Revised HLA-DP TCE-Core Permissiveness Model Better Defines Relapse Risk and Survival following Haploidentical Transplant.

The presence of an HLA-DPB1 nonpermissive mismatch (NPMM) by the TCE-3 model has been associated with improved survival following haploidentical donor transplantation (HIDT) using post-transplantation cyclophosphamide (PTCy). With the development of a revised model (TCE-Core) that further separates TCE-3 "group 3" alleles into "core" (C) and "noncore" (NC) alleles, a formerly permissive mismatch (PMM) resulting from group 3 alleles in both donor and recipient is now considered a C-NPMM if 1 or more of those alleles is NC. We aimed to study the additional effect of HLA-DPB1 C-NPMM according to the TCE-Core algorithm, as well as the directional vector of the mismatch, on outcomes following HIDT. To this end, we analyzed 242 consecutive HIDT recipients with acute leukemia or myelodysplastic syndrome who underwent transplantation between 2005 and 2021 (median age, 51 years; range, 19 to 80 years). The median follow-up was 62 months (range, 23 to 199 months). Of the 136 HIDTs classified as PMM by TCE-3, 73 were reclassified as a C-NPMM by the TCE-Core algorithm, of which 36 were in the graft-versus host (GVH) vector (37 were host-versus-graft [HVG] only). Given comparable survival between conventional NPMM and C-NPMM, GVH/bidirectional were analyzed together (nonpermissive). HVG-only C-NPMM were combined with HLA-DPB1-matched and PMM (permissive) because of similar outcomes. The presence of a TCE-Core-defined nonpermissive HLA-DP mismatch resulted in superior 5-year overall survival (OS) (66% versus 47%) and disease-free survival (DFS) (60% versus 43%). Compared to the conventional TCE-3 algorithm, TCE-Core identified a higher percentage of nonpermissive transplants (38% versus 23%) and better discriminated outcomes between nonpermissive and permissive status, with a larger difference in survival outcomes using TCE-Core compared to TCE-3 (OS Δ, 18.3% versus 12.7%; DFS Δ, 16.5% versus 8.5%). In multivariable analysis (MVA), a nonpermissive TCE-Core mismatch led to improved OS (hazard ratio [HR], .54; P = .003) and DFS (HR, .62; P = .013), largely due to decreased relapse risk (HR, .63; P = .049). In contrast, nonrelapse mortality (NRM) and graft-versus-host disease (GVHD) outcomes were not significantly impacted. In summary, the presence of nonpermissive TCE-Core HLA-DP mismatch strongly predicts survival following PTCy-based HIDT, owing to a reduction in relapse risk without a corresponding increase in GVHD or NRM. As a donor selection tool, TCE-Core appears to better discriminate HIDT outcomes while at the same time identifying a larger percentage of the potential donor pool.

Immunosuppression-Free Status at 1 Year after Haploidentical Hematopoietic Cell Transplantation with Post-Transplantation Cyclophosphamide.

The development of chronic graft-versus-host disease (GVHD) in 1-year survivors after matched related or unrelated hematopoietic cell transplantation was shown to be associated with higher nonrelapse mortality (NRM) and worse overall survival (OS). The impact of chronic GVHD requiring immunosuppression (IS) for recipients of haploidentical transplantation (HIDT) with post-transplantation cyclophosphamide (PTCy) who have survived to 1 year post-transplantation has not been studied previously and was investigated for this analysis. A total of 322 adult patients who underwent HIDT at our center were included in this study. The effect of IS-free status on post-transplantation outcomes was assessed. The median follow-up for survivors was 63.9 months (range, 18.3 to 165 months). A total of 163 patients (65%) were IS-free at 1 year post-HIDT. Baseline characteristics of this group were similar to those of patients still requiring IS, except for higher percentages of female donor-male recipient pairs (28% versus 15%; P =.03) and female donors (48% versus 30%; P =.008). Logistic regression to identify patients more likely to be on IS at 1 year post-HIDT identified the use of a female donor as a significant risk factor (odds ratio, 2.11; P = .009). In a Cox regression analysis, patients requiring IS at 1 year post-transplantation had higher NRM (hazard ratio [HR], 4.18; 95% confidence interval [CI], 1.80 to 6.72; P < .001) and showed a trend toward worse disease-free survival (DFS) (HR, 1.59; 95% CI, .95 to 2.66; P =.08), with no impact on OS (HR, 1.44; 95% CI, .90 to 2.31; P = .13) or relapse (HR, .77; 95% CI, .37 to 1.61; P = .49). These results indicate that use of a female donor is a significant risk factor for requiring IS at 1 year post-HIDT. Additionally, chronic GVHD requiring IS at 1-year post-HIDT no significant effect on relapse but is associated with higher NRM and a trend toward worse DFS.

