Reduced-intensity transplantation for lymphomas using haploidentical related donors vs HLA-matched unrelated donors. Blood. 2016;127:938-947. [PMID: 26670632 DOI: 10.1182/blood-2015-09-671834]

Real-world experience: Introduction of T cell replete haploidentical transplantations in a single center

Objectives

The aim of this study was to describe real-world data on outcomes of T cell replete haploidentical hematopoietic stem cell transplantation (HSCT) after the introduction of this modality in a single center and to compare them with different donor types.

Method

Outcomes of 30 consecutive patients with hematological malignancies that received T cell replete haploidentical HSCT with posttransplantation cyclophosphamide (PTCY) from 2016 to 2018 in our center were analyzed and compared to the outcome of human leukocyte antigen (HLA)-related and unrelated matched donor HSCT (n = 97) and to a historical cohort of T cell depleted haploidentical HSCT (n = 11).

Results

One year graft-versus-host-free, relapse-free survival in haploidentical HSCT was comparable with other donor types (haplo 40%, matched related donor [MRD] 33%, matched unrelated donor [MUD] 25%, p = 0.55). Non relapse mortality was high in haploidentical HSCT (50%), mostly due to infectious complications. However, relapse rates were only 3%, and OS and progression-free survival after 1 year were 47% and thereby also similar to HLA-matched HSCT in our center (MRD 53%, MUD 48%).

Conclusion

Our data show that T cell replete haploidentical HSCT has similar outcomes to HLA identical HSCT after introduction in our center. More strict adaptation on infection prevention was a crucial aspect of our learning curve. Overall, this type of transplantation is a feasible option when lacking an HLA-identical donor. This option has advantages over an unrelated donor as it brings less logistical challenges than MUD transplantations.

Standardizing Definitions of Hematopoietic Recovery, Graft Rejection, Graft Failure, Poor Graft Function, and Donor Chimerism in Allogeneic Hematopoietic Cell Transplantation: A Report on Behalf of the American Society for Transplantation and Cellular Therapy

Allogeneic hematopoietic cell transplantation (allo-HCT) is potentially curative for certain hematologic malignancies and nonmalignant diseases. The field of allo-HCT has witnessed significant advances, including broadening indications for transplantation, availability of alternative donor sources, less toxic preparative regimens, new cell manipulation techniques, and novel GVHD prevention methods, all of which have expanded the applicability of the procedure. These advances have led to clinical practice conundrums when applying traditional definitions of hematopoietic recovery, graft rejection, graft failure, poor graft function, and donor chimerism, because these may vary based on donor type, cell source, cell dose, primary disease, graft-versus-host disease (GVHD) prophylaxis, and conditioning intensity, among other variables. To address these contemporary challenges, we surveyed a panel of allo-HCT experts in an attempt to standardize these definitions. We analyzed survey responses from adult and pediatric transplantation physicians separately. Consensus was achieved for definitions of neutrophil and platelet recovery, graft rejection, graft failure, poor graft function, and donor chimerism, but not for delayed engraftment. Here we highlight the complexities associated with the management of mixed donor chimerism in malignant and nonmalignant hematologic diseases, which remains an area for future research. We recognize that there are multiple other specific, and at times complex, clinical scenarios for which clinical management must be individualized.

Increased Infections and Delayed CD4+ T Cell but Faster B Cell Immune Reconstitution after Post-Transplantation Cyclophosphamide Compared to Conventional GVHD Prophylaxis in Allogeneic Transplantation

Post-transplantation cyclophosphamide (PTCy) is being increasingly used for graft-versus-host disease (GVHD) prophylaxis after allogeneic hematopoietic cell transplantation (allo-HCT) across various donor types. However, immune reconstitution and infection incidence after PTCy-based versus conventional GVHD prophylaxis has not been well studied. We evaluated the infection density and immune reconstitution (ie, absolute CD4⁺ T cell, CD8⁺ T cell, natural killer cell, and B cell counts) at 3 months, 6 months, and 1 year post-HCT in 583 consecutive adult patients undergoing allo-HCT with myeloablative (n = 223) or reduced-intensity (n = 360) conditioning between 2012 and 2018. Haploidentical (haplo; n = 75) and 8/8 HLA-matched unrelated (MUD; n = 08) donor types were included. GVHD prophylaxis was PTCy-based in all haplo (n = 75) and in 38 MUD allo-HCT recipients, whereas tacrolimus/methotrexate (Tac/MTX) was used in 89 and Tac/Sirolimus (Tac/Sir) was used in 381 MUD allo-HCT recipients. Clinical outcomes, including infections, nonrelapse mortality (NRM), relapse, and overall survival (OS), were compared across the 4 treatment groups. The recovery of absolute total CD4⁺ T-cell count was significantly lower in the haplo-PTCy and MUD-PTCy groups compared with the Tac/MTX and Tac/Sir groups throughout 1 year post-allo-HCT (P = .025). In contrast, CD19⁺ B-cell counts at 6 months and thereafter were higher in the haplo-PTCy and MUD-PTCy groups compared with the Tac/MTX and Tac/Sir groups (P < .001). Total CD8⁺ T cell and NK cell recovery was not significantly different among the groups. Infection density analysis showed a significantly higher frequency of total infections in the haplo-PTCy and MUD-PTCy groups compared with the Tac/MTX and Tac/Sir groups (5.0 and 5.0 vs 1.8 and 2.6 per 1000-person days; P < .01) within 1 year of allo-HCT. The cumulative incidence of cytomegalovirus reactivation/infection at 1 year post-allo-HCT was higher in the haplo-PTCy group (51%) compared with the MUD-PTCy (26%), Tac/MTX (26%), or Tac/Sir (13%) groups (P < .001). The incidence of BK, human herpesvirus 6, and other viruses were also higher in the PTCy-based groups. Overall, the treatment groups had similar 2 year NRM (P = .27) and OS (P = .78) outcomes. Our data show that PTCy-based GVHD prophylaxis is associated with delayed CD4⁺ T cell but faster B cell immune reconstitution and a higher frequency of infections compared with conventional GVHD prophylaxis but has no impact on nonrelapse mortality or overall survival.

Cytokine release syndrome after haploidentical hematopoietic cell transplantation: an international multicenter analysis

Haploidentical related donor transplantation (haplo-HCT) is associated with cytokine release syndrome (CRS). We conducted a multicenter retrospective study to analyze risk factors for CRS and outcomes after haplo-HCT. We included 451 patients from four academic centers receiving both peripheral blood and bone marrow grafts. Severe CRS was more common with PB vs. BM grafts (19.5% vs 4.9%, OR 2.9, p = 0.05). Multivariable analysis identified recipient CMV sero-positivity, prior transplant, HCT-CI score and donor-recipient sex mismatch as risk factors for severe CRS. Outcomes were analyzed with no CRS as the comparison group. Overall survival (OS) was superior with mild CRS (HR 0.64, p = 0.05) and worst with severe CRS (HR 2.12, p = 0.0038). Relapse risk was significantly decreased in both mild CRS (HR 0.38, p < 0.0001) and severe CRS (HR 0.17, p < 0.0001) groups. The risk of non-relapse mortality was notably higher in severe CRS group (HR 8.0, p < 0.0001), but not in mild CRS group. Acute GVHD was similar among groups. Chronic GVHD at 1 year was 18.5% for no CRS, 23% for mild CRS, and 4.3% for severe CRS (p = 0.0023), with the competing risk of early mortality and short follow up of surviving patients contributing to the low chronic GVHD rates in the severe CRS group.

Identification of an Optimal Population for Allogeneic Hematopoietic Stem Cell Transplantation in Patients With Mature T and NK Cell Neoplasms

BACKGROUND/AIM

The prognosis of mature T and natural killer (NK) cell neoplasms still remains dismal, despite the advancements in the understanding of the heterogeneous features of these diseases. As allogeneic stem cell transplantation (alloSCT) is an attractive salvage option for relapsed/refractory patients, we conducted this study to identify those who might benefit the most from alloSCT.

PATIENTS AND METHODS

This was a retrospective, single-center, longitudinal cohort study of patients who received alloSCT between December 2019 and January 2000.

RESULTS

The median relapse-free survival and overall survival were 4.4 and 10.0 months, respectively. Disease control status at alloSCT and number of previous treatments were associated with survival outcomes. The conditioning intensity did not significantly alter survival.

