Allogeneic stem cell transplantation for older advanced MDS patients: improved survival with young unrelated donor in comparison with HLA-identical siblings

Comparison of older related vs younger unrelated donors for old recipients of allogeneic hematopoietic cell transplantation with AML or MDS- a large single center analysis

For patients undergoing allogeneic hematopoietic cell transplantation (alloHCT), HLA-matched related donors (MRDs) have traditionally been the preferred donor source. However, as the age of recipient increases, their sibling donors are likely aged as well. In this study, we investigated whether younger matched unrelated donors (MUDs) might be a better donor source than similarly aged siblings for patients over the age 60 years with AML or MDS. Four hundred ninety nine patients with AML or MDS age between 60 and 70 years who underwent alloHCT from an older MRD (donor age ≥50 years) or younger MUD (donor age ≤35 years) between 2010 and 2022 were evaluated. Of these, 360 (72%) patients received MUD and 139 (28%) received MRD grafts. The median recipient age was 64 and 66 years in the MRD and MUD groups, respectively. With median follow-up among survivors of 53 months (range 9, 147), 4-year PFS was 40% and 41% in the MRD and MUD groups, respectively (p=0.79). Four-year OS was 50% and 44% in the MRD and MUD group, respectively (p=0.15), with no differences in NRM, relapse, and acute or chronic GVHD. We also assessed effect of donor age in the MUD group between donor ages of 18-24 and 25-35 years; no differences in outcome were seen between the groups. We conclude that outcomes between older MRD and younger MUD for elderly patients with AML or MDS are comparable and there is no donor age effect among younger MUDs and the use of either donor is reasonable.

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.

Hematopoietic cell transplantation (HCT) in MDS patients of older age

Hematopoietic cell transplantation (HCT) has evolved to an essential treatment in younger and more recently in elderly patients with myelodysplastic syndrome (MDS), the age group with the highest incidence. Less intense conditioning regimens and improvements in supportive therapy have reduced considerably transplant related mortality and in the same time increased the access to this curative treatment. Timing of HCT in the course of the disease assumes a crucial role. Detection of disease progression, geriatric assessment, comorbidity evaluation, and identification of transplant-specific risks are becoming increasingly important in this context. Novel statistical methods, molecular biomarkers, and quantification of tumor burden pre- and post-HCT will play an essential role in years to come. More effective and less toxic treatments to reduce the tumor burden before and/or after HCT are expected to improve the outcome. In this review article we discuss the current views and what we can expect.

Comparison of Allogeneic Transplant Outcomes Between Matched Sibling Donors and Alternative Donors in Patients Over 50 Years of Age with Acute Myeloid Leukemia: 8/8 Allele-Matched Unrelated Donors and Unrelated Cord Blood Provide Better Leukemia-Free Survival Compared with Matched Sibling Donors During Nonremission Status

Acute myeloid leukemia (AML) is the most common indication for allogeneic hematopoietic cell transplantation (HCT). The increased availability of alternative donor sources has broadened donor types for older patients without HLA-matched sibling donors (MSD). It is uncertain if an MSD should be the first option for allogeneic HCT in patients with AML over 50 years of age. The objective of this study was to compare survival and other post-transplant outcomes between MSDs, 8/8 allele-matched unrelated donors (MUDs), 7/8 allele-MUDs, unrelated cord blood (UCB), and haploidentical donors for patients with AML over 50 years of age. We conducted a retrospective study to compare outcomes in 5704 patients with AML over 50 years of age and receiving allogeneic HCT between 2013 and 2021, using either MSD, 8/8 allele-MUD, 7/8 allele-MUD, UCB, or haploidentical donors in Japan. Complete remission (CR) and nonremission at HCT were analyzed separately for all analyses. In total, 3041 patients were CR, and 2663 patients were nonremission at the time of HCT. In multivariate analysis, donor type did not determine overall survival, irrespective of disease status at HCT. Leukemia-free survival (LFS) was significantly better for 8/8 allele-MUD (hazard ratio [HR], 0.77; 95% confidence interval [CI], 0.64 to 0.93; P = .005) and UCB (HR, 0.76; 95% CI, 0.65 to 0.88; P < .001), but not for 7/8 allele-MUD (HR, 0.97; 95% CI, 0.79 to 1.19; P = .794), and haploidentical donor (HR, 0.86; 95% CI, 0.70 to 1.05; P = .146) compared to the MSD group in nonremission status. However, donor type did not determine LFS among CR status. Relapse rates were significantly lower for 8/8 allele-MUD and UCB, whereas nonrelapse mortality was higher for UCB compared to the MSD group among both CR and nonremission status. Our registry-based study demonstrated that MSDs do not lead to superior survival compared to alternative donors for patients with AML over 50 years of age. Furthermore, 8/8 allele-MUDs and UCB provide better LFS compared with MSDs during nonremission status. Therefore, MSD is not necessarily the best donor option for allogeneic HCT in this population.

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.

Effect of donor age in patients with acute myeloid leukemia undergoing haploidentical hematopoietic cell transplantation vary by conditioning intensity and recipient age

We investigated the impact of donor age (younger [≤35 years] vs. older [>35 years]) after accounting for other non-HLA and HLA factors on outcomes of patients with acute myeloid leukemia undergoing HLA-haploidentical hematopoietic cell transplantation (n = 790). The effect differed by conditioning-partly related to the differences in the recipient age in myeloablative (MAC; median 46 years) versus reduced-intensity/non-myeloablative conditioning (RIC/NMA; median 61 years) groups. With MAC (n = 320), donor age had no impact on acute graft-versus-host disease (GVHD), but older donors were associated with a significantly higher risk of chronic GVHD (hazard ratio [HR]: 1.6, 95% confidence interval [CI]: 1.10-2.30, p = .02) independent of recipient age and other factors. Donor age had no impact on either relapse or non-relapse mortality (NRM). The impact of donor/recipient age on overall survival changed over time. Older donors were associated with significantly higher late overall mortality (>6 months) in younger recipients (≤ 50 years; HR: 2.2, 95% CI: 1.03-4.6, p = .04) but not older recipients. With RIC/NMA (n = 470), neither recipient's nor donor's age influenced the risk of GVHD. Donor age had no significant impact on the risk of relapse, but older donors were associated with a significantly higher risk of NRM (HR: 1.6, 95% CI: 1.02-2.6, p = .04) independent of recipient age. Older donor age was associated with significantly higher late overall mortality (>9 months) in older recipients (>50 years; HR: 1.66, 95% CI: 1.0-2.67; p = .049) but not in younger recipients. Donor selection based on donor age may require a tailored approach for a particular recipient.