Phase 2 study of PD-1 blockade following autologous transplantation for patients with AML ineligible for allogeneic transplant.

Allogeneic transplant remains the best postremission therapy for patients with nonfavorable risk acute myeloid leukemia (AML). However, some patients are ineligible because of psychosocial barriers, such as lack of appropriate caregiver support. We hypothesized that immune checkpoint inhibition after autologous transplant might represent effective postremission therapy in such patients. We conducted a phase 2 study of autologous transplantation followed by administration of pembrolizumab (8 cycles starting day +1). Twenty patients with nonfavorable AML in complete remission were treated (median age, 64 years; CR1, 80%); 55% were non-White and adverse-risk AML was present in 40%. Treatment was well tolerated, with only 1 nonrelapse death. Immune-related adverse events occurred in 9 patients. After a median follow-up of 80 months, 14 patients remain alive, with 10 patients in continuous remission. The estimated 2-year LFS was 48.4%, which met the primary end point of 2-year LFS >25%; the 2-year overall survival (OS), nonrelapse mortality, and cumulative incidences of relapse were 68%, 5%, and 46%, respectively. In comparison with a propensity score-matched cohort group of patients with AML receiving allogeneic transplant, the 3-year OS was similar (73% vs 76%). Patients in the study had inferior LFS (51% vs 75%) but superior postrelapse survival (45% vs 14%). In conclusion, programmed cell death protein-1 blockade after autologous transplant is a safe and effective alternative postremission strategy in patients with nonfavorable risk AML who are ineligible for allogeneic transplant, a context in which there is significant unmet need. This trial was registered at www.clinicaltrials.gov as #NCT02771197.

Extracorporeal photopheresis (ECP) improves overall survival in the treatment of steroid refractory acute graft-versus-host disease (SR aGvHD).

Steroid refractory acute graft-versus-host disease (SR aGvHD) is a major limitation of successful allogeneic hematopoietic stem cell transplantation (HSCT). Extracorporeal photopheresis (ECP) has been used to treat SR aGvHD effectively and with low treatment related toxicity. In this study, we retrospectively analyzed the outcomes of 103 Steroid Refractory aGvHD (SR aGvHD) patients to identify factors associated with improved outcomes including the use of ECP. A total of 79 patients received ECP as part of their SR aGVHD treatment compared to 24 patients who did not. Both groups had similar aGVHD grade and maximum organ stage at onset of aGVHD and treatment initiation. Patients in the group that received ECP had better OS (p = 0.01), DFS (p = 0.008), lower relapse (p = 0.05) and similar NRM compared to the group that did not receive ECP. Patients that received ECP treatment also had shorter hospital stays in the first 180 days after onset of SR aGvHD (20 vs. 38 days, p = 0.03). Multivariable analysis for OS indicated patient CMV status (CMV+ versus CMV-, HR 2.34, CI 1.16-4.69), regimen intensity (Myelo vs. non-Myeloablative, HR 0.39, CI 0.20-0.75), and the use of ECP (ECP vs. no ECP, HR 0.39, CI 0.20-0.75) were associated with OS. In summary, the use of ECP in the treatment of SR aGvHD results in improved overall survival secondary to lower relapse rates compared to other therapeutic modalities that do not incorporate ECP.

Lineage-Specific Relapse Prediction After Haploidentical Transplantation With Post-Transplant Cyclophosphamide Based on Recipient HLA-B-Leader Genotype and HLA-C-Group KIR Ligand.

