Clinical evidence of a graft-versus-Hodgkin's-lymphoma effect after reduced-intensity allogeneic transplantation

Classical Hodgkin Lymphoma: From Past to Future-A Comprehensive Review of Pathophysiology and Therapeutic Advances

Hodgkin lymphoma, a hematological malignancy of lymphoid origin that typically arises from germinal-center B cells, has an excellent overall prognosis. However, the treatment of patients who relapse or develop resistant disease still poses a substantial clinical and research challenge, even though current risk-adapted and response-based treatment techniques produce overall survival rates of over 95%. The appearance of late malignancies after the successful cure of primary or relapsed disease continues to be a major concern, mostly because of high survival rates. Particularly in pediatric HL patients, the chance of developing secondary leukemia is manifold compared to that in the general pediatric population, and the prognosis for patients with secondary leukemia is much worse than that for patients with other hematological malignancies. Therefore, it is crucial to develop clinically useful biomarkers to stratify patients according to their risk of late malignancies and determine which require intense treatment regimens to maintain the ideal balance between maximizing survival rates and avoiding late consequences. In this article, we review HL's epidemiology, risk factors, staging, molecular and genetic biomarkers, and treatments for children and adults, as well as treatment-related adverse events and the late development of secondary malignancies in patients with the disease.

Outcomes associated with allogeneic hematopoietic stem cell transplantation for relapsed and refractory Hodgkin lymphoma in the era of novel agents

BACKGROUND

Relapsed or refractory Hodgkin lymphoma (R/R HL) is a challenging disease with limited treatment options beyond brentuximab vedotin and checkpoint inhibitors. Herein we present the time-trend analysis of R/R HL patients who received allogeneic hematopoietic cell transplantation (allo-HCT) at our center from 2001-2017.

METHODS

The patients were divided into two distinct treatment cohorts: era1 (2001-2010), and era2 (2011-2017). The primary endpoint was overall survival (OS). Secondary endpoints included progression-free survival (PFS), non-relapse mortality (NRM), and cumulative incidence of acute and chronic graft versus host disease (GVHD).

RESULTS

Among the 51 patients included in the study, 29 were in era1, and 22 were in era2. There was decreased use of myeloablative conditioning in era2 (18% vs. 31%) compared to era1 and 95% of patients in era2 previously received brentuximab Vedotin (BV). Haploidentical donors were seen exclusively in era2 (0% vs. 14%) and more patients received alternative donor transplants (7% vs. 32%) in era2. The 4-year OS (34% vs. 83%, p < 0.001) and 4-year PFS (28% vs. 62%, p = 0.001) were significantly inferior in era1 compared to era2. The incidence of 1-year NRM was lower in era2 compared to era1 (5% vs. 34%, p = 0.06). The cumulative incidence of acute GVHD at day 100 was similar in both eras (p = 0.50), but the incidence of chronic GVHD at 1 year was higher in era2 compared to era1 (55% vs. 21%, p = 0.03).

CONCLUSIONS

Despite the advent of novel therapies, allo-HCT remains an important therapeutic option for patients with R/R HL.

The outcome of patients with Hodgkin lymphoma and early relapse after autologous stem cell transplant has improved in recent years

Hodgkin lymphoma (HL) patients who relapse after autologous-stem-cell- transplantation (auto-SCT) have traditionally had a poor prognosis. We analyzed 1781 adult HL patients who relapsed between 2006 and 2017 after a first auto-SCT. The 4-year overall survival (OS) after relapse continuously increased from 32% for patients relapsing in 2006-2008, to 63% for patients relapsing in 2015-2017 (p = 0.001). The improvement over time was predominantly noted in patients who had an early relapse (within 12 months) after auto-SCT (p = 0.01). On multivariate analysis, patients who relapsed in more recent years and those with a longer interval from transplant to relapse had a better OS, whereas increasing age, poor performance status, bulky disease, extranodal disease and presence of B symptoms at relapse were associated with a worse OS. Brentuximab vedotin (BV), checkpoint inhibitors (CPI) and second transplant (SCT2; 86% allogeneic) were used in 233, 91 and 330 patients respectively. The 4-year OS from BV, CPI, and SCT2 use was 55%, 48% and 55% respectively. In conclusion, the outcome after post-transplant relapse has improved significantly in recent years, particularly in the case of early relapse. These large-scale real-world data can serve as benchmark for future studies in this setting.

Reappraising the Role of Allogeneic Hematopoietic Stem Cell Transplantation in Relapsed and Refractory Hodgkin’s Lymphoma: Recent Advances and Outcomes

Hodgkin’s lymphoma is a rare yet highly curable disease in the majority of patients treated with modern chemotherapy regimens. For patients who fail to respond to or relapse after initial systemic therapies, treatment with high-dose chemotherapy and autologous hematopoietic stem cell transplantation can provide a cure for many with chemotherapy-responsive lymphoma. Patients who relapse after autologous transplant or those with chemorefractory disease have poor prognosis and represent a high unmet need. Allogeneic hematopoietic stem cell transplantation provides a proven curative therapy for these patients and should be considered, especially in young and medically fit patients. The use of newer agents in this disease such as brentuximab vedotin and immune checkpoint inhibitors can help bring more patients to transplantation and should be considered as well.