Choosing Between Older Matched Sibling Donor and Younger Matched Unrelated Donor in Allogeneic Hematopoietic Cell Transplantation: Comparison of Clinical Outcomes in Acute Myeloid Leukemia and Myelodysplastic Syndrome

The choice between an older matched sibling donor (MSD) and a younger matched unrelated donor (MUD) in allogeneic hematopoietic cell transplantation (HCT) remains a subject of ongoing debate. In this single-center retrospective study of 377 patients who received peripheral blood stem cell (PBSC) transplants for acute myeloid leukemia (AML) or myelodysplastic syndrome (MDS), we compared outcomes of 85 patients who received grafts from MSDs age >60 years and 292 patients who received grafts from MUDs age <30 years. Compared to recipients of MSD transplants, recipients of MUD transplants were younger and more likely to receive dual T cell depletion (TCD), a higher CD34+ cell dose, and a fresh graft. Recipients of MSD transplants were maintained on immunosuppressive therapy longer than those who received MUD grafts. We found no differences in overall survival, relapse-free survival, graft-versus-host disease (GVHD)-free and relapse-free survival, nonrelapse mortality, relapse, engraftment, graft failure, and acute GVHD between recipients of MSD grafts and recipients of MUD grafts. We report a higher 30-day incidence, but not 1-year incidence, of bloodstream infections among recipients of MUD transplants compared to subjects who received their grafts from a MSD. The incidence of moderate-severe chronic GVHD was higher in MSD graft recipients compared with MUD graft recipients in univariate analysis, but not in multivariate analysis. Although this difference could reflect the greater use of dual TCD, known to be associated with very low rates of chronic GVHD in MUD transplant recipients, the incidence of moderate-severe chronic GVHD was no different between MSD and MUD transplant recipients following propensity score matching, suggesting that other variables could be responsible. Taken together, our data suggest that in patients with AML or MDS who receive PBSC transplants, such factors as convenience, ease of access, and costs should be considered when selecting an older MSD over a younger MUD.

[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.

The next horizon now that everyone has a donor: Precision allogeneic transplantation

Post-transplant cyclophosphamide (PTCy) allows safe and effective partially matched donor allogeneic blood or marrow transplantation (alloBMT), so that almost everyone in need of the procedure now has a donor. Moreover, PTCy and other recent advances have lowered alloBMT mortality rates to less than half of that seen before the turn of the century, at costs that are substantially less than most newly approved anticancer agents. These advances also make tailoring BMT based on patients' unique diseases and characteristics now feasible for further improving outcomes. Personalizing every aspect of alloBMT, including conditioning, donor, graft type, and post-transplant maintenance is now possible. For example, alloBMT's antitumor activity historically was restricted to the allogeneic graft-versus-tumor effect directed against histocompatibility antigens. However, replacing exhausted immune systems with healthy non-exhausted, non-tolerant ones likely can enhance the activity of novel targeted therapies. The impressive results seen with tyrosine kinase inhibitors after alloBMT for patients with both Ph+ acute lymphoblastic leukemia and FLT/ITD+ acute myeloid leukemia herald the potential of precision BMT.

Impact of Donor Age on Allogeneic Hematopoietic Cell Transplantation Outcomes in Older Adults with Acute Myeloid Leukemia

Allogeneic hematopoietic cell transplantation (alloHCT) provides cure for older patients with acute myeloid leukemia (AML); however, disease relapse remains a major concern. Based on recent data suggesting that younger donor age confers the greatest benefit for alloHCT with matched unrelated donors (MUDs), we attempted to answer a practical question: which donor type provides the best outcomes when an older patient with AML has a matched sibling donor (MSD, also older) versus the best MUD? This retrospective cohort registry study accessed data from the Center for International Blood and Marrow Transplant Research (CIBMTR) in patients with AML age ≥ 50 years undergoing alloHCT from older MSDs (age ≥ 50 years) or younger MUDs (age ≤ 35 years) between 2011 and 2018. The study included common allograft types, conditioning regimens, and graft-versus-host disease (GVHD) prophylaxis. The primary outcome was relapse risk. Secondary outcomes included nonrelapse mortality (NRM), GVHD, disease-free survival (DFS), and overall survival. Among 4684 eligible patients, 1736 underwent alloHCT with an older MSD (median donor age, 60 years), and 2948 underwent alloHCT from a younger MUD (median donor age, 25 years). In multivariable analysis, compared to older MSDs, the use of younger MUDs conferred a decreased relapse risk (hazard ratio [HR], .86; P = .005) and a significantly lower adjusted 5-year cumulative incidence of relapse (35% versus 41%; P = .003), but was associated with an increased risk for chronic GVHD (HR, 1.18; 95% confidence interval [CI], 1.08 to 1.29; P = .0002) and greater NRM only in the earlier period of 2011 to 2015 (HR, 1.24; P = .016). The corresponding NRM rates were significantly lower in the more recent period of 2016 to 2018 (HR, .78; P = .017). The adjusted 5-year DFS probability was 44% (95% CI, 42% to 46%) with an alloHCT from younger MUDs compared to 41% (95% CI, 38% to 43%) with older MSDs (P = .04). In summary, for older patients with AML undergoing alloHCT, the use of younger MUDs is associated with decreased relapse risk and improved DFS compared with the use of older MSDs.

Should a matched sibling donor still be considered the primary option for allogeneic hematopoietic cell transplantation in patients over 50 years of age with myelodysplastic syndrome?

Human leukocyte antigen (HLA)-matched sibling donors (MSDs) are the preferred choice for allogeneic hematopoietic cell transplantation (HCT). However, as myelodysplastic syndrome (MDS) is most frequently diagnosed in the elderly, MSDs are also likely to be of advanced age. It is unclear whether an MSD should be considered the primary choice for allogeneic HCT in elderly patients with MDS. We retrospectively compared survival and other outcomes in 1787 patients with MDS over 50 years of age and receiving allogeneic HCT between 2014 and 2020, using either MSD (n = 214), 8/8 allele-matched unrelated donor (MUD) (n = 562), 7/8 allele-MUD (n = 334), or unrelated cord blood (UCB) (n = 677) in Japan. In multivariate analysis, compared to MSD transplants, the risk of relapse was significantly lower following 8/8MUD transplants (hazard ratio [HR], 0.74; P = 0.047), whereas non-relapse mortality was significantly higher following UCB transplants (HR, 1.43; P = 0.041). However, donor type did not determine overall survival, disease-free survival, or graft-versus-host disease (GVHD)-free, relapse-free survival, but chronic GVHD-free, relapse-free survival was better after UCB (HR, 0.80; P = 0.025) and 8/8MUD (HR, 0.81; P = 0.032) compared to MSD transplants. Our study demonstrated that MSDs are not superior to alternative HCT methods, such as 8/8MUD, 7/8MUD, or UCB, in this population.

Impact of donor age and relationship on outcomes of peripheral blood haploidentical hematopoietic cell transplantation

Here we describe a retrospective analysis of outcomes in 299 patients who underwent peripheral blood haplo-HCT with PTCy from July 2009 through May 2021 and their association with donor characteristics. Patients had mostly acute leukemias and high or very high DRI. Multivariate analyses were conducted examining OS, NRM, relapse, cytokine release syndrome, acute and chronic GVHD. Donor characteristics included age, sex, relationship, ABO status, CMV status, and HLA match grade. Our analysis revealed increasing donor age was associated with higher NRM (compared to age <30; age 30-44 HR, 1.65; P = 0.110, age >44 HR, 1.80; P = 0.056) but lower relapse risk (compared to age <30; age 30-44 HR, 0.61; P = 0.034, age > 44 HR, 0.71; P = 0.132). There were no differences in CRS, aGVHD or cGVHD. We found no difference in outcomes based on the donor-recipient relationship. No differences were found based on HLA match grade or DRB1 match status. Increasing donor age was associated with lower relapse risk but higher NRM, resulting in no difference in OS based on donor age. Other donor factors including relationship (parent/sibling/child/ maternal), CMV status, donor sex, HLA match grade, and DRB1 status were not associated with outcomes.

Donor Selection for Allogeneic Hematopoietic Cell Transplantation

BACKGROUND

In Germany, each year over 3000 patients with malignant and non-malignant hematologic and systemic diseases are treated by allo - geneic hematopoietic cell transplantation (HCT). Genetic donor-recipient disparities, especially those concerning variable human leukocyte antigens (HLA), mediate both an immunotherapeutic effect and the risk of damage to healthy tissues ("graft-versus-host disease"). The adoption of evidencebased strategies for donor selection has been crucial for the continuous improvement of survival rates after allogeneic HCT, with over 50% of patients transplanted for standard indications-such as early-stage acute myeloid leukemia-alive at three years post-transplant.