The role of NK cell alloreactivity on outcomes after T cell-replete haploidentical donor transplantation (HIDT) remains uncertain. After transplantation, newly formed NK cells are licensed through interactions of donor inhibitory KIR (iKIR) and NKG2A receptors with their cognate ligands on recipient cells. Donor NKG2A recognizes HLA-E bound by recipient HLA class I leader peptides, a process requiring methionine (M) at position -21 of the leader sequence. An rs1050458C/T dimorphism results in approximately 40% of individuals expressing at least one copy of -21M HLA-B (M/M or M/T [M+]), allowing ligand expression. We assessed the impact of recipient HLA-B-leader genotype (M+ versus M- [T/T]) and HLA-C-group iKIR missing ligand (ML, C1C1/C2C2 versus C1C2) on relapse and disease-free survival (DFS) in recipients of post-transplantation cyclophosphamide (PTCy)-based HIDT. Based on preclinical data, we hypothesized that the relative impact of each variable may depend on disease lineage (lymphoid versus myeloid). To this end, we analyzed outcomes of 322 consecutive PTCy-based HIDT recipients with hematologic malignancy who underwent transplantation at a single institution using standardized supportive care measures with mature follow-up (median 45 months). Primary endpoints were relapse and DFS of patients based on HLA-B-leader genotype and HLA-C-group iKIR ML. Planned subgroup analysis included patient with lymphoid versus myeloid malignancy. M+ HLA-B-leader genotype and HLA-C-group iKIR ML were seen in 42% and 49% of recipients, respectively. The presence of a recipient M+ B-leader (versus M-) improved overall survival (OS) and DFS and lowered cumulative incidence of relapse (CIR), an effect primarily seen in lymphoid malignancies (80% versus 51%, 72% versus 41%, 16% versus 42%, respectively). In contrast, myeloid malignancy patients benefited most from HLA-C-group iKIR ML with better OS and DFS and lower CIR (67% versus 51%, 64% versus 44%, 25% versus 45%, respectively). Multivariate analysis confirmed the disease-specific associations of improved relapse/DFS with M+ HLA-B-leader in lymphoid malignancy (hazard ratio [HR] 0.20, P < .001/HR 0.34, P <.001) and HLA-C-group iKIR ML in myeloid malignancy (HR 0.44, P = .004/HR 0.54, P = .009). Neither HLA-B-leader nor iKIR ML was associated with the incidence of non-relapse mortality or acute or chronic graft-versus-host disease. Two distinct NK cell education pathways predict relapse and DFS after HIDT-PTCy in a disease-specific manner: the presence of recipient M+ HLA-B-leader genotype improves outcome in patients with lymphoid malignancies, whereas HLA-C-group iKIR ML improves outcome in patients with myeloid malignancies. These findings strengthen the essential role of NK cells for optimal GVL in the context of HIDT-PTCy and may suggest different approaches to improving transplant outcome depending on disease type.

High-Dose Bendamustine, Etoposide, Cytarabine, and Melphalan (BeEAM) Conditioning Before Autologous Transplantation for Patients With Multiple Myeloma.

Single-agent high-dose melphalan (Mel) followed by autologous stem cell transplantation (ASCT) remains a standard of care in eligible patients with multiple myeloma (MM), and efforts to improve transplant outcomes by intensifying transplant conditioning have mostly failed. Bendamustine combines both alkylating and antimetabolite properties, can induce responses in MM resistant to other alkylators and represents a promising agent to combine with Mel prior to ASCT. We performed a phase II study to test the safety and efficacy of the high-dose chemotherapy combination of bendamustine, etoposide, cytarabine, and melphalan (BeEAM) in newly diagnosed MM patients up to 70 years of age. The primary study endpoint was the day 100 complete response rate. Sixty-five patients with a median (range) age of 59 (40-69) years underwent transplantation from 2015 to 2020. Other characteristics included Karnofsky performance status <80%, hematopoietic cell transplantation-comorbidity index ≥3, International Staging System III, and high-risk fluorescein in situ hybridization (FISH) in 35%, 46%, 26%, and 44%, respectively. ASCT after BeEAM was well tolerated, and there were no non-relapse deaths through 1 year after transplantation. Although at least 1 nonhematologic grade 3 toxicity was reported in 58 (89%) patients (including grade 3 febrile neutropenia in 48% and stomatitis/esophagitis in 28%), there were no grade ≥3 renal or hepatic toxicity and no grade ≥4 non-hematologic toxicity. The day 100 response rate was ≥CR1 and ≥ very good partial response (VGPR1) in 40% and 89%, respectively. With a median follow-up of 44 (13-70) months, the 3-year overall survival was 92%, 96%, and 90% for all patients and those with standard- and high-risk FISH, respectively. The corresponding values for 3-year progression-free survival was 57%, 72%, and 40%, respectively. When BeEAM-conditioned patients were compared to historical Mel-conditioned cohort, no significant differences were noted in relapse or survival outcomes in univariate or multivariable analysis. In summary, BeEAM was shown to be a safe and effective conditioning regimen before up-front autologous transplant for MM. Although the BeEAM regimen does not appear to offer a significant advantage over single-agent Mel, further studies combining bendamustine and melphalan in the front-line setting may be warranted.

A Phase II Trial of Melphalan Based Reduced-Intensity Conditioning for Transplantation of T-Replete HLA-Haploidentical Peripheral Blood Stem Cells with Posttransplant Cyclophosphamide in Patients with Hematologic Malignancies.

