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]

HLA epitope mismatch in haploidentical transplantation is associated with decreased relapse and delayed engraftment

HLA disparity is traditionally measured at the antigen or allele level, and its impact on haploidentical hematopoietic cell transplantation (haplo-HCT) with high-dose posttransplant cyclophosphamide (PTCy) is unclear. To the best of our knowledge, the relationship between HLA eplet-derived epitope mismatch (EM) and clinical outcome has not been examined in haplo-HCT. We retrospectively analyzed 148 patients who received a peripheral blood, T-cell-replete haplo-HCT with PTCy at a single center. HLA EM was quantified using an HLAMatchmaker-based method and was stratified by class and vector. The primary outcome was incidence of relapse. The total number of mismatched epitopes (MEs) per patient-donor pair in our patient population ranged from 0 to 51 (median, 24) in the graft-versus-host (GVH) direction and 0 to 47 (median, 24) in the host-versus-graft (HVG) direction. Higher HLA class II EM in the GVH direction was associated with a significantly reduced risk of relapse (adjusted hazard ratio [HR], 0.952 per ME; P = .002) and improved relapse-free survival (adjusted HR, 0.974 per ME; P = .020). Higher HLA class II EM in the HVG direction was associated with longer time to neutrophil (adjusted HR, 0.974 per ME; P = .013) and platelet (adjusted HR, 0.961 per ME; P = .001) engraftment. In peripheral blood haplo-HCT patients, increased HLA EM was associated with a protective effect on the risk of relapse in the GVH direction but a negative effect on time to count recovery in the HVG direction. HLA EM based on the HLA Matchmaker represents a novel strategy to predict clinical outcome in haplo-HCT.

Antithymocyte globulin for graft-versus-host disease prophylaxis: an updated systematic review and meta-analysis

Graft-versus-host disease (GVHD) remains a limiting factor for successful allogeneic hematopoietic cell transplantation (allo-HCT). Conflicting data exist on the benefit of ATG on post-transplant survival. We performed a systematic review of randomized controlled trials (RCTs) to assess benefits and harms of thymoglobulin and Fresenius (re-branded as Grafalon) ATG formulations in patients undergoing allo-HCT for a variety of hematologic malignancies and bone marrow failure syndromes. A comprehensive search of MEDLINE, EMBASE, and Cochrane Library was performed. Data on methodological quality, benefits, and harms were extracted for each trial and pooled under a random-effects model. Eight RCTs (1134 patients) met the inclusion criteria. Methodological quality ranged from moderate to very low. Pooled results showed no difference in overall survival (OS) with the use of ATG (hazard ratio (HR) = 0.97; 95% confidence interval (CI) = 0.74-1.28; P = 0.83). ATG reduced grade II/III acute GVHD (risk ratio (RR) = 0.61; 95% CI = 0.48-0.77; P < 0.0001), grade III/IV acute GVHD (RR = 0.52; 95% CI = 0.34-0.81; P = 0.004), and chronic GVHD (RR = 0.52; 95% CI = 0.40-0.69; P < 0.00001) without an increase in non-relapse mortality (NRM) (RR = 0.91; 95% CI = 0.74-1.13; P = 0.40). Future studies with better methodological quality are needed to provide conclusive answers related to optimal dosing and timing of ATG for prevention of GVHD.

Disability related to chronic graft -versus-host disease after alternative donor hematopoietic cell transplantation

We determined the incidence of disability related to chronic graft-versus-host disease (bronchiolitis obliterans, grade ≥2 keratoconjunctivitis sicca, sclerotic features or esophageal stricture) for three categories of alternative donor: cord blood, haplorelated marrow or peripheral blood with post-transplant cyclophosphamide, and unrelated single HLA-allele mismatched peripheral blood. Among 396 consecutive hematopoietic cell transplant recipients, 129 developed chronic graft-versus-host disease with 3-year cumulative incidences of 8% for cord blood, 24% for haplorelated grafts, and 55% for unrelated single HLA-allele mismatched peripheral blood. Disability rates were significantly lower for cord blood [hazard ratio (HR) 0.13; 95% confidence interval (CI): 0.1-0.4] and for the haplorelated group (HR 0.31; 95% CI: 0.1-0.7) compared to the rate in the group transplanted with unrelated single HLA-allele mismatched peripheral blood. Cord blood recipients were also >2-fold more likely to return to work/school within 3 years from the onset of chronic graft-versus-host disease (HR 2.54; 95% CI: 1.1-5.7, P=0.02), and the haplorelated group trended similarly (HR 2.38; 95% CI: 1.0-5.9, P=0.06). Cord blood recipients were more likely to discontinue immunosuppression than were recipients of unrelated single HLA-allele mismatched peripheral blood (HR 3.96; 95% CI: 1.9-8.4, P=0.0003), similarly to the haplorelated group (HR 4.93; 95% CI: 2.2-11.1, P=0.0001). Progression-free survival and non-relapse mortality did not differ between groups grafted from different types of donors. Our observations that, compared to recipients of unrelated single HLA-allele mismatched peripheral blood, recipients of cord blood and haplorelated grafts less often developed disability related to chronic graft-versus-host disease, and were more likely to resume work/school, should help better counseling of pre-hematopoietic cell transplant candidates.

