Nonmyeloablative conditioning, unmanipulated haploidentical SCT and post-infusion CY for advanced lymphomas

Bone marrow graft versus peripheral blood graft in haploidentical hematopoietic stem cells transplantation: a retrospective analysis in1344 patients of SFGM-TC registry

The use of peripheral blood (PB) or bone marrow (BM) stem cells graft in haploidentical hematopoietic stem cell transplantation with post-transplant cyclophosphamide (PTCy) for graft-versus-host disease (GVHD) prophylaxis remains controversial. Moreover, the value of adding anti-thymoglobulin (ATG) to PTCy is unknown. A total of 1344 adult patients received an unmanipulated haploidentical transplant at 37 centers from 2012 to 2019 for hematologic malignancy. We compared the outcomes of patients according to the type of graft, using a propensity score analysis. In total population, grade II-IV and III-IV acute GVHD (aGVHD) were lower with BM than with PB. Grade III-IV aGVHD was lower with BM than with PB + ATG. All outcomes were similar in PB and PB + ATG groups. Then, in total population, adding ATG does not benefit the procedure. In acute leukemia, myelodysplastic syndrome and myeloproliferative syndrome (AL-MDS-MPS) subgroup receiving non-myeloablative conditioning, risk of relapse was twice greater with BM than with PB (51 vs. 22%, respectively). Conversely, risk of aGVHD was greater with PB (38% for aGVHD II-IV; 16% for aGVHD III-IV) than with BM (28% for aGVHD II-IV; 8% for aGVHD III-IV). In this subgroup with intensified conditioning regimen, risk of relapse became similar with PB and BM but risk of aGVHD III-IV remained higher with PB than with BM graft (HR = 2.0; range [1.17-3.43], p = 0.012).

Immunomodulatory Effects of Bendamustine in Hematopoietic Cell Transplantation

Bendamustine (BEN) is a unique alkylating agent with efficacy against a broad range of hematological malignancies, although investigations have only recently started to delve into its immunomodulatory effects. These immunomodulatory properties of BEN in the context of hematopoietic cell transplantation (HCT) are reviewed here. Pre- and post-transplant use of BEN in multiple murine models have consistently resulted in reduced GvHD and enhanced GvL, with significant changes to key immunological cell populations, including T-cells, myeloid derived suppressor cells (MDSCs), and dendritic cells (DCs). Further, in vitro studies find that BEN enhances the suppressive function of MDSCs, skews DCs toward cDC1s, enhances Flt3 expression on DCs, increases B-cell production of IL-10, inhibits STAT3 activation, and suppresses proliferation of T- and B-cells. Overall, BEN has a broad range of immunomodulatory effects that, as they are further elucidated, may be exploited to improve clinical outcomes. As such, clinical trials are currently underway investigating new potential applications of BEN in the setting of allogeneic HCT.

PTCy-based haploidentical vs matched related or unrelated donor reduced-intensity conditioning transplant for DLBCL

This study retrospectively compared long-term outcomes of nonmyeloablative/reduced intensity conditioning (NMC/RIC) allogeneic hematopoietic cell transplantation (allo-HCT) from a haploidentical family donor (haplo-HCT) using posttransplant cyclophosphamide (PTCy) with those of matched sibling donor (MSD) and matched unrelated donor (MUD) with or without T-cell depletion (TCD+/TCD-) in patients with relapsed diffuse large B-cell lymphoma (DLBCL). Adult patients with DLBCL who had undergone their first NMC/RIC allo-HCT between 2008 and 2015 were included. Recipients of haplo-HCT were limited to those receiving graft-versus-host disease (GVHD) prophylaxis with PTCy. GVHD prophylaxis in MSD was limited to calcineurin inhibitor (CNI)-based approaches without in vivo TCD, while MUD recipients received CNI-based prophylaxis with or without TCD. Outcome analyses for overall survival (OS) and progression-free survival (PFS), nonrelapse mortality (NRM), and disease relapse/progression were calculated. A total of 1438 patients (haplo, 132; MSD, 525; MUD TCD+, 403; and MUD TCD-, 378) were included. Patients with haplo donors were significantly older, had a better performance status and had more frequently received total body irradiation-based conditioning regimens and bone marrow grafts than MSD and MUD TCD+ or TCD-. 3-year OS, PFS, NRM and relapse/progression incidence after haplo-HCT was 46%, 38%, 22%, and 41%, respectively, and not significantly different from outcomes of matched donor transplants on multivariate analyses. Haplo-HCT was associated with a lower cumulative incidence of chronic GVHD compared with MSD, MUD TCD+/TCD-. NMC/RIC haplo-HCT with PTCy seems to be a valuable alternative for patients with DLBCL considered for allo-HCT but lacking a matched donor.

