cell Transplantation

Infection contributes significantly to morbidity and mortality in hematopoietic cell transplantation. A complex interplay of host, graft, and technical factors contributes to infectious risk in the recipient. Host factors such as age, underlying disease, and comorbidities; central venous access; and the preparative regimen contribute to mucosal disruption, organ dysfunction, and immunodeficiency before hematopoietic cell transplantation. Graft factors, including donor histocompatibility, cell source, and graft components, along with immunosuppression and graft-versus-host disease, contribute to the speed of immune reconstitution. Evaluation of these factors, plus previous and posttransplant exposure to pathogens, is necessary to best assess an individual recipient's infection risk.

Influence of Donor Type (Sibling versus Matched Unrelated Donor versus Haploidentical Donor) on Outcomes after Clofarabine-Based Reduced-Intensity Conditioning Allograft for Myeloid Malignancies

Clofarabine-based reduced-intensity conditioning (RIC) regimens are well-established schedules for allograft in patients with myeloid malignancies. A retrospective study was conducted including all adults allografted in our department with such a regimen and disease with the aim to assess whether or not the donor type (matched sibling [MSD], matched unrelated [MUD], or haploidentical [haplo]) impacted outcomes. Between October 2009 and February 2018, 118 patients met the inclusion criteria. Thirty-six, 55, and 27 patients received a graft from an MSD, MUD, or haplo donor, respectively. Peripheral blood stem cells (PBSCs) were the source of graft for all patients. The median age of the entire cohort was 62 years (range, 20 to 73), and the median follow-up was 31 months (range, 4.5 to 106). All patients engrafted except 1 haplo recipient. Neutrophils (>.5 × 10⁹/L) and platelets (50 × 10⁹/L) recoveries were significantly delayed in the haplo group (P = .0003 and P < .0001) compared with MSD and MUD. Acute grades II to IV or III to IV graft-versus-host disease (GVHD) incidences were similar between the 3 groups as well as the incidence of moderate or severe chronic GVHD. Also, similar 2-year overall survival (OS; 64.7% versus 73.9% versus 60.2%, P = .39), disease-free survival (DFS; 57.7% versus 70.9% versus and 53.6%, P = .1), and GVHD relapse-free survival (37.9% versus 54.3% versus 38.9%, P = .23) were observed between MSD versus MUD versus haplo groups. The same was true when considering only acute myeloid leukemia (AML) cases. In multivariate analysis the type of donor remained independent of outcomes in this series, whereas myelodysplastic syndrome (versus AML), high disease risk index, and older donor (≥50 years) were associated with lower OS and DFS. These data suggest that haplo donors are an acceptable alternative for patients receiving a clofarabine-based RIC PBSC allograft for myeloid malignancies who lack an MSD or a MUD.

Thiotepa, Busulfan, and Fludarabine Conditioning Regimen in T Cell-Replete HLA-Haploidentical Hematopoietic Stem Cell Transplantation

We report the outcomes of 51 patients who underwent unmanipulated haploidentical hematopoietic stem cell transplantation (haplo-HSCT) with post-transplantation cyclophosphamide (PT-Cy) and antithymocyte globulin (ATG), from peripheral blood stem cells (PBSCs) or bone marrow, after receipt of a TBF (thiotepa, busulfan, and fludarabine) conditioning regimen. Their median age was 55 years (range, 16 to 72 years). Hematologic diagnoses included acute leukemias (n = 31), lymphoid neoplasm (n = 12), myeloproliferative neoplasm (n = 5), and myelodysplastic syndromes (n = 3). Thirty-seven patients (73%) were in complete remission. Graft-versus-host disease (GVHD) prophylaxis consisted of cyclosporine and mycophenolate for all patients, associated with ATG in 39 patients (76.5%). The median time to neutrophil engraftment was 17 days (range, 12 to 34 days). The cumulative incidences of grade II-IV and grade III-IV acute GVHD were 27.5% and 14%, respectively. In patients receiving a PBSC graft and ATG prophylaxis, grade II-IV aGVHD occurred in 16% of patients. The use of ATG and a lower thiotepa dose (5 mg/kg versus 10 mg/kg) were associated with a reduced cumulative incidence of grade II-IV acute GVHD (P = .03 and .005, respectively). The 2-year cumulative incidence of chronic GVHD was 29% and was significantly reduced to 13% with the lower thiotepa dose (P = .002). After a median follow-up of 25 months (range, 12 to 62 months), the cumulative incidences of nonrelapse mortality, relapse, overall survival (OS), disease-free survival (DFS), and GVHD-free, relapse-free survival (GFRFS) were 20%, 22.5%, 67%, 58%, and 51%, respectively. Pretransplantation disease status (complete remission versus others) was the main factor associated with OS, DFS, and GFRFS. In conclusion, the TBF conditioning regimen is an appealing platform in the haplo-HSCT setting with PT-Cy in terms of engraftment rate, toxicity, and disease control. We found no benefit of a thiotepa dose of 10 mg/kg compared with a dose of 5 mg/kg. ATG reduced the risk of acute GVHD without comprising outcomes.

Disability related to chronic graft -versus-host disease after alternative donor hematopoietic cell transplantation

We determined the incidence of disability related to chronic graft-versus-host disease (bronchiolitis obliterans, grade ≥2 keratoconjunctivitis sicca, sclerotic features or esophageal stricture) for three categories of alternative donor: cord blood, haplorelated marrow or peripheral blood with post-transplant cyclophosphamide, and unrelated single HLA-allele mismatched peripheral blood. Among 396 consecutive hematopoietic cell transplant recipients, 129 developed chronic graft-versus-host disease with 3-year cumulative incidences of 8% for cord blood, 24% for haplorelated grafts, and 55% for unrelated single HLA-allele mismatched peripheral blood. Disability rates were significantly lower for cord blood [hazard ratio (HR) 0.13; 95% confidence interval (CI): 0.1-0.4] and for the haplorelated group (HR 0.31; 95% CI: 0.1-0.7) compared to the rate in the group transplanted with unrelated single HLA-allele mismatched peripheral blood. Cord blood recipients were also >2-fold more likely to return to work/school within 3 years from the onset of chronic graft-versus-host disease (HR 2.54; 95% CI: 1.1-5.7, P=0.02), and the haplorelated group trended similarly (HR 2.38; 95% CI: 1.0-5.9, P=0.06). Cord blood recipients were more likely to discontinue immunosuppression than were recipients of unrelated single HLA-allele mismatched peripheral blood (HR 3.96; 95% CI: 1.9-8.4, P=0.0003), similarly to the haplorelated group (HR 4.93; 95% CI: 2.2-11.1, P=0.0001). Progression-free survival and non-relapse mortality did not differ between groups grafted from different types of donors. Our observations that, compared to recipients of unrelated single HLA-allele mismatched peripheral blood, recipients of cord blood and haplorelated grafts less often developed disability related to chronic graft-versus-host disease, and were more likely to resume work/school, should help better counseling of pre-hematopoietic cell transplant candidates.