Risk factors and timing of autologous stem cell transplantation for patients with peripheral T-cell lymphoma

High-dose chemotherapy with autologous stem cell transplantation (HDC-ASCT) is an option for patients with peripheral T-cell lymphoma (PTCL); however, neither prospective nor retrospective studies support proceeding with ASCT upfront, and the timing of HDC-ASCT remains controversial. We retrospectively analyzed the risk factors for outcomes of 570 patients with PTCL, including PTCL not otherwise specified (PTCL-NOS) and angioimmunoblastic T-cell lymphoma (AITL), who received ASCT for frontline consolidation (n = 98 and 75, respectively) or alternative therapies after either relapse (n = 112 and 75) or primary induction failure (PIF; n = 127 and 83) between 2000 and 2015. Significant risk factors for overall survival (OS) after upfront ASCT were a ≥ 2 prognostic index for T-cell lymphoma (P < 0.001) and partial response (PR) at ASCT (P = 0.041) in PTCL-NOS patients, and > 60 years of age (P = 0.0028) and PR at ASCT (P = 0.0013) in AITL patients. Performance status of ≥ 2 at ASCT (P < 0.001), receiving ≥ 3 regimens before ASCT (P = 0.018), and PR at ASCT (P = 0.018) in PTCL-NOS patients and > 60 years of age at ASCT (P = 0.0077) in AITL patients were risk factors for OS after ASCT with a chemosensitive PIF status. Strategies that carefully select PTCL patients may allow identification of individuals suitable for ASCT.

Advances in Transplantation for Lymphomas Resulting from CIBMTR Lymphoma Working Committee's Research Portfolio: A Five-Year Report (2013-2018)

The Center for International Blood and Marrow Transplant Research (CIBMTR) is a research collaboration between the National Marrow Donor Program (NMDP)/Be The Match and the Medical College of Wisconsin (MCW). The CIBMTR collaborates with the global scientific community to advance hematopoietic cell transplantation (HCT) and cellular therapy worldwide to increase survival and enrich quality of life for patients. The observation research program within CIBMTR is organized into 15 working committees. This review is aiming to highlight the observational research studies published by the CIBMTR Lymphoma Working committee over the last five years (2013-18) and to summarize how these studies have impacted the field by helping inform clinical practice in scenarios where prospective data from high quality randomized trials were not available or where owing to the rarity of a particular transplant indication such data were unlikely to be generated, outside the setting of a large observational research database. The salient findings reviewed include; (a) studies supporting role of autologous HCT in diffuse large B-cell lymphoma (DLBCL) patients with sensitive relapse of disease within one year of diagnosis, (b) role of autologous HCT vs allogeneic HCT in follicular lymphoma patients with early therapy failure, (c) prognostic scoring system development for classical Hodgkin lymphoma and DLBCL patients with prior autograft failure, (d) defining the role of alternative donor transplantation in lymphomas, (e) evaluating appropriate conditioning regimens for HCT in lymphoma, and (f) outcomes of HCT in rare lymphoid malignancies.

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

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

The Impact of Advanced Patient Age on Mortality after Allogeneic Hematopoietic Cell Transplantation for Non-Hodgkin Lymphoma: A Retrospective Study by the European Society for Blood and Marrow Transplantation Lymphoma Working Party

More than 60% of patients with non-Hodgkin lymphoma (NHL) are age >60 years at presentation. The purpose of this study was to compare the potential risks and benefits of allogeneic hematopoietic cell transplantation (alloHCT) in elderly patients with NHL with younger patients in a large sample, also taking into account comorbidity information. All patients age ≥18 years who had undergone alloHCT from a matched sibling or unrelated donor for NHL between 2003 and 2013 and were registered with the European Society for Blood and Marrow Transplantation were eligible for the study. The primary study endpoint was 1-year nonrelapse mortality (NRM). A total of 3919 patients were eligible and were categorized by age: young (Y), 18 to 50 y (n = 1772); middle age (MA), 51 to 65 y (n = 1967); or old (O), 66 to 77 y (n = 180). Follicular lymphoma was present in 37% of the patients; diffuse large B cell lymphoma, in 30%; mantle cell lymphoma, in 21%, and peripheral T cell lymphoma, in 11%. At the time of alloHCT, 85% of the patients were chemosensitive and 15% were chemorefractory. With a median follow-up of 4.5 years in survivors, NRM at 1 year was 13% for the Y group. 20% for the MA group, and 33% for the O group (P <.001), whereas relapse incidence and overall survival (OS) at 3 years in the 3 groups were 30%, 31%, and 28% (P = .355) and 60%, 54%, and 38% (P <.001), respectively. Multivariable adjustment for confounders, including sex, NHL subset, time from diagnosis, chemosensitivity, donor, and conditioning, confirmed older age as a significant predictor for NRM and OS, but not for relapse risk. Although comorbidity was a significant predictor of NRM in a subset analysis restricted to the 979 patients with comorbidity information available, age retained its significant impact on NRM. In conclusion, our data show that alloHCT in patients age >65 y provides similar NHL control as seen in younger patients but is associated with a higher NRM that is not fully explained by comorbidity. Thus, although alloHCT is feasible and effective in very old patients, the increased NRM risk must be taken into account when assessing the indication for alloHCT for NHL in this age group.

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

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HaploHSCT after RIC with ATG, PTCy, and cyclosporine is a feasible transplant regimen.

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Low rates of grade II to IV acute GVHD were observed.

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ATG use leads to higher rates of viral reactivation, particularly CMV and EBV.