Thiotepa and antithymocyte globulin-based conditioning prior to haploidentical transplantation with posttransplant cyclophosphamide in high-risk hematological malignancies

We report results of a thiotepa-based conditioning in haploidentical stem cell transplantation (haplo-SCT) with posttransplant cyclophosphamide (PT-CY) and antithymocyte globulin (ATG), for unmanipulated peripheral blood stem cell (PBSC) transplants, in 80 patients with hematological malignancies. Patients in complete remission (CR) received a thiotepa-busulfan-fludarabine (TBF) regimen, while patients with relapsed/refractory (R/R) malignancies received a sequential regimen consisting of thiotepa-etoposide-cyclophosphamide (TEC) and reduced-intensity conditioning (RIC). The median age was 52 (range, 17-72) years, 44% patients had R/R disease at transplant, and the median follow-up was 417 (range, 180-1595) days. The median days to neutrophil engraftment was 17 (range, 12-34). The cumulative incidences (CI) of acute graft-versus-host disease (GVHD) grade III to IV, severe chronic GVHD, nonrelapse mortality (NRM), and relapse were 16%, 16%, 26, and 26%, respectively. The 2-year overall survival (OS) and disease-free survival (DFS) were 53% and 47%, respectively. There were no significant differences between the patients in CR and R/R patients in terms of engraftment, GVHD, NRM, relapse, OS, or DFS. We conclude that thiotepa-based regimen with PT-CY can be modified with PBSC and ATG, still providing low toxicity, protection against GVHD, and low relapse incidence. Particularly encouraging are the results with the modification to sequential regimen in R/R patients.

Haploidentical Stem Cell Transplantation With Post-Transplantation Cyclophosphamide for Aggressive Lymphomas: How Far Have We Come and Where Are We Going?

Haploidentical hematopoietic stem cell transplantation (haplo-HSCT) with post-transplant cyclophosphamide (PTCy) offers universal donor availability and can potentially cure relapsed or primary refractory Hodgkin lymphoma (HL) and non-Hodgkin lymphoma (NHL). However, a conditioning regimen intensity that balances the graft-versus-lymphoma (GvL) effect with regimen-related toxicities (RRTs) has not yet been optimized. Limited data exist on the management of relapse, which is common post-transplant. Few prospective or randomized control trials have been conducted on lymphoma patients undergoing haplo-HSCT. Therefore, the current review aims to summarize published retrospective data in the field to help guide clinical decision making for high-risk patients. Retrospective studies in the field are characterized by variability in patient population and sample sizes, eligibility criteria, number of prior treatments (e.g., chemotherapy, radiation therapy, and autologous transplant), graft source (bone marrow or peripheral blood), as well as choice and intensity of the conditioning regimen (non-myeloablative, reduced intensity, or myeloablative). Nonetheless, common themes that emerge from the literature include: 1) Enhanced donor availability and selection with haplo-HSCT with success in heterogeneous patient populations; 2) Outcomes that are comparable if not superior to matched related (MRD) or unrelated (MUD) donor transplants; 3) The benefit of PTCy for reducing incidence of relapse and chronic graft-versus-host disease (GvHD); 4) Presence of co-morbidities leading to poorer transplant-related outcomes; and 5) The need for novel approaches to address disease relapse, particularly for patients with active disease at the time of transplant. Excellent transplant-related outcomes with haplo-HSCT with PTCy have been seen for HL and NHL based on retrospective data. Further studies are needed to determine integration with advanced cellular therapy techniques, such as chimeric antigen receptor (CAR) T-cell, antibody drug conjugates, and checkpoint inhibitors. Graft manipulation may be another avenue for future research.

Clofarabine-based reduced intensity conditioning regimen with peripheral blood stem cell graft and post-transplant cyclophosphamide in adults with myeloid malignancies

BACKGROUND

The Baltimore reduced-intensity conditioning (RIC) regimen using high-dose post-transplant cyclophosphamide (PTCY) is considered as a standard of care for haploidentical allogeneic stem cell transplantation (allo-SCT). However, it is associated with relatively low survivals and high incidence of relapse, especially when considering myeloid malignancies.

RESULTS

This retrospective study included 36 adults (males n = 18; median age: 60.5 years old; haplodonors n = 27; matched donors n = 8) with myeloid malignancies transplanted between March 2014 and March 2017 at the University Hospital of Nantes. Very encouraging results were observed with a 18-month overall survival (OS), disease-free survival (DFS) and relapse incidence (RI) of 72% ± 7.5%, 63.8 ± 8%, and 25 ± 6% respectively, and a GVHD relapse-free survival (GRFS) of 52.6 ± 8%. In univariate analysis, there were no differences regarding 18-month survivals between patients allografted: i) for acute myeloid leukemia vs myelodysplastic syndrome (OS 70 ± 11% vs 69.2 ± 13%, p = 0.3; DFS 64.7 ± 11% vs 61.5 ± 13%, p = 0.65), or ii) with haplo-identical vs other donors (OS: 66.2 ± 9% vs 88.8 ± 10.4%, p = 0.16; DFS 59 ± 9.5% vs 77.8%, p = 0.6).