Early CD8+-recovery independently predicts low probability of disease relapse but also associates with severe GVHD after allogeneic HSCT

In this single-center study we retrospectively evaluated the impact of early reconstitution of different lymphocyte subsets on patient outcomes after allogeneic hematopoietic stem cell transplantation (allo-HSCT). We found that CD8+ T-cell counts exceeding 50x10(6)/l as early as on day 28 post-transplantation correlated significantly with decreased relapse risk, with three-year relapse rates of 17.0% and 55.6% (P = 0.002), but were also associated with severe acute and chronic GVHD. Incidence of grade III-IV acute GVHD was 30.5% for those with early CD8+ T-cell recovery compared to 2.1% for those with lower CD8+ T-cell counts on day 28 post-transplant (HR = 20.24, P = 0.004). Early CD8+ T-cell reconstitution did not, however, affect the overall survival. Multivariate analysis showed that slow CD8+ T-cell reconstitution was strongly associated with increased risk of relapse (HR = 3.44, P = 0.026). A weaker correlation was found between CD4+ reconstitution and relapse-risk, but there was no such association with CD19+ B-cells or NK-cells. In conclusion, the early CD8+ T-cell recovery on day 28 post-transplant is associated with the lower risk of relapse but also predicts the impending severe GVHD, and thus could be useful in guiding timely treatment decisions.

Haploidentical transplantation is associated with better overall survival when compared to single cord blood transplantation: an EBMT-Eurocord study of acute leukemia patients conditioned with thiotepa, busulfan, and fludarabine

Background

Thiotepa-busulfan-fludarabine (TBF) is a widely used conditioning regimen in single umbilical cord blood transplantation (SUCBT). More recently, it was introduced in the setting of non-T cell depleted haploidentical stem cell transplantation (NTD-Haplo). Whether TBF based conditioning provides additional benefit in transplantation from a particular alternative donor type remains to be established.

Methods

This was a retrospective study based on an international European registry. We compared outcomes of de-novo acute myeloid leukemia patients in complete remission receiving NTD-Haplo (n = 186) vs. SUCBT (n = 147) following myeloablative conditioning (MAC) with TBF. Median follow-up was 23 months. Treatment groups resembled in baseline characteristics.

Results

SUCBT was associated with delayed engraftment and higher graft failure. In multivariate analysis no statistically significant differences were observed between the two groups in terms of acute or chronic graft-versus-host disease (GvHD) (HR = 1.03, p = 0.92 or HR = 1.86, p = 0.21) and relapse incidence (HR = 0.8, p = 0.65). Non-relapse mortality (NRM) was significantly higher in SUCBT as compared to NTD-Haplo (HR = 2.63, p = 0.001); moreover, SUCBT did worse in terms of overall survival (HR = 2.18, p = 0.002), leukemia-free survival (HR = 1.94, p = 0.007), and GvHD relapse-free survival (HR = 2.38, p = 0.0002).

Conclusions

Our results suggest that TBF-MAC might allow for a potent graft-versus-leukemia, regardless of the alternative donor type. Furthermore, in patients receiving TBF-MAC, survival with NTD-Haplo may be better compared to SUCBT due to decreased NRM.

Electronic supplementary material

The online version of this article (10.1186/s13045-018-0655-8) contains supplementary material, which is available to authorized users.

Is human leukocyte antigen-matched sibling donor transplant always better than haploidentical allograft?

Currently, haploidentical donor has been an alternative source of stem cell allografts for patients who have no human leukocyte antigen-matched sibling donor or unrelated donors. A number of studies indicated that treating hematological malignancy patients with haploidentical stem cell transplantation (haplo-SCT) could achieve comparable outcomes to those who underwent matched sibling donor transplantation (MSDT). In recent years, more and more evidence support the notion that haploidentical allografts may have a stronger graft-vs-leukemia (GVL) effect than MSDT. In this review, we summarized the transplant outcomes of haplo-SCT and MSDT, mainly focusing on the subgroup of patients who will benefit from the stronger GVL effects of haplo-SCT compared with MSDT. We also offered strategies of how to translate the strong antileukemia activity of haploidentical allograft into superior survival. Future directions of GVL effects in haplo-SCT settings were also discussed.

Efficacy of haploidentical hematopoietic stem cell transplantation compared to HLA-matched transplantation for primary refractory acute myeloid leukemia

Newly diagnosed acute myeloid leukemia (AML) failed to achieve complete remission after two courses of intensive chemotherapy. This was considered as primary refractory AML (PRR-AML), and still has a dismal prognosis. Allogeneic hematopoietic stem cell transplantation could be the only cure for these patients. However, the role of haploidentical hematopoietic stem cell transplantation (HID-HCT) for PRR-AML is still undetermined. We retrospectively analyzed the outcomes of 45 adult patients with PRR-AML who underwent HID-HCT, and compared it with the result of 53 patients who received HLA-matched related or unrelated donor transplantation (MD-HCT) during the same treatment period. The 3-year overall survival (OS), leukemia-free survival (LFS), cumulative incidence of relapse (CIR), and non-relapse mortality (NRM) rates in the HID-HCT group were 19.0, 16.5, 70.0, and 35.2%, respectively, but showed no significant differences from the results of MD-HCT. Multivariate analysis showed that complex karyotype with del(7) and time > 6 months from diagnosis to transplantation were associated with lower OS and LFS, and chronic GVHD demonstrated better OS and LFS in the entire cohort. Complex karyotype with del(7) was related with higher CIR and chronic GVHD with lower CIR. In conclusion, HID-HCT could be an alternative treatment strategy to improve the long-term survival in PRR-AML adult patients who have no HLA-matched donors.

