Risk Factors for Graft-versus-Host Disease in Haploidentical Hematopoietic Cell Transplantation Using Post-Transplant Cyclophosphamide

Post-transplant cyclophosphamide (PTCy) has significantly increased the successful use of haploidentical donors with a relatively low incidence of graft-versus-host disease (GVHD). Given its increasing use, we sought to determine risk factors for GVHD after haploidentical hematopoietic cell transplantation (haplo-HCT) using PTCy. Data from the Center for International Blood and Marrow Transplant Research on adult patients with acute myeloid leukemia, acute lymphoblastic leukemia, myelodysplastic syndrome, or chronic myeloid leukemia who underwent PTCy-based haplo-HCT (2013 to 2016) were analyzed and categorized into 4 groups based on myeloablative (MA) or reduced-intensity conditioning (RIC) and bone marrow (BM) or peripheral blood (PB) graft source. In total, 646 patients were identified (MA-BM = 79, MA-PB = 183, RIC-BM = 192, RIC-PB = 192). The incidence of grade 2 to 4 acute GVHD at 6 months was highest in MA-PB (44%), followed by RIC-PB (36%), MA-BM (36%), and RIC-BM (30%) (P = .002). The incidence of chronic GVHD at 1 year was 40%, 34%, 24%, and 20%, respectively (P < .001). In multivariable analysis, there was no impact of stem cell source or conditioning regimen on grade 2 to 4 acute GVHD; however, older donor age (30 to 49 versus <29 years) was significantly associated with higher rates of grade 2 to 4 acute GVHD (hazard ratio [HR], 1.53; 95% confidence interval [CI], 1.11 to 2.12; P = .01). In contrast, PB compared to BM as a stem cell source was a significant risk factor for the development of chronic GVHD (HR, 1.70; 95% CI, 1.11 to 2.62; P = .01) in the RIC setting. There were no differences in relapse or overall survival between groups. Donor age and graft source are risk factors for acute and chronic GVHD, respectively, after PTCy-based haplo-HCT. Our results indicate that in RIC haplo-HCT, the risk of chronic GVHD is higher with PB stem cells, without any difference in relapse or overall survival.     

Allogeneic Hematopoietic Stem Cell Transplantation for GATA2 Deficiency Using a Busulfan-Based Regimen

Allogeneic hematopoietic stem cell transplantation (HSCT) reverses the bone marrow failure syndrome due to GATA2 deficiency. The intensity of conditioning required to achieve reliable engraftment and prevent relapse remains unclear. Here, we describe the results of a prospective study of HSCT in 22 patients with GATA2 deficiency using a busulfan-based conditioning regimen. The study included 2 matched related donor (MRD) recipients, 13 matched unrelated donor (URD) recipients, and 7 haploidentical related donor (HRD) recipients. MRD and URD recipients received 4 days of busulfan and 4 days of fludarabine. HRD recipients received low-dose cyclophosphamide for 2 days, fludarabine for 5 days, 2 to 3 days of busulfan depending on cytogenetics, and 200 cGy total body irradiation. MRD and URD recipients received tacrolimus and short-course methotrexate for graft-versus-host disease (GVHD) prophylaxis. HRD recipients received high-dose post-transplant cyclophosphamide (PTCy) followed by tacrolimus and mycophenolate mofetil. At a median follow-up of 24 months (range, 9 to 50), 19 of 22 patients were alive with reversal of the disease phenotype and correction of the myelodysplastic syndrome, including eradication of cytogenetic abnormalities. Three patients died: 1 from refractory acute myelogenous leukemia, 1 from GVHD, and 1 from sepsis. There was a 26% incidence of grades III to IV acute GVHD in the MRD and URD groups and no grades III to IV acute GVHD in the HRD cohort. Similarly, there was a 46% incidence of chronic GVHD in the MRD and URD cohorts, whereas only 28% of HRD recipients developed chronic GVHD. Despite excellent overall disease-free survival (86%), GVHD remains a limitation using standard prophylaxis for GVHD. We are currently extending the use of PTCy to the MRD and URD cohorts to reduce GVHD.     