T-replete haploidentical donor transplants using posttransplant cyclophosphamide (haplo) have greatly expanded donor availability and are increasingly utilized. Haplo were originally performed using truly nonmyeloablative conditioning and a bone marrow graft. We have also developed myeloablative conditioning and peripheral blood stem cell (PBSC) grafts for use with haplo. However, some patients may not tolerate myeloablative conditioning but may still benefit from a more dose-intensified preparative regimen to control malignancy and diminish graft rejection. To this end, we enrolled 25 patients on a prospective phase II trial utilizing a regimen of fludarabine 30 mg/m2/day × 5 days and Melphalan 140 mg/m2 on day -1 (flu/Mel) followed by infusion of unmanipulated PBSC graft from a haploidentical donor. GVHD prophylaxis included cyclophosphamide 50 mg/kg/day on days 3 and 4, mycophenolate mofetil on day 35, and tacrolimus on day 180. Median age was 57 years (range from 35 to 68). Transplantation diagnosis included AML (n = 11), ALL (n = 4), MDS/MPD (n = 6), NHL/CLL (n = 3), and MM (n = 1). Using the refined Disease Risk Index (DRI), patients were low (n = 1), intermediate (n = 13), and high/very high (n = 11). 22 out of 25 patients engrafted with a median time to neutrophil and platelet engraftment of 18 days and 36 days, respectively. All engrafting patients achieved full peripheral blood T-lymphocyte and myeloid donor chimerism at day 30. The 180-day cumulative incidence for acute GVHD grades II-IV and III-IV was seen in 20% (95% CI 8%-37%) and 8% (95% CI 2%-22%), respectively. The 2-year cumulative incidence of chronic GVHD was 16% (95% CI 5%-33%) (moderate-severe 12% (95% CI 3%-27%)). After a median follow-up of 28.3 months, the estimated 2-year OS, DFS, NRM, and relapse were 56% (95%CI 33-74%), 44% (95%CI 23%-64%), 20% (95% CI 8%-37%), and 36% (95% CI 17%-55%), respectively. Among patients with high/very high risk DRI, 2-year OS was 53% compared to 69% for low/intermediate DRI. When compared with a contemporaneous cohort of patients at our center receiving haploidentical transplant with nonablative fludarabine, Cytoxan, and total body irradiation flu/Cy/TBI regimen, the outcomes were statistically similar to the 2-year OS at 56% vs. 63% p=0.75 and DFS at 44% vs. 46% p=0.65.

The Transplant Evaluation Rating Scale predicts overall survival after allogeneic hematopoietic stem cell transplantation.

To evaluate the impact of psychosocial risks on post-hematopoietic stem cell transplantation (HSCT) outcomes, we prospectively conducted psychosocial assessment of 556 consecutive allogeneic HSCT patients who received their first allogeneic transplant at our center between 2003 and 2017. The Transplant Evaluation Rating Scale (TERS) score was prospectively assessed by a psychologist before transplantation, and patients were categorized as low, intermediate, or high risk based on their TERS score. Patients in the high-risk TERS group had significantly longer hospital stays during the first 180 days and 1 year post-allogeneic HSCT compared with the low-risk group (16 vs 13 and 21 vs 16 days; P = .05 and .02, respectively). The survival estimates for low-, intermediate-, and high-risk TERS groups at 3 year were as follows: overall survival (OS), 73%, 60%, and 65%; disease-free survival (DFS), 63%, 55%, and 60%; nonrelapse mortality (NRM), 11%, 20%, and 17%; and relapse, 26%, 25%, and 23%, respectively. In a multivariable analysis, intermediate- and high-risk TERS scores predicted for inferior OS, similar DFS, and higher NRM compared with low-risk TERS score. In a subset analysis of patients with low/intermediate risk per Disease Risk Index, multivariable analysis showed that high- and intermediate-risk TERS scores predicted for significantly worse OS, worse DFS, higher NRM, and similar relapse rates compared with low-risk TERS score. Our findings show that psychosocial factors as measured by TERS score are strong predictors of morbidity and mortality after HSCT among patients with low/intermediate disease risk.

Class II HLA mismatch improves outcomes following haploidentical transplantation with posttransplant cyclophosphamide.

HLA disparity is the major predictor of outcome following unrelated donor (UD) transplantation, where a single mismatch (mm) at the HLA-A, HLA-B, HLA-C, or HLA-DRB1 locus leads to increased mortality, and mismatching at multiple loci compounds this effect. In contrast, HLA disparity has not been shown to increase mortality in the context of haploidentical transplant using posttransplant cyclophosphamide (PTCy). To better define the consequences of loci-specific HLA mm, we analyzed 208 consecutive patients undergoing haploidentical transplantation for hematologic malignancy using PTCy at our institution (median age, 52 years [range, 19-75 years]; peripheral blood stem cell, 66%; reduced-intensity conditioning, 59%). Median follow-up was 65.4 months (range, 34.3-157.2 months). In univariate analysis, a single class II HLA mm at HLA-DR, HLA-DQ or a nonpermissive (np) HLA-DP mm had a protective effect on disease-free and overall survival (OS), primarily a result of reduced relapse risk. Furthermore, this survival effect was cumulative, so that patients with 3 class II mm (HLA-DR, HLA-DQ, and np HLA-DP) had the best OS. In multivariate analysis, HLA-DR mm and np HLA-DP mm were both independently associated with improved OS (hazard ratio [HR], 0.43; P =.001; and HR, 0.47; P =.011, respectively). In contrast, single or multiple mm at HLA-A, HLA-B, or HLA-C loci had no effect on acute graft-versus-host disease (GVHD), nonrelapse mortality (NRM), relapse, or survival, although the presence of an HLA-A mm was associated with increased chronic GVHD incidence. The association of class II mm with lower relapse occurred without a corresponding increase in NRM or acute or chronic GVHD. These findings will require validation in larger registry studies.