Haploidentical versus matched donor stem cell transplantation for patients with hematological malignancies: a systemic review and meta-analysis

We compared the safety and efficacy of haploidentical stem cell transplantation (haplo-SCT) to matched donor SCT (matched-SCT) in treating hematological malignancies. The Medline, Cochrane, EMBASE, and Google Scholar databases were searched through 21 June 2017 using the search term "(hematological disease) AND matched AND (haploidentical OR haplo-identical OR haplo identical OR haplo transplantation OR haplo transplant OR haplo-SCT OR haplo-HSCT OR haplo-HCT)." Twenty-five studies enrolling 11,359 patients (haplo-SCT: 2677; matched-SCT: 8682) were included. The primary outcomes were acute and chronic graft-versus-host disease (GVHD), non-relapse mortality, and 1-year cumulative incidence of relapse. Haplo-SCT was associated with similar risks as matched-SCT for all primary endpoints. Subgroup analysis of patients who received a matched-SCT from a related donor revealed that patients who received haplo-SCT had a lower risk of acute GVHD. Among patients who received reduced-intensity conditioning (RIC), those who received haplo-SCT had a higher risk of acute grade II-IV GVHD and non-relapse mortality than did patients who received a matched-SCT from a related or unrelated donor. Haplo-SCT should continue to be considered as a safe and effective transplant option when a matched donor is unavailable, but it may not be suitable for patients who receive RIC.

Haplo-identical allografting with post-transplant cyclophosphamide in high-risk patients

Haplo-identical transplants (Haplo-Tx) are an important alternative for patients with hematological malignancies who lack a HLA-identical donor. Seventy-one T-replete Haplo-Tx were performed in 70 high-risk patients at our center; 22/70 (31%) patients with refractory/relapsed leukemia received sequential salvage therapy (SeqTh) with high-dose chemotherapy followed by Haplo-Tx during the chemotherapy-induced neutropenia. Graft-versus-host disease (GVHD) prophylaxis consisted of post-transplant cyclophosphamide (days + 3 and + 4) with tacrolimus and mycophenolic acid. After a median follow-up of 29.2 months, 3-year overall survival (OS) and event-free survival (EFS) were 43.8 and 40.2%, while 3-year cumulative incidences (CIs) of non-relapse mortality (NRM) and relapse (RI) were 27 and 33%. Day 100 and day 400 CI of grade III-IV acute and moderate-severe chronic GVHD were 11 and 15%. Three-year RI was significantly lower in patients in complete remission (CR) versus those not in CR at the time of transplant (21.5 vs. 48%, p = 0.009) and in patients who received PBSC as compared to BM (22 vs. 45%, p = 0.009). In patients treated with SeqTh, 3-year OS was 19%, while 3-year RI and NRM were 52 and 28% at a median follow-up of 50 months. Overall, Haplo-Tx was feasible in heavily pretreated high-risk patients without a suitable HLA-identical donor.

T Cell-Replete Haploidentical Peripheral Blood Hematopoietic Cell Transplantation for Treatment of T-Lymphoblastic Lymphoma

BACKGROUND There is currently little information on haploidentical hematopoietic cell transplantation (haplo-HCT) for T-lymphoblastic lymphoma (T-LBL). Data about peripheral blood stem cells (PBSC) as a reliable graft source for T-LBL treatment are lacking. MATERIAL AND METHODS T-LBL patients who underwent T cell-replete haploidentical peripheral blood hematopoietic cell transplantation (haplo-PBHCT) from July 2007 to January 2017 were retrospectively evaluated. RESULTS A total of 25 patients (age ≥15 years) with median age of 24 (range 15-51) years were enrolled. The median number of CD34+ cells infused was 5.0 (1.6-14.4) 106/kg. Sustained myeloid engraftment with full donor chimerism was achieved in all patients. The cumulative incidence of grades 2 to 4 acute graft-versus-host disease (GVHD) at day 100 was 24%. Two-year extensive chronic GVHD cumulative incidence was 20%. The 3-year overall survival rate for all patients was 70%. The median survival time of the complete remission (CR) group was better than that of the non-CR group (not reached vs. 9 m) (P<0.01). The relapse rate was 17% for patients who obtained CR and were given haplo-HCT as consolidation treatment. CONCLUSIONS This study indicates that haplo-PBHCT is a safe and effective method for the treatment of T-LBL.

Bone marrow versus peripheral blood as a graft source for haploidentical donor transplantation in adults using post-transplant cyclophosphamide-A systematic review and meta-analysis

BACKGROUND

Peripheral-blood (PB) and bone marrow (BM) are both widely used in hematopoietic stem cell transplantation (HSCT). However, it is unclear whether PB or BM produces a more satisfactory outcome in haploidentical HSCT, particularly for patients using post-transplant cyclophosphamide (PTCy), which is the standard therapy. However, to date, no meta-analysis focusing on this issue has been published.

METHODS

We systematically searched PubMed, MEDLINE, Web of Science, the Cochrane Library and the ClinicalTrials.gov website for studies regarding the use of BM or PB in haploidentical HSCT for hematological malignancies in adults using PTCy. Data were analyzed using Open Meta-Analyst statistical software.

RESULTS

Fourteen studies were extracted including four comparative retrospective reports and ten single-arm reports, with a total of 1759 patients received PTCy haploidentical HSCT (462 patients received PBSCT, 1297 patients received BMT). The pooled outcomes of comparative retrospective studies showed significantly higher incidence of grade III-IV acute graft-versus-host disease (GVHD) (OR = 1.741, 95%CI 1.032-2.938), incidence of grade IIIV acute GVHD (OR = 1.778, 95%CI 1.314, 2.406) and engraftment rate (OR = 1.843, 95%CI 1.066-3.185) in the PB group. No significant differences were found on the incidence of relapse, 2-year overall survival (OS) and disease-free survival (DFS), acute IIIV GVHD and chronic GVHD between PBSCT or BMT.