Stem-Cell Transplantation in Adult Patients with Relapsed/Refractory Hodgkin Lymphoma

Although the majority of patients with Hodgkin lymphoma (HL) are cured with initial therapy, in 85–90% of early stage and 70–80% of advanced-stage disease cases, relapse remains a major problem. Autologous stem-cell transplantation (auto-HCT) after salvage chemotherapy is currently considered to be the standard of care for patients who relapse after first-line chemotherapy or for whom first-line treatment fails. The curative capacity of auto-HCT has been improving with the introduction of new drug-based salvage strategies and consolidation strategies after auto-HCT. Allogeneic stem-cell transplantation (allo-HCT) represents a reasonable treatment option for young patients who relapse or progress after auto-HCT and have chemosensitive disease at the time of transplantation. Allo-HCT is a valid treatment strategy for patients with relapse/refractory HL (r/r HL) because the results have improved over time, mainly with the safe combination of allo-HCT and new drugs. Bearing in mind that outcomes after haploidentical stem-cell transplantation (haplo-HCT) are comparable with those for matched sibling donors and matched unrelated donors, haplo-HCT is now the preferred alternative donor source for patients with r/r HL without a donor or when there is urgency to find a donor if a matched related donor is not present. The development of new drugs such as anti-CD 30 monoclonal antibodies and checkpoint inhibitors (CPI) for relapsed or refractory HL has demonstrated high response rates and durable remissions, and challenged the role and timing of HCT. The treatment of patients with HL who develop disease recurrence or progression after allo-HCT remains a real challenge and an unmet need.

Organoid Technology: Current Standing and Future Perspectives

Organoids are powerful systems to facilitate the study of individuals' disorders and personalized treatments. Likewise, emerging this technology has improved the chance of translatability of drugs for pre-clinical therapies and mimicking the complexity of organs, while it proposes numerous approaches for human disease modeling, tissue engineering, drug development, diagnosis, and regenerative medicine. In this review, we outline the past/present organoid technology and summarize its faithful applications, then, we discuss the challenges and limitations encountered by 3D organoids. In the end, we offer the human organoids as basic mechanistic infrastructure for "human modelling" systems to prescribe personalized medicines. © AlphaMed Press 2021 SIGNIFICANCE STATEMENT: This concise review concerns about organoids, available methods for in vitro organoid formation and different types of human organoid models. We, then, summarize biological approaches to improve 3D organoids complexity and therapeutic potentials of organoids. Despite the existing incomprehensive review articles in literature that examine partial aspects of the organoid technology, the present review article comprehensively and critically presents this technology from different aspects. It effectively provides a systematic overview on the past and current applications of organoids and discusses the future perspectives and suggestions to improve this technology and its applications.

Haploidentical Stem Cell Transplantation in Lymphomas-Expectations and Pitfalls

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

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

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

Allo-HSCT in transplant-naïve patients with Hodgkin lymphoma: a single-arm, multicenter study

We evaluated the role of allogeneic hematopoietic stem cell transplantation (allo-HSCT) in transplant-naïve patients with relapsed/refractory Hodgkin lymphoma (HL) who failed to attain metabolic complete response (mCR) to 1 to 2 lines of salvage chemotherapyThose with residual but nonprogressive disease assessed by positron emission tomography/computed tomography scanning were eligible. An additional 1 to 2 cycles of salvage therapy were permissible in those with progressive disease or when required to bridge to allo-HSCT, with additional imaging at baseline before transplantation. Conditioning consisted of carmustine, etoposide, cytarabine, melphalan, and alemtuzumab. Donor lymphocyte infusions (DLI) were administered for mixed chimerism or residual or relapsed disease. Eleven patients had sibling donors, 13 had HLA-matched unrelated donors, and 7 had HLA-mismatched unrelated donors. There were no graft failures, and no episodes of grade 4 acute graft-versus-host disease (GVHD); only 19.4% of patients had grade 2 to 3 GVHD, and 22.2% had extensive chronic GVHD. The non-relapse mortality rate was 16.1% (95% confidence interval [CI], 7.1%-34.5%). Relapse incidence was 18.7% (95% CI, 8.2%-39.2%). The study met its primary objective, with a 3-year progression-free survival of 67.7% (95% CI, 48.4%-81.2%). Survival outcomes were equivalent in those with residual metabolically active disease immediately before transplantation (n = 24 [70.8%; 95% CI, 17.2%-83.7%]). Two of the 5 patients who relapsed received DLI and remained in mCR at latest follow-up, with a 3-year overall survival of 80.7% (95% CI, 61.9%-90.8%). We demonstrate encouraging results that establish a potential role for allo-HSCT in selected high-risk patients with HL. This trial was registered at www.clinicaltrials.gov as #NCT00908180.