Calcineurin Inhibitor–Free Graft-versus-Host Disease Prophylaxis with Post-Transplantation Cyclophosphamide and Brief-Course Sirolimus Following Reduced-Intensity Peripheral Blood Stem Cell Transplantation

Calcineurin inhibitors (CNIs) form the foundation of current graft-versus-host disease (GVHD) prophylaxis regimens. We hypothesized that a CNI-free regimen consisting of post-transplantation cyclophosphamide (PTCy) and brief-course sirolimus would reduce chronic GVHD and nonrelapse mortality (NRM) after reduced-intensity conditioning allogeneic peripheral blood stem cell transplantation (PBSCT). Twenty-six patients (median age, 61 years) underwent unmanipulated PBSCT from an 8/8 locus-matched donor (matched related donor, n = 17; natched unrelated donor, n = 9). GVHD prophylaxis consisted of PTCy and brief-course sirolimus. Donor engraftment occurred in all patients. The cumulative incidence (CI) of grade II-IV acute GVHD, grade III-IV acute GVHD, and chronic GVHD was 46%, 15%, and 31% respectively. One-year NRM was 4%. The median time to immunosuppression discontinuation was day +138. With a median follow-up of 20 months, the estimated 2-year overall survival was 71%, estimated disease-free survival was 64%, and estimated relapse incidence was 32%. In patients with a lymphoid malignancy (eg, chronic lymphoblastic leukemia, non-Hodgkin lymphoma, Hodgkin disease), 2-year disease-free survival was 100%, and there were no relapses. Good immune reconstitution was evidenced by low cytomegalovirus reactivation rate of 21% (4 of 19 at-risk patients). GVHD prophylaxis with PTCy and sirolimus achieves consistent donor engraftment, low rates of chronic GVHD and NRM, and excellent outcomes in recipients of HLA-identical related and unrelated donor allogeneic PBSCT.     

Prospective Randomized Study Comparing Myeloablative Unrelated Umbilical Cord Blood Transplantation versus HLA-Haploidentical Related Stem Cell Transplantation for Adults with Hematologic Malignancies

In this prospective randomized study, we compared the outcomes of single-unit umbilical cord blood transplantation (UCBT) and unmanipulated haploidentical stem cell transplantation (haplo-SCT) with post-transplantation cyclophosphamide (PTCy) in adults with hematologic malignancies. All patients received a myeloablative conditioning (MAC) regimen consisting of thiotepa, busulfan, and fludarabine, with antithymocyte globulin (ATG) added for UCBT recipients. Nineteen patients were randomized to UCBT and the other 26 to haplo-HSCT. Four patients (15%) allocated to the haplo-HSCT arm lacked a suitable donor and were crossed over to the UCBT arm. Finally, 23 underwent UCBT and 22 underwent haplo-HSCT. The cumulative incidence of neutrophil recovery was 87% at a median of 19 days (range, 13 to 24 days) in the UCBT arm versus 100% at a median of 17 days (range, 13 to 25 days) in the haplo-SCT arm (P = .04). Platelet recovery was 70% at a median of 40 days (range, 18 to 129 days) in the UCBT arm versus 86% at a median of 24 days (range, 12 to 127 days) in the haplo-HCT arm (P = .02). Rates of acute graft-versus-host disease (GVHD) grade II-IV or grade III-IV, overall chronic GVHD, and extensive chronic GVHD in the UCBT and Haplo-SCT arms were 43% versus 36% (P = .8), 9% versus 9% (P = 1), 66% versus 43% (P = .04), and 41% versus 23% (P = .2), respectively. Two-year nonrelapse mortality and relapse in the 2 arms were 52% versus 23% (P = .06) and 17% versus 23% (P = .5), respectively. Two-year disease-free survival, overall survival, and GVHD/relapse-free survival in the 2 arms were 30% versus 54% (P = .2), 35% versus 59% (P = .1), and 17% versus 40% (P = .04), respectively. Our data show that in the context of an MAC regimen, haplo-SCT with PTCy provides improved outcomes compared with ATG-containing single-unit UCBT.     