CONCLUSION

The "Clo-Baltimore regimen" is safe and feasible and provides good survivals for patients with myeloid malignancies and haplo-donors.

METHODS

Here, we report a variant of the Baltimore regimen, where 1) fludarabine was replaced by clofarabine, 2) bone marrow was replaced by peripheral blood stem cells, and 3) tacrolimus was replaced by cyclosporine, in a "Clo-Baltimore regimen".

Treatment of classical Hodgkin lymphoma in the era of brentuximab vedotin and immune checkpoint inhibitors

The majority of Hodgkin lymphoma patients are now cured with conventional first-line therapy; however, 10-15% of early-stage disease and less than 30% of advanced-stage patients are refractory(rare) or relapsed. Salvage second-line therapy combined with high-dose therapy and autologous stem-cell transplantation can cure 40-50% of patients. Recently novel agents (Brentuximab Vedotin and Immune Checkpoint inhibitors) have demonstrated evidence of therapeutic activity and are potential bridge to an allogeneic stem-cell transplantation. The review is aimed to present not only salvage strategies; indeed, the paper contains paragraphs about therapy and new treatment options at diagnosis.

Sequential Conditioning with Thiotepa in T Cell- Replete Hematopoietic Stem Cell Transplantation for the Treatment of Refractory Hematologic Malignancies: Comparison with Matched Related, Haplo-Mismatched, and Unrelated Donors

The results of conventional allogeneic stem cell transplantation (SCT) in refractory hematologic malignancies are poor. Sequential strategies have shown promising results in refractory acute myelogenous leukemia (AML), but have not been validated in a haploidentical (Haplo) transplant setting. We have developed a new sequential approach combining chemotherapy with broad antitumor activity (thiotepa 10 mg/kg, etoposide 400 mg/m², and cyclophosphamide 1600 mg/m² from day -15 to day -10), followed after 3 days of rest by a reduced-intensity conditioning regimen (fludarabine 150 mg/m², i.v. busulfan 6.4 mg/kg, and thymoglobulin 5 mg/kg from day -6 to day -2). High-dose post-transplantation cyclophosphamide was added in cases with Haplo donors. Seventy-two patients (median age, 54 years) with a refractory hematologic malignancy (44 with acute myelogenous leukemia, 7 with acute lymphoblastic leukemia, 15 with myelodysplastic syndrome/myeloproliferative neoplasms, and 6 with lymphomas) were included in this retrospective multicenter study. Donors were Haplo (n = 27), matched related (MRD; n = 16), and unrelated (UD; n = 29). With a median follow-up of 21 months, the 2-year overall survival (OS) and event-free survival (EFS) were 54.7% and 49.3%, respectively, in recipients of Haplo transplants, 49.2% and 43.8%, respectively, in recipients of MRD transplants, and 37.9% and 28%, respectively, in recipients of UD transplants. Compared with UD, the outcomes were improved in Haplo in terms of the incidences of acute grade II-IV graft-versus-host disease (GVHD) (11.1% versus 41.4%; P < .001) and GVHD-free, relapse-free survival (44.4 versus 10.3%; P = .022). These results support the safety and efficacy of a thiotepa-based sequential approach in allogeneic SCT with a Haplo donor with post-transplantation immune modulation. Thus, in patients with refractory hematologic malignancies, there seems to be no benefit in searching for a UD when a Haplo donor is readily available.

Post-Transplantation Cyclophosphamide-Based Haploidentical Transplantation as Alternative to Matched Sibling or Unrelated Donor Transplantation for Hodgkin Lymphoma: A Registry Study of the Lymphoma Working Party of the European Society for Blood and Marrow Transplantation

Purpose

To compare the outcome of patients with Hodgkin lymphoma who received post-transplantation cyclophosphamide–based haploidentical (HAPLO) allogeneic hematopoietic cell transplantation with the outcome of patients who received conventional HLA-matched sibling donor (SIB) and HLA-matched unrelated donor (MUD).

Patients and Methods

We retrospectively evaluated 709 adult patients with Hodgkin lymphoma who were registered in the European Society for Blood and Marrow Transplantation database who received HAPLO (n = 98), SIB (n = 338), or MUD (n = 273) transplantation.