Prospective phase 2 trial of ixazomib after nonmyeloablative haploidentical peripheral blood stem cell transplant.

Proteasome inhibition results in extensive immunomodulatory effects that augment natural killer cell cytotoxicity and inhibit aspects of T-cell, B-cell, and dendritic cell function. We performed a phase 2 study that examined the effects of ixazomib for graft-versus-host disease (GVHD) prophylaxis (up to 12 cycles) with posttransplant cyclophosphamide and tacrolimus after standard nonmyeloablative haploidentical donor transplantation (HIDT). Ixazomib was started on day +5 (4 mg on days 1, 8, and 15 of a 28-day cycle), with dose reductions allowed in future cycles for toxicity. All patients received peripheral blood stem cells. Twenty-five patients were enrolled with a median age of 62 years (range, 35-77 years) who had acute leukemia (4), myelodysplastic syndrome (7), non-Hodgkin lymphoma/Hodgkin lymphoma/chronic lymphocytic leukemia (8), and myeloma (6). The hematopoietic cell transplant comorbidity index was ≥3 in 68% of the patients. After a median follow-up of 33.5 months, the cumulative incidence of relapse/progression at 1 year was 24% and 44% at 3 years, which failed to meet the statistically predefined goal of decreasing 1-year risk of relapse. Engraftment occurred in all patients with no secondary graft failure, and 3-year nonrelapse mortality (NRM) was 12%. Cumulative incidence of grade 3 to 4 acute GVHD was 8%, whereas moderate-to-severe chronic GVHD occurred in 19%. Nineteen patients survive with an estimated 1-year overall survival (OS) of 84% and 3-year OS of 74%. Hematologic and cutaneous toxicities were common but manageable. The substitution of ixazomib for mycophenolate mofetil (MMF) post-HIDT results in reliable engraftment, comparable rates of clinically significant GVHD, relapse and NRM, and favorable OS. This trial was registered at www.clinicaltrials.gov as # NCT02169791.

Differences in Graft-versus-Host Disease Characteristics between Haploidentical Transplantation Using Post-Transplantation Cyclophosphamide and Matched Unrelated Donor Transplantation Using Calcineurin Inhibitors.

We assessed differences in presentation and response to therapy in 394 consecutive patients who developed acute or chronic graft-versus-host disease (GVHD) after receiving their first allogeneic transplantation (HSCT) from a 10/10 HLA allele-matched unrelated donor (MUD; n = 179) using calcineurin inhibitors or a T cell-replete haploidentical donor (haplo; n = 215) and post-transplantation cyclophosphamide at our center between 2005 and 2017. The median duration of follow-up for survivors was 52.5 months. The cumulative incidences for grade II-IV and grade III-IV acute GVHD at day 180 post HCT were similar, at 39% and 14%, respectively, for haplo-HSCT compared with 50% and 16% for MUD HSCT (P not significant). Haplo-HSCT recipients had a lower cumulative incidence of moderate to severe chronic GVHD, at 22% (severe, 19%), compared with 31% (severe, 29%) for MUD HSCT recipients (P = .026). The time to onset of moderate to severe chronic GVHD was faster for haplo-HSCT recipients (213 days versus 280 days; P = .011). Among patients with grade II-IV acute GVHD, there was no significant between-group difference in organ involvement, with skin the most affected (75% for haplo-HSCT versus 70% for MUD HSCT), followed by the gastrointestinal tract (71% versus 69%) and liver (14% versus 17% MUD). For chronic GVHD, haplo-HSCT recipients had less involvement of the eyes (46% versus 75% for MUD; P < .001) and of the joints/fascia (12% versus 36%; P = .001). Also for cGVHD patients, haplo-HSCT recipients and MUD HSCT recipients had similar all-cause mortality (22% versus 18%; P = .89), but the former were more likely to be off immunosuppression at 2 years post-HCT (63% versus 43%; P = .03) compared with MUD.

Improved Post remission survival of non- favorable risk Acute Myelogenous Leukemia (AML) patients following initial remission induction therapy with FLAG+/-Idarubicin versus 3 + 7 (Anthracycline + Cytarabine).