Second autologous stem cell transplantation for relapsed/refractory Hodgkin lymphoma after a previous autograft: a study of the lymphoma working party of the EBMT

The purpose of this study was to analyze the results of second autologous hematopoietic stem cell transplantation (ASCT2) for patients with relapsed/refractory Hodgkin lymphoma (HL) after a first transplantation (ASCT1). Outcomes for 56 patients receiving an ASCT2 registered in the EBMT database were analyzed. The 4-year cumulative incidences of non-relapse mortality and disease relapse/progression were 5% and 67%, respectively. The 4-year overall survival (OS) and progression-free survival (PFS) were 62% and 28%. In univariate analysis, relapse of HL within 12 months of ASCT1 was associated with a worse OS (35% versus 76%, p = 0.01) and PFS (19% versus 29%, p = 0.059). Chemosensitivity at ASCT2 predicted better outcomes (4-year OS 72% versus 29%, p = 0.002; PFS 31% versus 12%, p = 0.015). This series shows that ASCT2 is a safe procedure and a relatively effective option for patients with late relapses after ASCT1 and with chemosensitive disease who are not eligible for an allogeneic transplant.

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

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

Changes in patients population and characteristics of hematopoietic stem cell transplantation for relapsed/refractory Hodgkin lymphoma: an analysis of the Lymphoma Working Party of the EBMT

Indications for autologous (auto-HCT) and allogeneic transplantation (allo-HCT) in relapsed/refractory Hodgkin lymphoma (rrHL) have been long established. The expectation is that long-term outcomes have significantly improved over time with increased experience in these procedures. The objective of this study was to assess whether this is the case and to identify further areas of improvement. A total of 13,639 adult patients receiving an auto-HCT or allo-HCT for rrHL were reported to the European Society for Blood and Marrow Transplantation (EBMT) over a 25-year period. Regarding auto-HCT, recipients are younger, interval between diagnosis and transplant shorter, peripheral blood has become the universal stem cell source and the use of total body irradiation is almost non-existent in recent years. Allo-HCT is currently mostly used as a second transplant; recipients are younger, fitter and less frequently, chemorefractory. Reduced intensity conditioning protocols have vastly replaced myeloablative protocols. Increasing numbers of haplo-HCT have been reported. Both in auto-HCT and allo-HCT, NRM, PFS and OS have significantly improved but relapse remains the main cause of treatment failure. A better selection of patients and improvements in the supportive care has resulted in a reduction in the NRM. Relapse after HCT remains unchanged and further research is needed.

Impact of type of reduced-intensity conditioning regimen on the outcomes of allogeneic haematopoietic cell transplantation in classical Hodgkin lymphoma

Reduced-intensity conditioning (RIC) allogeneic haematopoietic cell transplantation (allo-HCT) is a curative option for select relapsed/refractory Hodgkin lymphoma (HL) patients; however, there are sparse data to support superiority of any particular conditioning regimen. We analyzed 492 adult patients undergoing human leucocyte antigen (HLA)-matched sibling or unrelated donor allo-HCT for HL between 2008 and 2016, utilizing RIC with either fludarabine/busulfan (Flu/Bu), fludarabine/melphalan (Flu/Mel140) or fludarabine/cyclophosphamide (Flu/Cy). Multivariable regression analysis was performed using a significance level of <0·01. There were no significant differences between regimens in risk for non-relapse mortality (NRM) (P = 0·54), relapse/progression (P = 0·02) or progression-free survival (PFS) (P = 0·14). Flu/Cy conditioning was associated with decreased risk of mortality in the first 11 months after allo-HCT (HR = 0·28; 95% CI = 0·10-0·73; P = 0·009), but beyond 11 months post allo-HCT it was associated with a significantly higher risk of mortality, (HR = 2·46; 95% CI = 0·1.32-4·61; P = 0·005). Four-year adjusted overall survival (OS) was similar across regimens at 62% for Flu/Bu, 59% for Flu/Mel140 and 55% for Flu/Cy (P = 0·64), respectively. These data confirm the choice of RIC for allo-HCT in HL does not influence risk of relapse, NRM or PFS. Although no OS benefit was seen between Flu/Bu and Flu/Mel 140; Flu/Cy was associated with a significantly higher risk of mortality beyond 11 months from allo-HCT (possibly due to late NRM events).

Nitrosourea, etoposide and cyclophosphamide followed by autologous stem cell transplantation for pediatric lymphoma patients

Treatment outcomes in pediatric lymphoma have improved substantially over the past 2 decades; however, the prognosis for patients with high risk or relapsed disease remains poor. We evaluated outcomes of high-dose chemotherapy (HDC) and autologous stem cell transplantation (auto-SCT) in 56 pediatric lymphoma patients. Patients received nitrosourea (51 BCNU; 5 ACNU), etoposide, and cyclophosphamide (BEC; AEC). Median age at HDC/auto-SCT was 12 years (range 2-17 years). Forty-four patients underwent HDC/auto-SCT because they did not achieve complete remission after induction chemotherapy. Eight patients showed relapse and four NK/T-cell lymphoma patients also underwent HDC/auto-SCT. BCNU pneumonitis was diagnosed in nine (16.0%) patients. Eight (14.3%) relapsed after HDC/auto-SCT. Treatment-related mortality occurred in three cases. Five-year event-free survival and overall survival rates were 74.8% [72.7% non-Hodgkin's lymphoma (NHL); 83.3% Hodgkin's disease (HD); 72.7%] and 83.6% (81.6% NHL; 91.7% HD), respectively. HDC/auto-SCT with BEC or AEC regimen for pediatric high-risk lymphoma patients showed feasible outcomes. However, treatment modifications are warranted to reduce relapse and toxicity.