METHODS

The PubMed database was selectively searched for literature on immunogenetic and clinical factors relevant to allogeneic HCT, as part of the process of establishing a German consensus statement on HCT donor selection.

RESULTS

The most important factor in donor selection is a match for the five major HLA loci (HLA-A, -B, -C, -DR, -DQ), either in genetically HLAidentical siblings or in unrelated but fully HLA-compatible donors from international registries. Additional selection criteria for the latter include com - patibility for the HLA-DP locus, donor age and sex, cytomegalovirus serostatus, and blood group. Related donors identical for only 50% of the HLA genes (haploidentical donors) as well as unrelated donors with a single HLA mismatch are both valid alternatives although they are associated with an up to 10% higher risk of mortality.

CONCLUSION

The refinement of donor selection strategies has been instrumental for the continuous improvement of patient survival rates after allogeneic HCT witnessed over the past decades. An interdisciplinary approach to donor selection based on up-to-date scientific evidence is crucial for optimizing patient outcomes.

Impact of Donor Age in Haploidentical-PTCy Versus MUD-PTCy HCT in AML patients

Haploidentical hematopoietic cell transplantation (HCT) with post-transplant cyclophosphamide (PTCy) graft-versus-host-disease (GVHD) prophylaxis is associated with inferior overall survival (OS) compared to HLA-matched unrelated donor (MUD) HCT with PTCy prophylaxis in patients undergoing reduced-intensity conditioning (RIC). Given prognostic implications of donor age, we investigated the differences in outcomes of patients with acute myeloid leukemia (AML, n=775) undergoing RIC-HCT with a younger MUD (donor age <35 years, n=84) versus younger haploidentical (donor age <35 years, n=302) versus an older haploidentical (≥35 years, n=389) donor. The older MUD group was excluded due to small numbers. Patients in the younger haploidentical group (median age 59.5 years) were somewhat younger than the younger MUD (median 66.8 years) and the older haploidentical (median 64.7 years) groups. More patients in the MUD group received peripheral blood grafts (82%) compared to the haploidentical groups (55-56%). In multivariate analysis, as compared to the younger MUD group, the younger haploidentical [hazard ratio (HR) 1.95, 95% confidence interval (CI) 1.22-3.12, p=0.005)] and the older haploidentical (HR 2.36, 95% CI 1.50-3.71, p<0.001) groups had a significantly inferior OS, and the younger haploidentical (HR 3.72, 95% CI 1.39-9.93, p=0.009) and older haploidentical group (HR 6.91, 95% CI 2.75-17.39, p<0.001) had a significantly higher risk of NRM. The older haploidentical group had a significantly higher risk of grade II-IV acute GVHD (HR 2.29, 95% CI 1.38-3.80, p=0.001) and grade III-IV acute GVHD (HR 2.70, 95% CI 1.09-6.71, p=0.03). There were no significant differences in chronic GVHD or relapse between the groups. Among adult AML patients in CR undergoing RIC-HCT with PTCy prophylaxis, a young MUD may be preferred over a younger haploidentical donor.

Human Leucocyte Antigen System and Selection of Unrelated Hematopoietic Stem Cell Donors: Impact of Patient-Donor (Mis)matching and New Challenges with the Current Technologies

The selection of hematopoietic stem cell donors for allogeneic transplantation (allo-HSCT) is mainly driven by human leucocyte antigen (HLA) matching between patient and donor, with HLA-identical matched siblings being the preferred choice in most situations. Although other clinical and demographical variables matter, especially, donor age, which is unequivocally associated with better transplant outcomes, the histocompatibility criteria have a central role in the search for the best donor, particularly in the setting of unrelated allo-HSCT where HLA disparities between patient and donor are frequent. The present review is focused on the role of HLA incompatibilities on patient outcome according to the most recent literature, in an attempt to guide transplant physicians and search coordinators during the process of adult unrelated-donor selection. The technological progresses in HLA typing, i.e., with next-generation sequencing (NGS), now allow disclosing a growing number of HLA incompatibilities associated with a heterogeneous and sometimes unknown spectrum of clinical severity. Their immunogenic characteristics, i.e., their position inside or outside the antigen recognition domain (ARD), their permissiveness, their intronic or exonic nature and even the expected expression of the HLA loci where those mismatches occur, will be presented and discussed here, integrating the advances in the immunobiology of transplantation with survival and toxicity outcomes reported in the most relevant studies, within the perspective of improving donor selection in the current practice.

Old age: the crown of life, our play's last act. Question and answers on older patients undergoing allogeneic hematopoietic cell transplantation

PURPOSE OF REVIEW

Several studies showed that age alone should not be used as an arbitrary parameter to exclude patients from allogeneic hematopoietic cell transplantation (HCT). The accessibility to allogeneic HCT programs for older patients with hematological diseases is growing up constantly. The Center for International Blood and Marrow Transplant Research has recently shown that over 30% of allogeneic HCT recipients are at least 60 years old and that nearly 4% are aged 70 or more. Historically, the use of allogeneic HCT among elderly patients has been limited by age restrictions, reflecting physicians' concerns regarding prohibitive transplant-related mortality and HCT-associated morbidity.

RECENT FINDINGS

The introduction of reduced intensity/toxicity conditioning regimens has allowed transplant Centers to carry out allogeneic HCT on patients previously considered not ideal candidates. The integration of specific risk scores could lead to better capture mental and physical frailties of older patients. Older adults less frequently have available medically fit siblings, able to donate, so, unrelated donors, familial haploidentical donors or umbilical cord blood grafts could potentially abrogate such a difficulty, allowing the curative potential of allogeneic HCT.

SUMMARY

The appropriate assessing of allogeneic HCT feasibility for elderly patients should be the resonate application of different clinical and biological principles.

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.

Donor Age and Non-Relapse Mortality: Study of Their Association after HLA-Matched Allogeneic Hematopoietic Cell Transplantation for Acute Myeloid Leukemia and Myelodysplastic Syndrome

The purpose of this retrospective study was to study the correlation between donor age (DA) and non-relapse mortality (NRM) and relapse incidence (RI) among patients treated with allogeneic hematopoietic cell transplantation (aHCT) for acute myeloid leukemia (AML) or myelodysplastic syndrome (MDS) in a single Canadian center. Data from 125 consecutive patients transplanted with a matched related or unrelated donor between 2015 and 2020 were analyzed using multivariable models. After a median follow-up of 2.8 years, the cumulative incidences of NRM and relapse were 19% and 35% at 5 years. Despite being independently associated with NRM and relapse-free survival (RFS), DA was not associated with RI. The independent determinants of NRM in addition to DA were patient age and hematopoietic cell transplantation comorbidity index (HCT-CI), independently of donor kinship. The effect of DA on NRM was found to be significantly increased over the age of 50 years. DA was not associated with incidence of acute graft-versus-host disease (aGVHD) but showed an association with the occurrence of chronic GVHD (cGVHD). In conclusion, younger donors should be favored to limit NRM and increase RFS in HLA-matched aHCT. The etiological mechanisms behind the association of DA with higher NRM remain to be elucidated.

