HLA-Mismatched Donors in Patients with Myelodysplastic Syndrome: An EBMT Registry Analysis

Advances in the management of higher-risk myelodysplastic syndromes: future prospects

Higher-risk myelodysplastic syndromes (HR-MDS) are defined using a number of prognostic scoring systems that include the degree of cytopenias, percentage of blasts, cytogenetic alterations, and more recently genomic data. HR-MDS encompasses characteristics such as progressive cytopenias, increased bone marrow blasts, unfavorable cytogenetics, and an adverse mutational profile. Survival is generally poor, and patients require therapy to improve outcomes. Hypomethylating agents (HMAs), such as azacitidine, decitabine, and more recently, oral decitabine/cedazuridine, are the only approved therapies for HR-MDS. These are often continued until loss of response, progression, or unacceptable toxicity. Combinations including an HMA plus other drugs have been investigated but have not demonstrated better outcomes compared to single-agent HMA. Moreover, in a disease of high genomic complexity such as HR-MDS, therapy targeting specific genomic abnormalities is of interest. This review will examine the biological underpinnings of HR-MDS, its therapeutic landscape in the frontline and relapsed settings, as well as the impact of hematopoietic stem cell transplantation, the only known curative intervention for this disease.

How I reduce and treat posttransplant relapse of MDS

ABSTRACT

Allogeneic hematopoietic stem cell transplantation (HSCT) is the only potentially curative option for patients with high-risk myelodysplastic syndromes (MDS). Advances in conditioning regimens and supportive measures have reduced treatment-related mortality and increased the role of transplantation, leading to more patients undergoing HSCT. However, posttransplant relapse of MDS remains a leading cause of morbidity and mortality for this procedure, necessitating expert management and ongoing results analysis. In this article, we review treatment options and our institutional approaches to managing MDS relapse after HSCT, using illustrative clinical cases that exemplify different clinical manifestations and management of relapse. We address areas of controversy relating to conditioning regimen intensity, chemotherapeutic bridging, and donor selection. In addition, we discuss future directions for advancing the field, including (1) the need for prospective clinical trials separating MDS from acute myeloid leukemia and focusing on posttransplant relapse, as well as (2) the validation of measurable residual disease methodologies to guide timely interventions.

The prognosis and risk factors for patients with complex karyotype myelodysplastic syndrome undergoing allogeneic haematopoietic stem cell transplantation

Allogeneic haematopoietic stem cell transplantation (HCT) is the curative treatment for myelodysplastic syndrome with a complex karyotype (CK-MDS). However, only a few studies have been limited to patients with CK-MDS undergoing allogeneic HCT. This study aimed to identify the risk factors for patients with CK-MDS undergoing allogeneic HCT. We included 691 patients with CK-MDS who received their first allogeneic HCT. The overall survival (OS) was the primary end-point, estimated using the Kaplan-Meier method. Prognostic factors were identified using a Cox proportional hazards model. The 3-year OS was 29.8% (95% confidence interval [CI]: 26.3-33.3). In the multivariable analysis, older age (hazard ratio [HR]: 1.44, 95% CI: 1.11-1.88), male sex (HR: 1.38, 95% CI: 1.11-1.71), poor haematopoietic cell transplant comorbidity index (HR: 1.47, 95% CI: 1.20-1.81), red blood cell transfusion requirement (HR: 1.58, 95% CI: 1.13-2.20), platelet transfusion requirement (HR: 1.85, 95% CI: 1.46-2.35), not-complete remission (HR: 1.55, 95% CI: 1.16-2.06), a high number of karyotype abnormality (HR: 1.63, 95% CI: 1.18-2.25) and monosomal karyotype (HR: 1.49, 95% CI: 1.05-2.12) were significantly associated with OS. Thus, the 3-year OS of allogeneic HCT was 29.8% in patients with CK-MDS, and we identified risk factors associated with poor OS.

Single-unit unrelated cord blood transplantation versus HLA-matched sibling transplantation in adults with advanced myelodysplastic syndrome: A registry-based study from the adult MDS working group of the Japanese society for transplantation and cellular therapy