CONCLUSION

The efficacy of PB is not inferior to BM for patients undergoing PTCy haploidentical HSCT with regard to primary outcomes, including OS, DFS, NRM and relapse. However, with regards to convenience and pain relief, PB graft is suitable for haploidentical HSCT, but with a higher risk of acute GVHD.

Allogeneic Hematopoietic Cell Transplantation for Older Adults with Acute Myeloid Leukemia

Acute myeloid leukemia (AML) is a disease that affects adults aged 65 years and above, and survival in this population is poor. Allogeneic hematopoietic cell transplantation (allo-HCT) is a potentially curative therapy for these patients but is underutilized due to frequent comorbidities and perceived higher risk of treatment-related mortality and non-relapse mortality. Increasing data supports the utility of allo-HCT in fit older patients after intensive chemotherapy resulting in improvement of outcomes. With the development of reduced intensity and non-myeloablative conditioning regimens that are associated with lower rates of treatment-related toxicity and mortality, this has allowed more older patients with AML to receive allo-HCT. In this review, we provide some guidance on appropriate selection of older patients as transplant candidates, benefits and risks associated with allo-HCT, conditioning regimen choice, and stem cell transplant sources as they relate to the conduct of stem cell transplantation in older patients.

Foscarnet treatment of cytomegalovirus infection in haploidentical or unrelated donor transplants

We studied 97 patients who developed cytomegalovirus (CMV) viremia following an allogeneic hemopoietic stem cell transplant (HSCT) between 2010 and 2015, treated with foscarnet, with the aim of assessing efficacy and safety. The donor was unrelated in 30 patients (UD) and a family HLA-haploidentical donor (HAPLO) in 67 patients: the former (UD) received a prophylaxis for graft-versus-host disease (GvHD), based on antithymocyte globulin (ATG); the latter (HAPLO) received GvHD prophylaxis, based on post-transplant cyclophosphamide (PT-CY). Renal and hematological toxicity were defined according to NCI-CTCAE4 criteria. In univariate analysis, CMV response was 84% in HAPLO vs 59% in UD grafts (p = 0.01) and 90 vs 66% (p = 0.02) for patients with a CMV viral load within or over the median value. In multivariate analysis, the CMV viral load was the strongest predictor of response to foscarnet (p = 0.02), followed by donor type (p = 0.06). Renal impairment developed in 14% of the patients. Overall survival was 69%:, advanced phase at transplant (p = 0.01) and ATG-based regimens (p = 0.02), were  the only two predicting factor. In conclusion, CMV response to foscarnet treatment is predicted by a lower CMV load and GvHD prophylaxis. Renal toxicity of foscarnet is not a limiting factor.

Outcomes of hematopoietic stem cell transplantation from unmanipulated haploidentical versus matched sibling donor in patients with acute myeloid leukemia in first complete remission with intermediate or high-risk cytogenetics: a study from the Acute Leukemia Working Party of the European Society for Blood and Marrow Transplantation

Allogeneic hematopoietic stem cell transplantation is the optimal care for patients with high-risk or intermediate - acute myeloid leukemia. In patients lacking matched sibling donor, haploidentical donors are an option. We compared outcomes of unmanipulated (Haplo) to matched sibling donor transplant in acute myeloid leukemia patients in first complete remission. Included were intermediate and high-risk acute myeloid leukemia in first complete remission undergoing Haplo and matched sibling donor transplant from 2007-2015, and reported to the ALWP of the EBMT. A propensity score technique was used to confirm results of main analysis: 2 matched sibling donors were matched with 1 Haplo. We identified 2654 pts (Haplo =185; matched sibling donor =2469), 2010 with intermediate acute myeloid leukemia (Haplo=122; matched sibling donor =1888) and 644 with high-risk acute myeloid leukemia (Haplo =63; matched sibling donor =581). Median follow up was 30 (range 1-116) months. In multivariate analysis, in intermediate - acute myeloid leukemia patients, Haplo resulted in lower leukemia-free survival (Hazard Ratio 1.74; P<0.01), overall-survival (HR 1.80; P<0.01) and GvHD-free-relapse-free survival (Hazard Ratio 1.32; P<0.05) and higher graft-versus-host disease (GvHD) non-relapse mortality (Hazard Ratio 3.03; P<0.01) as compared to matched sibling donor. In high-risk acute myeloid leukemia, no differences were found in leukemia-free survival, overall-survival, and GvHD-free- relapse-free survival according to donor type. Higher grade II-IV acute GvHD was observed for Haplo in both high-risk (Hazard Ratio 2.20; P<0.01) and intermediate risk (Hazard Ratio 1.84; P<0.01). A trend for a lower Relapse-Incidence was observed in Haplo among high-risk acute myeloid leukemia (Hazard Ratio 0.56; P=0.06). The propensity score analysis confirmed results. Our results underline that matched sibling donor is the first choice for acute myeloid leukemia patients in first complete remission. On the other hand, results of Haplo transplants are similar to matched sibling donor transplants in acute myeloid leukemia patients with high risk cytogenetics.

De-Escalation and Discontinuation of Empirical Antibiotic Treatment in a Cohort of Allogeneic Hematopoietic Stem Cell Transplantation Recipients during the Pre-Engraftment Period

To investigate rates and outcomes of antibiotic de-escalation during pre-engraftment neutropenia in allogeneic hematopoietic stem cell transplantation (HSCT) recipients. 110 consecutive HSCTs performed between January 2013 and March 2014 were analyzed. De-escalation was defined as narrowing the spectrum of antibiotic treatment either within (early) or after 96 hours (late) from starting antibiotics. Discontinuation, considered a form of de-escalation, was defined as stopping antibiotics before engraftment. De-escalation failure was defined as restarting/escalating antibiotics within 96 hours after de-escalation. Predictors of de-escalation were analyzed. Among 102 patients who started antibiotics and were included, 68 (67%) received monotherapy (mainly piperacillin-tazobactam, n = 58), whereas 34 (33%) received combination therapy (mainly meropenem plus glycopeptide, n = 24). Median duration of neutropenia was 17 days. Bloodstream infections (BSIs) were diagnosed in 28 patients (20%). Early de-escalation rate was 25.5% (n = 26) and mostly consisted of reducing the spectrum of β-lactams (n = 11, 42%). In comparison with theoretical scenario of continuing therapy until engraftment, the median savings in terms of antibiotic days were 10 for meropenem, 8 for piperacillin-tazobactam, and 7 for vancomycin. Failure rate of early de-escalation was 15% (4/26). Late de-escalation rate was 30.4% (n = 31) and failure rate 19% (6/31). The rate of de-escalation any time before engraftment was 55.9% (n = 57), including discontinuation in 33 patients (32%). Death at day 60 after HSCT occurred in 3 patients who never underwent de-escalation. Acute myeloid disease and BSIs were independent predictors of early de-escalation. De-escalation, including discontinuation, is feasible and safe in pre-engraftment neutropenia after allogeneic HSCT.