Reduced-Intensity Conditioning Followed by Related and Unrelated Allografts for Hematologic Malignancies: Expanded Analysis and Long-Term Follow-Up

Reduced-intensity conditioning (RIC) extends the curative potential of allogeneic hematopoietic cell transplantation (HCT) to patients with hematologic malignancies unable to withstand myeloablative conditioning. We prospectively analyzed the outcomes of 292 consecutive patients, median age 58 years (range, 19 to 75) with hematologic malignancies treated with a uniform RIC regimen of cyclophosphamide, fludarabine, and total body irradiation (200 cGy) with or without antithymocyte globulin and cyclosporine and mycophenolate mofetil graft-versus-host disease (GVHD) prophylaxis followed by allogeneic HCT at the University of Minnesota from 2002 to 6. Probability of 5-year overall survival was 78% for patients with indolent non-Hodgkin lymphoma, 53% for chronic myelogenous leukemia, 55% for Hodgkin lymphoma, 40% for acute myelogenous leukemia, 37% for myelodysplastic syndrome, 29% for myeloma, and 14% for myeloproliferative neoplasms. Corresponding outcomes for relapse were 0%, 13%, 53%, 37%, 39%, 75%, and 29%, respectively. Disease risk index (DRI) predicted both survival and relapse with superior survival (64%) and lowest relapse (16%) in those with low risk score compared with 24% survival and 57% relapse in those with high/very-high risk scores. Recipient cytomegalovirus (CMV)-positive serostatus was protective from relapse with the lowest rates in those also receiving a CMV-positive donor graft (29%). The cumulative incidence of 2-year nonrelapse mortality was 26% and was lowest in those receiving a matched sibling graft at 21%, with low (21%) or intermediate (18%) HCT-specific comorbidity index, and was similar across age groups. The incidence of grades II to IV acute GVHD was 43% and grades III to IV 27%; the highest rates were found in those receiving an unrelated donor (URD) peripheral blood stem cell (PBSC) graft, at 50%. Chronic GVHD at 1 year was 36%.Future approaches incorporating alternative GVHD prophylaxis, particularly for URD PBSC grafts, and targeted post-transplant antineoplastic therapies for those with high DRI are indicated to improve these outcomes.     

αβ T Cell-Depleted Haploidentical Hematopoietic Stem Cell Transplantation without Antithymocyte Globulin in Children with Chemorefractory Acute Myelogenous Leukemia

We evaluated the outcome of αβ T cell-depleted haploidentical hematopoietic stem cell transplantation (HSCT) in a cohort of children with chemorefractory acute myelogenous leukemia (AML). Twenty-two patients with either primary refractory (n = 10) or relapsed refractory (n = 12) AML in active disease status received a transplant from haploidentical donors. The preparative regimen included cytoreduction with fludarabine and cytarabine and subsequent myeloablative conditioning with treosulfan and thiotepa. Antithymocyte globulin was substituted with tocilizumab in all patients and also with abatacept in 10 patients. Grafts were peripheral blood stem cells engineered by αβ T cell and CD19 depletion. Post-transplantation prophylactic therapy included infusion of donor lymphocytes, composed of a CD45RA-depleted fraction with or without a hypomethylating agent. Complete remission was achieved in 21 patients (95%). The cumulative incidence of grade II-IV acute graft-versus-host disease (GVHD) was 18%, and the cumulative incidence of chronic GVHD was 23%. At 2 years, transplantation-related mortality was 9%, relapse rate was 42%, event-free survival was 49%, and overall survival was 53%. Our data suggest that αβ T cell-depleted haploidentical HSCT provides a reasonable chance of long-term survival in a cohort of children with chemorefractory AML and creates a solid basis for further improvement.     

Outcomes of Patients with Recurrent and Refractory Lymphoma Undergoing Allogeneic Hematopoietic Cell Transplantation with BEAM Conditioning and Sirolimus- and Tacrolimus-Based GVHD Prophylaxis

