Unrelated and alternative donor allogeneic stem cell transplant in patients with relapsed or refractory Hodgkin lymphoma: a systematic review

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.

In 2022, which is preferred: haploidentical or cord transplant?

Allogeneic hematopoietic stem cell transplantation is the treatment of choice for high-risk hematological malignancies such as acute myeloid and lymphocytic leukemia, myelodysplastic syndrome, and myeloproliferative disorders. Alternative donor transplantation from either haploidentical (haplo-SCT) or cord blood donor (CBT) is an established therapeutic alternative for patients who need transplants but lack a human leukocyte antigen-matched donor. Although haplo-SCT (mainly non-T-cell-depleted haplo-SCT with posttransplant cyclophosphamide) is increasing while CBT is decreasing worldwide (Figure 1), recent developments in CBT, especially cord blood expansion and other strategies to improve engraftment and immune reconstitution post-CBT, make CBT still a valuable option. This article discusses the 2 options based on the currently available data, focusing on adults, and tries to give some clues to help the transplant physician choose a haploidentical vs a cord blood donor. Given the limited numbers of published or ongoing well-designed randomized controlled trials comparing haplo-SCT to CBT and the overall similar clinical results in the available, mostly registry-based, and single-center studies, with substantial heterogeneity and variability, the decision to perform haplo-SCT or CBT in a given patient depends not only on the patient, disease, and donor characteristics and donor availability (although most if not all patients should have in principle an alternative donor) but also on the transplant physician's discretion and, most importantly, the center's experience and preference and ongoing protocols and strategies.

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.

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.

Indications for haematopoietic stem cell transplantation for haematological diseases, solid tumours and immune disorders: current practice in Europe, 2019

This is the seventh special EBMT report on the indications for haematopoietic stem cell transplantation for haematological diseases, solid tumours and immune disorders. Our aim is to provide general guidance on transplant indications according to prevailing clinical practice in EBMT countries and centres. In order to inform patient decisions, these recommendations must be considered together with the risk of the disease, the risk of the transplant procedure and the results of non-transplant strategies. In over two decades since the first report, the EBMT indications manuscripts have incorporated changes in transplant practice coming from scientific and technical developments in the field. In this same period, the establishment of JACIE accreditation has promoted high quality and led to improved outcomes of patient and donor care and laboratory performance in transplantation and cellular therapy. An updated report with operating definitions, revised indications and an additional set of data with overall survival at 1 year and non-relapse mortality at day 100 after transplant in the commonest standard-of-care indications is presented. Additional efforts are currently underway to enable EBMT member centres to benchmark their risk-adapted outcomes as part of the Registry upgrade Project 2020 against national and/or international outcome data.

Recombinant Pregnancy-Specific Glycoprotein 1 Has a Protective Role in a Murine Model of Acute Graft-versus-Host Disease

Acute graft-versus-host disease (aGVHD) is an immune-mediated reaction that can occur after hematopoietic stem cell transplantation in which donor T cells recognize the host antigens as foreign, destroying host tissues. Establishment of a tolerogenic immune environment while preserving the immune response to infectious agents is required for successful bone marrow transplantation. Pregnancy-specific glycoprotein 1 (PSG1), which is secreted by the human placenta into the maternal circulation throughout pregnancy, likely plays a role in maintaining immunotolerance to prevent rejection of the fetus by the maternal immune system. We have previously shown that PSG1 activates the latent form of transforming growth factor β1 (TGF-β), a cytokine essential for the differentiation of tolerance-inducing CD4⁺FoxP3⁺ regulatory T cells (Tregs). Consistent with this observation, treatment of naïve murine T cells with PSG1 resulted in a significant increase in FoxP3⁺ cells that was blocked by a TGF-β receptor I inhibitor. We also show here that PSG1 can increase the availability of active TGF-β in vivo. As the role of CD4⁺FoxP3⁺ cells in the prevention of aGVHD is well established, we tested whether PSG1 has beneficial effects in a murine aGHVD transplantation model. PSG1-treated mice had reduced numbers of tissue-infiltrating inflammatory CD3⁺ T cells and had increased expression of FoxP3 in T cells compared with vehicle-treated mice. In addition, administration of PSG1 significantly inhibited aGVHD-associated weight loss and mortality. On the other hand, administration of PSG1 was less effective in managing aGVHD in the presence of an alloimmune reaction against a malignancy in a graft-versus-leukemia experimental model. Combined, this data strongly suggests that PSG1 could be a promising treatment option for patients with aGVHD following bone marrow transplantation for a nonmalignant condition, such as an autoimmune disorder or a genetic immunodeficiency.