Comparison of outcomes following transplantation with T-replete HLA-haploidentical donors using post-transplant cyclophosphamide to matched related and unrelated donors for patients with AML and MDS aged 60 years or older

Allografting from HLA-haploidentical donors (HID) is being increasingly utilized worldwide for patients lacking a conventional matched donor. However, its efficacy in older patients with AML and MDS is unclear. We analyzed 127 consecutive allografts for AML/MDS patients aged ≥ 60 years at our center to compare outcomes using HID to those of contemporaneous transplants using matched sibling (MRD) or matched unrelated (MUD) donors. Patient characteristics were similar except HID transplants were more likely in non-white patients and were more commonly performed with reduced intensity conditioning and a marrow graft. For MRD, MUD and HID transplants respectively, 2-year estimates of non-relapse mortality (17, 23, and 9%), relapse (32, 34, and 33%), overall survival (OS) (62, 55, and 67%) and disease-free survival (DFS) (51, 43, and 58%) were not significantly different. Maximum cumulative incidences of grade 2-4 acute GVHD were not different (27, 37, 39%), but incidences of NIH grade moderate to severe (39, 35, 15%, p = 0.028 MUD vs. HID, p = 0.026 MRD vs. HID) and severe chronic GVHD (9, 12, 0%, p = 0.030 MUD vs. HID, p = 0.009 MRD vs. HID) were significantly higher in MRD and MUD than in HID transplants. On multivariable analysis, donor type was not a significant determinant of OS, DFS, TRM, or relapse. However, male gender and high/very high Disease Risk Index (DRI) were associated with significantly higher rates of relapse (HR 1.94, p = 0.047 for male gender, HR 2.48, p = 0.004 for high/very high DRI) and lower OS (HR 1.94, p = 0.018 for male gender, HR 1.80, p = 0.025 for high/very high DRI). HIDs are an acceptable alternative to matched donors in older patients with AML and MDS.

Cost-effectiveness analysis of haploidentical vs matched unrelated allogeneic hematopoietic stem cells transplantation in patients older than 55 years

Due to limited donor availability, high comorbidities, and cost issues, allogeneic hematopoietic stem cell transplant is not universally accessible. The aim of this study was to conduct a cost-effectiveness analysis of haploidentical vs matched unrelated transplant. This retrospective study included patients with hematological malignancies older than 55 years who underwent haploidentical or matched unrelated transplant between 2011 and 2013 in Marseille. The incremental cost-effectiveness ratio has been calculated using the mean overall survival and the mean transplant costs. Costs were calculated using a micro-costing strategy from the hospital perspective and a time horizon at 2 years. Haploidentical transplant was considered an innovative procedure and matched unrelated transplant as the reference. Probabilistic and sensitivity analyses were performed on the incremental cost-effectiveness ratio. During inclusion, 29 patients underwent haploidentical transplant and 63 matched unrelated transplant. In haploidentical and matched unrelated transplant, the mean overall survival was 19.4 (1.6) months and 15.1 (1.2) months (p = 0.06), respectively, and the mean cost was 98,304 (40,872) € and 151,373 (65,742) € (p < 0.01), respectively. The incremental cost-effectiveness ratio was assessed to -148,485 (-1,265,550; -64,368) € per life year gained. Among older patients suffering from hematological malignancies, haploidentical transplant seemed in our analysis to be cost-effective compared with matched unrelated transplant.

Clinical Impact of Pretransplant Multidrug-Resistant Gram-Negative Colonization in Autologous and Allogeneic Hematopoietic Stem Cell Transplantation

Multidrug-resistant Gram-negative bacteria (MDR-GNB) are an emerging cause of morbidity and mortality after hematopoietic stem cell transplantation (HSCT). Three-hundred forty-eight consecutive patients transplanted at our hospital from July 2012 to January 2016 were screened for a pretransplant MDR-GNB colonization and evaluated for clinical outcomes. A pretransplant MDR-GNB colonization was found in 16.9% of allo-HSCT and in 9.6% of auto-HSCT recipients. Both in auto- and in allo-HSCT, carriers of a MDR-GNB showed no significant differences in overall survival (OS), transplant-related mortality (TRM), or infection-related mortality (IRM) compared with noncarriers. OS at 2 years for carriers compared with noncarriers was 85% versus 81% (P = .262) in auto-HSCT and 50% versus 43% (P = .091) in allo-HSCT. TRM at 2 years was 14% versus 5% (P = .405) in auto-HSCT and 31% versus 25% (P = .301) in allo-HSCT. IRM at 2 years was 14% versus 2% (P = .142) in auto-HSCT and 23% versus 14% (P = .304) in allo-HSCT. In multivariate analysis, only grade III to IV acute graft-versus-host disease was an independent factor for reduced OS (P < .001) and increased TRM (P < .001) and IRM (P < .001). During the first year after transplant, we collected 73 GNB bloodstream infectious (BSI) episodes in 54 patients, 42.4% of which sustained by a MDR-GNB. Rectal swabs positivity associated with the pathogen causing subsequent MDR-GNB BSI episodes in 13 of 31 (41.9%). Overall, OS at 4 months from MDR-GNB BSI episode onset was of 67.9%, with a 14-day attributed mortality of 12.9%, not being significantly different between carriers and noncarriers (P = .207). We conclude that in this extended single-center experience, a pretransplant MDR-GNB colonization did not significantly influence OS, TRM, and IRM both in auto- and allo-HSCT settings and that MDR-GNB attributed mortality can be controlled in carriers when an early pre-emptive antimicrobial therapy is started in case of neutropenic fever.