Allogeneic hematopoietic stem cell transplantation (HCT) remains the only potential curative therapeutic modality for advanced myelodysplastic syndrome (MDS). Within HCT, the advancement of cord blood transplantation (CBT) procedures has resulted in a drastic expansion of CBT as a donor source for MDS. However, data comparing matched sibling donors (MSDs) HCT with CBT for advanced MDS, which was defined as refractory anemia with an excess of blasts (RAEB)-1 and RAEB-2 according to the World Health Organization classification at the time of HCT, have not been explored. We retrospectively compared survival and other posttransplant outcomes in 999 adult patients with advanced MDS after receiving allogeneic HCT in Japan between 2011 and 2020, using either MSD (n = 331) or single-unit unrelated cord blood (UCB) (n = 668). In the multivariate analysis, there were no significant differences in overall survival (hazard ratio [HR], 1.10; 95% confidence interval [CI], 0.90-1.34; P = 0.347), disease-free survival (HR, 1.01; 95% CI, 0.84-1.23; P = 0.845), relapse (HR, 0.88; 95% CI, 0.68-1.15; P = 0.370), or non-relapse mortality (HR, 1.15; 95% CI, 0.87-1.50; P = 0.310) between MSD recipients and UCB recipients. UCB was significantly associated with lower neutrophil (HR, 0.28; 95% CI, 0.24-0.33; P < 0.001) and lower platelet (HR, 0.29; 95% CI, 0.23-0.36; P < 0.001) recovery compared to MSD. UCB was significantly associated with a lower incidence of chronic graft-versus-host disease (GVHD) (HR, 0.57; 95% CI, 0.44-0.75; P < 0.001) and extensive chronic GVHD (HR, 0.46; 95% CI, 0.32-0.67; P < 0.001) compared to MSD. Similar results were observed after adjusting for differences between MSD and UCB recipients by propensity score matching analysis. Our study demonstrated that single CBT and MSD HCT had similar survival outcomes for adult patients with advanced MDS despite the lower hematopoietic recovery in CBT recipients and higher chronic GVHD in MSD recipients.

[Allogeneic hematopoietic stem cell transplantation for myelodysplastic syndromes]

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is one of the treatment options for myelodysplastic syndromes (MDS). This treatment is indicated as first-line treatment for high-risk MDS according to the IPSS and R-IPSS classifications and improves overall survival and progression-free survival. However, allo-HSCT is not indicated in first intention for low-risk MDS. It can be discussed in case of cytopenias needing transfusions, poor evolution under other treatment, or in case of poor prognosis molecular anomaly. Allo-HSCT is a treatment that can be complicated by early or late toxicities (graft versus host disease, infections, chemotherapy toxicity…). The decision to do an allo-HSCT is based on the benefit/risk ratio between the risk of progression from MDS to myeloid leukemia and the risk of transplant related mortality, which increases with the patient's age and comorbidities. The indication of a cytoreductive treatment before allo-HSCT depends on the blasts count, and on the delay before the allograft. The use of reduced intensity conditioning regimen and alternative donors such as haploidentical donors, expanded the indications for allo-HSCT. Relapse remains one of the main causes of mortality after allo-HSCT. Some genetic mutations and karyotype anomalies increase the risk of post-transplant relapse. Preventive treatments for relapse are currently being studied. Treatments such as azacytidine, donor lymphocytes infusions or targeted therapies can be used, prophylactically or preemptively.

Treatment strategy at the decision for allogeneic transplantation in patients with myelodysplastic syndrome in the era of azacitidine: A KSGCT prospective study

The optimal bridge strategy at the decision for allogeneic hematopoietic stem cell transplantation (HSCT) in patients with myelodysplastic syndrome (MDS) is unclear. We performed a prospective observational study in which 110 patients with MDS who were decided to undergo HSCT were enrolled. Among these 110 patients, 77 patients were enrolled in this study within 1 month from the decision for HSCT. Among these 77 patients, 13 patients had a human leukocyte antigen (HLA)-matched sibling, 54 patients started an unrelated donor search, and the other 10 patients directly selected cord blood (CB) at the decision for HSCT, and 13 (100%), 38 (70.4%), and 9 (90%) patients actually underwent HSCT within 1 year, respectively. The overall survival (OS) at 1 year from their enrollment was 70.9%, and the selection of azacitidine use at the decision for HSCT was not associated with OS. Among 60 of the 77 patients who actually underwent HSCT within a year from their enrollment, a lower relapse rate after HSCT was observed in those who selected CB at the decision to undergo HSCT. However, this preferable effect of CB selection disappeared when patients who were enrolled in this study in > 1 month from the decision for HSCT were additionally included in the analyses. In conclusion, the selection of bridge strategy at the decision for HSCT did not affect outcomes in patients with MDS. The immediate performance of HSCT may be associated with better outcomes.

Hematopoietic Cell Transplantation in the Management of Myelodysplastic Syndrome: An Evidence-Based Review from the American Society for Transplantation and Cellular Therapy Committee on Practice Guidelines

The sole curative therapy for myelodysplastic syndrome (MDS) is allogeneic hematopoietic cell transplantation (HCT). Here this therapeutic modality is reviewed and critically evaluated in the context of the evidence. Specific criteria were used for searching the published literature and for grading the quality and strength of the evidence and the strength of the recommendations. A panel of MDS experts comprising transplantation and nontransplantation physicians developed consensus treatment recommendations. This review summarizes the standard MDS indications for HCT and addresses areas of controversy. Recent prospective trials have confirmed that allogeneic HCT confers survival benefits in patients with advanced or high-risk MDS compared with nontransplantation approaches, and the use of HCT is increasing in older patients with good performance status. However, patients with high-risk cytogenetic or molecular mutations remain at high risk for relapse. It is unknown whether administration of novel therapies before or after transplantation may decrease the risk of disease relapse in selected populations. Ongoing and future studies will investigate revised approaches to disease risk stratification, patient selection, and post-transplantation approaches to optimize allogeneic HCT outcomes for patients with MDS.