The fludarabine, high dose cytarabine and G-CSF with or without idarubicin combination regimen, referred to as FLAG+/-Ida, is commonly used as a salvage regimen for relapsed/refractory AML but its use as initial induction therapy has been more limited. The impact of choice of induction regimen on post remission survival remains unclear. We retrospectively analyzed 304 consecutive AML patients, with non-favorable NCCN risk who received initial treatment at our center with either 7 + 3 (n = 86) or FLAG+/-Ida (n = 218). Patients in the FLAG+/-Ida group were more likely to achieve remission after one course of induction (74 % vs 62 %, p < 0.001) and had a faster time to achieve CR (30 days vs 37.5, p < 0.001) compared to 7 + 3. The time from diagnosis to transplant was shorter among CR patients after FLAG+/-Ida compared to 7 + 3 (115 vs. 151 days, p < 0.003). The 3-year post-remission OS and DFS was significantly better for patients receiving FLAG-Ida at 54 % and 49 % compared to 39 % and 32 % for 7 + 3 respectively (P = 0.01). Factors associated with post-remission survival included age at CR1, NCCN risk, induction regimen (FLAG+/-Ida vs 3 + 7 h 0.62, p = 0.01) and receipt of HCT. Our data, with the limitations inherent to a retrospective analysis, shows that achieving CR after FLAG+/-Ida has better post remission survival than 7 + 3.

Fludarabine and Total-Body Irradiation Conditioning before Ablative Haploidentical Transplantation: Long-Term Safety and Efficacy.

Although myeloablative conditioning (MAC) before haploidentical donor transplant (HIDT) with post-transplant cyclophosphamide is being increasingly used, the optimal preparative regimen remains unclear. In our initial trial, the feasibility of HIDT following a MAC preparative regimen using fludarabine and 12 Gy of total-body irradiation was demonstrated in 30 patients. We now present long-term outcome results, including an additional 52 patients, now with 47 months (16 to 96) median follow-up. Median patient age was 42 (19 to 61) years. The most common diagnoses were acute myelogenous leukemia (51%) and acute lymphoblastic leukemia (33%), and 39% had a high/very high disease risk index (DRI). Engraftment was universal with no cases of primary or secondary graft failure. Grade 3 to 4 acute graft-versus-host disease (GVHD) and moderate to severe chronic GVHD occurred in 17% and 23%, respectively. Nonrelapse mortality (NRM) was 7% at 1 year and 13% at 4 years. Estimated 4-year overall survival (OS), disease-free survival, and cumulative incidence of relapse (CIR) were 67%, 60%, and 27%, respectively. CIR was significantly higher in patients with high/very high- versus low/intermediate-risk DRI (38% versus 20%, P= .032), which led to inferior 4-year OS (50% versus 77%, P = .001). Median time to systemic immunosuppressive therapy (IST) discontinuation was 7.8 months, with 84% of patients off IST at 2 years post-transplant. Current GHVD-free, relapse-free survival (CGRFS) at 2, 3, and 4 years was 60%, 57%, and 60%, respectively. This approach to MAC HIDT results in universal engraftment; low rates of NRM, infection, and clinically significant GVHD; and relatively rapid IST discontinuation, resulting in high rates of CGRFS and survival.

Outcomes of haploidentical vs matched sibling transplantation for acute myeloid leukemia in first complete remission.

HLA-haploidentical hematopoietic cell transplantation (Haplo-HCT) using posttransplantation cyclophosphamide (PT-Cy) has improved donor availability. However, a matched sibling donor (MSD) is still considered the optimal donor. Using the Center for International Blood and Marrow Transplant Research database, we compared outcomes after Haplo-HCT vs MSD in patients with acute myeloid leukemia (AML) in first complete remission (CR1). Data from 1205 adult CR1 AML patients (2008-2015) were analyzed. A total of 336 patients underwent PT-Cy-based Haplo-HCT and 869 underwent MSD using calcineurin inhibitor-based graft-versus-host disease (GVHD) prophylaxis. The Haplo-HCT group included more reduced-intensity conditioning (65% vs 30%) and bone marrow grafts (62% vs 7%), consistent with current practice. In multivariable analysis, Haplo-HCT and MSD groups were not different with regard to overall survival (P = .15), leukemia-free survival (P = .50), nonrelapse mortality (P = .16), relapse (P = .90), or grade II-IV acute GVHD (P = .98). However, the Haplo-HCT group had a significantly lower rate of chronic GVHD (hazard ratio, 0.38; 95% confidence interval, 0.30-0.48; P < .001). Results of subgroup analyses by conditioning intensity and graft source suggested that the reduced incidence of chronic GVHD in Haplo-HCT is not limited to a specific graft source or conditioning intensity. Center effect and minimal residual disease-donor type interaction were not predictors of outcome. Our results indicate a lower rate of chronic GVHD after PT-Cy-based Haplo-HCT vs MSD using calcineurin inhibitor-based GVHD prophylaxis, but similar other outcomes, in patients with AML in CR1. Haplo-HCT is a viable alternative to MSD in these patients.

Who Is a Better Donor for Recipients of Allogeneic Hematopoietic Cell Transplantation: A Young HLA-Mismatched Haploidentical Relative or an Older Fully HLA-Matched Sibling or Unrelated Donor?