The current standard of care for patients with Hodgkin lymphoma (HL) and non-Hodgkin lymphoma (NHL) is high-dose conditioning followed by autologous stem cell transplantation (ASCT). For some patients (ie, those with highest-risk disease, insufficient stem cell numbers after mobilization, or bone marrow involvement) allogeneic hematopoietic cell transplantation (alloHCT) offers the potential for cure. However, the majority of patients undergoing alloHCT receive reduced-intensity conditioning as a preparative regimen, and studies assessing outcomes of patients after alloHCT with myeloablative conditioning are limited. In this retrospective study, we reviewed outcomes of 22 patients with recurrent and refractory NHL who underwent alloHCT with myeloablative BEAM conditioning and received tacrolimus/sirolimus as graft-versus-host disease (GVHD) prophylaxis at City of Hope between 2005 and 2018. With a median follow-up of 2.6 years (range, 1.0 to 11.2 years), the probabilities of 2-year overall survival and event-free survival were 58.3% (95% confidence interval [CI], 35.0% to 75.8%) and 45.5% (95% CI, 24.4% to 64.3%), respectively. The cumulative incidence of grade II to IV acute GVHD was 45.5% (95% CI, 23.8% to 64.9%), with only 1 patient developing grade IV acute GVHD. However, chronic GVHD was seen in 55% of the patients (n?=?12). Of the 22 eligible patients, 2 had undergone previous ASCT and 2 had undergone previous alloHCT. Both patients with previous ASCT developed severe regimen-related toxicity. Patients who underwent alloHCT with chemorefractory disease had lower survival rates, with 1-year OS and EFS of 44.4% and 33.0%, respectively. In conclusion, alloHCT with a BEAM preparative regimen and tacrolimus/sirolimus-based GVHD should be considered as an alternative option for patients with highest-risk lymphoma whose outcomes are expectedly poor after ASCT.     

Single Antigen–Mismatched Unrelated Hematopoietic Stem Cell Transplantation Using High-Dose Post-Transplantation Cyclophosphamide Is a Suitable Alternative for Patients Lacking HLA-Matched Donors

The optimal prophylaxis regimen for graft-versus-host disease (GVHD) in the setting of mismatched unrelated donor (MMUD) allogeneic hematopoietic stem cell transplantation (alloHSCT) is not defined. The use of high-dose post-transplant cyclophosphamide (PTCy) in haploidentical transplantation has proven feasible and effective in overcoming the negative impact of HLA disparity on survival. We hypothesized that PTCy could also be effective in the setting of MMUD transplantation. We retrospectively analyzed 86 consecutive adult recipients of alloHSCT in our institution, comparing 2 contemporaneous groups: PTCy MMUD (n?=?26) versus matched unrelated donor (MUD) (n?=?60). Graft source was primarily peripheral blood (92%). All PTCy MMUD were HLA 7/8 (differences in HLA class I loci in 92% of patients) and received PTCy plus tacrolimus ± mofetil mycophenolate as GVHD prophylaxis. No differences were observed between PTCy MMUD and MUD in the 100-day cumulative incidence of acute GVHD grades II to IV (31% versus 22%, respectively; P?=?.59) and III to IV (8% versus 10%, P?=?.67). There was a trend for a lower incidence of moderate to severe chronic GVHD at 1 year after PTCy MMUD in comparison with MUD (22% versus 41%, P?=?.098). No differences between PTCy MMUD and MUD were found regarding nonrelapse mortality (25% versus 18%, P?=?.52) or relapse rate (11% versus 19%, P?=?.18). Progression-free survival and overall survival at 2 years were similar in both cohorts (67% versus 54% [HR, .84; 95% CI, .38 to 1.88; P?=?.68] and 72% versus 57% [HR, .71; 95% CI, .31 to 1.67; P?=?.44], respectively). The 2-year cumulative incidence of survival free of moderate to severe chronic GVHD and relapse tended to be higher in the PTCy MMUD group (47% versus 24%; HR, .60; 95% CI, .31 to 1.14; P?=?.12). We conclude that HLA 7/8 MMUD transplantation using PTCy plus tacrolimus is a suitable alternative for those patients who lack a MUD.     