Suitability of haematopoietic cell donors: updated consensus recommendations from the WBMT standing committee on donor issues

The contribution of related donors to the globally rising number of allogeneic haematopoietic stem cell transplantations (HSCT) remains increasingly important, particularly because of the growing use of haploidentical HSCT. Compared with the strict recommendations on the suitability for unrelated donors, criteria for related donors allow for more discretion and vary between centres. In 2015, the donor outcome committee of the Worldwide Network for Blood and Marrow Transplantation (WBMT) proposed consensus recommendations of suitability criteria for paediatric and adult related donors. This Review provides updates and additions to these recommendations from a panel of experts with global representation, including the WBMT, the European Society for Blood and Marrow Transplantation donor outcome committee, the Center for International Blood and Marrow Transplant Research donor health and safety committee, the US National Marrow Donor Program, and the World Marrow Donor Association, after review of the current literature and guidelines. Sections on the suitability of related donors who would not qualify as unrelated donors have been updated. Sections on communicable diseases, clonal haematopoiesis of indeterminate potential, paediatric aspects including psychological issues, and reporting on serious adverse events have been added. The intention of this Review is to support decision making, with the goal of minimising the medical risk to the donor and protecting the recipient from transmissible diseases.

Relapse and Disease-Free Survival in Patients With Myelodysplastic Syndrome Undergoing Allogeneic Hematopoietic Cell Transplantation Using Older Matched Sibling Donors vs Younger Matched Unrelated Donors

IMPORTANCE

Matched sibling donors (MSDs) are preferred for allogeneic hematopoietic cell transplantation (allo-HCT) in myelodysplastic syndrome even if they are older. However, whether older MSDs or younger human leukocyte antigen-matched unrelated donors (MUDs) are associated with better outcomes remains unclear.

OBJECTIVE

To investigate whether allo-HCT for myelodysplastic syndrome using younger MUDs would be associated with improved disease-free survival and less relapse compared with older MSDs.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective cohort study assessed data reported to the Center for International Blood and Marrow Transplant Research database from 1761 adults 50 years or older with myelodysplastic syndrome who underwent allo-HCT using an older MSD or younger MUD between January 1, 2011, and December 31, 2017, with a median follow-up of 48 months. Data analysis was performed from January 8, 2019, to December 30, 2020.

INTERVENTIONS/EXPOSURES

Allo-HCT from an older MSD (donor age ≥50 years) or a younger MUD (donor age ≤35 years).

MAIN OUTCOMES AND MEASURES

The primary outcome was disease-free survival. Secondary outcomes were overall survival, relapse, nonrelapse mortality, acute graft-vs-host disease (GVHD), chronic GVHD, and GVHD-free relapse-free survival.

RESULTS

Of 1761 patients (1162 [66%] male; median [range] age, 64.9 [50.2-77.6] years in the MSD cohort and 66.5 [50.4-80.9] years in MUD cohort), 646 underwent allo-HCT with an older MSD and 1115 with a younger MUD. In multivariable analysis, the rate of disease-free survival was significantly lower in allo-HCTs with older MSDs compared with younger MUDs (hazard ratio [HR], 1.17; 95% CI, 1.02-1.34; P = .02), whereas the difference in overall survival rate of allo-HCT with younger MUDs vs older MSDs was not statistically significant (HR, 1.13; 95% CI, 0.98-1.29; P = .07). Allo-HCT with older MSDs was associated with significantly higher relapse (HR, 1.62; 95% CI, 1.32-1.97; P < .001), lower nonrelapse mortality (HR, 0.76; 95% CI, 0.59-0.96; P = .02), lower acute GVHD (HR, 0.52; 95% CI, 0.42-0.65; P < .001), chronic GVHD (HR, 0.77; 95% CI, 0.64-0.92; P = .005), and a lower rate of GVHD-free relapse-free survival beyond 12 months after allo-HCT (HR, 1.42; 95% CI, 1.02-1.98; P = .04).

CONCLUSIONS AND RELEVANCE

This cohort study found higher disease-free survival and lower relapse for allo-HCT in myelodysplastic syndrome using younger MUDs compared with older MSDs. The risk of nonrelapse mortality and GVHD was lower with older MSDs. These results suggest that the use of younger MUDs should be considered in the donor selection algorithm for myelodysplastic syndrome, in which it is pivotal to minimize relapse given limited treatment options for managing relapsed disease.

Targeting miR-126 disrupts maintenance of myelodysplastic syndrome stem and progenitor cells

BACKGROUND

Myelodysplastic syndrome (MDS) arises from a rare population of aberrant hematopoietic stem and progenitor cells (HSPCs). These cells are relatively quiescent and therefore treatment resistant. Understanding mechanisms underlying their maintenance is critical for effective MDS treatment.

METHODS

We evaluated microRNA-126 (miR-126) levels in MDS patients' sample and in a NUP98-HOXD13 (NHD13) murine MDS model along with their normal controls and defined its role in MDS HSPCs' maintenance by inhibiting miR-126 expression in vitro and in vivo. Identification of miR-126 effectors was conducted using biotinylated miR-126 pulldown coupled with transcriptome analysis. We also tested the therapeutic activity of our anti-miR-126 oligodeoxynucleotide (miRisten) in human MDS xenografts and murine MDS models.

RESULTS

miR-126 levels were higher in bone marrow mononuclear cells from MDS patients and NHD13 mice relative to their respective normal controls (P < 0.001). Genetic deletion of miR-126 in NHD13 mice decreased quiescence and self-renewal capacity of MDS HSPCs, and alleviated MDS symptoms of NHD13 mice. Ex vivo exposure to miRisten increased cell cycling, reduced colony-forming capacity, and enhanced apoptosis in human MDS HSPCs, but spared normal human HSPCs. In vivo miRisten administration partially reversed pancytopenia in NHD13 mice and blocked the leukemic transformation (combination group vs DAC group, P < 0.0001). Mechanistically, we identified the non-coding RNA PTTG3P as a novel miR-126 target. Lower PTTG3P levels were associated with a shorter overall survival in MDS patients.

CONCLUSIONS

MiR-126 plays crucial roles in MDS HSPC maintenance. Therapeutic targeting of miR-126 is a potentially novel approach in MDS.

Impact of allogeneic stem cell transplantation comorbidity indexes after haplotransplant using post-transplant cyclophosphamide

Background

Three different scoring systems have been developed to assess pre‐transplant comorbidity in allogeneic hematopoietic stem cell transplantation (Allo‐HSCT): the Hematopoietic Cell Transplantation‐Specific Comorbidity Index, the Comorbidity/Age index, and the Augmented Comorbidity/Age index. All were devised to predict overall survival (OS) and disease‐free survival (DFS) survivals and non‐relapse mortality (NRM) in patients receiving HLA‐matched Allo‐HSCT, but their performance has scarcely been studied in the haploidentical Allo‐HSCT setting with post‐transplant cyclophosphamide, a procedure in constant expansion worldwide.

Methods

To address this issue, their impact on survivals and NRM was examined in a cohort of 223 patients treated with haploidentical Allo‐HSCT in four different centers.

Results

With a median follow‐up of 35.6 months, 3‐year OS, DFS, and NRM were 48.1% ± 4%, 46.3% ± 4%, and 30.0% ± 3%, respectively. No impact was found for any of the three comorbidity scores in univariate analysis. In multivariate analyses, the only three factors associated with lower OS were DRI (p < 0.001), an older age of recipients (≥55 years old, p = 0.02) and of donors (≥40 years old, p = 0.005). Older donor age was also associated with lower DFS and higher NRM.

Conclusion

The comorbidity scores do not predict survivals nor NRM in haploidentical Allo‐HSCT with PTCY, suggesting that pre‐transplant comorbidities should not be a contra‐indication to this procedure.