Functional ectodermal organ regeneration as the next generation of organ replacement therapy

In this decade, substantial progress in the fields of developmental biology and stem cell biology has ushered in a new era for three-dimensional organ regenerative therapy. The emergence of novel three-dimensional cell manipulation technologies enables the effective mimicking of embryonic organ germ formation using the fate-determined organ-inductive potential of epithelial and mesenchymal stem cells. This advance shows great potential for the regeneration of functional organs with substitution of complete original function in situ. Organoids generated from multipotent stem cells or tissue stem cells via establishment of an organ-forming field can only partially recover original organ function owing to the size limitation; they are considered ‘mini-organs’. Nevertheless, they hold great promise to realize regenerative medicine. In particular, regeneration of a functional salivary gland and an integumentary organ system by orthotopic and heterotopic implantation of organoids clearly points to the future direction of organ regeneration research. In this review, we describe multiple strategies and recent progress in regenerating functional three-dimensional organs, focusing on ectodermal organs, and discuss their potential and future directions to achieve organ replacement therapy as a next-generation regenerative medicine.

Optimizing outcomes in relapsed/refractory Hodgkin lymphoma: a review of current and forthcoming therapeutic strategies

The outcome of patients with relapsed/refractory classical Hodgkin lymphoma (rr-cHL) has improved considerably in recent years owing to the approval of highly active novel agents such as brentuximab vedotin and Programmed Death-1 (PD-1) inhibitors. Although no randomized trials have been conducted to provide formal proof, it is almost undisputable that the survival of these patients has been prolonged. As autologous stem-cell transplantation (SCT) remains the standard of care for second-line therapy of most patients with rr-cHL, optimization of second-line regimens with the use of brentuximab vedotin, or, in the future, checkpoint inhibitors, is promising to increase both the eligibility rate for transplant and the final outcome. The need for subsequent therapy, and especially allogeneic SCT, can be reduced with brentuximab vedotin consolidation for 1 year, while pembrolizumab is also being tested in this setting. Several other drug categories appear to be active in rr-cHL, but their development has been delayed by the appearance of brentuximab vedotin, nivolumab and pembrolizumab, which have dominated the field of rr-cHL treatment in the last 5 years. Combinations of active drugs in chemo-free approaches may further increase efficacy and hopefully reduce toxicity in rr-cHL, but are still under development.

ESMO Consensus Conference on malignant lymphoma: management of 'ultra-high-risk' patients

The European Society for Medical Oncology (ESMO) consensus conference on malignant lymphoma was held on 20 June 2015 in Lugano, Switzerland, and included a multidisciplinary panel of 25 leading experts. The aim of the conference was to develop recommendations on critical subjects difficult to consider in detail in the ESMO Clinical Practice Guidelines. The following areas were identified: (1) the elderly patient, (2) prognostic factors suitable for clinical use and (3) the 'ultra-high-risk' group. Before the conference, the expert panel was divided into three working groups; each group focused on one of these areas in order to address clinically relevant questions relating to that topic. All relevant scientific literature, as identified by the experts, was reviewed in advance. During the consensus conference, each working group developed recommendations to address each of the questions devised by their group. These recommendations were then presented to the entire multidisciplinary panel and a consensus was reached. This manuscript presents recommendations regarding the management of the following 'ultra-high-risk' situations: (1) early central nervous system relapse of diffuse large B-cell lymphoma, (2) primary refractory Hodgkin lymphoma and (3) plasmablastic lymphoma. Results, including a summary of evidence supporting each recommendation, are detailed in this manuscript. All expert panel members approved this final article.

Allogeneic stem cell transplantation improves survival in relapsed Hodgkin lymphoma patients achieving complete remission after salvage treatment

Allogeneic stem cell transplant (alloSCT) is a current treatment option for patients with refractory/relapsed classic Hodgkin lymphoma (CHL), including those who have failed an autologous transplantation. We performed a retrospective multicenter analysis of 113 patients (median age 28 years; range 14-56; 54% males) with refractory/relapsed (R/R) CHL who had undergone alloSCT in Argentina. Kaplan-Meier was used to estimate overall (OS) and progression-free survival (PFS). Relapse rate (RR) and non-relapse mortality (NRM) were estimated with cumulative incidence analysis. Disease status at transplant was complete remission (CR) in 39%, partial remission (PR) in 44%, and stable/progressed disease (S/PD) in 17% of the patients. Donor type was matched related (MRD) in 60%, unrelated (URD) in 19%, and haploidentical (HID) in 21% of the patients. OS and PFS at 2 years were 43% and 27%, respectively, for all the cohort. In the univariate analysis, patients in CR showed better OS (p ≤ 0.001) and PFS (p ≤ 0.001), and lower NRM (p = 0.04). HID had better PFS (p = 0.04) and lower RR (p = 0.02). In the multivariate analysis, CR showed a significant impact on OS and PFS, and HID on PFS. AlloSCT is a feasible procedure in patients with CHL. Those in CR at the time of the transplant had better outcomes. Haploidentical transplantation is associated with better PFS in these patients with poor prognosis.