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

Haploidentical versus matched donor stem cell transplantation for patients with hematological malignancies: a systemic review and meta-analysis

We compared the safety and efficacy of haploidentical stem cell transplantation (haplo-SCT) to matched donor SCT (matched-SCT) in treating hematological malignancies. The Medline, Cochrane, EMBASE, and Google Scholar databases were searched through 21 June 2017 using the search term "(hematological disease) AND matched AND (haploidentical OR haplo-identical OR haplo identical OR haplo transplantation OR haplo transplant OR haplo-SCT OR haplo-HSCT OR haplo-HCT)." Twenty-five studies enrolling 11,359 patients (haplo-SCT: 2677; matched-SCT: 8682) were included. The primary outcomes were acute and chronic graft-versus-host disease (GVHD), non-relapse mortality, and 1-year cumulative incidence of relapse. Haplo-SCT was associated with similar risks as matched-SCT for all primary endpoints. Subgroup analysis of patients who received a matched-SCT from a related donor revealed that patients who received haplo-SCT had a lower risk of acute GVHD. Among patients who received reduced-intensity conditioning (RIC), those who received haplo-SCT had a higher risk of acute grade II-IV GVHD and non-relapse mortality than did patients who received a matched-SCT from a related or unrelated donor. Haplo-SCT should continue to be considered as a safe and effective transplant option when a matched donor is unavailable, but it may not be suitable for patients who receive RIC.

Recommendations for managing PD-1 blockade in the context of allogeneic HCT in Hodgkin lymphoma: taming a necessary evil

PD-1 blockade is an effective therapy in relapsed/refractory (R/R) classical Hodgkin Lymphoma (cHL) who have relapsed after or are ineligible for autologous hematopoietic cell transplantation (HCT). Although single-agent anti-PD-1 monoclonal antibodies (mAb’s) are associated with high response rates and durable remissions, available results to date suggest that a large majority of patients will eventually progress on therapy. Many of these patients are potential candidates for allogeneic HCT (allo-HCT) after receiving anti-PD-1 mAb’s, and allo-HCT remains for now the only treatment with demonstrated curative potential in this setting. However, initial reports suggested that allo-HCT in this setting may be associated with increased risk of early transplant-related toxicity, likely driven by lingering effects of PD-1 blockade. Furthermore, many patients with R/R cHL who undergo allo-HCT will relapse after transplantation, most often with limited treatment options. Here again, PD-1 blockade appears to yield high response rates, but with an increased risk of attendant immune toxicity. Many questions remain regarding the use of PD-1 blockade before or after allo-HCT, especially in relation to the feasibility, outcome, optimal timing, and method of allo-HCT after PD-1 blockade. Despite the scarcity of prospective data, these questions are unavoidable and must be tackled by clinicians in the routine care of patients with advanced cHL. We provide consensus recommendations of a working group based on available data and experience, in an effort to help guide treatment decisions until more definitive data are obtained.

Autologous transplantation versus allogeneic transplantation in patients with follicular lymphoma experiencing early treatment failure

BACKGROUND

Early treatment failure (ETF) in follicular lymphoma (FL), defined as relapse or progression within 2 years of frontline chemoimmunotherapy, is a newly recognized marker of poor survival and identifies a high-risk group of patients with an expected 5-year overall survival (OS) rate of approximately 50%. Transplantation is an established option for relapsed FL, but its efficacy in this specific ETF FL population has not been previously evaluated.

METHODS

This study compared autologous hematopoietic stem cell transplantation (auto-HCT) with either matched sibling donor (MSD) or matched unrelated donor (MUD) allogeneic hematopoietic cell transplantation (allo-HCT) as the first transplantation approach for patients with ETF FL (age ≥ 18 years) undergoing auto-HCT or allo-HCT between 2002 and 2014. The primary endpoint was OS. The secondary endpoints were progression-free survival, relapse, and nonrelapse mortality (NRM).

RESULTS

Four hundred forty FL patients had ETF (auto-HCT, 240; MSD hematopoietic stem cell transplantation [HCT], 105; and MUD HCT, 95). With a median follow-up of 69 to 73 months, the adjusted probability of 5-year OS was significantly higher after auto-HCT (70%) or MSD HCT (73%) versus MUD HCT (49%; P = .0008). The 5-year adjusted probability of NRM was significantly lower for auto-HCT (5%) versus MSD (17%) or MUD HCT (33%; P < .0001). The 5-year adjusted probability of disease relapse was lower with MSD (31%) or MUD HCT (23%) versus auto-HCT (58%; P < .0001).

CONCLUSIONS

Patients with high-risk FL, as defined by ETF, undergoing auto-HCT for FL have low NRM and a promising 5-year OS rate (70%). MSD HCT has lower relapse rates than auto-HCT but similar OS. Cancer 2018;124:2541-51. © 2018 American Cancer Society.

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.

Proceedings From the Fourth Haploidentical Stem Cell Transplantation Symposium (HAPLO2016), San Diego, California, December 1, 2016

The resurgence of haploidentical stem cell transplantation (HaploSCT) over the last decade is one of the most important advances in the field of hematopoietic stem cell transplantation (HSCT). The modified platforms of T cell depletion either ex vivo (CD34+ cell selection, "megadoses" of purified CD34+ cells, or selective depletion of T cells) or newer platforms of in vivo depletion of T cells, with either post-transplantation high-dose cyclophosphamide or intensified immune suppression, have contributed to better outcomes, with survival similar to that in HLA-matched donor transplantation. Further efforts are underway to control viral reactivation using modified T cells, improve immunologic reconstitution, and decrease the relapse rate post-transplantation using donor-derived cellular therapy products, such as genetically modified donor lymphocytes and natural killer cells. Improvements in treatment-related mortality have allowed the extension of haploidentical donor transplants to patients with hemoglobinopathies, such as thalassemia and sickle cell disease, and the possible development of platforms for immunotherapy in solid tumors. Moreover, combining HSCT from a related donor with solid organ transplantation could allow early tapering of immunosuppression in recipients of solid organ transplants and hopefully prevent organ rejection in this setting. This symposium summarizes some of the most important recent advances in HaploSCT and provides a glimpse in the future of fast growing field.