CONCLUSION

AlloSCT offers a cure chance for selected relapsed or refractory T and NK cell neoplasms, especially when used early and the disease is well controlled prior to transplantation.

Reduced dose of PTCy followed by adjuvant α-galactosylceramide enhances GVL effect without sacrificing GVHD suppression

Posttransplantation cyclophosphamide (PTCy) has become a popular option for haploidentical hematopoietic stem cell transplantation (HSCT). However, personalized methods to adjust immune intensity after PTCy for each patient’s condition have not been well studied. Here, we investigated the effects of reducing the dose of PTCy followed by α-galactosylceramide (α-GC), a ligand of iNKT cells, on the reciprocal balance between graft-versus-host disease (GVHD) and the graft-versus-leukemia (GVL) effect. In a murine haploidentical HSCT model, insufficient GVHD prevention after reduced-dose PTCy was efficiently compensated for by multiple administrations of α-GC. The ligand treatment maintained the enhanced GVL effect after reduced-dose PTCy. Phenotypic analyses revealed that donor-derived B cells presented the ligand and induced preferential skewing to the NKT2 phenotype rather than the NKT1 phenotype, which was followed by the early recovery of all T cell subsets, especially CD4⁺Foxp3⁺ regulatory T cells. These studies indicate that α-GC administration soon after reduced-dose PTCy restores GVHD-preventing activity and maintains the GVL effect, which is enhanced by reducing the dose of PTCy. Our results provide important information for the development of a novel strategy to optimize PTCy-based transplantation, particularly in patients with a potential relapse risk.

International retrospective study of allogeneic hematopoietic cell transplantation for activated PI3K-delta syndrome

Background:

Activated phosphoinositide 3-kinase delta syndrome (APDS) is a combined immunodeficiency with a heterogeneous phenotype considered reversible by allogeneic hematopoietic cell transplantation (HCT).

Objectives:

This study sought to characterize HCT outcomes in APDS.

Methods:

Retrospective data were collected on 57 patients with APDS1/2 (median age, 13 years; range, 2–66 years) who underwent HCT.

Results:

Pre-HCT comorbidities such as lung, gastrointestinal, and liver pathology were common, with hematologic malignancy in 26%. With median follow-up of 2.3 years, 2-year overall and graft failure–free survival probabilities were 86% and 68%, respectively, and did not differ significantly by APDS1 versus APDS2, donor type, or conditioning intensity. The 2-year cumulative incidence of graft failure following first HCT was 17% overall but 42% if mammalian target of rapamycin inhibitor(s) (mTORi) were used in the first year post-HCT, compared with 9% without mTORi. Similarly, 2-year cumulative incidence of unplanned donor cell infusion was overall 28%, but 65% in the context of mTORi receipt and 23% without. Phenotype reversal occurred in 96% of evaluable patients, of whom 17% had mixed chimerism. Vulnerability to renal complications continued post-HCT, adding new insights into potential nonimmunologic roles of phosphoinositide 3-kinase not correctable through HCT.

Conclusions:

Graft failure, graft instability, and poor graft function requiring unplanned donor cell infusion were major barriers to successful HCT. Post-HCT mTORi use may confer an advantage to residual host cells, promoting graft instability. Longer-term post-HCT follow-up of more patients is needed to elucidate the kinetics of immune reconstitution and donor chimerism, establish approaches that reduce graft instability, and assess the completeness of phenotype reversal over time.

Impact of donor age and kinship on clinical outcomes after T-cell-replete haploidentical transplantation with PT-Cy

Donor selection contributes to improve clinical outcomes of T-cell-replete haploidentical stem cell transplantation (haplo-SCT) with posttransplant cyclophosphamide (PT-Cy). The impact of donor age and other non-HLA donor characteristics remains a matter of debate. We performed a multicenter retrospective analysis on 990 haplo-SCTs with PT-Cy. By multivariable analysis, after adjusting for donor/recipient kinship, increasing donor age and peripheral blood stem cell graft were associated with a higher risk of grade 2 to 4 acute graft-versus-host-disease (aGVHD), whereas 2-year cumulative incidence of moderate-to-severe chronic GVHD was higher for transplants from female donors into male recipients and after myeloablative conditioning. Increasing donor age was associated with a trend for higher nonrelapse mortality (NRM) (hazard ratio [HR], 1.05; P = .057) but with a significant reduced risk of disease relapse (HR, 0.92; P = .001) and improved progression-free survival (PFS) (HR, 0.97; P = .036). Increasing recipient age was a predictor of worse overall survival (OS). Risk of relapse was higher (HR, 1.39; P < .001) in patients aged ≤40 years receiving a transplant from a parent as compared with a sibling. Moreover, OS and PFS were lower when the donor was the mother rather than the father. Pretransplant active disease status was an invariably independent predictor of worse clinical outcomes, while recipient positive cytomegalovirus serostatus and hematopoietic cell transplant comorbidity index >3 were associated with worse OS and PFS. Our results suggest that younger donors may reduce the incidence of aGVHD and NRM, though at higher risk of relapse. A parent donor, particularly the mother, is not recommended in recipients ≤40 years.

Checkpoint inhibition before haploidentical transplantation with posttransplant cyclophosphamide in Hodgkin lymphoma

We report on 59 Hodgkin lymphoma patients undergoing haploidentical stem cell transplantation (SCT; haplo-SCT) with posttransplant cyclophosphamide (PTCy) as graft-versus-host disease (GVHD) prophylaxis, comparing outcomes based on pretransplant exposure to checkpoint inhibitors (CPIs). Considering pretransplant characteristics, the 2 cohorts (CPI = 29 patients vs no-CPI = 30 patients) were similar, except for the number of prior lines of therapy (6 vs 4; P < .001). With a median follow-up of 26 months (range, 7.5-55 months), by univariate analysis, the 100-day cumulative incidence of grade 2-4 acute GVHD was 41% in the CPI group vs 33% in the no-CPI group (P = .456), whereas the 1-year cumulative incidence of moderate to severe chronic GVHD was 7% vs 8%, respectively (P = .673). In the CPI cohort, the 2-year cumulative incidence of relapse appeared lower compared with the no-CPI cohort (0 vs 20%; P = .054). No differences were observed in terms of overall survival (OS), progression-free survival (PFS), and nonrelapse mortality (NRM) (at 2 years, 77% vs 71% [P = .599], 78% vs 53% [P = .066], and 15% vs 21% [P = .578], respectively). By multivariable analysis, CPI before SCT was an independent protective factor for PFS (hazard ratio [HR], 0.32; P = .037). Stable disease (SD)/progressive disease (PD) was an independent negative prognostic factor for both OS and PFS (HR, 14.3; P < .001 and HR, 14.1; P < .001, respectively) . In conclusion, CPI as a bridge to haplo-SCT seems to improve PFS, with no impact on toxicity profile.

Comparing transplant outcomes in ALL patients after haploidentical with PTCy or matched unrelated donor transplantation

We compared outcomes of 1461 adult patients with acute lymphoblastic leukemia (ALL) receiving hematopoietic cell transplantation (HCT) from a haploidentical (n = 487) or matched unrelated donor (MUD; n = 974) between January 2005 and June 2018. Graft-versus-host disease (GVHD) prophylaxis was posttransplant cyclophosphamide (PTCy), calcineurin inhibitor (CNI), and mycophenolate mofetil (MMF) for haploidentical, and CNI with MMF or methotrexate with/without antithymoglobulin for MUDs. Haploidentical recipients were matched (1:2 ratio) with MUD controls for sex, conditioning intensity, disease stage, Philadelphia-chromosome status, and cytogenetic risk. In the myeloablative setting, day +28 neutrophil recovery was similar between haploidentical (87%) and MUD (88%) (P = .11). Corresponding rates after reduced-intensity conditioning (RIC) were 84% and 88% (P = .47). The 3-month incidence of grade II-IV acute GVHD (aGVHD) and 3-year chronic GVHD (cGVHD) was similar after haploidentical compared with MUD: myeloablative conditioning, 33% vs 34% (P = .46) for aGVHD and 29% vs 31% for cGVHD (P = .58); RIC, 31% vs 30% (P = .06) for aGVHD and 24% vs 29% for cGVHD (P = .86). Among patients receiving myeloablative regimens, 3-year probabilities of overall survival were 44% and 51% with haploidentical and MUD (P = .56). Corresponding rates after RIC were 43% and 42% (P = .6). In this large multicenter case-matched retrospective analysis, despite the limitations of a registry-based study (ie, unavailability of key elements such as minimal residual disease testing), our analysis indicated that outcomes of patients with ALL undergoing HCT from a haploidentical donor were comparable with 8 of 8 MUD transplantations.