Results

Median follow-up of survivors was 29 months. No differences were observed between groups in the incidence of acute graft-versus-host disease (GVHD). HAPLO was associated with a lower risk of chronic GVHD (26%) compared with MUD (41%; P = .04). Cumulative incidence of nonrelapse mortality at 1 year was 17%, 13%, and 21% in HAPLO, SIB, and MUD, respectively, and corresponding 2-year cumulative incidence of relapse or progression was 39%, 49%, and 32%, respectively. On multivariable analysis, relative to SIB, nonrelapse mortality was similar in HAPLO ( P = .26) and higher in MUD ( P = .003), and risk of relapse was lower in both HAPLO ( P = .047) and MUD ( P < .001). Two-year overall survival and progression-free survival were 67% and 43% for HAPLO, 71% and 38% for SIB, and 62% and 45% for MUD, respectively. There were no significant differences in overall survival or progression-free survival between HAPLO and SIB or MUD. The rate of the composite end point of extensive chronic GVHD and relapse-free survival was significantly better for HAPLO (40%) compared with SIB (28%; P = .049) and similar to MUD (38%; P = .59).

Conclusion

Post-transplantation cyclophosphamide–based HAPLO transplantation results in similar survival outcomes compared with SIB and MUD, which confirms its suitability when no conventional donor is available. Our results also suggest that HAPLO results in a lower risk of chronic GVHD than MUD transplantation.

Haploidentical Allogeneic Hematopoietic Cell Transplantation for Multiple Myeloma Using Post-Transplantation Cyclophosphamide Graft-versus-Host Disease Prophylaxis

Allogeneic (allo) hematopoietic cell transplantation (HCT) currently represents the only potentially curative therapy for patients affected by multiple myeloma (MM). Up to 30% of patients in western countries do not have a matched donor. Haploidentical HCT (haplo-HCT) may be an option, but currently, there are little available data regarding this treatment. We analyzed survival outcomes of 30 heavily pretreated MM patients who received haplo-HCT with post-transplantation cyclophosphamide as graft-versus-host-disease (GVHD) prophylaxis. Median neutrophil and platelet engraftments at day +30 were 87% (95% confidence interval [CI], 66% to 95%) and 60% (95% CI, 40% to 75%), respectively. The cumulative incidences of relapse or progression of disease (PD) and nonrelapse mortality at 18 months were 42% (95% CI, 23% to 59%) and 10% (95% CI, 2% to 24%), respectively. The cumulative incidence of grade II to IV acute GVHD at day +100 was 29% (95% CI, 14% to 47%). The cumulative incidence of chronic GVHD at 18 months was 7% (95% CI, 1% to 21%). With a median follow-up in survivors of 25 months (range, 15 to 73 months), the 18-month progression-free survival (PFS) and overall survival (OS) were 33% (95% CI, 17% to 50%) and 63% (95% CI, 44% to 78%), respectively. No differences were observed between peripheral blood and bone marrow graft in terms of engraftment, GVHD, or PD incidence. Chemorefractory disease at transplantation was associated with a lower/reduced 18-month PFS (9% versus 47%, P = .01) and OS (45% versus 74%, P = .03). This was explained by a higher PD incidence (55% versus 33%, P = .05). In this multicenter study, we report encouraging results with haplo-HCT for patients with heavily pretreated MM.

Nonmyeloablative Haploidentical Bone Marrow Transplantation with Post-Transplantation Cyclophosphamide for Pediatric and Young Adult Patients with High-Risk Hematologic Malignancies

Lower-intensity conditioning regimens for haploidentical blood or marrow transplantation (BMT) are safe and efficacious for adult patients with hematologic malignancies. We report data for pediatric/young adult patients with high-risk hematologic malignancies (n = 40) treated with nonmyeloablative haploidentical BMT with post-transplantation cyclophosphamide from 2003 to 2015. Patients received a preparative regimen of fludarabine, cyclophosphamide, and total body irradiation. Post-transplantation immunosuppression consisted of cyclophosphamide, mycophenolate mofetil, and tacrolimus. Donor engraftment occurred in 29 of 32 (91%), with median time to engraftment of neutrophils >500/µL of 16 days (range, 13 to 22) and for platelets >20,000/µL without transfusion of 18 days (range, 12 to 62). Cumulative incidences of acute graft-versus-host disease (GVHD) grades II to IV and grades III and IV at day 100 were 33% and 5%, respectively. The cumulative incidence of chronic GVHD was 23%, with 7% moderate-to-severe chronic GVHD, according to National Institutes of Health consensus criteria. Transplantation-related mortality (TRM) at 1 year was 13%. The cumulative incidence of relapse at 2 years was 52%. With a median follow-up of 20 months (range, 3 to 148), 1-year actuarial overall and event-free survival were 56% and 43%, respectively. Thus, we demonstrate excellent rates of engraftment, GVHD, and TRM in pediatric/young adult patients treated with this regimen. This approach is a widely available, safe, and feasible option for pediatric and young adult patients with high-risk hematologic malignancies, including those with a prior history of myeloablative BMT and/or those with comorbidities or organ dysfunction that preclude eligibility for myeloablative BMT.