Should all patients with Hodgkin lymphoma who relapse after autologous SCT be considered for allogeneic SCT?

This article has a companion Counterpoint by Moskowitz.

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.

Impact of graft-versus-lymphoma effect on outcomes after reduced intensity conditioned-alemtuzumab allogeneic haematopoietic stem cell transplantation for patients with mature lymphoid malignancies

Allogeneic haematopoietic stem cell transplant (allo-HSCT) offers potentially curative therapy for patients with relapsed/refractory lymphoid malignancies. Reduced-intensity conditioning (RIC) with Alemtuzumab reduces transplant-related mortality and graft-versus-host disease (GvHD), but may be associated with increased risk of relapse. With the aim of studying the effect of GVHD and donor lymphocyte infusions (DLI) on relapse, we performed a retrospective study of 288 patients (57% non-Hodgkin lymphoma, 24% Hodgkin lymphoma and 19% chronic lymphocytic leukaemia; 58% were relapsed/refractory) who underwent RIC-Alemtuzumab-HSCT between 2000 and 2012. Median follow-up time for survivors was 64 months. Five-year overall survival, relapse incidence, GvHD/relapse-free survival and non-relapse mortality were 47%, 33%, 37% and 28% respectively. Cumulative incidence of grade II-IV acute and extensive chronic GvHD was 22% and 21% at 100 days and 5 years respectively. On multivariate analysis, presence of GvHD (P = 0·03) and unrelated donor type (P = 0·03) were protective of relapse. 62/288 patients received DLI for either mixed donor chimerism (prophylactic DLI, n = 37) or clinical relapse (therapeutic DLI, n = 25). Prophylactic and therapeutic DLI successfully converted the patient to full or stable mixed donor chimerism in 78% and 56% of patients respectively. These data demonstrate good long-term outcomes and support the concept of the graft-vs-lymphoma effect as a key protective factor against relapse following RIC-Alemtuzumab allo-HSCT for patients with mature lymphoid malignancies.

Outcomes of Advanced Hodgkin Lymphoma after Umbilical Cord Blood Transplantation: A Eurocord and EBMT Lymphoma and Cellular Therapy & Immunobiology Working Party Study

Allogeneic stem cell transplantation is an alternative for patients with relapsed or refractory Hodgkin lymphoma (HL), but only limited data on unrelated umbilical cord blood transplantation (UCBT) are available. We analyzed 131 adults with HL who underwent UCBT in European Society for Blood and Marrow Transplantation centers from 2003 to 2015. Disease status at UCBT was complete remission (CR) in 59 patients (47%), and almost all patients had received a previous autologous stem cell transplantation. The 4-year progression-free survival (PFS) and overall survival (OS) were 26% (95% confidence interval [CI], 19% to 34%) and 46% (95% CI, 37% to 55%), respectively. Relapse incidence was 44% (95% CI, 36% to 54%), and nonrelapse mortality (NRM) was 31% (95% CI, 23% to 40%) at 4 years. In multivariate analysis refractory/relapsed disease status at UCBT was associated with increased relapse incidence (hazard ratio [HR], 3.14 [95% CI, 1.41 to 7.00], P = .005) and NRM (HR, 3.61 [95% CI, 1.58 to 8.27], P = .002) and lower PFS (HR, 3.45 [95% CI, 1.95 to 6.10], P < .001) and OS (HR, 3.10 [95% CI, 1.60 to 5.99], P = .001). Conditioning regimen with cyclophosphamide + fludarabine + 2 Gy total body irradiation (Cy+Flu+2GyTBI) was associated with decreased risk of NRM (HR, .26 [95% CI, .10 to .64], P = .004). Moreover, Cy+Flu+2GyTBI conditioning regimen was associated with a better OS (HR, .25 [95% CI, .12 to .50], P < .001) and PFS (HR, .51 [95% CI, .27 to .96], P = .04). UCBT is feasible in heavily pretreated patients with HL. The reduced-intensity conditioning regimen with Cy+Flu+2GyTBI is associated with a better OS and NRM. However, outcomes are poor in patients not in CR at UCBT.

Brentuximab vedotin prior to allogeneic stem cell transplantation in Hodgkin lymphoma: a report from the EBMT Lymphoma Working Party

Brentuximab vedotin (BV) is an anti-CD30 antibody-drug conjugate. Preliminary data suggest that BV might improve outcomes after allogeneic stem cell transplantation (SCT) for Hodgkin lymphoma (HL) when used as pre-transplant salvage therapy. Between 2010 and 2014, 428 adult patients underwent an allogeneic SCT for classical HL at participating centres of the European Society for Blood and Marrow Transplantation. We compared the outcomes of 210 patients who received BV prior to allogeneic SCT with that of 218 patients who did not receive BV. The median follow-up for survivors was 41 months. Patients in the BV group were more heavily pre-treated (median pre-allograft treatment lines: 4 vs. 3). The two groups were comparable in terms of disease status, performance status, comorbidities, prior autologous SCT, type of donor, conditioning and in vivo T cell depletion. In multivariate analysis, pre-allograft BV had no impact on acute graft-versus-host disease (GVHD), non-relapse mortality, cumulative incidence of relapse, progression-free survival or overall survival (OS), but significantly reduced the risk of chronic GVHD (hazard ratio = 0·64; 95% confidence interval = 0·45-0·92; P < 0·02). Older age, poor performance status, use of pre-transplant radiotherapy and active disease at SCT adversely affected OS. Patients allografted for HL after prior exposure to BV do not have a superior outcome after allogeneic SCT except for a lower risk of chronic GVHD. However, BV may improve the outlook of allogeneic SCT by helping otherwise refractory patients to achieve a more favourable disease status, facilitating allotransplant success.