Allogeneic stem cell transplantation for patients with myelodysplastic syndromes

Myelodysplastic syndromes (MDS) are a heterogenous group of clonal hematopoietic stem cell neoplasms primarily affecting older persons, associated with dysplastic changes of bone marrow cells, peripheral cytopenias, and various risk of leukemic transformation. Although treatment with several drugs has shown improved disease control, allogeneic hematopoietic stem cell transplantation (allo-HSCT) remains the only curative treatment for MDS. The number of patients receiving a transplant, as well as survival, have increased past years because of the use of reduce-intensity conditioning regimens (RIC) as well as the use of haploidentical donors for transplantation. With treatment-related mortality as main limitation, pre-transplant evaluation is essential to assess risks for this older group of patients. In a recent randomized study, allo-HSCT with RIC for patients >50 years old with higher-risk MDS demonstrated superiority in survival compared with hypomethylating agents. Genetic mutations have been shown to significantly impact treatment outcomes including after transplant. Recently, a transplant-specific risk score (which includes age, donor type, performance status, cytogenetic category, recipient's cytomegalovirus status, percentage of blasts, and platelet count) has shown superiority in transplantation outcome prediction, compared with previous scoring systems. Survival remains low for most patients with TP53 mutations and novel treatment strategies are needed, such as administration of natural killer cells post-transplant, as there is no clear evidence that maintenance therapy after transplantation can improve outcomes.

In 2022, which is preferred: haploidentical or cord transplant?

Allogeneic hematopoietic stem cell transplantation is the treatment of choice for high-risk hematological malignancies such as acute myeloid and lymphocytic leukemia, myelodysplastic syndrome, and myeloproliferative disorders. Alternative donor transplantation from either haploidentical (haplo-SCT) or cord blood donor (CBT) is an established therapeutic alternative for patients who need transplants but lack a human leukocyte antigen-matched donor. Although haplo-SCT (mainly non-T-cell-depleted haplo-SCT with posttransplant cyclophosphamide) is increasing while CBT is decreasing worldwide (Figure 1), recent developments in CBT, especially cord blood expansion and other strategies to improve engraftment and immune reconstitution post-CBT, make CBT still a valuable option. This article discusses the 2 options based on the currently available data, focusing on adults, and tries to give some clues to help the transplant physician choose a haploidentical vs a cord blood donor. Given the limited numbers of published or ongoing well-designed randomized controlled trials comparing haplo-SCT to CBT and the overall similar clinical results in the available, mostly registry-based, and single-center studies, with substantial heterogeneity and variability, the decision to perform haplo-SCT or CBT in a given patient depends not only on the patient, disease, and donor characteristics and donor availability (although most if not all patients should have in principle an alternative donor) but also on the transplant physician's discretion and, most importantly, the center's experience and preference and ongoing protocols and strategies.

Outcomes with mismatched unrelated donor allogeneic hematopoietic stem cell transplantation in adults: A systematic review and meta-analysis

Background

Allogeneic hematopoietic stem cell transplantation (HSCT) is a potentially curative therapy for various hematologic disorders. Alternative donor strategies such as mismatched unrelated donors (MMUD) offer the option of HSCT to patients lacking a human leukocyte antigen (HLA)-matched donor. We conducted a systematic review and meta-analysis to evaluate outcomes after MMUD-HSCT.

Methods

A literature search was performed on PubMed, Cochrane Library, and ClinicalTrials.gov from the inception date through April 6, 2022. After screening 2477 manuscripts, 19 studies were included. Data was extracted following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. Pooled analysis was done using the meta-package by Schwarzer et al. Proportions with 95% confidence intervals (CI) were computed.

Results

A total of 3336 patients from 19 studies were included. The median age was 52.1 years, and 53% of recipients were males. The graft source was bone marrow in 19% and peripheral blood stem cells in 81% of recipients. The median time to transplant from hematologic diagnosis was 10 (1-247) months. Hematologic diagnoses included myeloid (82.9%), lymphoid (41.1%), and other disorders (3%). The reduced intensity and myeloablative conditioning were used in 65.6% and 32% of recipients, respectively. In-vivo T-cell depletion was performed in 56.7% of the patients. Most patients had one (87.9%) or two (11.4%) antigen HLA-mismatch. The pooled 1-year overall survival (OS) was 63.9% (95% CI 0.57-0.71, n=1426/2706), and the pooled 3-year OS was 42.1% (95% CI 0.34.2-0.50, n=907/2355). The pooled progression-free survival was 46.6% (95% CI 0.39-0.55, n=1295/3253) after a median follow-up of 1.8 (range 1-6) years. The pooled relapse rate was 26.8% (95% CI 0.22-0.32, n=972/3253) after a median follow-up of 2.25 (1-3) years. The pooled incidence of acute (grade II-IV) graft-versus-host disease (GVHD) and chronic GVHD was 36.4% (95% CI 0.31-0.42, n=1131/3030) and 41.2% (95% CI 0.35-0.48, n=1337/3228), respectively. The pooled non-relapse mortality was 22.6% (95% CI 0.17-0.29, n=888/3196) after a median follow-up of 2.6 (1-5) years.