Hematopoietic Stem Cell Transplantation in T Cell and Natural Killer Cell Lymphomas: Update on Recent Advances

Mature T and natural killer (NK) cell non-Hodgkin lymphoma (T-NHL) has a poor prognosis. Data from existing retrospective and prospective studies have suggested that high-dose chemotherapy followed by autologous hematopoietic cell transplantation (auto-HCT) may improve the survival in patients with chemosensitive disease, either in the upfront or salvage setting. Auto-HCT is currently recommended to be used as frontline consolidation in peripheral T cell lymphoma not otherwise specified, angioimmunoblastic T cell lymphoma, anaplastic large cell lymphoma-anaplastic lymphoma kinase negative, NK/T cell (disseminated), and enteropathy-associated T cell lymphoma. However, about one-third of patients never reach transplantation because of early relapse or refractory disease. Allogeneic hematopoietic cell transplantation (allo-HCT), via its immunologic graft-versus-lymphoma effect, has been used to salvage patients with relapsed or refractory disease, resulting in long-term disease-free survival in a fraction of patients. However, the higher risk of transplant-related mortality due to regimen-related toxicities, graft-versus-host disease, and post-transplant infectious complications continues to limit the mainstream adoption of allo-HCT for this disease. Despite that, allo-HCT has been incorporated as part of the frontline treatment for aggressive subtypes of T-NHL, such as γδ T cell lymphoma and aggressive NK cell leukemia. Recent attempts to incorporate novel targeted T cell directed therapies into the treatment pathway of T-NHL may enhance treatment response and enable more patients to reach transplant, offering an alternative means of treating this disease.

Myeloablative Haploidentical Transplant as an Alternative to Matched Sibling Transplant for Peripheral T-Cell Lymphomas

The number of HLA-haploidentical allogeneic hematopoietic stem-cell transplantation (Haplo-HSCT) is increasing. Comparative studies about Haplo-HSCT versus allo-HSCT with HLA-matched sibling donors (MSD-HSCT) have been tried in leukemias and B-cell lymphomas. Few studies were reported in Peripheral T-cell lymphomas (PTCLs). We performed a multicenter retrospective study about 52 patients with PTCLs undergoing Haplo-HSCT (n = 20) or MSD-HSCT (n = 32). All Haplo-HSCT recipients received antithymocyte globulin (ATG) based graft versus host disease (GVHD) prophylaxis. The median follow-up for all survivors was 38 months. The 100-day cumulative incidence of grade II to IV acute GVHD was similar (19% in the MSD-HSCT group versus 28% in the Haplo-HSCT group, P = 0.52). The 2-year cumulative incidence of chronic GVHD (limited and extensive) after Haplo-HSCT (30%) was also similar with that in the MSD-HSCT group (50%, P = 0.15). The 3-year relapse rates (33% vs 27%, P = 0.84) and non-relapse mortality (21% vs 22%, P = 0.78) did not differ between these two groups. There were also no differences in 3-year overall survival (OS) (48% vs 50%, P = 0.78) and progression-free survival (47% vs 51%, P = 0.95) between these two groups. On multivariate analysis, prognostic index for T-cell lymphoma (PIT) score (higher than 1: hazard ratio [HR], 4.0; P = 0.003) and disease status (stable or progression disease before HSCT: HR, 2.8; P = 0.03) were independent variables associated with worse OS. We concluded that ATG-based haplo-HSCT platform could work as an alternative to MSD-HSCT for patients with PTCLs.

Nonmyeloablative Conditioning Regimen Including Low-Dose Total Marrow/Lymphoid Irradiation Before Haploidentical Transplantation with Post-Transplantation Cyclophosphamide in Patients with Advanced Lymphoproliferative Diseases

Low-dose total body irradiation (TBI) has long been used in nonmyeloablative conditioning (NMAC) regimens before allogeneic stem cell transplantation from haploidentical donors (haplo-SCT). More recently, the use of total marrow lymphoid irradiation (TMLI) instead of TBI in conditioning is increasing. This study aimed to evaluate outcomes in a cohort of patients treated with low-dose TMLI in terms of engraftment, full donor chimerism status, graft-versus-host disease (GVHD), and extrahematologic toxicities, and to compare these outcomes with those in a cohort of patients receiving conventional TBI-containing conditioning. This retrospective single-center study included 100 patients with advanced hematologic malignancies who underwent haplo-SCT. Between 2009 and 2011, the NMAC regimen consisted of cyclophosphamide, fludarabine, and low-dose TBI (2 Gy), and after 2011, TBI was replaced with TMLI (2 Gy). Patients received post-transplantation cyclophosphamide, calcineurin inhibitor, and mycophenolate mofetil as GVHD prophylaxis. For all patients, the median time to absolute neutrophil count (ANC) recovery to >0.5 × 10⁹/L was 21 days (range, 15 to 49 days), the 30-day incidence of ANC recovery was 97% (95% confidence interval [CI], 89% to 99%), the median time to achieve an unsupported platelet count >20 × 10⁹/L was 26 days (range, 12 to 67 days), and the 60-day rate of platelet engraftment was 99% (95% CI, 89% to 100%). Cumulative incidence of full donor chimerism by day 100 was 88% (95% CI 79-90). Grade II-IV acute GVHD occurred in 35% of the patients (95% CI, 26% to 45%) at a median of 40 days (range, 23 to 166 days). The incidence of moderate to severe chronic GVHD was 5% (95% CI, 2% to 10%). No differences between the TBI and TMLI cohorts were seen in terms of engraftment, full donor chimerism, and GVHD. No organ toxicity was observed in the first months after transplantation in either cohort. The overall 2-year OS and PFS rates were 63%, and 54%, respectively, and were comparable in the 2 groups (P = .548). The strongest finding was that TBI can be safely replaced by TMLI in terms of engraftment, achievement of full donor chimerism status, GVHD incidence, and extrahematologic toxicities.

Feasibility and Efficacy of CD45RA+ Depleted Donor Lymphocytes Infusion After Haploidentical Transplantation With Post-Transplantation Cyclophosphamide in Patients With Hematological Malignancies

Allogeneic stem cell transplantation from haploidentical donor using post-transplantation cyclophosphamide has been used to cure hematological diseases. Because of slow immunological reconstitution, there is an increased incidence of viral infection. The aim of our study was to prospectively evaluate the efficacy and the feasibility of a CD45RA+ depleted donor lymphocytes infusion (DLI) in terms of reduction of viral infection early after haploidentical transplantation. This a prospective single-center study. We enrolled 23 patients, of whom 19 were evaluable. Graft-versus-host disease (GVHD) prophylaxis was the same for all patients. The primary endpoint was 100-day cumulative incidence of viral infections. The primary endpoint was met, because the 100-day cumulative incidence of viral infection was 32%. The median time from transplantation to first CD45RA+ depleted DLI was 55 days (range, 46-63). 28% of patients had cytomegalovirus reactivation, no patients reactivated human herpesvirus-6; 1 patient developed BK virus related hemorrhagic cystitis. Most of the patients received the planned 3 infusions. Only 1 patient had development of grade 2 acute GVHD, and 2 patients had moderate chronic GVHD. All evaluable patients were off immunosuppressive therapy at last follow-up. The median follow-up was 12 months (range, 3-23), the 1-year overall survival and progression-free survival were 79% and 75%, respectively; the 100-day and 1-year non-relapse mortality were 5% and 12%, respectively. CD45RA+ depleted DLI are feasible in patients treated with haploidentical transplantation. The toxic profile is good with a low risk for development of both acute and chronic GVHD.

Post-transplantation cyclophosphamide reduces the incidence of acute graft-versus-host disease in patients with acute myeloid leukemia/myelodysplastic syndromes who receive immune checkpoint inhibitors after allogeneic hematopoietic stem cell transplantation

Background

Immune checkpoint inhibitors (ICIs) are being used after allogeneic hematopoietic stem cell transplantation (alloHCT) to reverse immune dysfunction. However, a major concern for the use of ICIs after alloHCT is the increased risk of graft-versus-host disease (GVHD). We analyzed the association between GVHD prophylaxis and frequency of GVHD in patients who had received ICI therapy after alloHCT.