Pharmacotherapeutic Management of Pediatric Lymphoma

Hodgkin lymphoma (HL) and non-Hodgkin lymphoma (NHL) comprise approximately 15% of all childhood malignancies. Cure rates for both lymphoma entities have evolved tremendously during the last couple of decades, raising the 5-year survival rates to almost 100% for HL and to 85% for NHL. The mainstay therapy for both malignancies is still chemotherapy-with different regimens recommended for different types of disease. In HL, combined modality treatment, i.e., chemotherapy followed by radiotherapy, has long been the standard regimen. In order to reduce long-term side effects, such as second malignancies, most major pediatric HL consortia have studied response-based radiotherapy reduction strategies over the last 3 decades. For recurrent disease, high-dose chemotherapy followed by an autologous or an allogeneic hematopoietic stem-cell transplant is an option. No targeted agents have yet gained regulatory approval for use in pediatric patients with lymphoma. For adult lymphoma patients, the CD20 antibody rituximab and the CD30 antibody-drug conjugate brentuximab vedotin are targeted agents used regularly in first- and second-line treatment regimens. More recently, immune checkpoint inhibitors, phosphatidyl-inositol-3-kinase inhibitors, and Bruton's tyrosine kinase inhibitors appear to be very promising new treatment options in adult lymphoma. Here, we discuss the current experience with these types of agents in pediatric lymphoma patients.

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.

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.

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.

Where Do the New Drugs Fit in for Relapsed/Refractory Hodgkin Lymphoma?

The standard approach for relapsed or refractory (rel/ref) Hodgkin lymphoma (HL) following frontline treatment failure is salvage therapy followed by consolidation with high-dose therapy and autologous stem cell transplant (HDT/ASCT). While this overall treatment paradigm has been in place for several decades, recent studies have aimed to improve the efficacy and tolerability of salvage therapies by incorporating newer drugs, such as brentuximab vedotin (BV) and checkpoint inhibitors. Following HDT/ASCT, survival is improved due to the availability of BV and the checkpoint inhibitors, nivolumab and pembrolizumab; however, for patients responding to checkpoint inhibition, the appropriate length of treatment and the role of allogeneic stem cell transplant are unclear. In this review, we discuss our management of rel/ref HL, with particular focus on how BV, nivolumab, and pembrolizumab are currently incorporated into the treatment paradigms for rel/ref HL.

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.

Relapse of Hodgkin lymphoma after autologous transplantation: Time to rethink treatment?

Relapse of Hodgkin lymphoma after autologous hematopoietic cell transplantation (autologous HCT) is a major therapeutic challenge. Its management, at least in younger patients, traditionally involves salvage chemotherapy aiming to achieve disease remission followed by consolidation with allogeneic hematopoietic cell transplantation (allogeneic HCT) in eligible patients. The efficacy of salvage therapy is variable and newer combination chemotherapy regimens have improved the outcomes. Factors such as shorter time to relapse after autologous HCT and poor performance status have been identified as predictors of poor outcome. Newer agents such as immunoconjugate brentuximab vedotin, checkpoint inhibitors (e.g., pembrolizumab, nivolumab), lenalidomide, and everolimus are available for the treatment of patients relapsing after autologous HCT. With the availability of reduced intensity conditioning allogeneic HCT, more patients are eligible for this therapy with lesser toxicity and better efficacy due to graft versus lymphoma effects. Alternative donor sources such as haploidentical stem cell transplantation and umbilical cord blood transplantation are expanding this procedure to patients without HLA-matched donors. However, strategies aimed at reduction of disease relapse after reduced intensity conditioning allogeneic HCT are needed to improve the outcomes of this treatment. This review summarizes the current data on salvage chemotherapy and HCT strategies used to treat patients with relapsed Hodgkin lymphoma after prior autologous HCT.