Risk factors for outcome after allogeneic stem cell transplantation in patients with advanced phase CML

Allogeneic hematopoietic stem-cell transplantation (HSCT) remains the only curative option for patients with advanced chronic myeloid leukemia (CML). However, outcome is dismal and of short follow-up. The objective of the study was to determine long-term outcome and risk factors in patients with a history of CML Blast Crisis (BC; n = 96) or accelerated phase (n = 51) transplanted between 1990 and 2018. At transplant, patients had a median age of 39 (range 7–76) years and were in ≥CP2 (n = 70), in AP (n = 40) or in BC (n = 37) with a diagnosis-HSCT interval of median 1.9 (range 0.3–24.4) years. Overall survival (OS) amounted 34% (95% CI 22–46) and progression-free survival (PFS) 26% (95% CI 16-36) at 15 years. Adverse risk factors for OS and PFS were low CD34⁺ count in the graft, donor age (>36 years) and BC. Cumulative incidence of Non-Relapse Mortality (NRM) was 28% (95% CI 18–38) and of relapse (RI) 43% (95% CI 33–53) at 15 years. PB-HSCT and HSCT after 2008 were favorable prognostic factors for NRM, while family donor and patient age >39 years were independently associated with higher RI. HSCT resulted in long-term OS in patients with advanced CML. OS was improved in non-BC patients, with donors ≤36 years and with higher CD34⁺ dose in the graft.

Relationship of donor age and relationship to outcomes of haploidentical transplantation with posttransplant cyclophosphamide

Allogeneic blood or marrow transplantation (BMT) physicians seek to optimize all possible variables to improve outcomes. Selectable factors include conditioning, graft-versus-host disease (GVHD) prophylaxis, graft source, and donor. Many patients, especially those with eligible haploidentical (haplo) donors, will have multiple donor options. We seek to identify factors to optimize the choice of haplo donors when using posttransplantation cyclophosphamide (PTCy) GVHD prophylaxis. We evaluated the effect of modifiable donor characteristics (donor age and relationship) on outcomes following haplo BMT with a uniform nonmyeloablative conditioning and PTCy. From 2002 to 2017, 889 consecutive adult patients underwent nonmyeloablative haplo BMT with PTCy. Median follow-up among survivors was 2.5 years after BMT. Median recipient age was 59 (range: 18 to 76) years and median donor age was 40 (range: 13 to 79) years. Multivariable analyses demonstrated that increasing donor age by decade was associated with poorer overall survival (hazard ratio [HR], 1.13 [1.05, 1.22; P = .0015]), worse progression-free survival (HR, 1.09 [1.02, 1.16; P = .015]), and a higher risk for grade 2 to 4 and grade 3 to 4 GVHD (1.3 [1.06, 1.61; P = .013]), but not for chronic GVHD (HR, 1.06 [0.94, 1.2]; P = .37). These less-favorable results with older donors were attributable to worse nonrelapse mortality (HR, 1.19 [1.05, 1.34]; P = .006), not relapse. Parents were associated with inferior outcomes compared with sibling donors, whereas no significant differences were observed between parental donors. These data suggest that the youngest, adult-sized donors should be preferred when multiple haplo donors are available.

Impact of the combination of donor age and HLA disparity on the outcomes of unrelated bone marrow transplantation

Impact of donor age considering HLA disparity on hematopoietic cell transplantation (HCT) outcomes has not been fully evaluated. We evaluated 8486 patients who received unrelated bone marrow transplantation (UR-BMT) from 8/8 or 7/8 HLA-matched donors. Compared to 8/8 HLA-matched younger donors (<40 years), 8/8 HLA-matched older donors (subdistribution hazard ratio [SHR], 1.16; 95% CI, 0.97-1.38) and 7/8 HLA-matched younger donors (SHR, 1.33; 95% CI, 1.11-1.58) were associated with increased risk of grade III-IV acute graft-versus-host disease (aGVHD). 7/8 HLA-matched older donors had further increased risk (SHR, 2.00; 95% CI, 1.68-2.38) due to interaction between donor age and HLA disparity (p for interaction = 0.038). Progression-free survival (PFS) after UR-BMT with 8/8 HLA-matched younger donors was comparable to that after UR-BMT with 8/8 HLA-matched older donors, whereas UR-BMT with 7/8 HLA-matched younger or older donors was significantly associated with lower PFS than UR-BMT with 8/8 HLA-matched younger donors (younger donor; HR, 1.12; 95% CI, 1.04-1.21, older donor; HR, 1.28; 95% CI, 1.17-1.40; p for interaction = 0.079). In conclusion, adverse effect of increased donor age requires attention, especially in HLA-mismatched UR-BMT due to interaction between donor age and HLA disparity. Intensive aGVHD prophylaxis may be required to improve outcomes after HCT with mismatched older donors.

Short Dysfunctional Telomere Is Highly Predictive of Dismal Outcome in MDS but Not in AML Patients

Background: A trigger for initiation the clonal hematopoietic stem cells disorders could be short telomere length probably due to chromosomal instability. The relationship between relative telomere length (RTL) and the two linked hematological stem cell disorders, myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML) is still unclear.

Materials and Methods: We evaluated the role of RTL in MDS (n=96) and AML (n=130) at the time of diagnosis using a real time quantitative polymerase chain reaction (RT-PCR) technique. The median value of RTL (1) was set as the cutoff for statistical comparison. Overall survival (OS) is defined as the time from diagnosis to death or last follow-up.

Results: RTL was significantly longer in both MDS and AML cases versus control (p<0.0001) and was significantly longer in MDS versus AML cases (p =0.03). RTL correlated negatively with age in MDS (p <0.0001) but not in AML cases. RTL was also significantly shorter in MDS cases with pancytopenia and poor risk cytogenetics (p < 0.0001 for each) and short RTL was significantly associated with inferior survival (p = 0.007), while RTL showed no significant impact on OS in AML cases. Moreover, short RTL retained independent prognostic value in multivariate analysis (HR= 3.42 [95% CI, 8.97-19.35], p = 0.004).

Conclusion: RTL showed an association with both AML and MDS; however, short RTL was an independent poor prognostic factor in MDS patients only.

Impact of donor and recipient characteristics on graft-versus-host disease and survival in HLA-matched sibling hematopoietic stem cell transplantation

OBJECTIVE

To analyze the impact of donor- and recipient-related factors on Graft-versus-host disease (GVHD) and overall survival of transplantation from matched sibling donors.

METHOD

we retrospectively analyzed the clinical features of 68 consecutive hematological patients undergoing allogeneic hematopoietic stem cell transplantation (allo-HSCT) from matched sibling from 2011 and 2017.

RESULTS

The incidence of Ⅱ- Ⅳacute GVHD (aGVHD) and chronic GVHD (cGVHD) after transplantation was 13.6 % and 19.7 %, respectively. We also noted the donor and recipient characteristics had no impact on Ⅱ- Ⅳ aGVHD incidence.We found sex mismatch (F-M) did not increase the risk of cGVHD in the model if a female donor was younger than 30 years (P = 1.000), but cGVHD increased if the female donor was ≥30 years (P = 0.002). Recipients≥40 years undergoing HCT from donors ≥30 years were at higher risk for cGVHD (P = 0.021). Development of Ⅱ- Ⅳ aGVHD and cGVHD had no effect on overall survival (P = 0.159, 0.081). Non-remission status at allo-HCT was linked to lower overall survival (P = 0.001).

CONCLUSION

The incidence of cGVHD was higher when male recipients received hematopoietic progenitor cells from female ≥30 years donors, and when older than 40 years recipients received hematopoietic progenitor cells from ≥30 years donors. Patients in non-remission status at allo-HCT was inclined to have lower overall survival.