T cell replete HLA-mismatched haploidentical transplantation (HIDT) with post-transplant cyclophosphamide is increasingly becoming an acceptable treatment approach for patients lacking timely access to a suitably matched related donor transplant (MRDT) or matched unrelated donor transplant (MUDT). Multiple recent registry and single-center studies have shown comparable overall survival (OS) and disease-free survival (DFS) rates among HIDT, MRDT, and MUDT with a significantly lower risk of acute and chronic graft-versus-host disease (GVHD) among HIDT recipients. Candidates for allogeneic hematopoietic stem cell transplantation (HSCT) often have access to multiple donor sources, and a relevant question is whether outcomes can be improved with a younger HLA-mismatched haploidentical donor (≤35 years) rather than an older matched related donor (≥35 years) or matched unrelated donor (≥35 years). We analyzed 406 consecutive allogenic HSCT recipients, with a median age of 54 years (range, 19 to 77), after a MRDT with a donor age of ≥35 years (n = 222), MUDT with a donor age of ≥35 years (n = 91), and HIDT with a donor age of ≤35 years (n = 93). Median follow-up time for survivors was 51.5 months. Compared with MRDT and MUDT, HIDT recipients had a similar median age at time of HSCT, hematopoietic cell transplant comorbidity index, disease risk index distribution, and donor recipient sex matching. The survival estimates and relapse incidence at 3 years post-HSCT were OS (64% for MRDT, 54% for MUDT, and 62% for HIDT), DFS (55% for MRDT, 44% for MUDT, and 58% for HIDT), Transplant related mortality (TRM) (19% for MRDT, 16% for MUDT, and 18% for HIDT), and relapse (26% for MRDT, 37% for MUDT, and 24% for HIDT). HIDT recipients had better 3-year relapse rates compared with MUDT recipients (24% versus 37%, P= .048), with similar DFS and OS in a univariate analysis. MRDT recipients had a better relapse rate (26% versus 37%, P = .042) compared with MUDT recipients. Recipients of HIDT also had significantly lower rates of moderate to severe chronic GVHD compared with MRDT and MUDT recipients (P = .01). Multivariable analysis showed no effect of donor on OS, DFS, relapse, and TRM. Recipients of HIDT from a young donor ≤35 years had similar OS, lower rates of chronic GVHD, and better chronic GVHD-free, relapse-free survival compared with patients undergoing transplantation with an MRD or a MUD donor ≥35 years. This study suggests that given a situation where a choice between a young haploidentical relative and an older matched unrelated donor is to be made, one can achieve similar survival with a haploidentical donor and significantly lower rates of chronic GVHD.

Fevers post infusion of T-cell replete hla mismatched haploidentical hematopoietic stem cells with post-transplant cyclophosphamide: risk factors and impact on transplant outcomes.

Fever is a common early complication after infusion of stem cells in patients undergoing T-replete HLA haploidentical transplantation using post-transplant cyclophosphamide (PTCY). We analyzed the records of 172 haploidentical transplant patients to identify risk factors and to assess the impact of such fevers on transplant morbidity and mortality. One hundred and seventy-two patients received haploidential hematopoietic stem cell transplantation (haplo-HSCT) using PBSC (n = 103) or marrow (n = 69) grafts. One hundred and forty patients (81%) experienced fever (T ≥ 100.5 °F or >38 °C) with median onset on d + 2. Compared to patients who did not develop fevers, patients with fevers received higher median CD34+ cell dose (5.00 vs. 3.08 × 106/kg, p < 0.001), CD3+ cell dose (12.8 vs. 4.5 × 107/kg), were more likely to have received a myeloablative regimen (50% vs. 9%, p < 0.001), and PBSC source (71% vs. 9%, p < 0.001). Cox model showed that fever had no impact on TRM, GVHD, OS, and DFS. In the logistic regression to identify correlation with fevers, higher degree of HLA mismatches and use of PBSC were all predictors of developing fever. Fevers between infusion of the T-Cell replete graft and administration of PTCY are very common in Haplo-HSCT. This complication is transient and had no impact on post-transplant morbidity and mortality.

The Dilemma of Conditioning Intensity: When Does Myeloablative Conditioning Improve Outcomes for Allogeneic Hematopoietic Cell Transplantation.