Conclusion

MMUD-HSCT has demonstrated favorable outcomes with an acceptable toxicity profile. It represents a promising option in patients lacking an HLA-matched or haploidentical donor and may expand HSCT access to underrepresented racial and ethnic populations.

Comparison of outcomes for HLA-matched sibling and haplo-identical donors in Myelodysplastic syndromes: report from the chronic malignancies working party of EBMT

Myelodysplastic syndromes (MDS) are the second common indication for an Allo-HCT. We compared the outcomes of 1414 matched sibling (MSD) with 415 haplo-identical donors (HD) transplanted with post-transplant cyclophosphamide (PTCy) as GVHD prophylaxis between 2014 and 2017. The median age at transplant with MSD was 58 and 61 years for HD. The median time to neutrophil engraftment was longer for HD being 20 vs 16 days for MSD (p < 0.001). Two-year overall survival (OS) and PFS (progression free survival) with MSD were significantly better at 58% compared with 50%, p ≤ 0.001, and 51% vs 47%, p = 0.029, with a HD. Relapse at 2 years was lower with a HD 23% than with MSD 29% (p = 0.016). Non relapse mortality (NRM) was higher with HD in the first 6 months post-transplant [HR 2.59 (1.5–4.48) p < 0.001] and was also higher at 2 years being 30% for HD and 20% for MSD, p ≤ 0.001. The incidence of acute GVHD grade II-IV and III–IV at 100 days was comparable for MSD and HD, however, chronic GVHD at 2 years was significantly higher with MSD being 44% vs 32% for HD (p < 0.001). After multivariable analysis, OS and primary graft failure were significantly worse for HD particularly before 6 months [HR 1.93(1.24–3.0)], and HR [3.5(1.5–8.1)]. The median age of HD 37 (IQR 30–47) years was significantly lower than sibling donors 56 (IQR 49–62 years) p < 0.001. However, there was no effect on NRM, relapse or PFS. This data set suggests that a MSD donor remains the preferred choice in MDS over a haplo donor. Transplants with haploidentical donors result in satisfactory long-term outcome, justifying it’s use when no better donor is available.

Single Cord Blood Transplantation Versus HLA-Haploidentical-related Donor Transplantation Using Posttransplant Cyclophosphamide in Patients With Hematological Malignancies

BACKGROUND

Unrelated cord blood (UCB) and haploidentical related donor transplantation using posttransplant cyclophosphamide (PTCy-haplo) have become alternative options to treat patients with hematological malignancies without a HLA-matched donor.

METHODS

We conducted a retrospective study using registry data from the Kyoto Stem Cell Transplantation Group for patients with hematological malignancies who received their first allogeneic hematopoietic cell transplantation using a single UCB unit (n = 460) or PTCy-haplo (N = 57) between 2013 and 2019.

RESULTS

We found that overall survival in the UCB group was comparable to that in the PTCy-haplo group (hazard ratio, 1.00; 95% confidence interval, 0.66-1.52), although neutrophil and platelet engraftment were significantly delayed. Nonrelapse mortality risk and the incidence of graft-versus-host disease in the UCB group were also comparable to those in the PTCy-haplo group. Although the relapse risk was similar between the UCB group and the PTCy-haplo group regardless of the disease risk, acute myeloid leukemia patients benefit from UCB transplant with a significantly lower relapse rate (hazard ratio, 0.38; 95% confidence interval, 0.18-0.76).

CONCLUSIONS

UCB transplant gives outcomes comparable to PTCy-haplo transplant, and both UCB and PTCy-haplo units are suitable as alternative donor sources for patients without an HLA-matched sibling or unrelated donor.

Biologic Assignment Trial of Reduced-Intensity Hematopoietic Cell Transplantation Based on Donor Availability in Patients 50-75 Years of Age With Advanced Myelodysplastic Syndrome

PURPOSE

Allogeneic hematopoietic cell transplantation (HCT) is the only potentially curative therapy for myelodysplastic syndromes (MDS), although it is infrequently offered to older patients. The relative benefits of HCT over non-HCT therapy in older patients with higher-risk MDS have not been defined.