Less Is More: Superior Graft-versus-Host Disease-Free/Relapse-Free Survival with Reduced-Intensity Conditioning and Dual T Cell Depletion in Acute Myelogenous Leukemia

In this study, we compared the outcomes of patients with acute myelogenous leukemia (AML) in complete remission treated with myeloablative conditioning (MAC) and those treated with reduced-intensity conditioning (RIC) before allogeneic hematopoietic stem cell transplantation (allo-HCT). In addition, we explored the efficacy of dual T cell depletion using anti-thymocyte globulin (ATG) and post-transplantation cyclophosphamide (PTCy) for the prevention of graft-versus-host disease (GVHD) in patients undergoing RIC allo-HCT. Our study cohort comprised 356 adults with AML in complete remission who underwent allo-HCT between 2013 and 2018. One hundred eleven patients (31.2%) received a MAC regimen, and 245 (68.8%) received an RIC regimen. One hundred seventy-one of the patients who received an RIC regimen (68.4%) received ATG, PTCy, and cyclosporine (ATG-PTCY-CsA) for GVHD prophylaxis in accordance with our institutional protocol. Data were collected retrospectively and updated in July 2019. With a median follow-up of 14.5 months (range, 0 to 76 months), 161 patients (45.2%) died, and 66 (18.5%) relapsed. Two-year overall survival (OS), relapse-free survival (RFS), and GVHD-free/RFS (GRFS) were 55%, 52.6%, and 35%, respectively. The intensity of the conditioning regimen, with or without ATG-PTCY-CsA, did not have a significant impact on OS and RFS. However, RIC in combination with ATG-PTCY-CsA was associated with a significantly lower cumulative incidence of acute GVHD and chronic GVHD. The use of RIC with ATG-PTCy-CsA was a significant predictor for higher GRFS secondary to the reduction of clinically relevant GVHD (P= .0001). In patients with AML, RIC allografts and dual T cell modulation with ATG and PTCy led to superior GRFS. The use of this GVHD prophylaxis strategy, along with mitigation of conditioning toxicity using RIC, may result in better long-term quality of life for allo-HCT recipients.     

Reduced-Intensity Conditioning and Dual T Lymphocyte Suppression with Antithymocyte Globulin and Post-Transplant Cyclophosphamide as Graft-versus-Host Disease Prophylaxis in Haploidentical Hematopoietic Stem Cell Transplants for Hematological Malignancies

Haploidentical hematopoietic stem cell transplantation (haploHSCT) with conditioning regimens using post-transplant cyclophosphamide (PTCy) for peripheral blood stem cell (PBSC) grafts is limited by comparably higher rates of acute and chronic graft-versus-host disease (GVHD). Antithymocyte globulin (ATG) may mitigate this risk. We evaluated haploHSCT after reduced-intensity conditioning (RIC) with ATG, PTCy, and cyclosporine to prevent rejection and GVHD. Fifty adults underwent haploHSCT from August 2016 to February 2018. RIC included fludarabine (30 mg/m²/day on days –5 to –2), busulfan (3.2 mg/m²/day on days –3 and –2), and total body irradiation (200 cGy) on day –1. Unmanipulated PBSCs were infused on day 0. GVHD prophylaxis included ATG (4.5 mg/kg over days –3 to –1), PTCy (50 mg/kg/day on days +3 and +4), and cyclosporine from day +5. Median age was 56 years (range, 22 to 70 years); 25 (73.5%) patients were in first complete remission (CR1), 5 (14.7%) were in second complete remission (CR2), and 8 (23.5%) had active disease. Median time to neutrophil engraftment was 16 days (range, 8 to 43 days). At day +100, the cumulative incidence of acute GVHD of any grade, and grades III to IV was 38.3% and 5.2%, respectively. Mild chronic GVHD was seen in 15.5%. Cytomegalovirus (CMV) reactivation occurred in 37 (74%) cases and CMV disease occurred in 4 (11.5%) cases. Epstein-Barr virus (EBV) reactivation occurred in 21 (61.8%) patients. The incidence of histologically confirmed post-transplantation lymphoproliferative disorder (PTLD) was 5.8%. Four patients received rituximab. There were no CMV, EBV, or PTLD-related deaths. Six-month and 1-year overall survival (OS), cumulative incidence of relapse (CIR), and nonrelapse mortality (NRM) were 73.9%, 10.2%, and 19.4%, respectively, and 48.1%, 16% and 38.2%, respectively. Infection was the most common cause of death (18%). Unmanipulated haploidentical PBSC transplantation following RIC with ATG, PTCy, and cyclosporine as a GVHD prevention strategy results in low rates of acute and chronic GVHD.     

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.     