Reduced-intensity and non-myeloablative allogeneic stem cell transplantation from alternative HLA-mismatched donors for Hodgkin lymphoma: a study by the French Society of Bone Marrow Transplantation and Cellular Therapy

Allogeneic stem cell transplantation (allo-SCT) following a non-myeloablative (NMA) or reduced-intensity conditioning (RIC) is considered a valid approach to treat patients with refractory/relapsed Hodgkin lymphoma (HL). When an HLA-matched donor is lacking a graft from a familial haploidentical (HAPLO) donor, a mismatched unrelated donor (MMUD) or cord blood (CB) might be considered. In this retrospective study, we compared the outcome of patients with HL undergoing a RIC or NMA allo-SCT from HAPLO, MMUD or CB. Ninety-eight patients were included. Median follow-up was 31 months for the whole cohort. All patients in the HAPLO group (N=34) received a T-cell replete allo-SCT after a NMA (FLU-CY-TBI, N=31, 91%) or a RIC (N=3, 9%) followed by post-transplant cyclophosphamide. After adjustment for significant covariates, MMUD and CB were associated with significantly lower GvHD-free relapse-free survival (GRFS; hazard ratio (HR)=2.02, P=0.03 and HR=2.43, P=0.009, respectively) compared with HAPLO donors. In conclusion, higher GRFS was observed in Hodgkin lymphoma patients receiving a RIC or NMA allo-SCT with post-transplant cyclophosphamide from HAPLO donors. Our findings suggest they should be favoured over MMUD and CB in this setting.

Reappraising the timing of transplant for indolent non-Hodgkin lymphomas

INTRODUCTION

Indolent non-Hodgkin lymphomas (iNHL) remain incurable with standard approaches. The timing of autologous stem cell transplant (ASCT) is changing following the introduction of new drugs that can potentially defer the transplant, improved reduced intensity conditioning (RIC) and haploidentical allogeneic SCT (allo-SCT).

AREAS COVERED

The most relevant aspects concerning the role of hematopoietic stem cell transplantation in the management of iNHL are discussed. Literature search methodology included examination of PubMed index and meeting presentations. Expert commentary: ASCT is not currently employed as consolidation in first-line, being reserved to patients with refractory/relapsed disease. The curative potential of graft-versus-lymphoma (GVL) after RIC allo-SCT could be particularly beneficial in patients with iNHL relapsing after ASCT. This scenario could be modified in the near future by better definition of high-risk patients at diagnosis, by the improvement of minimal residual disease (MRD) evaluation and by the introduction of new drugs in the therapeutic algorithm.

Post-transplant bendamustine reduces GvHD while preserving GvL in experimental haploidentical bone marrow transplantation

Advances in haploidentical bone marrow transplantation (h-BMT) have drastically broadened the treatment options for patients requiring BMT. The possibility of significantly reducing the complications resulting from graft-versus-host disease (GvHD) with the administration of post-transplant cyclophosphamide (PT-CY) has substantially improved the efficacy and applicability of T cell-replete h-BMT. However, higher frequency of disease recurrence remains a major challenge in h-BMT with PT-CY. There is a critical need to identify novel strategies to prevent GvHD while sparing the graft-versus-leukaemia (GvL) effect in h-BMT. To this end, we evaluated the impact of bendamustine (BEN), given post-transplant, on GvHD and GvL using clinically relevant murine h-BMT models. We provide results indicating that post-transplant bendamustine (PT-BEN) alleviates GvHD, significantly improving survival, while preserving engraftment and GvL effects. We further document that PT-BEN can mitigate GvHD even in the absence of Treg. Our results also indicate that PT-BEN is less myelosuppressive than PT-CY, significantly increasing the number and proportion of CD11b(+) Gr-1(hi) cells, while decreasing lymphoid cells. In vitro we observed that BEN enhances the suppressive function of myeloid-derived suppressor cells (MDSCs) while impairing the proliferation of T- and B-cells. These results advocate for the consideration of PT-BEN as a new therapeutic platform for clinical implementation in h-BMT.