CD3+ graft cell count influence on chronic GVHD in haploidentical allogeneic transplantation using post-transplant cyclophosphamide

The effects of graft or donor characteristics in haploidentical hematopoietic cell transplantation (HCT) using post-transplant cyclophosphamide (PT-Cy) are largely unknown. In this multicenter retrospective study we analyzed the correlations between graft cell composition (CD34+, CD3+) and donor features on transplant outcomes in 234 patients who underwent HCT between 2010 and 2016. On multivariate analysis, the use of peripheral blood stem cells (PBSC) was associated with an increased incidence of grade 2-4 acute GVHD [HR 1.94, 95% confidence Interval (CI) = 1.01-3.98, p = 0.05]. An elevated CD3+ graft content was associated with an increased incidence of all-grade chronic GVHD [HR 1.36 (95% CI = 1.06-1.74), p = 0.01]. This effect was confirmed only for the PBSC graft group. A higher CD34+ graft content had a protective role on non-relapse mortality [HR 0.78 (95% CI = 0.62-0.96), p = 0.02] but this was confirmed only for the bone marrow (BM)-derived graft cohort. Donor characteristics did not influence any outcomes. GVHD prophylaxis should be modulated accordingly to CD3+ graft content, especially when a PBSC graft is used. These results need further validation in prospective trials.

Allogeneic hematopoietic stem cell transplantation for T-cell lymphomas

Mature T- and natural killer (NK)-cell neoplasms comprise a group of morphologically, immunophenotypically, molecularly, and clinically heterogeneous disorders with generally unfavorable outcome. Results of first-line chemotherapy are unsatisfactory for the most common T-cell lymphomas (peripheral T-cell lymphoma, not otherwise specified; angioimmunoblastic T-cell lymphoma; anaplastic large cell lymphomas; anaplastic lymphoma tyrosine kinase-negative) as well as for many other entities. High-dose therapy followed by autologous hematopoietic stem cell transplantation (HSCT) is widely recommended for consolidation after a complete or partial remission is achieved. However, about one-third of patients never reach transplantation because of early relapse or refractoriness. Targeted therapies have recently been developed; combinations with chemotherapy may improve outcomes, but long-term results from prospective studies are largely missing. In this situation, allogeneic HSCT remains a valuable treatment option inducing long-lived remissions in about 30% to 50% of patients with relapsed and refractory T-cell lymphoma able to proceed to transplantation. Results of allogeneic transplantation for consolidation in first remission are less defined and its indications remain controversial. With growing evidence that haploidentical HSCT also works in lymphoma, more patients can be brought to transplantation. Decreasing the morbidity and mortality of allogeneic transplantation is a continuous challenge. Integrating new drugs into transplant concepts and setting up prospective studies involving allogeneic transplantation remain unmet needs that warrant urgent study in a group of disorders in which classical chemotherapy and new drugs have generated results, which are far from optimal until today.

Peripheral Blood Grafts for T Cell-Replete Haploidentical Transplantation Increase the Incidence and Severity of Cytokine Release Syndrome

T cell-replete post-transplant cyclophosphamide (PTCy)-based protocols have led to increasing use of haploidentical allogeneic hematopoietic cell transplantation (haploHCT). With this approach, bidirectional alloreactivity causing nonengraftment or severe graft-versus-host disease (GVHD) is no a longer major barrier to haploHCT. PTCy eliminates alloreactive lymphocytes but spares CD34⁺ stem cells and regulatory T lymphocytes, resulting in reliable hematopoietic recovery with relatively low incidence of GVHD. The immediate post-haploHCT course, usually before PTCy administration, is often complicated by cytokine release syndrome (CRS). The predictors of CRS and its effect on outcomes post-transplant have not been fully ascertained. We analyzed the outcomes of 66 patients who received haploHCT at our institution. Using published CRS criteria we identified 48 patients who developed CRS. In multivariate analysis peripheral blood grafts were significantly associated with grade ≥ 2 CRS, compared with bone marrow. Grade ≥ 2 CRS (compared with grade < 2) was not associated with differences in overall survival or nonrelapse mortality. Severe CRS was associated with a statistically nonsignificant trend toward higher incidences of grades III to IV acute GVHD, especially in the context of peripheral blood grafts. CRS is a common complication after T cell-replete peripheral blood haploHCT, but post-transplant survival outcomes may not be affected in those with severe CRS.

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

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

Grade II Acute Graft-versus-Host Disease and Higher Nucleated Cell Graft Dose Improve Progression-Free Survival after HLA-Haploidentical Transplant with Post-Transplant Cyclophosphamide

Compared with standard graft-versus-host disease (GVHD) prophylaxis platforms, post-transplantation cyclophosphamide (PTCy) after T cell-replete HLA-haploidentical (haplo) bone marrow transplantation (BMT) reduces the risk of grades III to IV acute (a) and chronic (c) GVHD, but maintains similar rates of grade II aGVHD. Given that mild GVHD has been associated with reduced treatment failure in HLA-matched BMT, we evaluated the risk factors for and effects of GVHD on survival in 340 adults with hematologic malignancies who engrafted after nonmyeloablative haplo-BMT with PTCy, mycophenolate mofetil, and tacrolimus. The cumulative incidence at 100 days of grade II and grades III to IV aGVHD were 30% (95% confidence interval [CI], 25% to 35%) and 2% (95% CI, 1% to 4%), respectively. The 1-year cumulative incidence of cGVHD was 10% (95% CI, 7% to 13%). In landmark analyses at 100 days, the 4-year probabilities of overall survival (OS) and progression-free survival (PFS) were, 48% (95% CI, 41% to 56%) and 39% (95% CI, 32% to 47%) for patients without grades II to IV aGVHD, compared with 63% (95% CI, 53% to 73%) and 59% (95% CI, 50% to 71%) for patients with grade II aGVHD (P = .05 and P = .009). In multivariable modeling, when compared with patients who never experienced GVHD, the hazard ratio (HR) for OS and PFS in patients with grade II aGVHD was .78 (95% CI, .54 to 1.13; P = .19) and .69 (95% CI, .48 to .98; P = .04). Higher nucleated cell graft dose was also associated with improved OS (HR, .88; 95% CI, .78 to 1.00; P = .05) and PFS (HR, .89; 95% CI, .79 to 1.0; P = .05) and decreased risk of grades III to IV aGVHD (subdistribution HR, .66; 95% CI, .46 to .96; P = .03). PTCy reduces grades III to IV aGVHD and cGVHD, but retains similar incidence of grade II aGVHD, the development of which improves PFS. Higher nucleated cell graft dose goals may also improve survival after nonmyeloablative haplo-BMT with PTCy.