Methods

A retrospective study was performed in 21 patients with acute myeloid leukemia (n=16) or myelodysplastic syndromes (n=5) who were treated with antiprogrammed cell death protein 1 (16 patients) or anticytotoxic T lymphocyte-associated antigen 4 (5 patients) therapy for disease relapse after alloHCT. Associations between the type of GVHD prophylaxis and incidence of GVHD were analyzed.

Results

Four patients (19%) developed acute GVHD. The incidence of acute GVHD was associated only with the type of post-transplantation GVHD prophylaxis; none of the other variables included (stem cell source, donor type, age at alloHCT, conditioning regimen and prior history of GVHD) were associated with the frequency of acute GVHD. Twelve patients received post-transplantation cyclophosphamide (PTCy) for GVHD prophylaxis. Patients who received PTCy had a significantly shorter median time to initiation of ICI therapy after alloHCT compared with patients who did not receive PTCy (median 5.1 months compared with 26.6 months). Despite early ICI therapy initiation, patients who received PTCy had a lower observed cumulative incidence of grades 2–4 acute GVHD compared with patients who did not receive PTCy (16% compared with 22%; p=0.7). After controlling for comorbidities and time from alloHCT to ICI therapy initiation, the analysis showed that PTCy was associated with a 90% reduced risk of acute GVHD (HR 0.1, 95% CI 0.02 to 0.6, p=0.01).

Conclusions

ICI therapy for relapsed acute myeloid leukemia/myelodysplastic syndromes after alloHCT may be a safe and feasible option. PTCy appears to decrease the incidence of acute GVHD in this cohort of patients.

Grade 3-4 cytokine release syndrome is associated with poor survival in haploidentical peripheral blood stem cell transplantation

The information on the impact of cytokine release syndrome (CRS) on haploidentical donor peripheral blood stem cell transplant (haploPBSCT) outcomes is limited. We retrospectively evaluated 98 patients who underwent haploPBSCT between June 2012 and June 2019 for the onset and severity of CRS per the ASTCT guidelines. The incidence of CRS was 93% (91/98). Outcomes were compared between grade 1-2 and 3-4 CRS. Eighty-one patients developed grade 1-2 CRS (89%) and 10 (11%) developed grade 3-4 CRS. Compared to grade 1-2 CRS, grade 3-4 CRS experienced adverse survival (73.7% vs. 30%, p<.001), inferior relapse-free survival (64.0% vs. 20%, p<.001), and higher non-relapse mortality (NRM) (16.4% vs. 60%, p<.001) at 1-year. Propensity score-based multivariable analyses revealed worse survival (HR 2.71, p=.04), and higher NRM (SHR 4.51, p=.006) with grade 3-4 CRS. Our study shows that grade 3-4 CRS was adversely associated with survival. Therefore, early identification and preventive strategies are warranted.

Haploidentical stem cell transplantation vs matched unrelated donor transplantation in adults with hematologic malignancies: a systematic review and meta-analysis

OBJECTIVES

Haploidentical hematopoietic stem cell transplantation (Haplo-SCT) and matched unrelated donor transplantation (MUD-SCT) are two important options when a matched sibling donor (MSD) is unavailable. Several studies comparing Haplo-SCT and MUD-SCT have reported inconsistent clinical outcomes. Therefore, it is necessary to synthesize the existing evidence regarding outcomes of stem cell transplantations comparing Haplo-SCT with MUD-SCT.

METHODS

We searched for titles of articles in MEDLINE (PubMed), Cochrane library, EMBASE database that compared transplantation with Haplo-SCT versus MUD-SCT. To compare clinical outcomes between Haplo-SCT and MUD-SCT, we performed a meta-analysis of 17 studies and reported the pooled odd ratios (OR) of 6 endpoints including overall survival (OS), progression free survival (PFS), non-relapse mortality (NRM), relapse rate (RR), acute graft-versus-host disease (aGVHD) and chronic graft- versus-host disease (cGVHD).

RESULTS

We found that Haplo-SCT was associated with a comparable OS (pooled OR of 0.99, 95% Confidence Interval (CI) 0.86-1.14), PFS (OR 1.00, 95% CI 0.88-1.15), NRM (OR 0.83, 95% CI 0.65-1.04) and RR (OR 1.08, 95% CI 0.95-1.22) compared to MUD-SCT. We also found a significantly decreased risk of aGVHD (OR 0.74, 95% CI 0.62-0.88) and cGVHD (OR 0.50, 95% CI 0.38-0.66) in Haplo-SCT group.

CONCLUSION

Results of this meta-analysis demonstrates that Haplo-SCT achieves comparable clinical outcomes compared to MUD-SCT in terms of OS, PFS, TRM and RR, but is better than MUD-SCT in terms of decreased aGVHD and cGVHD risk. Haplo-SCT is a valid option for patient needing urgent transplantation.

Association of Reduced-Intensity Conditioning Regimens With Overall Survival Among Patients With Non-Hodgkin Lymphoma Undergoing Allogeneic Transplant

Importance

Reduced-intensity conditioning and nonmyeloablative conditioning (RIC-NMAC) regimens are frequently used in allogeneic hematopoietic cell transplant (HCT) for non-Hodgkin lymphoma. However, the optimal RIC-NMAC regimen in allogeneic HCT for non-Hodgkin lymphoma is not known.

Objective

To investigate whether RIC-NMAC regimens at a higher end of the intensity spectrum are associated with increased nonrelapse mortality and lower overall survival compared with RIC-NMAC regimens at the lower end of the intensity spectrum in patients with non-Hodgkin lymphoma undergoing allogeneic HCT.

Design, Setting, and Participants

This cohort study used data from 1823 adult patients with non-Hodgkin lymphoma in the Center for International Blood and Marrow Transplant Research registry. Included patients underwent allogeneic HCT using matched related or unrelated donors between January 2008 and December 2016. Statistical analysis was performed from June 1, 2019, to February 10, 2020.

Interventions

Patients received 1 of 4 RIC-NMAC regimens: fludarabine-intravenous busulfan (Flu-Bu), approximately 6.4 mg/kg (n = 458); fludarabine-melphalan (Flu-Mel140), 140 mg/m2 (n = 885); fludarabine-cyclophosphamide (Flu-Cy) (n = 391); or Flu-Cy with 2 Gy total body irradiation (Flu-Cy-2GyTBI) (n = 89).

Main Outcomes and Measures

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

Results

Of 1823 patients, 1186 (65%) were male, with a mean (SD) age of 54.8 (9.9) years. The 4-year adjusted OS was 58% in the Flu-Bu cohort, 67% in the Flu-Cy-2GyTBI cohort, 49% in the Flu-Mel140 cohort, and 63% in the Flu-Cy cohort (P < .001). After adjustment for age, Karnofsky performance score, HCT comorbidity index, NHL subtype, remission status at HCT, and the use of antithymocyte globulin or alemtuzumab, the regression analysis showed a significantly higher mortality risk associated with Flu-Mel140 compared with Flu-Bu (hazard ratio [HR], 1.34; 95% CI, 1.13-1.59; P < .001). Compared with the Flu-Cy cohort, the Flu-Mel140 cohort had a higher risk of chronic GVHD (HR, 1.38; 95% CI, 1.15-1.65; P < .001). The Flu-Mel140 regimen was associated with a higher nonrelapse mortality risk (HR, 1.78; 95% CI, 1.37-2.31; P < .001) compared with the Flu-Bu regimen.

Conclusions and Relevance

The findings suggest that use of the more intense RIC-NMAC regimen, Flu-Mel140, may have a negative association with overall survival and may be associated with higher nonrelapse mortality. The Flu-Bu and Flu-Cy regimens with or without 2GyTBI regimens appeared to provide comparable overall survival.