Improving outcomes after allogeneic hematopoietic cell transplantation for Hodgkin lymphoma in the brentuximab vedotin era

Allogeneic hematopoietic cell transplantation (allo HCT) remains a valuable alternative for relapsed/refractory (R/R) Hodgkin lymphoma (HL). Data on allo HCT outcomes in the era of new HL therapies are needed. We evaluated 72 R/R HL patients who received reduced intensity conditioning (RIC) allo HCT and compared the time periods 2009-2013 (n=20) to 2000-2008 (n=52). Grafts included HLA-matched sibling (35%), unrelated donor (8%) and umbilical cord blood (UCB, 56%). In recent period, patients more often received brentuximab vedotin (BV, 60% vs 2%), had fewer comorbidities (Sorror index 0: 60% vs 12%) and were in complete remission (50% vs 23%). Median follow-up was 4.4 years. Three-year progression-free survival (PFS) improved for patients treated between 2009-2013 (49%, 95% CI 26-68%) as compared to the earlier era (23%, 95% CI 13-35%, p=0.02). Overall survival (OS) at 3-years was 84% (95% CI 57-94%) vs 50% (95% CI 36-62%, p=0.01), reflecting lower non-relapse mortality and relapse rates. In multivariate analysis mortality was higher among those with chemoresistance (HR 3.83, 95% CI 1.38-10.57), while treatment during the recent era was associated with better OS (HR for period 2009-2013: 0.24, 95% CI 0.07-0.79) and PFS (HR 0.46, 95% CI 0.23-0.92). Allo HCT in patients with R/R HL is now a more effective treatment.

Treatment of relapsed and refractory Hodgkin Lymphoma

Despite the high first-line cure rates in patients with Hodgkin Lymphoma (HL) still 10%-20% of patients suffer from relapsed or refractory disease. High-dose chemotherapy (HDCT) followed by autologous stem cell transplant (ASCT) is standard of care for suitable patients with relapsed or refractory HL and allows for cure in approximately 50%. Due to the poor prognosis of high-risk patients even with HDCT and ASCT, consolidation strategies have been evaluated to improve the cure rates. For patients with recurrence after HDCT and ASCT, treatment is palliative in most cases. The anti-CD30 antibody-drug conjugate brentuximab vedotin (BV) has been shown to induce high response rates in these patients; however, durable responses were reported in a small percentage of patients only. For carefully selected patients with multiple relapses, dose-reduced allogeneic transplant (RICallo) is a potentially curative option. The role of RICallo will have to be re-evaluated in the era of anti-programmed death-1 (PD1) antibodies.

Impact of Pretransplantation (18)F-Fluorodeoxyglucose-Positron Emission Tomography on Survival Outcomes after T Cell-Depleted Allogeneic Transplantation for Hodgkin Lymphoma

Pretransplant (18)F-fluorodeoxyglucose (FDG) positron emission tomography status is an important prognostic factor for outcomes after autologous stem cell transplantation (SCT) in Hodgkin lymphoma (HL), but its impact on outcomes after allogeneic SCT remains unclear. We retrospectively evaluated outcomes after T cell-depleted allogeneic SCT of 116 patients with nonprogressive HL according to pretransplant Deauville scores. Endpoints were overall survival (OS), progression-free survival (PFS), relapse rate (RR), and nonrelapse-related mortality (NRM). OS, PFS, and RR did not differ significantly between the Deauville 1 to 2 and Deauville 3 to 5 cohorts (OS: 77.5% versus 67.3%, P = .49; PFS: 59.4% versus 55.7%, P = .43; RR: 20.9% versus 22.6%, P = .28 at 4 years). Differences in PFS remained statistically nonsignificant when comparisons were made between Deauville 1 to 3 and Deauville 4 to 5 cohorts (60.9% versus 51.4%, P = .10), and RR remained very similar (21.5% versus 23.8%, P = .42). Multivariate analyses demonstrated trends toward significance for an effect of Deauville score on PFS (hazard ratio 1.82 for Deauville 4 to 5, P = .06) and for number of lines of prior therapy on OS (hazard ratio 2.34 for >5 lines, P = .10). The latter effect appeared to be driven by higher NRM rather than increased RR. Our findings suggest that Deauville score before allogeneic SCT in patients with nonprogressive HL has a relatively modest impact on survival outcomes in comparison with the impact in autologous SCT and that predictive values for the individual patient remain low, indicating that residual FDG-avid disease should not preclude allogeneic SCT. Furthermore, our findings bring into question the importance of attainment of metabolic complete response in this setting if it is at the expense of increasing NRM risk.

Alemtuzumab-BEAM as conditioning for allogeneic hematopoietic stem cell transplantation in relapsed/refractory Hodgkin lymphoma: a single-center analysis

Purpose

Treatment of refractory Hodgkin disease deserves specific considerations. Recently, alemtuzumab-BEAM has been introduced in allogeneic hematopoietic stem cell transplantation (HSCT) in these patients.

Methods

We retrospectively analyzed the outcome of 20 patients with relapsed/refractory Hodgkin’s lymphoma (HL) who received allogeneic HSCT following conditioning therapy with alemtuzumab-BEAM.

Results

Treatment-related toxicity was tolerable. Half of the patients (50 %) had infections. Of these, 50 % were found to have pneumonia or catheter-related infections. In 20 %, an oral mucositis was observed. Acute graft-versus-host disease (GvHD) (≥grade 2) was seen in three patients. Complete remission (CR) could be achieved in 17 patients (85 %), 2 patients had persistent Hodgkin disease, and 1 patient died from infection prior to CR evaluation. Median progression-free survival and overall survival were 17.9 and 67.5 months, respectively. From the 17 CR patients, 8 had a relapse after a median of 10 months. Notably, of the eight patients relapsing after HSCT, all patients received another salvage treatment and four patients are still alive, whereas the other four patients died due to further progress. Six out of the remaining nine patients are still in CR, whereas the other three died from chronic GvHD and multi-organ failure. Overall, seven patients experienced chronic GvHD.