Myelodysplastic Syndromes: How to Recognize Risk and Avoid Acute Myeloid Leukemia Transformation

PURPOSE OF REVIEW

To understand how myelodysplastic syndromes (MDS) transform to AML and to describe how transformation can be predicted and prevented.

RECENT FINDINGS

Recent genomic analyses have shown that MDS progression to AML is associated with clonal expansion and clonal evolution. Mutation profiles of MDS change during progression and new mutations in signaling genes and transcription factors emerge. AML transformation can be predicted by several parameters including International Prognostic Scoring System IPSS risk category and transfusion requirements. The prognostic relevance of the acquisition of some gene mutations (i.e., IDH1 and 2, CBL, FT3, RAS, NPM1, TP53, and ASXL1) has to be prospectively validated. The most effective preventive therapy for AML transformation is allogeneic stem cell transplantation. Hypomethylating agents have been associated with prolonged time to AML transformation even in patients who did not achieve an objective response. The recent progress in the understanding of the molecular events leading to transformation and the event of new effective therapies open new avenues for a better prediction and prevention of AML transformation in patients with MDS.

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.

Outcomes of Related and Unrelated Donor Searches Among Patients with Primary Immunodeficiency Diseases Referred for Allogeneic Hematopoietic Cell Transplantation

Patients with primary immunodeficiencies (PIDs) are potentially cured by allogeneic hematopoietic cell transplantation (HCT). The spectrum of PIDs has expanded greatly beyond those that present in infancy or are diagnosed on newborn screening and require urgent, preemptive HCT. Many PID diagnoses are now made later in life, and the role of HCT is only considered for severe disease manifestations; in these cases, the kinetics and goals of a donor search may be different than for severe combined immunodeficiency. Across all PIDs, related donor searches have the additional selection factor of the inherited disease, and such searches may yield more limited options than searches for patients with hematologic malignancies; thus, unrelated donor options often become more critical in these patients. We retrospectively evaluated the outcomes of donor searches among patents with PIDs referred for HCT at the National Institutes of Health, where the minimum patient age for evaluation is 3 years and where donor options include matched sibling donors or matched related donors, HLA-haploidentical (haplo), or 7-8/8 HLA matched unrelated donors (mMUDs/MUDs). Patient (n = 161) and donor demographics, MUD search results, HLA typing, pedigrees, mutation testing, and donor selection data were collected. The National Marrow Donor Program HapLogic 8/8 HLA match algorithm was used to predict the likelihood of a successful MUD search and categorized as very good, good, fair, poor, very poor, or futile per the Memorial Sloan Kettering Cancer Center (MSKCC) Search Prognosis method. There were significant differences by PID mode of inheritance in patient age, disposition (receipt of HCT or not), donor source, and donor relatedness. A related or unrelated donor option could be identified for 94% of patients. Of living first-degree relatives (median, 3; range, 0 to 12 per patient), a median of 1 donor remained for autosomal dominant and X-linked (XL) diseases after HLA typing, mutation testing, and other exclusions, and a median of 2 donors remained for autosomal recessive (AR) diseases. Among patients with a PID of known mode of inheritance (n = 142), the best related donor was haplo for 99 (70%) patients, with 56 (39%) haplos age 40 years or older and 5 (4%) second-degree haplos; 13 (9%) had no family donor options. The best related donor was a heterozygote/asymptomatic carrier of the PID mutation in 36 (49%) patients with AR or XL disease (n = 73). Among patients with MUD search performed (n = 139), 53 (38%) had very poor/futile 8/8 MUD searches, including 6 (32%) of those with unknown PID mutation and therefore no family donor options. The MSKCC Search Prognosis was less favorable for those of non-European ancestry compared with European ancestry (P = .002). Most patients of Hispanic or African ancestry had very poor/futile MUD searches, 71% and 63%, respectively. No HCT recipients with very poor/futile MUD searches (n = 38) received 8/8 MUD grafts. Alternative donor options, including haplo and unrelated donors, are critical to enable HCT for patients with PIDs. MUD search success remains low for those of non-European ancestry, and this is of particular concern for patients with PIDs caused by an unknown genetic defect. Among patients with PIDs, related donor options are reduced and haplos age 40 years and older and/or mutation carriers are often the best family option.

Advances in chronic myelomonocytic leukemia and future prospects: Lessons learned from precision genomics

In the latest World Health Organization classification of myeloid neoplasms, chronic myelomonocytic leukemia (CMML) exists as a separate entity under the category of myelodysplastic/myeloproliferative (MDS/MPN) overlap syndromes. Outcomes remain uniformly poor with a median overall survival of ~2 years and an inherent risk of transformation into acute myeloid leukemia (15-20% over 5 years). Due to unique biologic characteristics such as overlapping features of myelodysplasia and myeloproliferation, and clinical diversity despite relative genomic homogeneity, CMML represents a unique model to study chronic myeloid tumor biology. Recent advances have focused on understanding the role of putative genomic abnormalities, in particular, clonal evolution of pathogenic alterations in genes regulating the epigenome (TET2), chromatin architecture (ASXL1), spliceosome complex (SRSF2, SF3B1) and cell signaling (NRAS, KRAS, CBL, JAK2). Disease prognostication has evolved from purely clinical prognostic models to those incorporating pathogenic gene variations. Therapeutic options in this disease remain dismal with only two agents approved by the United States Food and Drug Administration, namely 5-azacitidine and decitabine. Allogeneic hematopoietic stem cell transplantation remains the sole curative option in this disease; however is associated with substantial treatment-related morbidity and mortality. Future areas of research include opportunities to further improve disease prognostication by employing novel technologies such as machine learning, incorporation of methylation and cytokine signatures, in addition to gene mutations; insights into clonal origins of this disease, and novel therapeutic strategies.

Leveraging JAK-STAT regulation in myelofibrosis to improve outcomes with allogeneic hematopoietic stem-cell transplant

Primary myelofibrosis (PMF) is a disease characterized by bone marrow fibrosis, extramedullary hematopoiesis, risk of transformation to acute myeloid leukemia, and a substantial symptom burden with diminished quality of life. Allogeneic hematopoietic cell transplantation (HCT) is the only curative option; however, disease relapse and graft versus host disease (GVHD) are significant barriers to long-term survival. The discovery of the JAK2 V617F mutation, and subsequent development of JAK inhibitors, resulted in improved survival and significant improvements in spleen volumes and symptom scores. Though the effect of JAK inhibition on transplant outcome is poorly understood, using JAK inhibition to achieve maximal response prior to HCT is standard practice at major centers. After allogeneic HCT, a significant proportion of patients with steroid-refractory GVHD have clinical responses to JAK inhibition. Targeting this pathway is a key component in the management of patients with PMF before and after allogeneic HCT.