METHODS

We conducted a multicenter biologic assignment trial comparing reduced-intensity HCT to hypomethylating therapy or best supportive care in subjects 50-75 years of age with intermediate-2 or high-risk de novo MDS. The primary outcome was overall survival probability at 3 years. Between January 2014 and November 2018, we enrolled 384 subjects at 34 centers. Subjects were assigned to the Donor or No-Donor arms according to the availability of a matched donor within 90 days of study registration.

RESULTS

The median follow-up time for surviving subjects was 34.2 months (range: 2.3-38 months) in the Donor arm and 26.9 months (range: 2.4-37.2 months) in the No-Donor arm. In an intention-to-treat analysis, the adjusted overall survival rate at 3 years in the Donor arm was 47.9% (95% CI, 41.3 to 54.1) compared with 26.6% (95% CI, 18.4 to 35.6) in the No-Donor arm (P = .0001) with an absolute difference of 21.3% (95% CI, 10.2 to 31.8). Leukemia-free survival at 3 years was greater in the Donor arm (35.8%; 95% CI, 29.8 to 41.8) compared with the No-Donor arm (20.6%; 95% CI, 13.3 to 29.1; P = .003). The survival benefit was seen across all subgroups examined.

CONCLUSION

We observed a significant survival advantage in older subjects with higher-risk MDS who have a matched donor identified and underwent reduced-intensity HCT, when compared with those without a donor. HCT should be included as an integral part of MDS management plans in fit older adults with higher-risk MDS.

Haploidentical Hematopoietic Stem Cell Transplantation Versus Umbilical Cord Blood Transplantation in Hematologic Malignancies: A Systematic Review and Meta-Analysis

Haploidentical hematopoietic stem cell transplantation (Haplo-SCT) and umbilical cord blood transplantation (UCBT) are two important alternatives when a matched sibling donor is unavailable. Several studies have reported inconsistent clinical outcomes comparing Haplo-SCT and UCBT. Therefore, it is necessary to synthesize the existing evidence regarding outcomes of stem cell transplantations comparing Haplo-SCT with UCBT. We searched article titles that compared transplantation with Haplo-SCT and UCBT in MEDLINE (PubMed), Cochrane library, and EMBASE database. To compare clinical outcomes between Haplo-SCT and UCBT, we performed a meta-analysis of 12 studies and reported the pooled odds ratios (ORs) of 6 end points including overall survival (OS), progression-free survival (PFS), nonrelapse mortality (NRM), relapse rate (RR), acute graft-versus-host disease (aGVHD), and chronic graft-versus-host disease (cGVHD). We found that Haplo-SCT was associated with a significantly superior OS (pooled OR of 0.74, 95% confidence interval [CI] 0.68 to 0.80) and PFS (0.77, 95% CI 0.72 to 0.83), as well as a lower NRM (0.72, 95% CI 0.64 to 0.80) and aGVHD (0.87, 95% CI 0.77 to 0.98) compared to the UCBT group. We also found a significantly increased risk of cGVHD in Haplo-SCT group (1.40, 95% CI 1.22 to 1.62). In terms of RR, Haplo-SCT was comparable to UCBT (0.91, 95% CI 0.79 to 1.05). Results of this meta-analysis demonstrate that Haplo-SCT results in better clinical outcomes compared to UCBT in terms of OS, PFS, TRM, and aGVHD, but is inferior to UCBT in terms of increased cGVHD risk. Further prospective comparisons between Haplo-SCT and UCBT are needed.

Effects of Acute and Chronic Graft-versus-myelodysplastic Syndrome on Long-term Outcomes Following Allogeneic Hematopoietic Cell Transplantation

PURPOSE

Potent graft-versus-tumor (GVT) effects associated with graft-versus-host disease (GVHD) might be dependent on hematologic disease type and status. However, the data regarding the impact of GVHD on transplant outcomes for patients with myelodysplastic syndrome (MDS) are limited.

EXPERIMENTAL DESIGN

We retrospectively evaluated the impact of acute and chronic GVHD on transplant outcomes for a large cohort of adult patients with a low-risk (n = 1,193) and high-risk (n = 1,926) MDS treated by first allogeneic hematopoietic cell transplantation between 2001 and 2017.

RESULTS

The multivariate analysis, in which development of GVHD was treated as a time-dependent covariate, showed that acute and chronic GVHD at any grade or severity did not improve overall mortality, relapse, or nonrelapse mortality (NRM) in low-risk MDS. For patients with high-risk MDS, development of limited chronic GVHD was significantly associated with lower overall mortality [HR, 0.66; 95% confidence interval (CI), 0.50-0.86; P = 0.002]. This is probably due to that the reduced risk of relapse with grade III-IV acute GVHD (HR, 0.41; 95% CI, 0.25-0.65; P = 0.0002), or limited (HR, 0.57; 95% CI, 0.39-0.83; P = 0.003) or extensive (HR, 0.56; 95% CI, 0.41-0.77; P = 0.0004) chronic GVHD was offset by increased NRM with grade III-IV acute GVHD or extensive chronic GVHD in high-risk MDS.