Choice of Unmanipulated T Cell Replete Graft for Haploidentical Stem Cell Transplant and Posttransplant Cyclophosphamide in Hematologic Malignancies in Adults: Peripheral Blood or Bone Marrow-Review of Published Literature

Allogeneic hematopoietic stem cell transplantation (SCT) is often the only curative option for many patients with malignant and benign hematological stem cell disorders. However, some issues are still of concern regarding finding a donor like shrinking family sizes in many societies, underrepresentation of the ethnic minorities in the registries, genetic variability for some races, and significant delays in obtaining stem cells after starting the search. So there is a considerable need to develop alternate donor stem cell sources. The rapid and near universal availability of the haploidentical donor is an advantage of the haploidentical SCT and an opportunity that is being explored currently in many centers especially using T cell replete graft and posttransplant cyclophosphamide. This is probably because it does not require expertise in graft manipulation and because of the lower costs. However, there are still lots of unanswered questions, like the effect of use of bone marrow versus peripheral blood as the source of stem cells on graft-versus-host disease, graft versus tumor, overall survival, immune reconstitution, and quality of life. Here we review the available publications on bone marrow and peripheral blood experience in the haploidentical SCT setting.

Impact of conditioning intensity in T-replete haplo-identical stem cell transplantation for acute leukemia: a report from the acute leukemia working party of the EBMT

BACKGROUND

Increasing numbers of patients are receiving haplo-identical stem cell transplantation (haplo-SCT) for treatment of acute leukemia with reduced intensity (RIC) or myeloablative (MAC) conditioning regimens. The impact of conditioning intensity in haplo-SCT is unknown.

METHODS

We performed a retrospective registry-based study comparing outcomes after T-replete haplo-SCT for patients with acute myeloid (AML) or lymphoid leukemia (ALL) after RIC (n = 271) and MAC (n = 425). Regimens were classified as MAC or RIC based on published criteria.

RESULTS

A combination of post-transplant cyclophosphamide (PT-Cy) with one calcineurin inhibitor and mycophenolate mofetil (PT-Cy-based regimen) for graft-versus-host disease (GVHD) prophylaxis was used in 66 (25%) patients in RIC and 125 (32%) in MAC groups. Patients of RIC group were older and had been transplanted more recently and more frequently for AML with active disease at transplant. Percentage of engraftment (90 vs. 92%; p = 0.58) and day 100 grade II to IV acute GVHD (24 vs. 29%, p = 0.23) were not different between RIC and MAC groups. Multivariable analyses, run separately in AML and ALL, showed a trend toward higher relapse incidence with RIC in comparison to MAC in AML (hazard ratio (HR) 1.34, p = 0.09), and no difference in both AML and ALL in terms of non-relapse mortality (NRM) chronic GVHD and leukemia-free survival. There was no impact of conditioning regimen intensity in overall survival (OS) in AML (HR = 0.97, p = 0.79) but a trend for worse OS with RIC in ALL (HR = 1.44, p = 0.10). The main factor impacting outcomes was disease status at transplantation (HR ≥ 1.4, p ≤ 0.01). GVHD prophylaxis with PT-Cy-based regimen was independently associated with reduced NRM (HR 0.63, p = 0.02) without impact on relapse incidence (HR 0.99, p = 0.94).

CONCLUSIONS

These data suggest that T-replete haplo-SCT with both RIC and MAC, in particular associated with PT-Cy, are valid options in first line treatment of high risk AML or ALL.

Maternal T-Cell Engraftment Interferes With Human Leukocyte Antigen Typing in Severe Combined Immunodeficiency

OBJECTIVES

To report the laboratory investigation of a case of severe combined immunodeficiency (SCID) with maternal T-cell engraftment, focusing on the interference of human leukocyte antigen (HLA) typing by blood chimerism.

METHODS

HLA typing was performed with three different methods, including sequence-specific primer (SSP), sequence-specific oligonucleotide, and Sanger sequencing on peripheral blood leukocytes and buccal cells, from a 3-month-old boy and peripheral blood leukocytes from his parents. Short tandem repeat (STR) testing was performed in parallel.

RESULTS

HLA typing of the patient's peripheral blood leukocytes using the SSP method demonstrated three different alleles for each of the HLA-B and HLA-C loci, with both maternal alleles present at each locus. Typing results from the patient's buccal cells showed a normal pattern of inheritance for paternal and maternal haplotypes. STR enrichment testing of the patient's CD3+ T lymphocytes and CD15+ myeloid cells confirmed maternal T-cell engraftment, while the myeloid cell profile matched the patient's buccal cells.

CONCLUSIONS

Maternal T-cell engraftment may interfere with HLA typing in patients with SCID. Selection of the appropriate typing methods and specimens is critical for accurate HLA typing and immunologic assessment before allogeneic hematopoietic stem cell transplantation.

Hematopoietic stem cell transplantation for patients with AML in first complete remission

Postremission therapy in patients with acute myeloid leukemia (AML) may consist of continuing chemotherapy or transplantation using either autologous or allogeneic stem cells. Patients with favorable subtypes of AML generally receive chemotherapeutic consolidation, although recent studies have also suggested favorable outcome after hematopoietic stem cell transplantation (HSCT). Although allogeneic HSCT (alloHSCT) is considered the preferred type of postremission therapy in poor- and very-poor-risk AML, the place of alloHSCT in intermediate-risk AML is being debated, and autologous HSCT is considered a valuable alternative that may be preferred in patients without minimal residual disease after induction chemotherapy. Here, we review postremission transplantation strategies using either autologous or allogeneic stem cells. Recent developments in the field of alternative donors, including cord blood and haploidentical donors, are highlighted, and we discuss reduced-intensity alloHSCT in older AML recipients who represent the predominant category of patients with AML who have a high risk of relapse in first remission.