Shortened-Duration Tacrolimus after Nonmyeloablative, HLA-Haploidentical Bone Marrow Transplantation

With post-transplantation cyclophosphamide (PTCy) as graft-versus-host disease (GVHD) prophylaxis, nonmyeloablative HLA-haploidentical (NMA haplo) and HLA-matched blood or marrow transplantation (BMT) have comparable outcomes. Early discontinuation of immunosuppression may reduce the risk of relapse and improve immune reconstitution, but may increase the risk of GVHD. We conducted a prospective trial of NMA haplo BMT for patients with hematologic malignancies (median age, 61 years), evaluating the safety of early discontinuation of tacrolimus. All patients received T cell-replete bone marrow followed by high-dose PTCy, mycophenolate mofetil, and tacrolimus. Tacrolimus was prespecified to stop without taper at day +90, +60, or +120, contingent on having ≥5% donor T cells, no relapse, and no grade II-IV acute or significant chronic GVHD. Safety stopping rules were based on ≥5% graft failure, ≥10% nonrelapse mortality (NRM), or a ≥20% combined incidence of severe acute and chronic GVHD from the tacrolimus stop date through day +180. Of the 47 patients in the day +90 arm, 23 (49%) stopped tacrolimus as planned. Of the 55 patients in the day +60 arm, 38 (69%) stopped as planned. Safety stopping criteria were not met. In both arms, at day +180, the probability of grade II-IV acute GVHD was <40%, that of grade III-IV acute GVHD was <8%, and that of NRM was <5%. The 1-year probabilities of chronic GVHD and NRM were <15% and <10%, respectively, in both arms. The 1-year GVHD-free relapse-free survival was higher in the day 60 arm. Thus, stopping tacrolimus as early as day +60 is feasible and carries acceptable risks after NMA haplo BMT with PTCy. This approach may facilitate post-transplantation strategies for relapse reduction.

Blood and Marrow Transplant Clinical Trials Network Report on the Development of Novel Endpoints and Selection of Promising Approaches for Graft-versus-Host Disease Prevention Trials

Graft-versus-host disease (GVHD) is a common complication after hematopoietic cell transplantation (HCT) and associated with significant morbidity and mortality. Preventing GVHD without chronic therapy or increasing relapse is a desired goal. Here we report a benchmark analysis to evaluate the performance of 6 GVHD prevention strategies tested at single institutions compared with a large multicenter outcomes database as a control. Each intervention was compared with the control for the incidence of acute and chronic GVHD and overall survival and against novel composite endpoints: acute and chronic GVHD, relapse-free survival (GRFS), and chronic GVHD, relapse-free survival (CRFS). Modeling GRFS and CRFS using the benchmark analysis further informed the design of 2 clinical trials testing GVHD prophylaxis interventions. This study demonstrates the potential benefit of using an outcomes database to select promising interventions for multicenter clinical trials and proposes novel composite endpoints for use in GVHD prevention trials.

Fludarabine and Busulfan versus Fludarabine, Cyclophosphamide, and Rituximab as Reduced-Intensity Conditioning for Allogeneic Transplantation in Follicular Lymphoma

Large, multicenter studies comparing commonly used reduced-intensity conditioning (RIC) approaches in follicular lymphoma (FL) have not been performed. Using the Center for International Blood and Marrow Transplant Research database, we report the outcomes of the 2 most commonly used RIC approaches, fludarabine and busulfan (Flu/Bu) versus fludarabine, cyclophosphamide, and rituximab (FCR) in FL patients. We evaluated 200 FL patients undergoing allogeneic hematopoietic cell transplantation (allo-HCT) who received RIC with either Flu/Bu (n = 98) or FCR (n = 102) during 2008 to 2014. All patients received peripheral blood grafts, and graft-versus-host disease (GVHD) prophylaxis was limited to calcineurin inhibitor-based approaches. Median follow-up of survivors in the Flu/Bu and FCR groups was 48 months and 46 months, respectively. On univariate analysis in the Flu/Bu and FCR groups, the 3-year rates of nonrelapse mortality (11% versus 11%, P = .94), relapse/progression (18% versus 15%, P = .54), progression-free survival (PFS) (71% versus 74%, P = .65), and overall survival (OS) (73% versus 81%, P = .18) were not significantly different. On multivariate analysis no difference was seen between the FCR and Flu/Bu cohorts in terms of grades II to IV (relative risk [RR], 1.06; 95% confidence interval [CI], .59 to 1.93; P = .84) or grades III to IV (RR, 1.18; 95% CI, .47 to 2.99; P = .72) acute GVHD, nonrelapse mortality (RR, .83; 95% CI, .38 to 1.82; P = .64), relapse/progression (RR, .99; 95% CI, .49 to 1.98; P = .97), PFS (RR, .92; 95% CI, .55 to 1.54; P = .76), or OS (RR, .70; 95% CI, .40 to 1.23; P = .21) risk. However, RIC with FCR was associated with a significantly reduced chronic GVHD risk (RR, .52; 95% CI, .36 to .77; P = .001). RIC with either Flu/Bu or FCR in patients with FL undergoing allo-HCT provides excellent 3-year OS, with acceptable rates of nonrelapse mortality. FCR-based conditioning was associated with a lower risk of chronic GVHD.

