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

Autologous Stem Cell Transplant in Hodgkin's and Non-Hodgkin's Lymphoma, Multiple Myeloma, and AL Amyloidosis

Human body cells are stem cell (SC) derivatives originating from bone marrow. Their special characteristics include their capacity to support the formation and self-repair of the cells. Cancer cells multiply uncontrollably and invade healthy tissues, making stem cell transplants a viable option for cancer patients undergoing high-dose chemotherapy (HDC). When chemotherapy is used at very high doses to eradicate all cancer cells from aggressive tumors, blood-forming cells and leukocytes are either completely or partially destroyed. Autologous stem cell transplantation (ASCT) is necessary for patients in those circumstances. The patients who undergo autologous transplants receive their own stem cells (SCs). The transplanted stem cells first come into contact with the bone marrow and then undergo engraftment, before differentiating into blood cells. ASCT is one of the most significant and innovative strategies for treating diseases. Here we focus on the treatment of Hodgkin's lymphoma, non-Hodgkin's lymphoma, multiple myeloma, and AL amyloidosis, using ASCT. This review provides a comprehensive picture of the effectiveness and the safety of ASCT as a therapeutic approach for these diseases, based on the currently available evidence.

Allogeneic Stem Cell Transplantation for Relapsed and Refractory Hodgkin Lymphoma: Real World Experience of a Single Center

Introduction: Refractory and relapsed Hodgkin lymphoma (R/R HL) is associated with poor prognosis, and allogeneic stem cell transplantation (allo-SCT) remains the only potentially curative approach.

Aim: The aim of the study was to evaluate the feasibility of allotransplantation in R/R HL setting.

Material: Overall, 24 patients (17 men and 7 women) at a median age of 27 years (range 18–44) underwent allo-SCT between 2002 and 2020.

Results: Nineteen patients received prior autologous stem cell transplantation (ASCT1) whereas eight patients received second ASCT (ASCT2) after failure of ASCT1. Six patients received only brentuximab vedotin (BV; n = 4) or BV followed by checkpoint inhibitors (CPI; n = 2) before entering allo-SCT. Median time from ASCT1 to allo-SCT was 17.1 months. Fifteen patients received grafts from unrelated donors. Peripheral blood was a source of stem cells for 16 patients. Reduced-intensity conditioning was used for all patients. Disease status at transplant entry was as follows: complete remission (CR; n = 4), partial response (PR; n = 10), and stable disease (SD; n = 10). Acute and chronic graft-versus-host disease (GVHD) developed in 13 (54%) and 4 (16%) patients, respectively. Median follow-up for the entire cohort was 13.3 months. At the last follow-up, 17 (71%) patients died. The main causes of death were disease progression (n = 10), infectious complications (n = 6), and steroid-resistant GVHD (n = 1). Non-relapse mortality at 12 months was 25%. At the last follow-up, seven patients were alive; six patients were in CR, and one had PR. The 2-year overall survival (OS) was 40%.

Conclusion: Chemosensitive disease at transplant was associated with better outcome. Allo-SCT allows for long-term survival in refractory and relapsed HL.

Generation of an immunodeficient mouse model of tcirg1-deficient autosomal recessive osteopetrosis

Background

Autosomal recessive osteopetrosis is a rare skeletal disorder with increased bone density due to a failure in osteoclast bone resorption. In most cases, the defect is cell-autonomous, and >50% of patients bear mutations in the TCIRG1 gene, encoding for a subunit of the vacuolar proton pump essential for osteoclast resorptive activity. The only cure is hematopoietic stem cell transplantation, which corrects the bone pathology by allowing the formation of donor-derived functional osteoclasts. Therapeutic approaches using patient-derived cells corrected ex vivo through viral transduction or gene editing can be considered, but to date functional rescue cannot be demonstrated in vivo because a relevant animal model for xenotransplant is missing.

Methods

We generated a new mouse model, which we named NSG oc/oc, presenting severe autosomal recessive osteopetrosis owing to the Tcirg1^oc mutation, and profound immunodeficiency caused by the NSG background. We performed neonatal murine bone marrow transplantation and xenotransplantation with human CD34⁺ cells.

Results

We demonstrated that neonatal murine bone marrow transplantation rescued NSG oc/oc mice, in line with previous findings in the oc/oc parental strain and with evidence from clinical practice in humans. Importantly, we also demonstrated human cell chimerism in the bone marrow of NSG oc/oc mice transplanted with human CD34⁺ cells. The severity and rapid progression of the disease in the mouse model prevented amelioration of the bone pathology; nevertheless, we cannot completely exclude that minor early modifications of the bone tissue might have occurred.

Conclusion

Our work paves the way to generating an improved xenograft model for in vivo evaluation of functional rescue of patient-derived corrected cells. Further refinement of the newly generated mouse model will allow capitalizing on it for an optimized exploitation in the path to novel cell therapies.

•

Ex vivo corrected autologous HSCs might cure Autosomal Recessive Osteopetrosis (ARO).

•

There is no animal model to prove in vivo functional rescue of corrected human cells.

•

NSG oc/oc mice display osteoclast-rich cell-autonomous ARO and immunodeficiency.

•

Human CD34⁺ cell-transplanted NSG oc/oc mice show human cell chimerism in the BM.

•

Further improvements will allow in vivo evaluating corrected patient-derived cells.