Melphalan-Based Reduced-Intensity Conditioning is Associated with Favorable Disease Control and Acceptable Toxicities in Patients Older Than 70 with Hematologic Malignancies Undergoing Allogeneic Hematopoietic Stem Cell Transplantation

Allogeneic hematopoietic stem cell transplantation (alloHCT) is offered increasingly to elderly patients with hematologic malignancies. However, outcome data in those who are 70 years or older are limited, and no standard conditioning regimen has been established for this population. In this retrospective study we evaluated the outcome of 53 consecutive patients aged 70 years and older who underwent alloHCT with melphalan-based reduced-intensity conditioning (RIC) at City of Hope. Engraftment was prompt, with median time to neutrophil engraftment of 15 days. More than 95% of patients achieved complete donor chimerism within 6 weeks from HCT, consistent with the "semiablative" nature of this regimen. With a median follow-up of 31.1 months, the 2-year overall survival (OS), progression-free survival (PFS), and nonrelapse mortality (NRM) were 68.9%, 63.8%, and 17.0%, respectively. Cumulative incidence of relapse at 1 and 2 years was 17.0% and 19.3%, respectively. One hundred-day cumulative incidence of grades II to IV acute graft-versus-host disease was 37.7% (grades III to IV, 18.9%), and 2-year cumulative incidence of chronic graft-versus-host disease was 61.9% (extensive, 45.9%). The only significant predictor for poor OS was high/very high disease risk index. Transplant-related complications and morbidities observed here did not differ from the commonly expected in younger patients treated with RIC. In conclusion, alloHCT with a melphalan-based conditioning regimen is associated with acceptable toxicities and NRM, lower incidence of relapse, and favorable OS and PFS in patients aged 70 years or older.

Development of an Unrelated Donor Selection Score Predictive of Survival after HCT: Donor Age Matters Most

Donor factors, in addition to HLA matching status, have been associated with recipient survival in unrelated donor (URD) hematopoietic cell transplantation (HCT); however, there is no hierarchical algorithm that weights the characteristics of individual donors against each other in a quantitative manner to facilitate donor selection. The goal of this study was to develop and validate a donor selection score that prioritizes donor characteristics associated with better survival in 8/8 HLA-matched URDs. Two separate patient/donor cohorts, the first receiving HCT between 1999 and 2011 (n = 5952, c1), and the second between 2012 and 2014 (n = 4510, c2) were included in the analysis. Both cohorts were randomly spilt, 2:1, into training and testing sets. Despite studying over 10,000 URD transplants, we were unable to validate a donor selection score. The only donor characteristic associated with better survival was younger age, with 2-year survival being 3% better when a donor 10 years younger is selected. These results support previous studies suggesting prioritization of a younger 8/8 HLA-matched donor. This large dataset also shows that none of the other donor clinical factors tested were reproducibly associated with survival, and hence flexibility in selecting URDs based on other characteristics is justified. These data support a simplified URD selection process and have significant implications for URD registries.

Donor age determines outcome in acute leukemia patients over 40 undergoing haploidentical hematopoietic cell transplantation

Haploidentical hematopoietic cell transplantation (haplo-HCT) is being increasingly used in acute leukemia patients as an alternative transplant modality when matched sibling or matched unrelated donors are unavailable. As several potential haploidentical relative donors are typically available for a given patient, optimizing donor selection to improve clinical outcome is crucial. The impact of donor age and kinship on the outcome of acute leukemia patients is not clearly established in this setting. Using the multinational registry of the acute leukemia working party of the European society for blood and marrow transplantation we retrospective analyzed the clinical outcome of 1270 acute myeloid leukemia and acute lymphoblastic leukemia patients who underwent haplo-HCT between 2005 and 2015. Patients over the age of 40 were significantly affected by increasing donor age resulting in higher non-relapse mortality (NRM) [Hazard ratio (HR)=1.86, confidence interval (CI) 95%, 1.18-2.94; P = .007], inferior leukemia-free survival (LFS) (HR = 1.59, CI 95%, 1.13-2.24; P = .007), and overall survival (OS) (HR = 1.74, CI 95%, 1.22-2.47; P = .002) when donors were over the age of 40. Additionally, kinship was found to be prognostically significant as patients transplanted from children donors over the age of 35 experienced an increased rate of NRM (HR = 1.82, CI 95%, 1.13-2.9; P = .01), inferior LFS (HR = 1.5, CI 95%, 1.05-2.13; P = .03), and OS (HR = 1.5, CI 95%, 1.04-2.15; P = .03). For patients younger than 40 years, donor age and kinship were mostly not clinically impactful. Our data establish donor age and kinship as significant determinants of outcome following haplo-HCT for acute leukemia patients.

Selecting the Best Donor for Haploidentical Transplant: Impact of HLA, Killer Cell Immunoglobulin-Like Receptor Genotyping, and Other Clinical Variables

The use of post-transplant cyclophosphamide (PTCy)-based haploidentical (haplo) transplant is increasing worldwide. However, because multiple potential haplo donors are usually available, data-driven guidance is clearly needed to help transplant centers prioritize donors. To that end, we retrospectively analyzed 208 consecutive donor-recipient pairs receiving PTCy-based haplo transplant at a single institution. Median recipient and donor age were 52 years (range, 19 to 75) and 38 years (range, 15 to 73), peripheral blood stem cell was the stem cell source in 66%, and myeloablative conditioning was used in 41%. Median follow-up for surviving patients was 33 months (range, 7 to 130). Donor variables analyzed included age, sex, relationship, cytomegalovirus (CMV) status, ABO compatibility, HLA disparity, and several natural killer (NK) alloreactivity models. Multivariate Cox analysis was used to adjust for known patient, disease, and transplant covariates. Donor characteristics independently associated with improved survival included presence of HLA-DR mismatch, HLA-DP nonpermissive mismatch, killer cell immunoglobulin-like receptor (KIR) receptor-ligand mismatch, and KIR B/x haplotype with KIR2DS2. Donor characteristics associated with inferior survival included parental donor relationship and the use of a CMV-seronegative donor for a CMV-seropositive patient. Increased HLA disparity (≥4/10 HLA allelic mismatches [graft-versus-host direction]) resulted in relapse protection at the expense of increased nonrelapse mortality with no associated survival effect. We further propose a donor risk factor scoring system to permit a more evidence-based selection algorithm for potential haplo donors. This large, single-institution analysis demonstrates the importance of HLA-DR/HLA-DP disparity, NK alloreactivity, and other clinical variables in the haplo donor selection process and suggests that KIR and HLA-DP genotyping should be performed routinely for haplo donor selection.

Allogeneic stem cell transplantation benefits for patients ≥ 60 years with acute myeloid leukemia and FLT3 internal tandem duplication: a study from the Acute Leukemia Working Party of the European Society for Blood and Marrow Transplantation

Intermediate-risk cytogenetic acute myeloid leukemia with an internal tandem duplication of FLT3 (FLT3-ITD) is associated with a high risk of relapse, and is now a standard indication for allogeneic stem cell transplantation. Nevertheless, most studies supporting this strategy have been performed in young patients. To address the benefit of allogeneic transplantation in the elderly, we made a selection from the European Society for Blood and Marrow Transplantation registry of de novo intermediate-risk cytogenetic acute myeloid leukemia harboring FLT3-ITD in patients aged 60 or over and transplanted from a related or unrelated donor between January 2000 and December 2015. Two hundred and ninety-one patients were identified. Most patients received a reduced-intensity conditioning (82%), while donors consisted of an unrelated donor in 161 (55%) patients. Two hundred and twelve patients received their transplantation in first remission, 37 in second remission and 42 in a more advanced stage of the disease. The 2-year leukemia-free survival rate was 56% in patients in first remission, 22% in those in second remission and 10% in patients with active disease, respectively (P<0.005). Non-relapse mortality for the entire cohort was 20%. In multivariate analysis, disease status at transplantation was the most powerful predictor of worse leukemia-free survival, graft-versus-host disease and relapse-free survival, and overall survival. In this elderly population, age was not associated with outcome. Based on the current results, allogeneic transplantation translates into a favorable outcome in fit patients ≥ 60 with FLT3-ITD acute myeloid leukemia in first remission, similarly to current treatment recommendations for younger patients.