How to Approach a Hodgkin Lymphoma Patient With Relapse After Autologous SCT: Allogeneic SCT

Hodgkin lymphoma (HL) is a highly curable B-cell lymphoma, and ∼90% of patients who present with early-stage (stage I-II) disease and 70% of patients who present with late-stage disease will be cured with standard frontline treatment. For patients with relapsed or refractory (r/r) disease after initial therapy, the standard of care is salvage chemotherapy, followed by autologous transplantation (autoSCT). Although this approach will cure a significant proportion of patients, upto 50% of patients will experience disease progression after autoSCT, and this population has historically had a very poor prognosis. In the past, further salvage chemotherapy, followed by allogeneic transplantation (alloSCT), has been the only option associated with a significant probability of long-term survival, owing to a graft-versus-lymphoma effect. However, this approach has been complicated by high rates of treatment-related morbidity and mortality and a high risk of disease relapse. Furthermore, many patients have been unable to proceed to alloSCT because of disease refractoriness, poor performance status, or the lack of a donor. However, significant therapeutic advances in recent years have greatly expanded the options for patients with post-autoSCT r/r HL. These include the anti-CD30 antibody-drug conjugate brentuximab vedotin and the checkpoint inhibitors nivolumab and pembrolizumab, as well as increasing experience with alternative donor alloSCT, especially from haploidentical donors. In the present review, we discuss the current role of alloSCT in the treatment of HL after autoSCT relapse.

Reduced-Intensity Haploidentical Bone Marrow Transplantation with Post-Transplant Cyclophosphamide for Solid Tumors in Pediatric and Young Adult Patients

High-risk, recurrent, or refractory solid tumors in pediatric, adolescent, and young adult (AYA) patients have an extremely poor prognosis despite current intensive treatment regimens. We piloted an allogeneic bone marrow transplant platform using reduced-intensity conditioning (RIC) and partially HLA-mismatched (haploidentical) related donors for this population of pediatric and AYA solid tumor patients. Sixteen patients received fludarabine, cyclophosphamide, melphalan, and low-dose total body irradiation RIC haploidentical BMT (haploBMT) followed by post-transplantation cyclophosphamide (PTCy), mycophenolate mofetil, and sirolimus. All assessable patients were full donor chimeras on day 30 with a median neutrophil recovery of 19 days and platelet recovery of 21 days. One patient (7%) exhibited secondary graft failure associated with concomitant infection. The median follow-up time was 15 months. Overall survival was 88%, 56%, and 21% at 6, 12, and 24 months, respectively. Median survival from transplant date was 14 months with a median progression-free survival 7 months. We observed limited graft-versus-host disease in 3 patients and nonrelapse mortality in 1 patient. We demonstrated that RIC haploBMT with PTCy is feasible and has acceptable toxicities in patients with incurable pediatric and AYA solid tumors; thus, this approach serves as a platform for post-transplant strategies to prevent relapse and optimize progression-free survival.

Allogeneic Transplantation for Follicular Lymphoma: Does One Size Fit All?

Follicular lymphoma (FL) exhibits striking biologic and clinical heterogeneity. Patients with newly diagnosed asymptomatic or low-bulk disease may be observed or managed with immunotherapies alone. Chemoimmunotherapy is considered a standard treatment for patients with advanced, symptomatic disease. In patients with FL who achieve at least a partial remission after first-line chemoimmunotherapy, autologous (auto-) hematopoietic cell transplantation (HCT) consolidation is not recommended; however, most patients with FL experience disease relapse after frontline therapies, with the experience of therapy failure within 2 years of first-line treatments predicting poor survival. Despite remarkable efficacy, even in patients who experience failure with other therapies, auto-HCT and allogeneic (allo-) HCT remain underutilized in relapsed/refractory FL, even among healthy and younger patients. Early use of auto-HCT consolidation should be considered a standard therapy option for high-risk patients who experience early failure of chemoimmunotherapy (< 2 years). For patients with FL who experience failure of frontline therapies late (> 2 years), deferring auto-HCT until later in the disease course is reasonable. Allo-HCT is best reserved for medically fit individuals with heavily pretreated disease, persistent marrow involvement, refractory, but low-bulk, disease, and in those who experience a failure to mobilize stem cells for auto-HCT. Allo-HCT is also a reasonable option for patients with FL who experience failure with a prior autograft; lower-intensity conditioning regimens and HLA-matched related donors are preferred in that setting. Future research should focus on the eradication of minimal residual disease before HCT and the prevention of disease relapse after HCT by integrating novel targeted agents into pre-HCT and post-HCT regimens.