Reduced-intensity transplantation for lymphomas using haploidentical related donors vs HLA-matched unrelated donors

We evaluated 917 adult lymphoma patients who received haploidentical (n = 185) or HLA-matched unrelated donor (URD) transplantation either with (n = 241) or without antithymocyte globulin (ATG; n = 491) following reduced-intensity conditioning regimens. Haploidentical recipients received posttransplant cyclophosphamide-based graft-versus-host disease (GVHD) prophylaxis, whereas URD recipients received calcineurin inhibitor-based prophylaxis. Median follow-up of survivors was 3 years. The 100-day cumulative incidence of grade III-IV acute GVHD on univariate analysis was 8%, 12%, and 17% in the haploidentical, URD without ATG, and URD with ATG groups, respectively (P = .44). Corresponding 1-year rates of chronic GVHD on univariate analysis were 13%, 51%, and 33%, respectively (P < .001). On multivariate analysis, grade III-IV acute GVHD was higher in URD without ATG (P = .001), as well as URD with ATG (P = .01), relative to haploidentical transplants. Similarly, relative to haploidentical transplants, risk of chronic GVHD was higher in URD without ATG and URD with ATG (P < .0001). Cumulative incidence of relapse/progression at 3 years was 36%, 28%, and 36% in the haploidentical, URD without ATG, and URD with ATG groups, respectively (P = .07). Corresponding 3-year overall survival (OS) was 60%, 62%, and 50% in the 3 groups, respectively, with multivariate analysis showing no survival difference between URD without ATG (P = .21) or URD with ATG (P = .16), relative to haploidentical transplants. Multivariate analysis showed no difference between the 3 groups in terms of nonrelapse mortality (NRM), relapse/progression, and progression-free survival (PFS). These data suggest that reduced-intensity conditioning haploidentical transplantation with posttransplant cyclophosphamide does not compromise early survival outcomes compared with matched URD transplantation, and is associated with significantly reduced risk of chronic GVHD.

Haploidentical Hematopoietic Stem Cell Transplantation: A Global Overview Comparing Asia, the European Union, and the United States

One of the major projects of the Worldwide Network for Blood and Marrow Transplantation (WBMT) is to promote hematopoietic stem cell transplantation (HSCT) in emerging countries in the world. For these countries, HLA haploidentical HSCT (haplo-HSCT) from family members is an attractive approach because of its cost effectiveness. To learn the current status, including recent trends, of haplo-HSCT, the WBMT invited speakers from major transplant centers in 3 regions (Asia, Europe, and North America) to present at its annual WBMT Joint Session. This article represents the direct reports from these 3 speakers in addition to introductions by 2 WBMT speakers who address data from the Global Transplant Activity survey. It must be emphasized, however, that certain promising results of haplo-HSCT presented in this article were obtained at well-experienced institutes.

Outcomes of Haploidentical Stem Cell Transplantation for Lymphoma with Melphalan-Based Conditioning

Haploidentical transplantation (Haplo-SCT) with post-transplantation cyclophosphamide (PTCy) is increasingly utilized for the treatment of lymphoma and almost exclusively with the nonmyeloablative fludarabine (Flu)/cyclophosphamide/total body irradiation (TBI) conditioning regimen. We present early results of a reduced-intensity (RIC) regimen utilizing fludarabine and melphalan (FM) for the treatment of advanced lymphoma. All patients with a diagnosis of lymphoma or chronic lymphocytic leukemia (CLL) who received Haplo-SCT at the University of Texas MD Anderson Cancer Center between 2009 and 2014 were reviewed (N = 22). Patients received Flu 160 mg/m(2) and melphalan 100 mg/m(2) to 140 mg/m(2) with thiotepa 5 mg/kg or 2 Gy TBI. Because of concerns of increased treatment-related mortality (TRM) with the melphalan 140 mg/m(2) regimen (FM140), a RIC regimen with melphalan 100 mg/m(2) (FM100) was devised. Rituximab was included for CD20(+) disease. Graft-versus-host disease prophylaxis consisted of PTCy 50 mg/kg on days +3 and + 4, tacrolimus, and mycophenolate mofetil. Sixty-eight percent of all patients were not in complete remission at the time of transplantation. The 2-year progression-free survival (PFS) and overall survival (OS) for the entire cohort were 54%, 1-year TRM was 19%, and the cumulative incidence of relapse at 2 years was 27%. Two-year PFS for Hodgkin lymphoma, non-Hodgkin lymphoma, and CLL/small lymphocytic lymphoma were 57%, 51%, and 75%. Patients treated with FM100 compared to FM140 had equivalent PFS (71% versus 37%, P = .246) and OS (71% versus 58%, P = .32). These early results establish Flu and melphalan 100 mg/m(2) with 2 Gy TBI or thiotepa 5 mg/kg as a very promising conditioning regimen for the treatment of advanced lymphoma with Haplo-SCT and PTCy.