Multicenter Phase II Study on Haploidentical Bone Marrow Transplantation Using a Reduced-Intensity Conditioning Regimen and Posttransplantation Cyclophosphamide in Patients with Poor-Prognosis Lymphomas

Allogeneic stem cell transplantation from haploidentical donors using unmanipulated bone marrow and posttransplantation cyclophosphamide has been largely employed to cure high-risk lymphomas. However, the increased incidence of relapse associated with the use of a nonmyeloablative conditioning regimen is still considered a concerning issue. The aim of our study was to prospectively evaluate the efficacy and feasibility of a reduced-intensity conditioning regimen, including thiotepa, cyclophosphamide, and fludarabine, in high-risk lymphoma patients. This was a prospective multicenter study. We enrolled 49 patients, of whom 47 were evaluable. Graft source (bone marrow) and graft-versus-host disease (GVHD) prophylaxis were the same for all patients. The primary endpoint was the proportion of patients free of disease progression at 1 year. The primary endpoint was met, as 29 out of 47 patients were alive and free of disease at 1 year (1-year progression-free survival, 60%). Forty-five recipients engrafted and achieved full donor chimerism at day 100. The cumulative incidences (CIs) of ANC engraftment at 30 days and platelet engraftment at 60 days were 89% and 83%, respectively. Two patients experienced graft failure. The CIs of day 100 grades 2 to 4 acute GVHD and 2-year moderate-to-severe chronic GVHD were 26% and 16%, respectively. With a median follow-up of 47.5 months (range, 22 to 74), the 4-year progression-free survival and overall survival were 54% and 64%, respectively. The 4-year CI of relapse was 28%, and the 4-year nonrelapse mortality was 15%. Thiotepa-based reduced-intensity conditioning was well tolerated with encouraging survival in a cohort of patients with poor-prognosis lymphoma. Both the incidence of relapse and nonrelapse mortality were acceptable.

Allogeneic Stem Cell Transplantation in Mantle Cell Lymphoma in the Era of New Drugs and CAR-T Cell Therapy

MCL is an uncommon lymphoproliferative disorder that has been regarded as incurable since its identification as a distinct entity. Allogeneic transplantation for two decades has represented the only option capable of ensuring prolonged remissions and possibly cure. Despite its efficacy, its application has been limited by feasibility limitations and substantial toxicity, particularly in elderly patients. Nevertheless, the experience accumulated over time has been wide though often scattered among retrospective and small prospective studies. In this review, we aimed at critically revise and discuss available evidence on allogeneic transplantation in MCL, trying to put available evidence into the 2020 perspective, characterized by unprecedented development of novel promising therapeutic agents and regimens.

Post-transplant cyclophosphamide versus antithymocyte globulin in allogeneic hematopoietic cell transplantation: a meta-analysis

Graft-versus-host disease (GVHD) prophylaxis based on post-transplant cyclophosphamide (PTCy) or antithymocyte globulin (ATG) is widely used in allogeneic hematopoietic stem cell transplantations (allo-HCT). The differential impacts of PTCy and ATG on transplantation outcomes are not well characterized. Here we report a meta-analysis of PTCy versus ATG in allo-HCT. Ten studies were eligible, and a total of 1871 patients were included. The incidence of II-IV aGVHD, III-IV aGVHD, and NRM were significantly lower in PTCy arm (HR = 0.63, 95% CI 0.45-0.89; HR = 0.35, 95% CI 0.16-0.77; HR = 0.59, 95% CI 0.48-0.73). PTCy was associated with a better OS and PFS (HR = 0.62, 95% CI = 0.53-0.73; HR = 0.76, 95% CI 0.62-0.93). The relapse rate and cGVHD incidence were not significantly different between PTCy and ATG (HR = 0.85, 95% CI 0.68-1.07; HR = 0.65, 95% CI 0.38-1.12). Thus, compared with ATG, PTCy has a better aGVHD control and OS benefit, without increasing relapse risk, which needs further validation in prospective randomized trials.

How we treat mature B-cell neoplasms (indolent B-cell lymphomas)

Mature B cell neoplasms, previously indolent non-Hodgkin lymphomas (iNHLs), are a heterogeneous group of malignancies sharing similar disease courses and treatment paradigms. Most patients with iNHL have an excellent prognosis, and in many, treatment can be deferred for years. However, some patients will have an accelerated course and may experience transformation into aggressive lymphomas. In this review, we focus on management concepts shared across iNHLs, as well as histology-specific strategies. We address open questions in the field, including the influence of genomics and molecular pathway alterations on treatment decisions. In addition, we review the management of uncommon clinical entities including nodular lymphocyte-predominant Hodgkin lymphoma, hairy cell leukemia, splenic lymphoma and primary lymphoma of extranodal sites. Finally, we include a perspective on novel targeted therapies, antibodies, antibody-drug conjugates, bispecific T cell engagers and chimeric antigen receptor T cell therapy.

Steroid-refractory chronic graft-versus-host disease: treatment options and patient management

Chronic graft-versus-host disease (cGVHD) is one of the major causes of late mortality after allogenic hematopoietic stem cell transplantation. Moderate-to-severe cGVHD is associated with poor health-related quality of life and substantial disease burden. While corticosteroids with or without calcineurin inhibitors comprise the first-line treatment option, the prognosis for patients with steroid-refractory cGVHD (SR-cGVHD) remains poor. The mechanisms underlying steroid resistance are unclear, and there are no standard second-line treatment guidelines for patients with SR-cGVHD. In this review, we provide an overview on current treatment options of cGVHD and use a series of theoretical case studies to elucidate the rationale of choices of second- and third-line treatment options for patients with SR-cGVHD based on individual patient profiles.

Incorporation of posttransplant cyclophosphamide as part of standard immunoprophylaxis for all allogeneic transplants: a retrospective, single institution study

The addition of posttransplant cyclophosphamide (PTCy) to standard graft-versus-host disease (GVHD) prophylaxis following haploidentical blood stem transplants has resulted in relatively low rates of GVHD. As GVHD remains a major cause of morbidity and mortality in patients receiving transplants from matched donors, we began to use PTCy in all blood stem cell transplants in 2016 and compared our recent experience with PTCy after matched sibling and unrelated donor transplants (N = 49) to the earlier 2-year period (N = 41) when PTCy was not used. Endpoints included graft-versus-host, relapse-free-survival (GRFS), overall survival, non-relapse mortality, and percentage of patients disease-free and off immunosuppression (DFOI) at 1 year and at the last follow-up. The difference in GRFS between the standard and the PTCy cohort was not statistically significant. There was a statistically improved relapse-free and overall survival in the PTCY cohort that was due to a significant decrease in non-relapse mortality secondary to GVHD. There was also a borderline statistically improved DFOI at 1 year and at last follow-up in the PTCY group. These results suggest that PTCy after HLA-matched transplants provides at least comparable efficacy to other GVHD strategies and may allow more frequent discontinuation of immunosuppression.

Haploidentical related donor compared to HLA-identical donor transplantation for chemosensitive Hodgkin lymphoma patients

Background

Allogeneic stem cell transplantation from haploidentical donor using an unmanipulated graft and post-transplantation cyclophosphamide (PT-Cy) is growing. Haploidentical transplantation with PT-Cy showed a major activity in Hodgkin lymphoma (HL), reducing the relapse incidence. The most important predictive factor of survival and toxicity was disease status before transplantation, which was better in patients with well controlled disease.

Methods

We included 198 HL in complete (CR) or partial remission (PR) before transplantation. Sixty-five patients were transplanted from haploidentical donor and 133 from a HLA identical donor (both sibling and unrelated donors). Survival analysis was defined according to the EBMT criteria. Survival curves were generated by using Kaplan-Meier method and differences between groups were compared by the log rank test or by the log rank test for trend when appropriated.

Results

The PFS, OS, and RI were significantly better in patients in CR compared to PR (55% vs 29% p = 0.001, 74% vs 55% p = 0.03, 27% vs 55% p <  0.001, respectively). The 2-year PFS was significantly better for HAPLO than HLA-id (63% vs 37%, p = 0.03), without difference in OS. The 1-year NRM was not different. The 2-year relapse incidence (RI) was lower in the HAPLO group (24% vs 44%, p = 0.008). Patients in CR receiving haplo HSCT showed higher 2-year PFS and lower 2-year RI than those allografted with HLA-id donor (75% vs 47%, p <  0.001 and 11% vs 34%, p < 0.001, respectively). In multivariate analysis, donor type and disease status before transplantation were independent predictors of PFS as well as they predict the risk of relapse. Disease status at transplantation and age were independently associated to OS.

Conclusions

Nonetheless this is a retrospective study, limiting the wide applicability of results, data from this analysis suggest that HLA mismatch can induce a strong graft versus lymphoma effect leading to an enhanced PFS.