CONCLUSIONS

These data demonstrated a survival benefit of the graft-versus-MDS effect is present only in high-risk MDS patients with limited chronic GVHD.See related commentary by Eckel and Deeg, p. 6404.

Outcome of allogeneic hematopoietic stem cell transplantation for hypoplastic myelodysplastic syndrome

The prognosis of patients with hypoplastic myelodysplastic syndrome (hMDS) after receiving allogeneic hematopoietic stem cell transplantation (allo-HSCT) remains unclear. This study aimed to evaluate the outcomes of patients with hMDS after allo-HSCT. Between September 2013 and October 2019, a total of 20 consecutive patients with hMDS and 1 patient with clonal cytopenia of undermined significance (CCUS) who underwent allo-HSCT, which included procedures with 9 matched sibling donors, 2 matched unrelated donors, 4 mismatched unrelated donors and 6 haploidentical donors, were enrolled in this study. The median time for myeloid engraftment was 11 days (range 9-17 days), and that for platelet engraftment was 10 days (range 7-17 days). The cumulative incidence (CI) of myeloid and platelet recovery was 95.2 ± 6.0% and 90.5 ± 7.3%, respectively. The CI rates were 40.0 ± 11.3% for grades II-III acute graft-versus-host disease (GVHD), 36.8 ± 11.5% for chronic GVHD and 23.8 ± 9.6% for nonrelapse mortality. No patients experienced relapse. Sixteen surviving patients were followed up for a median of 1113 days (range 110-2305 days), and the overall survival and relapse-free survival rates were both 72.7 ± 10.6%. This limited retrospective analysis suggests that patients with hMDS had a favorable survival after allo-HSCT.

Recent progress in haploidentical transplantation: is this the optimal choice for alternative donor transplantation?

PURPOSE OF REVIEW

This article is intended to review recent trends and improvements in haploidentical transplantation to understand its current status and future direction.

RECENT FINDINGS

The noninferiority of haploidentical donors compared with other donor sources, including HLA-matched related or unrelated donors, has been demonstrated in patients with various hematological diseases. The development of graft-versus-host-disease (GVHD) prophylaxis using posttransplant cyclophosphamide has effectively reduced transplant-related mortality caused by GVHD, graft rejection, and other related complications. Novel GVHD prophylactic methods and other supportive strategies are under intense investigation to reduce the risk of infections and retain graft-versus-leukemia/lymphoma effects after transplantation.

SUMMARY

Recent progress in haploidentical stem cell transplantation has broadened the availability of donor sources for patients with hematological diseases. It is important to compare and examine the impact of donor sources on transplant outcomes to achieve a better understanding about the appropriate donor choice for each patient.

Which lower risk myelodysplastic syndromes should be treated with allogeneic hematopoietic stem cell transplantation?

Indications of allogeneic hematopoietic stem cell transplantation (HSCT) remain controversial in patients with lower risk myelodysplastic syndrome. We review prognostic factors in lower risk MDS, delineating patients with relatively poor risk who may potentially benefit from HSCT during the disease course. Results of HSCT in those patients, and main efforts to decrease non-relapse mortality (NRM) are detailed. Prospective studies are needed to determine more precisely which lower risk MDS patients may benefit from transplantation.

Haploidentical Hematopoietic Stem Cell Transplantation Followed by 'Post-Cyclophosphamide': The Future of Allogeneic Stem Cell Transplant

Allogeneic hematopoietic cell transplant (Allo-HCT) is a potentially curative therapy for many malignant and nonmalignant hematological diseases. However, a suitable human leukocyte antigens (HLAs)-matched donor may not be available when the patient is in urgent need of a stem cell transplant. This challenge has been ameliorated to a large extent by the introduction of haploidentical donors. This type of donor shares one HLA haplotype with the recipient. Therefore, a patient's full sibling has a 50% chance of being haploidentical and a patient's biologic parents and children will all be haploidentical, thus providing an immediately accessible, motivated donor for almost every recipient. Haploidentical transplants previously incurred prohibitively poor outcomes, preventing their widespread use. However, several recent advances have dramatically improved the results, making them a more viable donor source. In this review, we discuss different types of donors used for Allo-HCT with a particular focus on the use of haploidentical donors and their future potential.

Contemporary treatment approaches to CMML - Is allogeneic HCT the only cure?

Chronic Myelomonocytic Leukemias are frequently diagnosed in older adults. Their prognosis is heterogeneous, but several prognostic factors can identify patients with an expected survival of a few years only, including among younger patients eligible for allogeneic stem cell transplantation. Based on the retrospective data available, we discuss how to identify CMML patients for whom curative therapy must be envisaged. We emphasize that, although transplantation remains the only path to cure in CMML, it can be envisaged in only a minority of patients. Despite increased donor availability, its potential remains limited by significant rates of mortality caused both by the procedure and by post-transplantation relapses. We review the options available to bridge patients to transplant, the management of transplantation itself (choice of donor, graft source and condition regimen), and finally the potential for post-transplantation interventions. Our review underscores the need for further prospective studies of allogeneic stem cell transplantation in CMML.