Comparison of outcomes in hematological malignancies treated with haploidentical or HLA-identical sibling hematopoietic stem cell transplantation following myeloablative conditioning: A meta-analysis

Purpose

Haploidentical and human leukocyte antigen (HLA)-identical sibling hematopoietic stem transplantation are two main ways used in allogeneic hematopoietic stem cell transplantation (allo-HSCT). In recent years, remarkable progress has been made in haploidentical allo-HSCT (HID-SCT), and some institutions found HID-SCT had similar outcomes as HLA-identical sibling allo-HSCT (ISD-SCT). To clarify if HID-SCT has equal effects to ISD-SCT in hematologic malignancies, we performed this meta-analysis.

Methods

Relevant articles published prior to February 2017 were searched on PubMed. Two reviewers assessed the quality of the included studies and extracted data independently. Odds ratio (OR) and 95% confidence intervals (CIs) were calculated for statistical analysis.

Results

Seven studies including 1919 patients were included. The rate of platelet engraftment is significantly lower after HID-SCT versus ISD-SCT while there is no difference in neutrophil engraftment (OR = 2.58, 95% CI = 1.70–3.93, P < 0.00001). The risk of acute graft-versus-host disease (GVHD) is significantly higher after HID-SCT versus ISD-SCT (OR = 1.88, 95% CI = 1.42–2.49, P < 0.00001), but the relapse rate is lower in HID-SCT group (OR = 0.70, 95% CI = 0.55–0.90, P = 0.005). The incidence rates of overall survival (OS) and disease-free-survival/leukemia-free survival/relapse-free survival (DFS/LFS/RFS) after ISD-SCT are all significantly superior to HID-SCT (OR = 1.32, 95% CI = 1.08–1.62, P = 0.006; OR = 1.25, 95% CI = 1.03–1.52, P = 0.02). There is no significant difference in transplantation related mortality (TRM) rate after HID-SCT and ISD-SCT.

Conclusion

After myeloablative conditioning, patients receiving ISD-SCT have a faster engraftment, lower acute GVHD and longer life expectancy compared to HID-SCT with GVHD prophylaxis (cyclosporine A, methotrexate, mycophenolate mofetil and antithymoglobulin; CsA + MTX + MMF + ATG). Currently, HID-SCT with GVHD prophylaxis (CsA + MTX + MMF + ATG) may not replace ISD-SCT when HLA-identical sibling donor available.

Impact on early outcomes and immune reconstitution of high-dose post-transplant cyclophosphamide vs anti-thymocyte globulin after reduced intensity conditioning peripheral blood stem cell allogeneic transplantation

We have compared prospectively the outcome and immune reconstitution of patients receiving either post-transplant cyclophosphamide (PTCY) (n = 30) or anti-thymocyte globulin ATG (n = 15) as Graft-versus-host disease (GVHD) prophylaxis after reduced-intensity conditioning (RIC) allogeneic peripheral blood stem cell (PBSC) transplantation (allo-SCT). The outcome and immune reconstitution of patients receiving either of these two regimens were compared prospectively. This study allowed also to investigate the impact of PTCY between haplo-identical vs matched donors and of clofarabine as part of the RIC regimen. The γ/δ T-cells, α/β T-cells (CD8⁺ and CD4⁺), NK T-cells, NK cells, B-cells, Tregs and monocytes were analyzed by flow cytometry from a total of 583 samples. In the PTCY group significant delayed platelets recovery, higher CD3+ donor chimerism, higher HHV-6 and lower EBV reactivations were observed. Early survival advantage for CD4+ T-cells, Tregs and α/β T-cells was documented in the PTCY group while it was the case for α/β T-cells, NK cells and monocytes in the ATG group. Higher counts of NK and monocytes were observed at days +30 and/or day+60 in the ATG group. Both results were retained even in the case of mismatched donors. However, higher percentages of CD4+ T-cells, α/β T-cells and Tregs were observed with haplo-identical donors in the PTCY group. Finally, clofarabine was responsible for early survival advantage of NK T-cells in the PTCY group while it abrogated the early survival advantage of γ/δ T-cells in the ATG group. In conclusion, there are marked differences in the immunological effects of ATG vs PTCY as GVHD prophylaxis for RIC PBSC allo-SCT.

Comparable survival using a CMV-matched or a mismatched donor for CMV+ patients undergoing T-replete haplo-HSCT with PT-Cy for acute leukemia: a study of behalf of the infectious diseases and acute leukemia working parties of the EBMT

The role of donor CMV serostatus in the setting of non T-cell depleted haplo-HSCT with post-transplant cyclophosphamide (PT-Cy) has not been specifically addressed so far. Here we analyzed the impact of the donor CMV serological status on the outcome of 983 CMV seropositive (CMV+), acute leukemia patients receiving a first, non T-cell depleted haplo-HSCT registered in the EBMT database. The 1-year NRM was 21.3% (95% CI: 18.4-24.8) and 18.8% (95% CI: 13.8-25.5) in the CMV D+/R+ and D-/R+ pairs, respectively (p = 0.40). Similarly, 1-year OS was 55.1% (95% CI: 50.1-58.0) and 55.7% (95% CI: 48.0-62.8) in the same groups (p = 0.50). The other main outcomes were comparable. No difference in NRM nor OS was observed after stratification for the intensity of conditioning and multivariate anaysis confirmed the lack of significant association with NRM or OS. In conclusion, the choice of a CMV-seronegative donor did not impair early survival of CMV-seropositive patients with acute leukemia after a first, non T-cell depleted haploidentical HSCT and PT-Cy among this series of 983 consecutive patients. Future research may focus on the assessment of the hierarchy of all the donor variables.