T Cell Depletion as an Alternative Approach for Patients 55 Years or Older Undergoing Allogeneic Stem Cell Transplantation as Curative Therapy for Hematologic Malignancies

T cell-depleted (TCD) allogeneic hematopoietic stem cell transplantation (HSCT) is curative treatment for hematologic malignancies in adults, shown to reduce graft-versus-host disease (GVHD) without increased relapse. We retrospectively reviewed a single-center, 11-year experience of 214 patients aged ≥ 55 years to determine tolerability and efficacy in the older adult. Most patients (70%) had myeloid diseases, and most acute leukemias were in remission. Median age was 61 years, with related and unrelated donors ≥8/10 HLA matched. Hematopoietic cell transplantation-specific comorbidity index scores were intermediate and high for 84%. Conditioning regimens were all myeloablative. Grafts were peripheral blood stem cells (97%) containing CD3 dose ≤103-4/kg body weight, without pharmacologic GVHD prophylaxis. With median follow-up of 70 months among survivors, Kaplan-Meier estimates of overall and relapse-free survival were 44% and 41%, respectively (4 years). Cumulative incidence of nonrelapse mortality at day +100 was only 10%. Incidence of GVHD for acute (grades II to IV) was 9% at day +100 and for chronic was 7% at 2 and 4 years (8 extensive, 1 overlap). Median Karnofsky performance status for patients > 2 years post-transplant was 90%. As 1 of the largest reports for patients ≥2 aged ≥55 years receiving TCD HSCTs, it demonstrates curative therapy with minimal GVHD, similar to that observed in a younger population.

Donor and recipient age, gender and ABO incompatibility regardless of donor source: validated criteria for donor selection for haematopoietic transplants

Prior data indicate similar outcomes after transplants from human leukocyte antigen (HLA)-haplotype-matched relatives, HLA-identical siblings and HLA-matched unrelated donors. We used our prospective data set to answer a clinically important question: who is the best donor for a person with acute leukaemia transplanted in first complete remission. Patients were randomly divided into training (n=611) and validation (n=588) sets. A total of 1199 consecutive subjects received a transplant from an HLA-haplotype-matched relative using granulocyte colony-stimulating factor and anti-thymocyte globulin (n=685) or an HLA-identical sibling (n=514); 3-year leukaemia-free survivals (LFSs) were 75 and 74% (P=0.95), respectively. The multivariate model identified three major risk factors for transplant-related mortality (TRM): older donor/recipient age, female-to-male transplants and donor-recipient ABO major-mismatch transplants. A risk score was developed based on these three features. TRMs were 8%, 15% and 31% for subjects with scores of 0-1, 2 and 3, respectively, (P<0.001). Three-year LFSs were 78%, 74% and 58%, respectively, (P=0.003). The risk score was validated in an independent cohort. In conclusion, our data confirm donor source is not significantly correlated with transplant outcomes. Selection of the best donor needs to consider donor-recipient age, matching for gender and ABO incompatibility among persons with acute leukaemia receiving related transplants under our transplant modality.

Long-term follow-up of a retrospective comparison of reduced-intensity conditioning and conventional high-dose conditioning for allogeneic transplantation from matched related donors in myelodysplastic syndromes

This study shows the long-term updated outcomes of a multicenter retrospective study which analyzed 843 patients with myelodysplastic syndrome (MDS) who underwent transplantation with an HLA-identical sibling donor with either reduced-intensity conditioning (RIC) in 213 patients, or standard myeloablative conditioning (MAC) in 630 patients. In multivariate analysis, the 13-year relapse rate was significantly increased after RIC (31% after MAC vs 48% in RIC; HR, 1.5; 95% CI, 1.1-1.9; P=0.04), but with no differences in overall survival (OS) (30% after MAC vs 27% in RIC; P=0.4) and PFS (29 vs 21%, respectively, P=0.3). Non-relapse mortality was higher in MAC (40 vs 31%; P=0.1), especially in patients older than 50 years (50 vs 33%, P<0.01). In addition, long-term follow-up confirms the importance of other variables on 13-year OS, mainly MDS risk category, disease phase, cytogenetics and receiving a high donor cell dose, irrespective of the conditioning regimen used.

Related haploidentical donors are a better choice than matched unrelated donors: Counterpoint

Publisher's Note: This article has a companion Point by Fuchs. Publisher's Note: Join in the discussion of these articles at Blood Advances Community Conversations.

Related haploidentical donors are a better choice than matched unrelated donors: Point

Publisher's Note: This article has a companion Counterpoint by Shaw. Publisher's Note: Join in the discussion of these articles at Blood Advances Community Conversations.

Strategies before, during, and after hematopoietic cell transplantation to improve T-cell immune reconstitution

T-cell immune reconstitution (IR) after allogeneic hematopoietic cell transplantation (allo-HCT) is highly variable between patients and may take several months to even years. Patients with delayed or unbalanced T-cell IR have a higher probability of developing transplantation-related morbidity, mortality, and relapse of disease. Hence, there is a need for strategies to better predict and improve IR to reduce these limitations of allo-HCT. In this review, we provide an update of current and in-near-future clinically relevant strategies before, during, and after transplantation to achieve successful T-cell IR. Potent strategies are choosing the right HCT source (eg, donor-recipient matching, cell dose, graft manipulation), individualized conditioning and serotherapy (eg, antithymocyte globulin), nutritional status, exercise, home care, modulation of microbiota, enhancing homeostatic peripheral expansion, promoting thymopoiesis, and the use of adjuvant-targeted cellular immunotherapies. Strategies to prevent graft-versus-host disease are important as well because this complication and the subsequent need for immunosuppression affects T-cell IR and function. These options aim for personalized precision transplantation, where allo-HCT therapy is designed to boost a well-balanced T-cell IR and limit complications in individual patients, resulting in overall lower morbidity and higher survival chances.

Donor age and C1orf132/MIR29B2C determine age-related methylation signature of blood after allogeneic hematopoietic stem cell transplantation

Background

Our recent study demonstrated that DNA methylation status in a set of CpGs located in ELOVL2, C1orf132, TRIM59, KLF14, and FHL2 can accurately predict calendar age in blood. In the present work, we used these markers to evaluate the effect of allogeneic hematopoietic stem cell transplantation (HSCT) on the age-related methylation signature of human blood.

Methods

DNA methylation in 32 CpGs was investigated in 16 donor-recipient pairs using pyrosequencing. DNA was isolated from the whole blood collected from recipients 27–360 days (mean 126) after HSCT and from the donors shortly before the HSCT.

Results

It was found that in the recipients, the predicted age did not correlate with their calendar age but was correlated with the calendar age (r = 0.94, p = 4 × 10⁻⁸) and predicted age (r = 0.97, p = 5 × 10⁻¹⁰) of a respective donor. Despite this strong correlation, the predicted age of a recipient was consistently lower than the predicted age of a donor by 3.7 years (p = 7.8 × 10⁻⁴). This shift was caused by hypermethylation of the C1orf132 CpGs, for C1orf132 CpG_1. Intriguingly, the recipient-donor methylation difference correlated with calendar age of the donor (r = 0.76, p = 6 × 10⁻⁴). This finding could not trivially be explained by shifts of the major cellular factions of blood.

Conclusions

We confirm the single previous report that after HSCT, the age of the donor is the major determinant of age-specific methylation signature in recipient’s blood. A novel finding is the unique methylation dynamics of C1orf132 which encodes MIR29B2C implicated in the self-renewing of hematopoietic stem cells. This observation suggests that C1orf132 could influence graft function after HSCT.

Electronic supplementary material

The online version of this article (doi:10.1186/s13148-016-0257-7) contains supplementary material, which is available to authorized users.