Nonmyeloablative Alternative Donor Transplantation for Hodgkin and Non-Hodgkin Lymphoma: From the LWP-EBMT, Eurocord, and CIBMTR

PURPOSE

To compare the outcomes of patients with Hodgkin or non-Hodgkin lymphoma undergoing nonmyeloablative haploidentical or unrelated cord blood (UCB) hematopoietic cell transplantation.

PATIENTS AND METHODS

We retrospectively studied 740 patients with Hodgkin lymphoma (n = 283, 38%) and non-Hodgkin lymphoma (n = 457, 62%) age 18-75 years who received transplantations from 2009 to 2016. Data were reported to the Lymphoma Working Party of the European Society for Blood and Marrow Transplantation, Eurocord, or Center for International Blood and Marrow Transplant Research. Of the 526 patients who received haploidentical transplantation, 68% received bone marrow and 32% received peripheral blood. All patients received a uniform transplantation conditioning regimen (2 Gy of total-body irradiation, cyclophosphamide, and fludarabine) and graft-versus-host disease prophylaxis (calcineurin inhibitor and mycophenolate). In addition, patients who received a haploidentical transplantation received posttransplantation cyclophosphamide.

RESULTS

Compared with haploidentical bone marrow and peripheral-blood transplantations and adjusted for age, lymphoma subtype, and disease status, survival was lower after UCB transplantation (hazard ratio [HR], 1.55; P = .001; and HR, 1.59; P = .005, respectively). Similarly, progression-free survival was lower after UCB transplantations compared with haploidentical bone marrow and peripheral-blood transplantations (HR, 1.44; P = .002; and HR, 1.86; P < .0001), respectively. The 4-year overall and progression-free survival rates after UCB transplantation were 49% and 36%, respectively, compared with 58% and 46% after haploidentical bone marrow transplantation and 59% and 52% after peripheral-blood transplantation, respectively. Lower survival was attributed to higher transplantation-related mortality after UCB transplantation compared with haploidentical bone marrow and peripheral-blood transplantation (HR, 1.91; P = .0001; and HR, 2.27; P = .0002, respectively).

CONCLUSION

When considering HLA-mismatched transplantation for Hodgkin or non-Hodgkin lymphoma, the data support haploidentical related donor transplantation over UCB transplantation.

Post transplant cyclophosphamide based haplo-identical transplant versus umbilical cord blood transplant; a meta-analysis

OBJECTIVES

Both haplo-identical transplant (haplo) and umbilical cord transplant (UC) are valuable graft options for patients without available matched relative. Previous studies showed inconsistent outcomes comparing Post transplant Cyclophosphamide based haplo (PTCy-haplo) and UC; therefore, we attempt to compare the studies by mean of meta-analysis.

METHODS

We searched for titles of articles in MEDLINE (PubMed), Cochrane library, EMBASE database and Google scholar that compared transplantation with PTCy-haplo versus UC. We conducted a random-effect meta-analysis of seven studies involving a total of 3434 participants and reported the pooled odd ratios (OR) of acute graft-versus-host disease (aGVHD), chronic graft-versus-host disease (cGVHD), relapse and overall survival (OS) between PTCy-haplo and UC groups.

RESULTS

We found a significantly decreased risk of aGVHD and relapse in the PTCy-haplo group compared to the UC group with a pooled OR of 0.78, 95% Confidence Interval (CI) 0.67-0.92, I2=0%, and 0.74, 95% CI 0.57-0.97, I2=23.9% respectively. We also found a significantly increased rate of cGVHD and OS with a pooled OR of 1.41, 95% CI 1.02-1.95, I2=56.8%, and 1.77, 95% CI 1.1-2.87, I2=82.5%, respectively.

CONCLUSION

Our meta-analysis of clinical trials demonstrated superior outcome from PTCy-haplo group compared to the UC group in terms of decreased rate of aGVHD and relapse as well as the increased rate of OS but inferior in terms of increased cGVHD risk compared to UC transplant.