Low Nonrelapse Mortality after HLA-Matched Related 2-Step Hematopoietic Stem Cell Transplantation Using Cyclophosphamide for Graft-versus-Host Disease Prophylaxis and the Potential Impact of Non- Cyclophosphamide-Exposed T Cells on Outcomes

The use of cyclophosphamide (CY) for bidirectional tolerization of recipient and donor T cells is associated with reduced rates of graft-versus-host disease (GVHD) and nonrelapse mortality (NRM) after HLA-matched hematopoietic stem cell transplantation (HSCT). However, recurrent disease remains the primary barrier to long-term survival. We extended our 2-step approach to HLA-matched related HSCT using a radiation-based myeloablative conditioning regimen combined with a high dose of T cells in an attempt to reduce relapse rates while maintaining the beneficial effects of CY tolerization. After conditioning, patients received their grafts in 2 components: (1) a fixed dose of 2 × 10⁸/kg T cells, followed 2 days later by CY, and (2) a CD34-selected graft containing a small residual amount of non-CY-exposed T cells, at a median dose of 2.98 × 10³/kg. Forty-six patients with hematologic malignancies were treated. Despite the myeloablative conditioning regimen and use of high T cell doses, the cumulative incidences of grade II-IV acute GVHD, chronic GVHD, and NRM at 1 year and 5 years were very low, at 13%, 9%, and 4.3%, respectively. This contributed to a high overall survival of 89.1% at 1 year and 65.8% at 5 years. Relapse was the primary cause of mortality, with a cumulative incidence of 23.9% at 1 year and 45.7% at 5 years. In a post hoc analysis, relapse rates were significantly lower in patients receiving greater than versus those receiving less than the group median of non-CY-exposed residual T cells in the CD34 product (19.3% versus 58.1%; P = .009), without a concomitant increase in NRM. In its current form, this 2-step regimen was highly tolerable, but strategies to reduce relapse, potentially the addition of T cells not exposed to CY, are needed.     

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

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

Lowered-intensity preparative regimen for allogeneic stem cell transplantation delays acute graft-versus-host disease but does not improve outcome for advanced hematologic malignancy.

Reduced conditioning intensity has extended the option of allogeneic hematopoietic stem cell transplantation to patients who cannot tolerate fully myeloablative regimens. However, relapse and graft-versus-host disease (GVHD) continue to be major causes of morbidity and mortality. We prospectively tested whether a moderate reduction of the intensity of the preparative regimen would lead to significant reduction in regimen-related toxicity without compromising tumor control in a cohort of 44 patients ineligible for conventional hematopoietic stem cell transplantation. Patients were conditioned with fludarabine, busulfan, mycophenolate, and total lymphoid irradiation. Tacrolimus and methotrexate were given as prophylaxis for GVHD. Donors were 5 of 6 or 6 of 6 matched family members. The median age was 61 years. Eleven patients had comorbid conditions that precluded conventional myeloablative transplantation. Fatal regimen-related organ toxicity occurred in 3 patients. The cumulative incidence of grade 2 to 4 or grade 3 to 4 acute GVHD by day 100 was 38% (95% confidence interval [CI] = 25%, 55%) and 20% (95% CI = 10%, 39%), respectively, with a median time to onset of 66 days. For the entire cohort, 1-year overall survival, disease-free survival, and relapse rates were 54% (95% CI = 41%, 71%), 47% (95% CI = 35%, 65%), and 37% (95% CI = 19%, 51%), respectively. Outcomes differed based on stage of disease at time of transplantation, advanced (n = 19) versus nonadvanced (n = 25). Median survival times were 138 days and 685 days for subjects with advanced and nonadvanced disease, respectively (P =.005). After adjusting for age and comorbidity, disease stage continued to be significantly associated with overall survival (P =.005). In conclusion, a moderate reduction in conditioning dose intensity resulted in delayed onset of acute GVHD (compared with historical controls). A reduction in conditioning intensity is associated with poor survival for patients with advanced-stage disease, highlighting the importance of the conditioning regimen for tumor control.     