Transplant strategies in relapsed/refractory Hodgkin lymphoma

The majority of patients with Hodgkin lymphoma (HL) are cured with initial therapy. However, high-dose therapy with autologous hematopoietic cell transplant (AHCT) allows for the cure of an additional portion of patients with relapsed or primary refractory disease. Positron emission tomography-negative complete remission before AHCT is critical for long-term disease control. Several salvage options are available with comparable response rates, and the choice can be dependent of comorbidities and logistics. Radiation therapy can also improve the remission rate and is an important therapeutic option for selected patients. Brentuximab vedotin (BV) maintenance after AHCT is beneficial in patients at high risk for relapse, especially those with more than 1 risk factor, but can have the possibility of significant side effects, primarily neuropathy. Newer agents with novel mechanisms of action are under investigation to improve response rates for patients with subsequent relapse, although are not curative alone. BV and the checkpoint inhibitors nivolumab and pembrolizumab are very effective with limited side effects and can bridge patients to curative allogeneic transplants (allo-HCT). Consideration for immune-mediated toxicities, timing of allogeneic hematopoietic cell transplant based on response, and the potential for increased graft-versus-host disease remain important. Overall, prospective investigations continue to improve outcomes and minimize toxicity for relapsed or primary refractory HL patients.

Combined Haploidentical and Umbilical Cord Blood Allogeneic Stem Cell Transplantation for High-Risk Lymphoma and Chronic Lymphoblastic Leukemia

Limited studies have reported on outcomes for lymphoid malignancy patients receiving alternative donor allogeneic stem cell transplants. We have previously described combining CD34-selected haploidentical grafts with umbilical cord blood (haplo-cord) to accelerate neutrophil and platelet engraftment. Here, we examine the outcome of patients with lymphoid malignancies undergoing haplo-cord transplantation at the University of Chicago and Weill Cornell Medical College. We analyzed 42 lymphoma and chronic lymphoblastic leukemia (CLL) patients who underwent haplo-cord allogeneic stem cell transplantation. Patients underwent transplant for Hodgkin lymphoma (n = 9, 21%), CLL (n = 5, 12%) and non-Hodgkin lymphomas (n = 28, 67%), including 13 T cell lymphomas. Twenty-four patients (52%) had 3 or more lines of therapies. Six (14%) and 1 (2%) patients had prior autologous and allogeneic stem cell transplant, respectively. At the time of transplant 12 patients (29%) were in complete remission, 18 had chemotherapy-sensitive disease, and 12 patients had chemotherapy-resistant disease. Seven (17%), 11 (26%), and 24 (57%) patients had low, intermediate, and high disease risk index before transplant. Comorbidity index was evenly distributed among 3 groups, with 13 (31%), 14 (33%), and 15 (36%) patients scoring 0, 1 to 2, and ≥3. Median age for the cohort was 49 years (range, 23 to 71). All patients received fludarabine/melphalan/antithymocyte globulin conditioning regimen and post-transplant graft-versus-host disease (GVHD) prophylaxis with tacrolimus and mycophenolate mofetil. The median time to neutrophil engraftment was 11 days (range, 9 to 60) and to platelet engraftment 19.5 days (range, 11 to 88). Cumulative incidence of nonrelapse mortality was 11.6% at 100 days and 19 % at one year. Cumulative incidence of relapse was 9.3% at 100 days and 19% at one year. With a median follow-up of survivors of 42 months, the 3-year rates of GVHD relapse free survival, progression-free survival, and overall survival were 53%, 62%, and 65%, respectively, for these patients. Only 8% of the survivors had chronic GVHD. In conclusion, haplo-cord transplantation offers a transplant alternative for patients with recurrent or refractory lymphoid malignancies who lack matching donors. Both neutrophil and platelet count recovery is rapid, nonrelapse mortality is limited, excellent disease control can be achieved, and the incidence of chronic GVHD is limited. Thus, haplo-cord achieves high rates of engraftment and encouraging results.