The Predicted Indirectly Recognizable HLA Epitopes (PIRCHE) Score for HLA Class I Graft-versus-Host Disparity Is Associated with Increased Acute Graft-versus-Host Disease in Haploidentical Transplantation with Post-Transplantation Cyclophosphamide

The Predicted Indirectly Recognizable HLA Epitopes (PIRCHE) score quantifies the number of PIRCHEs in patient-donor pairs and represents an in silico measure of indirect alloreactivity. This biologic process is defined as T cell recognition of epitopes derived from mismatched, allogeneic HLA peptides that are subsequently presented by shared HLA molecules. Its association with clinical outcome has not been examined in haploidentical hematopoietic cell transplantation (haplo-HCT) with post-transplantation cyclophosphamide (PTCy). We hypothesized that the PIRCHE score (PS) would correlate with indirect alloreactivity and predict graft-versus-host disease (GVHD) risk and the incidence of relapse after haplo-HCT with PTCy. We retrospectively analyzed 148 patients who underwent peripheral blood stem cell T cell-replete haplo-HCT with PTCy at a single center between 2009 and 2016. For each patient-donor pair, the PS was calculated using the PIRCHE online matching tool. PSs were categorized by class and vector. The median class I graft-versus-host (GVH) PS was 11 (range, 0 to 56), and the median class I host-versus-graft (HVG) PS was 10 (range, 0 to 51). Class I GVH PS was associated with increased risk of grade II-IV acute GVHD (adjusted hazard ratio, 1.03 per PS unit increase; 95% confidence interval, 1.01 to 1.05; P= .008) but not of chronic GVHD or relapse. Our data show that use of the PS is a novel strategy for predicting clinical outcome in haplo-HCT; further studies using registry data and prospective cohorts are warranted to validate these findings.

In MDS, is higher risk higher reward?

Patients with higher-risk myelodysplastic syndrome (HR-MDS) are defined by the original or revised International Prognostic Scoring System and specific genetic features. Treatment of HR-MDS is challenging. Allogeneic hematopoietic stem cell transplantation, the only curative approach, is feasible in a minority of fit or intermediate fitness patients aged <70 to 75 years who are willing to face the risks of the procedure. Response to azacitidine and decitabine, the only approved drugs for HR-MDS and considered the standard of care, is partial and transient in most patients. The development of novel more personalized and efficient drugs is an unmet medical need. During the last decade, there have been substantial advances in understanding the multiple molecular, cellular, and immunological disturbances involved in the pathogenesis of myelodysplastic syndrome. As a result, a number of clinical and translational studies of new more focused treatment approaches for HR-MDS patients are underway. In contrast to acute myeloid leukemia, they have not resulted in any new drug approval. This review addresses the benefits and limitations of current treatment alternatives, offers a practical individualized treatment approach, and summarizes the clinical trials in progress for HR-MDS.

Haploidentical Stem Cell Transplantation With Posttransplant Cyclophosphamide Therapy vs Other Donor Transplantations in Adults With Hematologic Cancers: A Systematic Review and Meta-analysis

Importance

Use of haploidentical (HAPLO) stem cell transplantation with posttransplant cyclophosphamide is rapidly increasing in adults with hematologic cancers. However, its specific role compared with other transplant strategies has yet to be identified.

Objective

To synthesize the existing evidence regarding outcomes of stem cell transplantations comparing HAPLO stem cell transplantation and posttransplant cyclophosphamide therapy with transplantations from matched related donors (MRDs), matched unrelated donors (MUDs), or mismatched unrelated donors (MMUDs).

Data Sources

PubMed, Cochrane Library, ClinicalTrials.gov, and meeting abstracts were searched for the key words haploidentical and cyclophosphamide from inception through March 1, 2019.

Study Selection

Studies comparing HAPLO stem cell transplantation and posttransplant cyclophosphamide therapy with transplantations from other donors in adults with hematologic cancers were eligible for meta-analysis.

Data Extraction and Synthesis

Pooled odds ratios (ORs) and 95% CIs were calculated using a random-effects model.

Main Outcomes and Measures

Main outcomes were all-cause mortality, nonrelapse mortality, and relapse.

Results

A total of 30 studies including 22 974 participants were analyzed. HAPLO stem cell transplantation with posttransplant cyclophosphamide therapy was associated with increased all-cause mortality compared with MRDs (OR, 1.17; 95% CI, 1.05-1.30), similar all-cause mortality compared with MUDs (OR, 1.06; 95% CI, 0.96-1.18), and reduced all-cause mortality compared with MMUDs (OR, 0.75; 95% CI, 0.61-0.92). Regarding nonrelapse mortality, HAPLO stem cell transplantation with posttransplant cyclophosphamide was associated with worse outcomes compared with MRDs (OR, 1.20; 95% CI, 1.04-1.40) but better outcomes compared with MUDs (OR, 0.75; 95% CI, 0.61-0.92) and MMUDs (OR, 0.51; 95% CI, 0.25-1.02). In terms of relapse, HAPLO stem cell transplantation with posttransplant cyclophosphamide was associated with similar outcome compared with MRDs (OR, 1.01; 95% CI, 0.86-1.17) and MMUDs (OR, 1.06; 95% CI, 0.77-1.47) but showed increased relapse compared with MUDs (OR, 1.20; 95% CI, 1.03-1.40).

Conclusions and Relevance

Results of this meta-analysis suggest that MRDs, if available, remain the optimal donors regarding mortality and HAPLO stem cell transplantation with posttransplant cyclophosphamide may be preferred over MMUDs. Prospective comparisons with MUDs are needed.