Haploidentical Hematopoietic Cell Transplantation Using Post-transplant Cyclophosphamide for Children with Non-malignant Diseases

Haploidentical hematopoietic cell transplantation (HCT) is a valuable curative option for children with non-malignant diseases. Haploidentical HCT using post-transplant cyclophosphamide (PTCy) is a readily available option in the absence of an HLA-matched donor. We conducted a retrospective single-center study on the outcome of haploidentical HCT in children with non-malignant diseases. We gathered data from 44 patients underwent HCT in the period 2015 to 2020. The indications for HCT were bone marrow failure, primary immunodeficiency, metabolic disorders, and hemoglobinopathy. Median age at HCT was 4 years (range 0.7–20). The conditioning regimens were myeloablative (n?=?17) or reduced intensity (n?=?27). After a median follow-up of 20 months (range 4–71), 2-year overall survival was 89% and 2-year GvHD-free relapse-free survival (GRFS) was 66%. Incidence of primary graft failure was 13.6%. Cumulative incidence of grade II–IV acute and moderate/severe chronic GvHD were 20% and 6.4%, respectively. Younger age at HCT (<?4 years) and primary immunodeficiency were significantly associated with better GRFS (p?<?0.05). In conclusion, haploidentical HCT using PTCy is feasible and curative in children with non-malignant diseases lacking an HLA-matched donor. Early diagnosis and referral in addition to timely treatment can further improve outcomes.

     

Outcomes of Salvage Haploidentical Transplant with Post-Transplant Cyclophosphamide for Rescuing Graft Failure Patients: a Report on Behalf of the Francophone Society of Bone Marrow Transplantation and Cellular Therapy

Prognosis of patients with graft failure is dismal, and retransplantation is the sole option for long-term survival. To address the interest of haploidentical transplantation as a salvage option in this context, we analyzed data from 24 patients with graft failure or loss retransplanted with a haploidentical donor who received post-transplant cyclophosphamide (PTCy) as graft-versus-host disease prophylaxis (GVHD). Fludarabine-based reduced-intensity conditioning was used in 23 patients and the Baltimore regimen in 14 patients. The median delay between previous and salvage transplantation for graft failure was 63 days (range, 39 to 98). In addition to PTCy, all patients received cyclosporine, and 22 patients also received mycophenolate mofetil for GVHD prophylaxis. With a median follow-up of 353 days (range, 16 to 2010), 1-year overall survival (OS) was 56% (95% confidence interval, 38% to 81%). Transplant complications accounted for 80% of deaths. The cumulative incidence of neutrophil engraftment at day +30 was 79%. Cumulative incidence of grades II to IV acute GVHD at day 100 was 14%, and 1-year cumulative incidence of chronic GVHD was 31%. One-year cumulative incidence of relapse was 13%. Stem cell source did not impact on engraftment, GVHD, relapse, or OS. Salvage haploidentical transplant with PTCy for rescuing graft failure patients leads to an acceptable 1-year OS and might be a valid option in this poor situation.     

Single-Unit Cord Blood Transplantation after Granulocyte Colony-Stimulating Factor–Combined Myeloablative Conditioning for Myeloid Malignancies Not in Remission

High disease burden in myeloablative allogeneic hematopoietic stem cell transplantation is associated with adverse outcomes in patients with acute myelogenous leukemia (AML) and myelodysplastic syndrome (MDS). Quiescent leukemia stem cells could be induced to enter cell cycle by granulocyte colony-stimulating factor (G-CSF) administration and become more susceptible to chemotherapy. We report on the outcome of unrelated cord blood transplantation (CBT) using a conditioning regimen of 12 Gy total body irradiation, G-CSF–combined high-dose cytarabine, and cyclophosphamide in 61 adult patients with AML or advanced MDS not in remission. With a median follow-up of 97 months, the probability of overall survival and cumulative incidence of relapse at 7 years were 61.4% and 30.5%, respectively. In multivariate analysis, poor-risk cytogenetics and high lactate dehydrogenase values at CBT were independently associated with inferior survival. These data demonstrate that CBT after G-CSF–combined myeloablative conditioning is a promising curative option for patients with myeloid malignancies not in remission.     