T Cell-Replete Haploidentical Transplantation with Post-Transplantation Cyclophosphamide for Hodgkin Lymphoma Relapsed after Autologous Transplantation: Reduced Incidence of Relapse and of Chronic Graft-versus-Host Disease Compared with HLA-Identical Related Donors

Allogeneic hematopoietic stem cell transplantation (SCT) represents a potential curative strategy for patients with Hodgkin lymphoma (HL) relapsing after autologous SCT (ASCT), but the incidence of disease relapse is still high. We performed a retrospective study on 64 patients with HL relapsing after ASCT to compare outcomes after HLA-identical SCT (HLAid-SCT; n = 34) and haploidentical SCT with post-transplantation cyclophosphamide (PT-Cy) (Haplo-SCT; n = 30). All patients engrafted, with a significantly shorter median time for neutrophil and platelet engraftment after HLAid compared with Haplo-SCT (14 days versus 19 days and 11 days versus 23 days, respectively; P < .005). With a median follow-up of 47 months, 3-year overall survival (OS), 3 -year progression-free survival (PFS), and 1-year nonrelapse mortality (NRM) were 53%, 44% and 17%, respectively. Recipients of Haplo-SCT were less likely to experience disease relapse (3-year cumulative incidence of relapse, 13% versus 62%; P = .0001) and chronic graft- versus-host disease (GVHD; 3% versus 32%; P = .003), resulting in improved PFS (60% versus 29%; P = .04) and GVHD-free/relapse-free survival (47% versus 17%; P = .06). The 3-year OS did not differ between the 2 groups (56% versus 54%; P not significant), and NRM was higher after Haplo-SCT, but the difference did not reach statistical significance (26% versus 9%; P = .09). On multivariate Cox regression analysis, receipt of Haplo-SCT (hazard ratio [HR], .17; P = .02) and achieving optimal disease control (complete remission before SCT: HR, .6; P < .0001) were the only independent variables associated with a reduced risk of disease relapse. Haplo-SCT is a valid option for patients with HL relapsing after ASCT, with a reduced incidence of relapse compared with HLAid SCT.

[Use of alternative donors for allogeneic haematopoietic cell transplantation in lymphoid neoplasms: Guidelines from the Francophone Society of Bone Marrow Transplantation and Cellular Therapy (SFGM-TC)]

Despite great improvements in the outcome of patients with lymphoma, some may still relapse or present with primary refractory disease. In these situations, allogeneic haematopoietic cell transplantation (allo-HCT) is a potentially curative option, in particular in the case of relapse after autologous stem cell transplantation. Recently, novel agents such as anti-PD1 and BTK inhibitors have started to challenge the use of allo-HCT for relapsed or refractory lymphoma. During the 2016 annual workshop of the Francophone Society of Bone Marrow Transplantation and Cellular Therapy (SFGM-TC), we performed a comprehensive review of the literature published in the last 10 years and established guidelines to clarify the indications and transplant modalities in this setting. This manuscript reports on general considerations regarding allo-HCT for lymphoma and elaborates on the use of alternative donors in this setting.

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.

Immune Checkpoint Blockade and Hematopoietic Stem Cell Transplant

Allogeneic hematopoietic stem cell transplant (HSCT) relies primarily upon graft-versus-tumor activity for cancer eradication. Relapse remains the principal cause of treatment failure after HSCT, implying frequent immune escape, which in at least some cases, appears to be mediated by increased expression of inhibitory immune checkpoints. In an attempt to restore anti-tumor immunity, checkpoint blockade therapy (CBT) targeting PD-1 and CLTA-4 has been used in conjunction with both allogeneic and autologous HSCT. Clinical experience in this setting is limited to several small clinical trials and case series, but together they suggest that treatment with CBT can effectively amplify anti-tumor immune responses. However, intrinsic to its mechanism is also the risk that CBT in the HSCT setting may also cause significant immune toxicity. Fatal immune-related adverse events and graft-versus-host disease have been observed, but in most cases, immune side effects appear to be reversible with steroids and CBT discontinuation. As clinical investigation continues, improved understanding of immune checkpoint biology will be critical to optimize safe and efficacious treatment strategies.

Similar outcomes after haploidentical transplantation with post-transplant cyclophosphamide versus HLA-matched transplantation: a meta-analysis of case-control studies

Background

Outcomes of haploidentical hematopoietic cell transplantation (haplo-HCT) with post-transplant cyclophosphamide (PT-Cy) have greatly improved. It remains unknown whether haplo-HCT with PT-Cy was associated with poor outcomes when compared with HLA-matched HCT. To address this issue, we performed a meta-analysis to compare outcomes of haplo-HCT with PT-Cy with those of HLA-matched HCT.

Methods

A systematic search for case-control studies were performed in PubMed, Embase and Cochrane Library databases. Using a random model, the risk ratios (RRs) and 95% confidence intervals (95% CI) were pooled for the final analysis.

Results

Nine case-control studies including 2258 patients (827 patients in the haplo-HCT with PT-Cy group, 748 controls from HLA-matched related donors (MRD), and 683 controls from HLA-matched unrelated donors (MUD)) met the inclusion criteria. No differences were found between haplo-HCT with PT-Cy and HLA-matched HCT with regard to acute graft-versus-host-disease (GVHD), non-relapse mortality, relapse, progression free survival and overall survival. However, haplo-HCT with PT-Cy was found to be associated with a lower incidence of moderate to severe chronic GVHD (Haplo vs MRD: RR=0.54; 95% CI=0.39-0.75; Haplo vs MUD: RR=0.70; 95% CI=0.56-0.88).

Conclusions

The results of this meta-analysis suggest that haplo-HCT with PT-Cy can achieve comparable outcomes with those of HLA-matched HCT. Haploidentical donors can be a feasible and valid alternative when conventional HLA-matched donors are unavailable.

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.

Advances in the pathophysiology and treatment of relapsed/refractory Hodgkin's lymphoma with an emphasis on targeted therapies and transplantation strategies

Hodgkin’s lymphoma (HL) is highly curable with first-line therapy. However, a minority of patients present with refractory disease or experience relapse after completion of frontline treatment. These patients are treated with salvage chemotherapy followed by autologous stem cell transplantation (ASCT), which remains the standard of care with curative potential for refractory or relapsed HL. Nevertheless, a significant percentage of such patients will progress after ASCT, and allogeneic hematopoietic stem cell transplantation remains the only curative approach in that setting. Recent advances in the pathophysiology of refractory or relapsed HL have provided the rationale for the development of novel targeted therapies with potent anti-HL activity and favorable toxicity profile, in contrast to cytotoxic chemotherapy. Brentuximab vedotin and programmed cell death-1-based immunotherapy have proven efficacy in the management of refractory or relapsed HL, whereas several other agents have shown promise in early clinical trials. Several of these agents are being incorporated with transplantation strategies in order to improve the outcomes of refractory or relapsed HL. In this review we summarize the current knowledge regarding the mechanisms responsible for the development of refractory/relapsed HL and the outcomes with current treatment strategies, with an emphasis on targeted therapies and hematopoietic stem cell transplantation.