Conclusion

In summary, alemtuzumab-BEAM is a well-tolerated conditioning therapy for allogeneic HSCT with high response rates in refractory HL.

Double umbilical cord blood transplant is effective therapy for relapsed or refractory Hodgkin lymphoma

A sub-group of patients with Hodgkin Lymphoma (HL) who relapse after autologous stem cell transplant can achieve long-term disease-free-survival after allogeneic stem cell transplant (alloSCT). There is limited information regarding the tolerability and efficacy of double umbilical cord blood transplant (dUCBT) for relapsed/refractory HL. We analyzed 27 consecutive, heavily pre-treated patients receiving dUCBT for relapsed/refractory HL at two centers from 2003-2014. The majority of patients relapsed <6 months after autologous stem cell transplant. A total of 15 patients received myeloablative (most commonly melphalan, fludarabine, thiotepa and anti-thymocyte globulin [ATG]) and 12 non-myeloablative conditioning regimens (fludarabine, cyclophosphamide, 200cGy total body irradiation +/- ATG). All patients engrafted; median time to neutrophil and platelet engraftment was 17 and 37 days, respectively. Overall response rate was 68%; 58% achieved complete remission. Median progression-free survival (PFS) was 12.2 months; median overall survival was 27 months. Cumulative incidences of relapse and of non-relapse mortality at 5 years were 30% and 37.9%, respectively; 5-year PFS was 31.3% (95%CI 10.1-52.5). There was a trend toward inferior PFS in patients with lymph node size ≥2 cm at the time of alloSCT (p = 0.07) and toward inferior survival in patients with chemorefractory disease pre-alloSCT (p = 0.12). dUCBT is feasible in patients with heavily pre-treated HL and can achieve long-term disease-free survival in approximately 30% of patients.

Salvage treatment for relapsed/refractory Hodgkin lymphoma: role of allografting, brentuximab vedotin and newer agents

INTRODUCTION

Second-line, salvage chemotherapy followed by high-dose chemotherapy and autologous stem cell transplantation (AUTO-SCT) is the standard of care for patients with relapsed/refractory (R/R) Hodgkin lymphoma (HL). Approximately 50% of patients relapse after AUTO-SCT and their prognosis is generally poor. Brentuximab Vedotin (BV) has demonstrated efficacy in this setting and allogeneic (ALLO)-SCT represents an option with curative potential in this subgroup of patients.

AREAS COVERED

A systematic review has been conducted to explore the actual knowledge on ALLO-SCT, BV and newer agents in R/R HL.

EXPERT OPINION

The introduction of BV in clinical practice has significantly improved the management of post-AUTO-SCT relapses and the drug can induce durable remissions in a subset of R/R HL. Allografting select patients has been used to improve clinical outcomes and recent case series have begun to explore BV as a potential 'bridge' to allo-SCT, even though the optimal timing of ALLO-SCT after BV response remains undetermined. However, reduced tumor burden at the time of ALLO-SCT is a key factor to decrease relapse risk. Based on the unique composition of the tumor, more recently new agents such as PD-1 inhibitors have been developed. The potential role of PD-1 inhibitors with ALLO-SCT remains to be explored.

A donor-specific epigenetic classifier for acute graft-versus-host disease severity in hematopoietic stem cell transplantation

Background

Allogeneic hematopoietic stem cell transplantation (HSCT) is a curative treatment for many hematological conditions. Acute graft-versus-host disease (aGVHD) is a prevalent immune-mediated complication following HSCT. Current diagnostic biomarkers that correlate with aGVHD severity, progression, and therapy response in graft recipients are insufficient. Here, we investigated whether epigenetic marks measured in peripheral blood of healthy graft donors stratify aGVHD severity in human leukocyte antigen (HLA)-matched sibling recipients prior to T cell-depleted HSCT.

Methods

We measured DNA methylation levels genome-wide at single-nucleotide resolution in peripheral blood of 85 HSCT donors, matched to recipients with various transplant outcomes, with Illumina Infinium HumanMethylation450 BeadChips.

Results

Using genome-wide DNA methylation profiling, we showed that epigenetic signatures underlying aGVHD severity in recipients correspond to immune pathways relevant to aGVHD etiology. We discovered 31 DNA methylation marks in donors that associated with aGVHD severity status in recipients, and demonstrated strong predictive performance of these markers in internal cross-validation experiments (AUC = 0.98, 95 % CI = 0.96–0.99). We replicated the top-ranked CpG classifier using an alternative, clinical DNA methylation assay (P = 0.039). In an independent cohort of 32 HSCT donors, we demonstrated the utility of the epigenetic classifier in the context of a T cell-replete conditioning regimen (P = 0.050).

Conclusions

Our findings suggest that epigenetic typing of HSCT donors in a clinical setting may be used in conjunction with HLA genotyping to inform both donor selection and transplantation strategy, with the ultimate aim of improving patient outcome.

Electronic supplementary material

The online version of this article (doi:10.1186/s13073-015-0246-z) contains supplementary material, which is available to authorized users.