Sequential Conditioning with Thiotepa in T Cell- Replete Hematopoietic Stem Cell Transplantation for the Treatment of Refractory Hematologic Malignancies: Comparison with Matched Related, Haplo-Mismatched, and Unrelated Donors

The results of conventional allogeneic stem cell transplantation (SCT) in refractory hematologic malignancies are poor. Sequential strategies have shown promising results in refractory acute myelogenous leukemia (AML), but have not been validated in a haploidentical (Haplo) transplant setting. We have developed a new sequential approach combining chemotherapy with broad antitumor activity (thiotepa 10 mg/kg, etoposide 400 mg/m², and cyclophosphamide 1600 mg/m² from day -15 to day -10), followed after 3 days of rest by a reduced-intensity conditioning regimen (fludarabine 150 mg/m², i.v. busulfan 6.4 mg/kg, and thymoglobulin 5 mg/kg from day -6 to day -2). High-dose post-transplantation cyclophosphamide was added in cases with Haplo donors. Seventy-two patients (median age, 54 years) with a refractory hematologic malignancy (44 with acute myelogenous leukemia, 7 with acute lymphoblastic leukemia, 15 with myelodysplastic syndrome/myeloproliferative neoplasms, and 6 with lymphomas) were included in this retrospective multicenter study. Donors were Haplo (n = 27), matched related (MRD; n = 16), and unrelated (UD; n = 29). With a median follow-up of 21 months, the 2-year overall survival (OS) and event-free survival (EFS) were 54.7% and 49.3%, respectively, in recipients of Haplo transplants, 49.2% and 43.8%, respectively, in recipients of MRD transplants, and 37.9% and 28%, respectively, in recipients of UD transplants. Compared with UD, the outcomes were improved in Haplo in terms of the incidences of acute grade II-IV graft-versus-host disease (GVHD) (11.1% versus 41.4%; P < .001) and GVHD-free, relapse-free survival (44.4 versus 10.3%; P = .022). These results support the safety and efficacy of a thiotepa-based sequential approach in allogeneic SCT with a Haplo donor with post-transplantation immune modulation. Thus, in patients with refractory hematologic malignancies, there seems to be no benefit in searching for a UD when a Haplo donor is readily available.

Outcomes of haploidentical stem cell transplantation for chronic lymphocytic leukemia: a retrospective study on behalf of the chronic malignancies working party of the EBMT

Allogeneic hematopoietic stem cell transplantation (HCT) may result in long-term disease control in high-risk chronic lymphocytic leukemia (CLL). Recently, haploidentical HCT is gaining interest because of better outcomes with post-transplantation cyclophosphamide (PTCY). We analyzed patients with CLL who received an allogeneic HCT with a haploidentical donor and whose data were available in the EBMT registry. In total 117 patients (74% males) were included; 38% received PTCY as GVHD prophylaxis. For the whole study cohort OS at 2 and 5 yrs was 48 and 38%, respectively. PFS at 2 and 5 yrs was 38 and 31%, respectively. Cumulative incidence (CI) of NRM in the whole group at 2 and 5 years were 40 and 44%, respectively. CI of relapse at 2 and 5 yrs were 22 and 26%, respectively. All outcomes were not statistically different in patients who received PTCY compared to other types of GVHD prophylaxis. In conclusion, results of haploidentical HCT in CLL seem almost identical to those with HLA-matched donors. Thereby, haploidentical HCT is an appropriate alternative in high risk CLL patients with a transplant indication but no available HLA-matched donor. Despite the use of PTCY, the CI of relapse seems not higher than observed after HLA-matched HCT.

Allogeneic stem cell transplantation for sickle cell disease

PURPOSE OF REVIEW

As the safety and availability of allogeneic hematopoietic stem cell transplantation (HSCT) have improved, this procedure is becoming a viable option for nonmalignant conditions such as sickle cell disease (SCD). There are very few treatment options available for SCD, and even with optimal care SCD patients still suffer from a myriad of comorbidities to multiple organ systems and have a decreased life span. In this review, we will summarize results from trials of HSCT for children or adults with SCD using a variety of graft sources as well as conditioning and graft-versus-host disease prophylaxis regimens, and discuss the unique challenges that arise in these patients.

RECENT FINDINGS

AlloHSCT for SCD has been performed on small numbers of patients at multiple centers around the world using several different transplant platforms, and early outcomes are encouraging. Overall survival is excellent, although graft failure remains a challenge.

SUMMARY

As alloHSCT becomes safer and more widely available, the procedure should be considered for patients with severe disease phenotypes in whom the potential benefits of transplantation outweigh the complications from the disease. AlloHSCT has been shown to reverse or at least halt the progression of end-organ damage secondary to SCD. More research is needed to understand the mechanisms underlying graft failure in SCD recipients, as well as to understand the biopsychosocial underpinnings of persistent pain in the posttransplant period to maximize the benefit from the transplant procedure.

Post-Transplantation Cyclophosphamide-Based Haploidentical Transplantation as Alternative to Matched Sibling or Unrelated Donor Transplantation for Hodgkin Lymphoma: A Registry Study of the Lymphoma Working Party of the European Society for Blood and Marrow Transplantation

Purpose

To compare the outcome of patients with Hodgkin lymphoma who received post-transplantation cyclophosphamide–based haploidentical (HAPLO) allogeneic hematopoietic cell transplantation with the outcome of patients who received conventional HLA-matched sibling donor (SIB) and HLA-matched unrelated donor (MUD).

Patients and Methods

We retrospectively evaluated 709 adult patients with Hodgkin lymphoma who were registered in the European Society for Blood and Marrow Transplantation database who received HAPLO (n = 98), SIB (n = 338), or MUD (n = 273) transplantation.

Results

Median follow-up of survivors was 29 months. No differences were observed between groups in the incidence of acute graft-versus-host disease (GVHD). HAPLO was associated with a lower risk of chronic GVHD (26%) compared with MUD (41%; P = .04). Cumulative incidence of nonrelapse mortality at 1 year was 17%, 13%, and 21% in HAPLO, SIB, and MUD, respectively, and corresponding 2-year cumulative incidence of relapse or progression was 39%, 49%, and 32%, respectively. On multivariable analysis, relative to SIB, nonrelapse mortality was similar in HAPLO ( P = .26) and higher in MUD ( P = .003), and risk of relapse was lower in both HAPLO ( P = .047) and MUD ( P < .001). Two-year overall survival and progression-free survival were 67% and 43% for HAPLO, 71% and 38% for SIB, and 62% and 45% for MUD, respectively. There were no significant differences in overall survival or progression-free survival between HAPLO and SIB or MUD. The rate of the composite end point of extensive chronic GVHD and relapse-free survival was significantly better for HAPLO (40%) compared with SIB (28%; P = .049) and similar to MUD (38%; P = .59).