Allogeneic stem cell transplantation in poor prognosis peripheral T-cell lymphoma: the impact of different donor type on outcome

We report the outcome of 68 patients with advanced peripheral T-cell lymphoma receiving transplantation from haploidentical or from conventional donors. The 4-year OS, PFS, 2-year cumulative incidence of relapse and 2-year GRFS was 75%, 70%, 21%, and 51%, respectively. Survival was not affected by donor type. The 2-year NRM was 9%, lower after related or haploidentical donor (21% vs 0% vs 7%; p = 0.06). Grade 2-4 aGVHD cumulative incidence was significantly different after transplantation from haploidentical vs matched sibling vs unrelated donor, and (24% vs 35% vs 58%, p = 0.024). The familial donor cohort was compared to the unrelated cohort. Familial donor induced less grade 2-4 aGVHD, with a trend to less grade 3-4 aGVHD or moderate-severe cGVHD. The OS and PFS were not different, while the relapse risk and NRM were reduced. Allo-SCT is highly effective in T-cell lymphoma, with low NRM and low relapse rate. The incidence of aGVHD was lower after haploidentical transplantation. Related donor may challenge unrelated transplant reducing the risk of relapse and NRM.

Haploidentical Stem Cell Transplantation in Lymphomas-Expectations and Pitfalls

T-cell replete Haploidentical stem cell transplantation (Haplo-SCT) with Post-transplant cyclophosphamide (PT-Cy) is an emerging therapeutic option for patients with advanced relapsed or refractory lymphoma. The feasibility of this platform is supported by several retrospective studies showing a toxicity profile that is improved relative to umbilical cord blood and mismatched unrelated donor (UD) transplant and comparable to matched unrelated donor transplant. In particular, cumulative incidence of chronic graft-versus-host disease (GVHD) is reduced after Haplo-SCT relative to UD and matched related donor (MRD) transplant thanks to PT-Cy employed as GVHD prophylaxis. This achievement, together with a similar incidence of acute GVHD and disease relapse, results in a promising advantage of Haplo-SCT in terms of relapse-free/GVHD free survival. Unmet needs of the Haplo-SCT platform are represented by the persistence of a not negligible rate of non-relapse mortality, especially due to infections and disease relapse. Future efforts are warranted in order to reduce life-threatening infections and to employ Halo-SCT with PT-Cy as a platform to build new immunotherapeutic strategies.

Salvage Therapy for Hodgkin's Lymphoma: A Review of Current Regimens and Outcomes

Relapse/refractory Hodgkin lymphoma patients are still a clinical concern. Indeed, despite more effective first-line chemotherapy regimens and better stratification of unresponsive patients by clinical factors and use of early PET, roughly one-third of such patients need salvage chemotherapy and consolidation with high-dose chemotherapy. In this paper, the authors review the different salvage treatments, with special emphasis on newer combinations with brentuximab vedotin or check point inhibitors. The overall response rate is constantly increasing, with a complete remission rate approaching 80%. Functional response evaluation by PET imaging is a strong predictive factor of longer survival, and more sophisticated tools, such as detection of circulating tumour DNA, are emerging to refine the disease-status assessment after treatment. Consolidation by high-dose chemotherapy is still considered the standard of care in chemosensitive patients, leading to a high fraction of patients towards long-term disease control. Maintenance therapy with BV is now approved, reducing disease relapse/progression. An increasing number of Hodgkin lymphoma patients will be cured after first- and second-line therapy, and long-term toxicity needs to be continuously assessed and avoided.

Assessing Early Supportive Care Needs among Son or Daughter Haploidentical Transplantation Donors

Increasingly, adolescent, young adult, and adult children are relied upon as donors for their parents undergoing blood and marrow stem cell transplant. How family functioning impacts donors' decision making and whether haploidentical donor children have unique supportive care needs is unknown. In this qualitative research study, we conducted 15 semistructured telephone interviews among individuals who underwent blood or marrow stem cell donation for their parent. Interviews explored donors' perspectives of the transplant experience across the trajectory from screening through early post-transplant follow-up and elicited unmet needs. Major themes included: (1) perception of choice, (2) act of giving back, (3) burdens of donation, (4) anticipated health benefit to parent, and (5) impact of donation on parent/child relationship. The majority of participants described high family functioning, but strain was also evident. Family functioning rarely was reported as affecting the decision to donate, with all donors expressing a sense of obligation. Participants were overwhelmingly satisfied with their decision and the ability to give back to their parent. Suggestions for the health care team to improve the donation experience focused on increased education about potential delays in screening, better description of possible complications for recipients, and provision of emotional support following donation.

Ixazomib for Chronic Graft-versus-Host Disease Prophylaxis following Allogeneic Hematopoietic Cell Transplantation

Chronic graft-versus-host disease (cGVHD) is major cause of morbidity and mortality following allogeneic hematopoietic cell transplantation (HCT). Ixazomib is an oral, second-generation, proteasome inhibitor that has been shown in preclinical models to prevent GVHD. We conducted a phase I/II trial in 57 patients to evaluate the safety and efficacy of ixazomib administration for cGVHD prophylaxis in patients undergoing allogeneic HCT. Oral ixazomib was administered on a weekly basis for a total of 4 doses, beginning days +60 through +90, to recipients of matched related donor (MRD, n = 25) or matched unrelated donor (MUD, n = 26) allogeneic HCT in phase II portion of the study, once the recommended phase II dose of 4 mg was identified in phase I (n = 6). All patients received peripheral blood graft and standard GVHD prophylaxis of tacrolimus and methotrexate. Ixazomib administration was safe and well tolerated, with thrombocytopenia, leukopenia, gastrointestinal complaints, and fatigue the most common adverse events (>10%). In phase II (n = 51), the cumulative incidence of cGVHD at 1 year was 36% (95% confidence interval [CI], 19% to 54%) in the MRD cohort and 39% (95% CI, 21% to 56%) in the MUD cohort. One-year cumulative incidence of nonrelapse mortality (NRM) and relapse was 0% and 20% (95% CI, 8% to 36%) in the MRD cohort, respectively. In the MUD cohort, the respective NRM and relapse rates were 4% (0% to 16%) and 34% (17% to 52%). The outcomes on the study were compared post hoc with contemporaneous matched Center for International Blood and Marrow Transplant Research (CIBMTR) controls. This post hoc analysis showed no significant improvement in cGVHD rates in both the MRD (hazard ratio [HR] = 0.85, P = .64) or MUD cohorts (HR = 0.68, P = .26) on the study compared with CIBMTR controls. B cell activating factor plasma levels were significantly higher after ixazomib dosing in those who remained cGVHD free compared with those developed cGVHD. This study shows that the novel strategy of short-course oral ixazomib following allogeneic HCT is safe but did not demonstrate significant improvement in cGVHD incidence in recipients of MRD and MUD transplantation compared with matched CIBMTR controls. This study is registered at www.clinicaltrials.gov as NCT02250300.

PTCy ameliorates GVHD by restoring regulatory and effector T-cell homeostasis in recipients with PD-1 blockade

Graft-versus-host disease (GVHD) after allogeneic hematopoietic stem cell transplantation (allo-HSCT) is a significant cause of morbidity and mortality. Regulatory T cells (Tregs) are critical mediators of immune tolerance after allo-HSCT. Clinical studies have indicated that programmed cell death 1 (PD-1) blockade before allo-HSCT involves a risk of severe GVHD. However, the mechanisms underlying GVHD induction resulting from PD-1 blockade remain unclear. We investigated the impact of PD-1 expression of donor T cells on T-cell reconstitution and GVHD using murine models. We first demonstrated that inhibition of PD-1 signaling induced aggressive expansion of CD4+ conventional T cells; however, Tregs could not maintain expansion because of high susceptibility to apoptosis, resulting in discordant immune recovery and subsequent development of severe GVHD. We then evaluated the impact of posttransplantation cyclophosphamide (PTCy) on abnormal T-cell reconstitution after PD-1 blockade. PTCy efficiently ameliorated GVHD after transplantation from a PD-1-/- donor and extended overall survival by safely regulating the proliferation and apoptosis of T-cell subsets. Notably, in the first 2 weeks after administration of PTCy, Tregs regained their ability to continuously proliferate, resulting in well-balanced reconstitution of donor T-cell subsets. In conclusion, the influence of PD-1 blockade differed within T-cell subsets and caused unbalanced reconstitution of T-cell subsets, resulting in severe GVHD. PTCy successfully restored T-cell homeostasis and ameliorated GVHD induced by PD-1-/- donor T cells. These findings may help explain the pathophysiology behind the observation that PTCy may mitigate the incidence and impact of GVHD associated with prior exposure to PD-1 blockade.