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.

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.

Umbilical cord blood transplantation in adults with advanced hodgkin's disease: high incidence of post-transplant lymphoproliferative disease

We report the outcome of 30 consecutive patients with Hodgkin disease (HD) who underwent single-unit UCBT. Most (90%) patients had failed previous autologous hematopoietic stem cell transplantation. The conditioning regimens were based on combinations of thiotepa, busulfan, cyclophosphamide or fludarabine, and antithymocyte globulin. The cumulative incidence (CI) of myeloid engraftment was 90% [95% confidence interval (C.I.), 74-98%] with a median of 18 d (range, 10-48). CI of acute graft-versus-host disease (GvHD) grades II-IV was 30% (95% C.I., 17-44%), while the incidence of chronic GVHD was 42% (95% C.I., 23-77%). The non-relapse mortality (NRM) at 100 d and 4 yr was 30% (95% C.I., 13-46%) and 47% (95% C.I., 29-65%), respectively. EBV-related post-transplant lymphoproliferative disease (EBV-PTLD) accounted for more than one-third of transplant-related death, with an estimate incidence of 26% (95% C.I., 9-44). The incidence of relapse at 4 yr was 25% (95% C.I., 9-42%). Four-year event-free survival (EFS) and overall survival (OS) were 28% and 30%, respectively. Despite a high NRM and an unexpected high incidence of EBV-PTLD, UCBT in heavily pretreated HD patients is an option for patients lacking a suitable adult donor, provided the disease is not in refractory relapse.

Indications for allo- and auto-SCT for haematological diseases, solid tumours and immune disorders: current practice in Europe, 2015

This is the sixth special report that the European Society for Blood and Marrow Transplantation regularly publishes on the current practice and indications for haematopoietic SCT for haematological diseases, solid tumours and immune disorders in Europe. Major changes have occurred in the field of haematopoietic SCT over the last years. Cord blood units as well as haploidentical donors have been increasingly used as stem cell sources for allo-SCT, thus, augmenting the possibility of finding a suitable donor for a patient. Continuous refinement of conditioning strategies has also expanded not only the number of potential indications but also has permitted consideration of older patients or those with co-morbidity for a transplant. There is accumulating evidence of the role of haematopoietic SCT in non-haematological disorders such as autoimmune diseases. On the other hand, the advent of new drugs and very effective targeted therapy has challenged the role of SCT in some instances or at least, modified its position in the treatment armamentarium of a given patient. An updated report with revised tables and operating definitions is presented.

Role of cytotoxic therapy with hematopoietic cell transplantation in the treatment of Hodgkin lymphoma: guidelines from the American Society for Blood and Marrow Transplantation

The role of hematopoietic cell transplantation (HCT) in the therapy of Hodgkin lymphoma (HL) in pediatric and adult patients is reviewed and critically evaluated in this systematic evidence-based review. Specific criteria were used for searching the published literature and for grading the quality and strength of the evidence and the strength of the treatment recommendations. Treatment recommendations based on the evidence are included and were reached unanimously by a panel of HL experts. Both autologous and allogeneic HCT offer a survival benefit in selected patients with advanced or relapsed HL and are currently part of standard clinical care. Relapse remains a significant cause of failure after both transplant approaches, and strategies to decrease the risk of relapse remain an important area of investigation.

Stem cell transplantation in Hodgkin lymphoma

Patients with Hodgkin lymphoma (HL) who relapse following effective front-line therapy are offered salvage second-line chemotherapy regimens followed by high-dose therapy and autologous stem cell transplantation (HDT/ASCT). Randomized studies comparing HDT/ASCT with conventional chemotherapy in patients with relapsed refractory HL have shown significant improvement in progression-free survival and freedom from treatment failure but were not powered to show improvements in overall survival. For patients who relapse after salvage HDT/ASCT, novel therapies exist as a bridge to allogeneic SCT. In this article, we review indications and results of autologous and allogeneic SCT in HL.