Modern approaches to HLA-haploidentical blood or marrow transplantation

Allogeneic blood or bone-marrow transplantation (alloBMT) is a potentially curative treatment for a variety of haematological malignancies and nonmalignant diseases. Historically, human leukocyte antigen (HLA)-matched siblings have been the preferred source of donor cells owing to superior outcomes compared with alloBMT using other donors. Although only approximately one-third of patients have an HLA-matched sibling, nearly all patients have HLA-haploidentical related donors. Early studies using HLA-haploidentical alloBMT resulted in unacceptably high rates of graft rejection and graft-versus-host disease (GVHD), leading to high nonrelapse mortality and consequently poor survival. Several novel approaches to HLA-haploidentical alloBMT have yielded encouraging results with high rates of successful engraftment, effective GVHD control and favourable outcomes. In fact, outcomes of several retrospective comparative studies seem similar to those seen using other allograft sources, including those of HLA-matched-sibling alloBMT. In this Review, we provide an overview of the three most-developed approaches to HLA-haploidentical alloBMT: T-cell depletion with 'megadose' CD34(+) cells; granulocyte colony-stimulating factor-primed allografts combined with intensive pharmacological immunosuppression, including antithymocyte globulin; and high-dose, post-transplantation cyclophosphamide. We review the preclinical and biological data supporting each approach, results from major clinical studies, and completed or ongoing clinical studies comparing these approaches with other alloBMT platforms.

Idiopathic Pneumonia Syndrome and Thrombotic Microangiopathy Following Nonmyeloablative Haploidentical Peripheral Blood Stem Cell Transplantation and Posttransplant Cyclophosphamide: A Case Report

Posttransplant high-dose cyclophosphamide (pT-HDCy) following T-cell-replete haploidentical bone marrow (BM) transplantation has been successfully utilized to control alloreactivity, mainly in ameliorating graft-versus-host disease (GVHD) and graft rejection. Recently, peripheral blood stem cells (PBSCs) have also been suggested to be a feasible and effective graft alternative to BM in the same setting. We report a case with refractory Hodgkin lymphoma treated with haploidentical PBSC transplantation with nonmyeloablative conditioning and pT-HDCy. Although engraftment with complete donor chimerism was achieved without classical GVHD, the patient suffered from idiopathic pneumonia syndrome followed by thrombotic microangiopathy. Although idiopathic pneumonia syndrome and thrombotic microangiopathy improved after treatment, the patient's lymphoma rapidly progressed nonetheless. This outcome may suggest that the alloreactivity against the classical GVHD targets is successfully eradicated by pT-HDCy, but alloreactivity against the lungs and endothelial cells is differentially preserved when utilizing granulocyte colony-stimulating factor-mobilized PBSCs as the graft source. The graft-versus-Hodgkin lymphoma effect was not observed in our patient.

Current role of autologous and allogeneic stem cell transplantation for relapsed and refractory hodgkin lymphoma

Classical Hodgkin lymphoma (cHL) is a relatively rare disease, with approximately 9,200 estimated new cases and 1,200 estimated deaths per year in the United States. First-line chemo-radiotherapy leads to cure rates approaching 80% in patients with advanced-stage disease. However, 25 to 30% of these patients are not cured with chemotherapy alone (i.e., the ABVD regimen) and show either primary refractoriness to chemotherapy, early disease relapse or late disease relapse. Second-line salvage high-dose chemotherapy (HDC) and autologous stem cell transplantation (SCT) have an established role in the management of refractory/relapsed cHL, leading to durable responses in approximately 50% of relapsed patients and a minority of refractory patients. However, due to the poor responses to second-line salvage chemotherapy and dismal long-term disease control of primary refractory and early relapsed patients, their treatment represents an unmet medical need. Allogeneic SCT represents, by far, the only strategy with a curative potential for these patients; however, as discussed in this review, it’s role in cHL remains controversial. Despite a general consensus that early relapsed and primary refractory patients represent a clinical challenge requiring effective treatments to achieve long-term disease control, there has been no consensus on the optimal therapy that should be offered to these patients. This review will briefly discuss the clinical results and the main issues regarding autologous SCT as well as the current role of allogeneic SCT.