Reduced-Toxicity Myeloablative Conditioning Consisting of Fludarabine/Busulfan/Low-Dose Total Body Irradiation/Granulocyte Colony-Stimulating Factor–Combined Cytarabine in Single Cord Blood Transplantation for Elderly Patients with Nonremission Myeloid Malignancies

The optimal intensity of a conditioning regimen might be dependent on not only age and comorbidities but also disease activity and the type of graft source. We evaluated the outcome of unrelated single cord blood transplantation (CBT) using a conditioning regimen of fludarabine 180 mg/m², i.v. busulfan 9.6 mg/kg, 4 Gy total body irradiation, granulocyte colony-stimulating factor–combined high-dose cytarabine (12 g/m²) in 23 elderly patients (median, 64 years) with nonremission myeloid malignancies between 2013 and 2018 in our institution. All but 1 patient achieved neutrophil engraftment at a median of 23.5 days (range, 18 to 50). With a median follow-up of 28 months, the probabilities of overall survival (OS), disease-free survival (DFS), and cumulative incidence of relapse at 2 years were 62%, 52%, and 26%, respectively. The cumulative incidences of nonrelapse mortality at 100 days and 2 years were 9% and 22%, respectively. In the univariable analysis a higher proportion of blasts in bone marrow and in peripheral blood and a monosomal or complex karyotype were significantly associated with inferior OS and DFS. Poor cytogenetics were significantly associated with inferior DFS and increased relapse incidence. These data demonstrate that this reduced-toxicity myeloablative conditioning regimen was tolerable and effective in terms of engraftment, relapse, and survival in single CBT for elderly patients with nonremission myeloid malignancies.     

Haploidentical Stem Cell Transplantation with Post-Transplant Cyclophosphamide in Fanconi Anemia: Improving Outcomes with Improved Supportive Care in India

Fanconi anemia is the most common inherited bone marrow failure syndrome, and hematopoietic stem cell transplantation (HSCT) is the only curative option. Post-transplant cyclophosphamide (PTCy) is challenging in this group of children, given their increased sensitivity to chemotherapy. We performed a retrospective analysis of the data on children diagnosed with Fanconi anemia who underwent a haploidentical HSCT with PTCy from January 2014 to December 2019. Nineteen children (male/female, 0.75:1) underwent 21 haplo-HSCTs with PTCy. Fludarabine, low-dose cyclophosphamide, and 200 centi-gray total body irradiation were included in the conditioning regimen with 25 mg/kg PTCy on days +3 and +4. Haplo-graft was from a sibling in 38% and father in 57% of transplants. The source of stem cells was peripheral blood stem cells in 81% and bone marrow in 19% of transplants, with a median CD34 dose of 5.0 × 10⁶/kg. We documented engraftment in 84% and primary graft failure in 10% of transplants. N-acetylcysteine (NAC) was infused concomitantly during cyclophosphamide in 13 children. Grade 2 and 3 mucositis was lower among those who received NAC as compared to those who did not (30% and 15% versus 33% and 50%), while transaminitis was higher among those who did not receive the infusion. The incidence of acute graft-versus-host disease (GVHD) was 68%, and 81% of these were steroid responsive (grade I/II). We documented chronic GVHD in 25% children, predominantly involving the skin and mouth, which responded to low-dose steroids and ruxolitinib. Serum ferritin was monitored twice weekly as a surrogate marker for cytokine release syndrome due to nonavailability of IL-6 levels. A 1- or 2-log increase in the titers of ferritin associated with clinical features guided the early addition of steroids in the periengraftment period. The mean survival was found to be less among those with high serum ferritin (>10,000 ng/dL) in the periengraftment period as compared to those with ferritin <10,000 ng/dL (mean survival of 25 ± 10 months versus 50 ± 6 months, respectively). The overall survival in our cohort was 68.4%, with a mean survival time of 41.5 months (95% confidence interval, 29.3 to 53.8 months), with a statistically significant correlation between inferior outcome and having received over 15 transfusions before HSCT (P = .01). PTCy can be considered a viable option in children with Fanconi anemia, particularly in resource-limited settings given the high costs of HSCTs. Focused interventions in this subset of children help improve survival outcomes. Early identification of cytokine release syndrome and risk-adapted steroid therapy during engraftment helps prevent mortality. The concomitant use of NAC during cyclophosphamide infusion helps reduce oxygen free radical related tissue damage and regimen-related toxicity.