Impact of Reduced-Intensity Conditioning Regimens on Outcomes in Diffuse Large B Cell Lymphoma Undergoing Allogeneic Transplantation

Reduced-intensity conditioning (RIC) regimens are frequently used for allogeneic hematopoietic cell transplantation (allo-HCT) in patients with diffuse large B cell lymphoma (DLBCL). However, the RIC regimen with the best risk/benefit profile for allo-HCT in DLBCL is not known. This is particularly important because patients with DLBCL undergoing allo-HCT in the future would be enriched for those whose lymphoma has failed chimeric antigen receptor T cell (CAR-T) therapy or other novel immunotherapies, with potentially more advanced disease and suboptimal performance scores. Using the Center for International Blood and Marrow Transplant Research (CIBMTR) database, we report the outcomes of the 3 most commonly used allo-HCT RIC regimens in patients with DLBCL. Our analysis included a total of 562 adult DLBCL patients in the CIBMTR registry undergoing allo-HCT using matched related or unrelated donors, between 2008 and 2016. Patients received 1 of 3 RIC regimens: fludarabine/i.v. busulfan ~6.4 mg/kg (Flu/Bu), fludarabine/melphalan 140 mg/m² (Flu/Mel140), or BCNU/etoposide/cytarabine/melphalan (BEAM). Accordingly, the study group was divided into 3 groups: Flu/Bu (n = 151), Flu/Mel140 (n = 296), and BEAM (n = 115). Relative to Flu/Bu, the Flu/Mel140 (hazard ratio [HR], 2.33; 95% confidence interval [CI], 1.42 to 3.82; P = .001) and BEAM (HR, 2.54; 95% CI, 1.34 to 4.80; P = .004) regimens were associated with a risk of higher nonrelapse mortality (NRM). Although the risk of relapse with Flu/Mel140 was lower than that with Flu/Bu (HR, .70; 95% CI, .52 to .95; P = .02), this did not translate to improved progression-free survival (HR, 1.04) or overall survival (HR, 1.30). There was a significantly higher risk of grade III-IV acute graft-versus-host disease with BEAM compared with Flu/Bu (HR, 2.19; 95% CI, 1.10 to 4.35; P = .03). In the chemosensitive subset, multivariate analysis showed a significantly higher mortality risk with Flu/Mel140 (HR, 1.48; 95% CI, 1.07 to 2.04; P = .02) relative to Flu/Bu conditioning. In the largest analysis comparing the impact of various RIC regimens on the survival of DLBCL patients undergoing allo-HCT, our results suggest that Flu/Bu is a better RIC choice in less fit or heavily pretreated patients due to lowest NRM risk.

Considerations for haploidentical versus unrelated donor transplants

Haploidentical transplantation is increasingly performed worldwide due to novel methods to control alloreactivity between the donor and recipient. This major advancement has increased donor availability to almost all patients in need. Outcomes with haploidenitcal donors have also improved and prompted many groups to compare outcomes between haploidentical and HLA-matched donor transplants. In this review, we provide a summary of available data on haploidentical transplants performed with post transplant cyclophosphamide-based graft-versus-host disease (GVHD) prophylaxis and HLA-matched unrelated donor transplants.

Nonmyeloablative Conditioning Regimen before T Cell Replete Haploidentical Transplantation with Post-Transplant Cyclophosphamide for Advanced Hodgkin and Non-Hodgkin Lymphomas

Allogeneic hematopoietic stem cell transplantation (allo-SCT) is a valid option in patients with refractory lymphomas. HLA haploidentical stem cell transplantation (haplo-SCT) expanded the accessibility to allogeneic hematopoietic cell transplantation. The aims of study were to retrospectively assess the toxicity and efficacy of haplo-SCT using nonmyeloablative conditioning in patients with advanced lymphoma. In total, 147 patients with advanced lymphoma at 2 partner institutions were included. Patients received a uniform nonmyeloablative conditioning regimen and graft-versus-host disease (GVHD) prophylaxis. The primary endpoints were progression-free survival (PFS), overall survival (OS), GVHD, nonrelapse mortality, and GVHD, relapse-free survival (GRFS). Median follow-up was 39 months (range, 6 to 114 months). The median age was 46 years (range, 19 to 71 years). Sixty-five percent of patients were in complete remission (CR) at transplantation. Cumulative incidence of grade II to IV acute GVHD was 30% (95% confidence interval [Cl], 23% to 38%). Two-year cumulative incidence of all grades of chronic GVHD was 13% (95% CI, 8% to 20%). Two-year cumulative incidence of disease relapse was 19% (95% CI, 14% to 27%), with a higher incidence in patients not being in CR at allo-HCT (CR versus not CR: 12% versus 33%, P = .006). Two-year PFS, OS, and GRFS were 66% (95% CI, 59-75), 73% (95% CI, 66-81), and 56% (95% CI, 48-65), respectively. Haplo-SCT with post-transplantation cyclophosphamide may be considered a valid option for patients with aggressive lymphoma and deserves further evaluation.

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

PURPOSE OF REVIEW

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

RECENT FINDINGS

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

SUMMARY

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

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.

Allogeneic Transplantation and Chimeric Antigen Receptor-Engineered T-Cell Therapy for Relapsed or Refractory Mantle Cell Lymphoma

Mantle cell lymphoma (MCL) accounts for fewer than 10% of non-Hodgkin lymphoma. There is a high initial response rate to chemotherapy and rituximab, but a nearly universal risk of relapse. Allogeneic hematopoietic cell transplantation (allo-HCT) provides one of the only curative options. We review the role of allo-HCT for relapsed and refractory (R/R) MCL and discuss a novel promising approach using autologous chimeric antigen receptor-engineered T (CAR-T) cells. We review preliminary safety and efficacy data of 2 pivotal trials investigating the use of CD19-targeted CAR-T cells for R/R MCL after ibrutinib failure and discuss potential timing of these approaches.

Current Trends on Hemopoietic Stem Cells

Advances in single-cell technology and genetic mouse models have resulted in the identification of new types of hemopoietic stem cells (HSC), resulting in baffling observations, suggesting a reconsideration of the long-held notion that all hematopoietic cells in the adult are derived from HSCs. The existence of long-lived HSC-independent hematopoiesis has led to the conclusion that despite the single hierarchical differentiation route that generates functional blood types, other differentiation routes exist in-vivo. Heterogeneity in the HSC population and the evolving knowledge around HSC has translated to it's improved application as a therapeutic tool for various blood disorders. The reprogramming of non-hematopoietic somatic and mature blood cells to pluripotency with their subsequent differentiation into hematopoietic stem cells/progenitor cells and the introduction of new generation sequencing holds the potential for the resolution of ambiguities involved in HSC bone marrow transplantation. There is a change in the paradigm for HSC transplantation donor selection. Donor choice favors haploidentical HCT than cord blood. This review provides a general overview of the current events around hemopoietic stem cells, with emphasis on the rising trend of HSC transplantation, especially haploidentical stem cell transplantation.