Conclusion

Post-transplantation cyclophosphamide–based HAPLO transplantation results in similar survival outcomes compared with SIB and MUD, which confirms its suitability when no conventional donor is available. Our results also suggest that HAPLO results in a lower risk of chronic GVHD than MUD transplantation.

Where Do the New Drugs Fit in for Relapsed/Refractory Hodgkin Lymphoma?

The standard approach for relapsed or refractory (rel/ref) Hodgkin lymphoma (HL) following frontline treatment failure is salvage therapy followed by consolidation with high-dose therapy and autologous stem cell transplant (HDT/ASCT). While this overall treatment paradigm has been in place for several decades, recent studies have aimed to improve the efficacy and tolerability of salvage therapies by incorporating newer drugs, such as brentuximab vedotin (BV) and checkpoint inhibitors. Following HDT/ASCT, survival is improved due to the availability of BV and the checkpoint inhibitors, nivolumab and pembrolizumab; however, for patients responding to checkpoint inhibition, the appropriate length of treatment and the role of allogeneic stem cell transplant are unclear. In this review, we discuss our management of rel/ref HL, with particular focus on how BV, nivolumab, and pembrolizumab are currently incorporated into the treatment paradigms for rel/ref HL.

Haploidentical transplant in patients with myelodysplastic syndrome

The only curative treatment in patients with intermediate or high-risk myelodysplastic syndrome (MDS) is allogeneic hematopoietic stem cell transplantation (HSCT), which usually results in a long-term, disease-free survival rate of between 30% and 50%, depending on the disease risk and the type of donor. In patients without an HLA-matched sibling donor, a family haploidentical donor is an alternative option. The present study reports the European Group for Blood and Marrow Transplantation activity for haploidentical transplantation in MDS patients. A total of 228 patients transplanted from a mismatched HLA-related donor between 2007 and 2014 were studied. The median age at transplant was 56 years. Eighty-four (37%) patients had MDS transformed into acute myeloid leukemia at the time of transplant. Ex vivo T-cell depletion was used in 34 patients. One hundred ninety-four patients received a T-cell replete transplant and 102 patients received posttransplant cyclophosphamide (PT-CY) as graft-versus-host disease (GVHD) prophylaxis. The cumulative incidences of acute and chronic GVHD in PT-CY vs other patients were 25% vs 37% and 37% vs 24%, respectively. The cumulative incidence of nonrelapse mortality was 55% in patients who did not receive PT-CY (no PT-CY) and 41% in patients who did receive PT-CY. Three-year overall survival was 28% in no PT-CY patients and 38% in PT-CY patients. In multivariable analysis, the main risk factors were the intensity of the conditioning regimen and the use of PT-CY. In conclusion, the outcomes of MDS patients who received an haploidentical transplant are close to the results other transplantations from HLA-mismatched donors with approximately one-third of patients alive and free of disease 3 years after transplant, and the use of PT-CY may improve their outcomes.

Haploidentical hematopoietic cell transplantation for adult acute myeloid leukemia: a position statement from the Acute Leukemia Working Party of the European Society for Blood and Marrow Transplantation

Allogeneic blood or marrow hematopoietic cell transplantation continues to be the most potent anti-leukemic treatment for adult patients with standard, high-risk, or chemo-refractory acute myeloid leukemia. Until recently, this procedure was generally limited to those recipients who had an available matched-sibling donor or matched-unrelated donor. Technical advances in graft cell processing and manipulation, control of bidirectional T cell alloreactivity, graft-versus-host disease prophylaxis, and other supportive measures in haploidentical transplantation now enable nearly all patients with acute myeloid leukemia to benefit from the graft-versus-leukemia effect with substantial reduction in procedure-related mortality. Over recent years, haploidentical donors have been increasingly adopted as a valid donor source in allogeneic hematopoietic cell transplantation for acute myeloid leukemia in the absence of an HLA-matched donor. Among centers of the European Society for Blood and Marrow Transplantation, the use of haploidentical related donor transplantation has increased by 250% since 2010, and 291% since 2005. On behalf of the Acute Leukemia Working Party of the European Society for Blood and Marrow Transplantation, we summarize recent utilization trends in haploidentical transplantation for acute myeloid leukemia and describe the transformative changes in haploidentical hematopoietic cell transplantation techniques over the past decade, which have led to the current widespread use of this procedure. Furthermore, we review the efficacy of haploidentical hematopoietic cell transplantation for acute myeloid leukemia from available studies, including preliminary comparative studies, and bring attention to remaining unanswered questions and directions for future research. We conclude this report with our recommendations for the role of haploidentical hematopoietic cell transplantation in acute myeloid leukemia.

Meta-analysis of the actions of antithymocyte globulin in patients undergoing allogeneic hematopoietic cell transplantation

Graft-versus-host disease (GVHD) is a serious complication associated with allogeneic hematopoietic cell transplantation (allo-HCT). Antithymocyte globulin (ATG) is widely used prior to allo-HCT for GVHD prevention, though evidence of its efficacy remains unclear. We therefore identified nine randomized controlled trials (RCTs), enrolling 1089 patients (554 in the ATG group and 535 in the non-ATG group) to conduct a meta-analysis of the actions of ATG in allo-HCT. A relative risk or risk ratio (RR) and 95% confidence interval (CI) were calculated for each outcome. Rabbit ATG reduced overall acute (a) GVHD (RR 0.77, 95% CI 0.67-0.89, P = 0.0004), grade III-IV aGVHD (RR 0.53, 95% CI 0.32-0.88, P = 0.01), overall chronic (c) GVHD (RR 0.52, 95% CI 0.42-0.64, P < 0.00001) and extensive cGVHD (RR 0.28, 95% CI 0.18-0.43, P < 0.00001), without increased risk of relapse (RR 1.17, 95% CI 0.91-1.49, P = 0.23). By contrast, horse ATG did not reduce overall aGVHD (RR 1.25, 95% CI 0.88-1.79, P = 0.22) or cGVHD (RR 1.67, 95% CI 0.96-2.91, P = 0.07). ATG marginally reduced 100-day transplant related mortality (RR 0.75, 95% CI 0.56-1.00, P = 0.05) without compromising overall survival or increased risk of infections. Further studies are required to evaluate the optimal dosage and formulation of ATG in different conditioning regimens of transplantation with varied sources of graft and donor.