PD-1 blockade for relapsed lymphoma post-allogeneic hematopoietic cell transplant: high response rate but frequent GVHD

Given the limited treatment options for relapsed lymphoma post-allogeneic hematopoietic cell transplantation (post-allo-HCT) and the success of programmed death 1 (PD-1) blockade in classical Hodgkin lymphoma (cHL) patients, anti-PD-1 monoclonal antibodies (mAbs) are increasingly being used off-label after allo-HCT. To characterize the safety and efficacy of PD-1 blockade in this setting, we conducted a multicenter retrospective analysis of 31 lymphoma patients receiving anti-PD-1 mAbs for relapse post-allo-HCT. Twenty-nine (94%) patients had cHL and 27 had ≥1 salvage therapy post-allo-HCT and prior to anti-PD-1 treatment. Median follow-up was 428 days (range, 133-833) after the first dose of anti-PD-1. Overall response rate was 77% (15 complete responses and 8 partial responses) in 30 evaluable patients. At last follow-up, 11 of 31 patients progressed and 21 of 31 (68%) remain alive, with 8 (26%) deaths related to new-onset graft-versus-host disease (GVHD) after anti-PD-1. Seventeen (55%) patients developed treatment-emergent GVHD after initiation of anti-PD-1 (6 acute, 4 overlap, and 7 chronic), with onset after a median of 1, 2, and 2 doses, respectively. GVHD severity was grade III-IV acute or severe chronic in 9 patients. Only 2 of these 17 patients achieved complete response to GVHD treatment, and 14 of 17 required ≥2 systemic therapies. In conclusion, PD-1 blockade in relapsed cHL allo-HCT patients appears to be highly efficacious but frequently complicated by rapid onset of severe and treatment-refractory GVHD. PD-1 blockade post-allo-HCT should be studied further but cannot be recommended for routine use outside of a clinical trial.

Is myeloablative dose intensity necessary in allogeneic hematopoietic cell transplantation for lymphomas?

The advent of novel immunotherapy and tyrosine kinase inhibitors has ushered a new era in the treatment of Hodgkin and non-Hodgkin lymphomas. Allogeneic hematopoietic cell transplantation remains, however, a vital component in the management and potential cure of lymphomas, especially in the relapsed setting. Considering the biological and clinical heterogeneity of various subtypes of lymphomas, the optimal intensity of conditioning regimens remains controversial. Reduced intensity conditioning regimens have broadened applicability of the procedure to older and frail patients. Observational studies suggest that although reduced intensity allografting is associated with higher risk of relapse, overall survival is comparable and in some cases even better, than observed with myeloablative regimens. Here, we review the available published data pertaining to allogeneic hematopoietic cell transplantation using reduced intensity or myeloablative conditioning for various lymphoma histologies. Owing to the lack of randomized prospective trials, recommendations are mainly based on registry and single-institution studies. Special emphasis must be given to implementing strategies to prevent relapse when using reduced intensity regimens. Identifying particular patients who may benefit from myeloablative regimens in lymphomas remains to be better defined.

Fever after peripheral blood stem cell infusion in haploidentical transplantation with post-transplant cyclophosphamide

OBJECTIVE/BACKGROUND

Noninfection-related fever can occur after peripheral blood stem cell infusion in haploidentical hematopoietic stem cell transplantation with post-transplant cyclophosphamide. The objective of this study was to analyze the incidence of fever and characterize some clinical features of affected patients.

METHODS

A retrospective case-series study with 40 patients who received haploidentical hematopoietic stem cell transplantation was carried out.

RESULTS

Thirty-three patients (82.5%) developed fever; no baseline characteristic was associated with its development. Median time to fever onset was 25.5h (range, 9.5-100h) and median peak temperature was 39.0°C (range, 38.1-40.5°C). Not a single patient developed hemodynamic or respiratory compromise that required admission to the intensive care unit. Fever was not explained by infection in any case. Ninety-one percent of the febrile episodes resolved within 96h of cyclophosphamide administration. No significant difference in overall survival, event-free survival, or graft versus host disease-free/relapse-free survival was found in the group of febrile individuals after peripheral blood stem cell infusion.

CONCLUSION

Fever after peripheral blood stem cell infusion in this clinical setting was common; it usually subsides with cyclophosphamide administration. The development of fever was not associated with an adverse prognosis.

Outcomes of haploidentical transplant compared with matched donor allogeneic stem cell transplant

The risk of acute and chronic graft-versus-host disease (GVHD) with haploidentical transplant with post-transplant high-dose cyclophosphamide may be lower compared with matched unrelated donor transplant and largely similar to matched related donor transplant. The lower probability of GVHD with the haploidentical donor may result in a risk of nonrelapse mortality that is at least similar to or even lower than the matched donor. The incidence of relapse and survival are also largely similar to different donor types. Haploidentical transplant may be associated with slower engraftment. Given a lower risk of GVHD, haploidentical transplant has gained popularity. Additionally, the use of post-transplant high-dose cyclophosphamide has been extended to lower the risk of GVHD with matched donor and mismatched unrelated donor transplant.