Graft Cryopreservation Does Not Impact Overall Survival after Allogeneic Hematopoietic Cell Transplantation Using Post-Transplantation Cyclophosphamide for Graft-versus-Host Disease Prophylaxis

The COVID-19 pandemic has created significant barriers to timely donor evaluation, cell collection, and graft transport for allogeneic hematopoietic stem cell transplantation (allo-HCT). To ensure availability of donor cells on the scheduled date of infusion, many sites now collect cryopreserved grafts before the start of pretransplantation conditioning. Post-transplantation cyclophosphamide (ptCY) is an increasingly used approach for graft-versus-host disease (GVHD) prophylaxis, but the impact of graft cryopreservation on the outcomes of allo-HCT using ptCY is not known. Using the Center for International Blood and Marrow Transplant Research (CIBMTR) database, we compared the outcomes of HCT using cryopreserved versus fresh grafts in patients undergoing HCT for hematologic malignancy with ptCY. We analyzed 274 patients with hematologic malignancy undergoing allo-HCT between 2013 and 2018 with cryopreserved grafts and ptCY. Eighteen patients received bone marrow grafts and 256 received peripheral blood stem cell grafts. These patients were matched for age, graft type, disease risk index (DRI), and propensity score with 1080 patients who underwent allo-HCT with fresh grafts. The propensity score, which is an assessment of the likelihood of receiving a fresh graft versus a cryopreserved graft, was calculated using logistic regression to account for the following: disease histology, Karnofsky Performance Score (KPS), HCT Comorbidity Index, conditioning regimen intensity, donor type, and recipient race. The primary endpoint was overall survival (OS). Secondary endpoints included acute and chronic graft-versus-host disease (GVHD), non-relapse mortality (NRM), relapse/progression and disease-free survival (DFS). Because of multiple comparisons, only P values <.01 were considered statistically significant. The 2 cohorts (cryopreserved and fresh) were similar in terms of patient age, KPS, diagnosis, DRI, HCT-CI, donor/graft source, and conditioning intensity. One-year probabilities of OS were 71.1% (95% confidence interval [CI], 68.3% to 73.8%) with fresh grafts and 70.3% (95% CI, 64.6% to 75.7%) with cryopreserved grafts (P = .81). Corresponding probabilities of OS at 2 years were 60.6% (95% CI, 57.3% to 63.8%) and 58.7% (95% CI, 51.9% to 65.4%) (P = .62). In matched-pair regression analysis, graft cryopreservation was not associated with a significantly higher risk of mortality (hazard ratio [HR] for cryopreserved versus fresh, 1.05; 95% CI, .86 to 1.29; P = .60). Similarly, rates of neutrophil recovery (HR, .91; 95% CI, .80 to 1.02; P = .12), platelet recovery (HR, .88; 95% CI, .78 to 1.00; P = .05), grade III-IV acute GVHD (HR, .78; 95% CI, .50 to 1.22; P = .27), NRM (HR, 1.16; 95% CI, .86 to 1.55; P = .32) and relapse/progression (HR, 1.21; 95% CI, .97 to 1.50; P = .09) were similar with cryopreserved grafts versus fresh grafts. There were somewhat lower rates of chronic GVHD (HR, 78; 95% CI, .61 to .99; P = .04) and DFS (HR for treatment failure, 1.19; 95% CI, 1.01 to 1.29; P = .04) with graft cryopreservation that were of marginal statistical significance after adjusting for multiple comparisons. Overall, our data indicate that graft cryopreservation does not significantly delay hematopoietic recovery, increase the risk of acute GVHD or NRM, or decrease OS after allo-HCT using ptCY.

Relapse of Hodgkin lymphoma after autologous hematopoietic cell transplantation: A current management perspective

Hodgkin lymphoma (HL) is a highly responsive disease with nearly 70% of patients experiencing cure after front-line chemotherapy. Patients who experience disease relapse receive salvage chemotherapy followed by consolidation with autologous hematopoietic cell transplantation (auto-HCT). Nearly 50% of patients relapse after an auto-HCT and constitute a subgroup with poor prognosis. Novel treatments such as immune checkpoint inhibitors and an anti-CD30 monoclonal antibody are currently approved for patients relapsing after auto-HCT; however, the duration of remission with these therapies remains limited. Allogeneic HCT is currently the only potentially curative treatment modality for patients relapsing after a prior auto-HCT. Early clinical trials with chimeric antigen receptor T-cell therapy targeting CD30 are underway for patients with relapsed/refractory HL and are already demonstrating safety and promising efficacy.

Rabbit ATG/ATLG in preventing graft-versus-host disease after allogeneic stem cell transplantation: consensus-based recommendations by an international expert panel

This collaborative initiative aimed to provide recommendations on the use of polyclonal antithymocyte globulin (ATG) or anti-T lymphocyte globulin (ATLG) for the prevention of graft-versus-host disease (GvHD) after allogeneic hematopoietic stem cell transplantation (HSCT). A comprehensive review of articles released up to October, 2018 was performed as a source of scientific evidence. Fourteen clinically relevant key questions to the domains indication, administration, and post-transplant management were developed and recommendations were produced using the Delphi technique involving a Panel of 14 experts. ATG/ATLG was strongly recommended as part of myeloablative conditioning regimen prior to matched or mismatched unrelated bone marrow or peripheral blood allogeneic HSCT in malignant diseases to prevent severe acute and chronic GvHD. ATG/ATLG was also recommended prior to HLA-identical sibling peripheral HSCT with good but lesser bulk of evidence. In reduced intensity or nonmyeloablative conditioning regimens, ATG/ATLG was deemed appropriate to reduce the incidence of acute and chronic GvHD, but a higher risk of relapse should be taken into account. Recommendations regarding dose, application, and premedication were also provided as well as post-transplant infectious prophylaxis and vaccination. Overall, these recommendations can be used for a proper and safe application of polyclonal ATG/ATLG to prevent GvHD after allogeneic HSCT.

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.

Posttransplantation cyclophosphamide improves transplantation outcomes in patients with AML/MDS who are treated with checkpoint inhibitors

BACKGROUND

There have been concerns regarding increased peritransplantation complications, especially severe acute graft-versus-host disease (aGVHD), in patients with prior use of checkpoint inhibitors (CPI) before hematopoietic stem cell transplantation (HSCT).

METHODS

The authors performed a retrospective study of 43 patients with acute myeloid leukemia and/or myelodysplastic syndromes who were treated with an antiprogrammed cell death protein 1 (PD-1) (32 patients) or anticytotoxic T-lymphocyte-associated protein 4 (CTLA-4) (9 patients) blockade or both (2 patients) prior to HSCT with the primary outcome of aGVHD by day 100 after HSCT. Outcome analyses were stratified by GVHD prophylaxis as use of post-HSCT cyclophosphamide (PTCy) (22 patients) or not (non-PTCy) (21 patients).

RESULTS

The PTCy group demonstrated a trend toward lower grade 3 to 4 aGVHD when compared with the non-PTCy group (5% vs 22%), although the rates of grade 2 to 4 aGVHD were comparable (49% vs 56%). The interval between CPI and HSCT did not appear to impact the incidence of aGVHD. However, a higher incidence of grade 3 to 4 aGVHD was observed in patients who received >4 treatments of CPI prior to HSCT if they were not given PTCy as GVHD prophylaxis (43% vs 12%). Matched control analyses using patients with no prior use of CPI confirmed the increase in grade 3 to 4 aGVHD with those agents. However, that increased risk was limited to patients who did not receive PTCy and was not observed in patients who received PTCy as GVHD prophylaxis. Despite persistent improvement in GVHD with the use of PTCy, disease control was not compromised and progression-free survival at 1 year was found to be superior for patients treated with PTCy compared with those not receiving PTCy among patients with prior use of CPI (55% vs 22%).

CONCLUSIONS

The results of the current study indicated that HSCT with prior use of CPI appears feasible in patients with acute myeloid leukemia and/or myelodysplastic syndromes and the use of PTCy as GVHD prophylaxis improves outcomes.

Eligibility Criteria for Patients Undergoing Allogeneic Hematopoietic Cell Transplantation

Eligibility assessment of a potential candidate for allogeneic hematopoietic cell transplantation (allo-HCT) is a complex yet vital component of pretransplant evaluation. Although no formal standardized consensus exists to guide this process, transplant centers follow institutional standard operating procedures and parameters to approve candidacy of an individual patient. Consideration for allo-HCT is dependent on a myriad of interrelated factors, including disease-related (eg, appropriate indication, disease status, prior therapies), patient-related (eg, age, functional status, frailty, comorbidities), psychosocial, and economic factors. A multidisciplinary approach is optimal for patient selection and requires the efforts of transplant coordinators, nurses, advanced practice providers, social workers, psychologists, financial specialists, and physicians. This article reviews the data and provides general guidelines that may be used in making an informed decision when evaluating a prospective candidate for allo-HCT. These recommendations are based on published data, expert commentary, reviews, and institutional practices. In the end, the eligibility assessment and decision to consider allo-HCT as the optimal choice of treatment for an individual patient are truly as much an "art" as it is the "science" of medicine, encompassing a multidisciplinary approach to minimize harm without compromising the curative potential-all essential doctrines of the Hippocratic Oath.