The impact of conditioning intensity on different disease risk index (DRI) groups has not been evaluated. We retrospectively analyzed acute myelogenous leukemia (AML)/myelodysplastic syndrome (MDS) hematopoietic cell transplantation (HCT) recipients in 2 groups based on DRI, to assess the impact of conditioning intensity on overall survival (OS), disease free survival (DFS), relapse, and nonrelapse mortality (NRM). A total of 380 patients with either high/very high (n = 148) or low/intermediate DRI (n = 232) myeloid malignancy (AML, n = 278; MDS, n = 102) were included in the analysis. Median follow-up for survivors was 35 months. Median age was 58years (range, 18 to 75). Patient and transplant-related characteristics were 41% reduced-intensity conditioning (RIC), 59% myeloablative conditioning (MAC), 13% bone marrow graft, 29% matched related donor, 49% matched unrelated donor, 22% haploidentical donor, and 52% HCT-specific comorbidity index ≥ 3. Among patients with high/very high DRI, there was no difference in OS, DFS, relapse, and NRM between RIC and MAC conditioning groups. For low/intermediate risk DRI recipients of MAC had better 3-year OS estimate (69% versus 57%, P = .001), DFS (65% versus 51%, P = .003), and lower relapse (3-year cumulative incidence, 17% versus 32%; P = .01) but similar NRM (19% versus 17%, P = .04) to RIC recipients. On multivariable analysis MAC was associated with better DFS (hazard ratio [HR], .58; 95% confidence interval [CI], .39-.88; P = .01), lower relapse (HR, .56; 95% CI, .32 to .97; P = .038), and similar NRM (HR, 1.11; 95% CI, .54 to 2.26; P = .781) compared with RIC in the low/intermediate DRI group. Intensity had no impact on HCT outcomes in the high/very high DRI group. MAC improves DFS and relapse compared with RIC among AML/MDS patients with low/intermediate DRI. The finding of no such benefit in high/very high DRI needs to be further explored in a larger cohort with a longer follow-up.

Safety and efficacy of rituximab-based first line treatment of chronic GVHD.

Initial therapy of chronic GVHD (cGvHD) has not changed for over three decades, despite limited efficacy and long-term toxicity. We have previously shown in a small pilot study the feasibility of rituximab-based first-line therapy of cGVHD. To better assess safety and efficacy, we now evaluate 69 patients that received rituximab as part of their initial treatment. Median follow-up for surviving patients was 47 (11-81) months. Resolution of cGVHD occurred in 49 patients with median time to IST discontinuation of 349 (138-920) days. The cumulative incidence (CI) of cGHVD resolution was 41%, 69 and 77% at 1-, 2- and 3-years, respectively. No systemic corticosteroids were used in 27 patients, and 67% received ≤ 10 mg/kg cumulative exposure. Overall survival (OS) at 1-, 2- and 3-years following cGVHD diagnosis was 87, 79 and 77% respectively; corresponding rates of non-relapse mortality (NRM) were 10%, 16 and 19%. The probability of being alive and free of cGVHD at 1-, 2-, and 3-years was 36, 55, and 57% respectively. This study demonstrates the feasibility and efficacy of rituximab-based first-line cGVHD treatment. This approach demonstrates significant activity and avoids long courses of corticosteroids in most patients.

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

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

Superior Survival of Black Versus White Patients Following Post-Transplant Cyclophosphamide-Based Haploidentical Transplantation for Adults with Hematologic Malignancy.

Available evidence from large registry studies has shown inferior survival for black adult patients following both unrelated donor and cord blood transplantation. Post-transplant cyclophosphamide (PTCy)-based haploidentical donor transplantation (HIDT) is being increasingly used in ethnic minorities. However, no studies of the impact of race on outcomes following HIDT have been reported. We analyzed 203 consecutive patients (123 white, 80 black) who underwent first HIDT using PTCy for hematologic malignancy at a single institution. Median recipient age was 53 (range, 19-75) years. Peripheral blood stem cells (PBSCs) were used as the stem cell source in 66% of patients, and conditioning intensity was myeloablative (MA) in 41%. After a median follow-up of 36 months, the estimated 3-year overall survival (OS), disease-free survival (DFS), and cumulative incidence of relapse (CIR) were significantly better in black patients, compared with white patients (72% [95% confidence interval (CI), 60% to 81%], 65% [95% CI, 52% to 75%], and 25% [95% CI, 16% to 35] versus 50% [95% CI, 40% to 59%], 45% [95% CI, 36% to 54%], and 39% [95% CI, 31% to 47%], respectively; P < .001 for OS and DFS, P = .015 for CIR). In contrast, 3-year nonrelapse mortality was similar between black (11%) and white (16%) patients, as were the incidences of acute graft-versus-host disease (GVHD) and moderate-to-severe chronic GVHD. Improved survival was noted in all subgroups of black patients-younger versus older, male versus female, lower versus higher disease risk index, MA versus non-MA conditioning, or PBSC versus marrow stem cell source. In multivariate analysis, black race was independently associated with better OS (hazard ratio [HR], .47; P = .003), DFS (HR, .49; P = .003), and relapse (HR, .49; P = .01). Black patients achieve superior outcomes to their white counterparts following PTCy-based HIDT due to a decreased incidence of disease relapse.