Immune off-target effects of Brentuximab Vedotin in relapsed/refractory Hodgkin Lymphoma

Hodgkin Lymphoma (HL) is associated with deep microenvironment re-shaping and myeloid dysfunction. Given that only limited data are available regarding the role of Brentuximab Vedotin (BV) as single agent in transplant-naive relapsed/refractory (R/R) patients and its off-target effects on immune system, we evaluated the amount of regulatory T-cells (T-regs), myeloid-derived suppressor cells (MDSC) subpopulations, and their functional marker, serum arginase-1 (s-Arg-1), in peripheral blood of 15 consecutive R/R HL patients. After a median of four BV cycles, the overall response rate (complete response + partial response) was 47%, with 4 (27%) complete metabolic remissions. BV reduced the absolute number of three MDSC subtypes and s-Arg-1 levels. Patients with baseline s-Arg-1 ≥200 ng/ml had inferior progression-free survival at 36 months compared to those with low s-Arg-1. T-regs dysfunction was recovered by BV: absolute T-regs count was increased after treatment with BV, independently of metabolic response achieved, with a significant reduction of CD30⁺ T-regs. Our data disclose off-target effects of BV in the microenvironment that could explain its deep and durable clinical efficacy.

CD83 is a new potential biomarker and therapeutic target for Hodgkin lymphoma

Chemotherapy and hematopoietic stem cell transplantation are effective treatments for most Hodgkin lymphoma patients, however there remains a need for better tumor-specific target therapy in Hodgkin lymphoma patients with refractory or relapsed disease. Herein, we demonstrate that membrane CD83 is a diagnostic and therapeutic target, highly expressed in Hodgkin lymphoma cell lines and Hodgkin and Reed-Sternberg cells in 29/35 (82.9%) Hodgkin lymphoma patient lymph node biopsies. CD83 from Hodgkin lymphoma tumor cells was able to trogocytose to surrounding T cells and, interestingly, the trogocytosing CD83+T cells expressed significantly more programmed death-1 compared to CD83-T cells. Hodgkin lymphoma tumor cells secreted soluble CD83 that inhibited T-cell proliferation, and anti-CD83 antibody partially reversed the inhibitory effect. High levels of soluble CD83 were detected in Hodgkin lymphoma patient sera, which returned to normal in patients who had good clinical responses to chemotherapy confirmed by positron emission tomography scans. We generated a human anti-human CD83 antibody, 3C12C, and its toxin monomethyl auristatin E conjugate, that killed CD83 positive Hodgkin lymphoma cells but not CD83 negative cells. The 3C12C antibody was tested in dose escalation studies in non-human primates. No toxicity was observed, but there was evidence of CD83 positive target cell depletion. These data establish CD83 as a potential biomarker and therapeutic target in Hodgkin lymphoma.

Risk-adapted transplant strategies for high-risk Hodgkin lymphoma: are we there?

PURPOSE OF REVIEW

The treatment of high-risk classic Hodgkin lymphoma (cHL) patients remains challenging, especially after autologous stem cell transplant (ASCT) failure. Moreover, the outcome of chemorefractory patients is still poor.

RECENT FINDINGS

The development of novel targeted therapies has changed the therapeutic options for high-risk patients. To improve outcome, treatment algorithms should integrate up-front, newly established prognostic markers. Tandem ASCT instead of single ASCT has been proposed as an option to improve outcome for high-risk patients. Availability of less toxic reduced intensity conditioning regimens and recent development in haploidentical transplantation have widened applicability and improved outcomes of allo-hematopoietic cell transplantation. Their exact role in cHL is still controversial and there is no consensus on the optimal transplantation strategy. In this context, results of tandem ASCT should also be compared with those of the autologous/reduced intensity conditioning-allo tandem approach. In this review, we discuss how transplantation strategies (auto and allo) can fit into the salvage treatment plan for patients with relapsed/refractory cHL, taking into account the new drugs available and integrating modern risk assessment.

SUMMARY

We speculated that improvements could be achieved by transplanting patients in earlier phases of their disease, if necessary after 'bridging' using the new drugs, and we propose an algorithm integrating the different treatment options.

Patient age and number of apheresis days may predict development of secondary myelodysplastic syndrome and acute myelogenous leukemia after high-dose chemotherapy and autologous stem cell transplantation for lymphoma

BACKGROUND

The goal of our study was to find predictors for the development of secondary myelodysplastic syndrome or acute myelogenous leukemia (s-MDS/AML) in patients with relapsed or refractory lymphoma who received high-dose chemotherapy and autologous stem cell transplantation (ASCT).

STUDY DESIGN AND METHODS

We conducted a retrospective review of 295 patients with relapsed or refractory lymphoma who had undergone their first stem cell collection and ASCT. Patient, disease, and treatment characteristics were collected. The primary goal of this study was to analyze the association between the number of apheresis days needed to collect the requisite stem cell dose in addition to the previously described factors such as age, sex, number and type of prior chemotherapeutic regimens, disease type and status, and the risk of developing s-MDS/AML.

RESULTS

Twenty-two patients of 295 were diagnosed with s-MDS/AML after a median follow-up of 62 months. Multivariate analysis using a classification and regression tree showed that the incidence of s-MDS/AML was lowest in patients who were not more than 55 years old at transplantation and in whom the target cell dose was collected in fewer than two apheresis sessions (5-year cumulative incidence, 1%), whereas incidence was highest in patients who were more than 55 years old at transplantation and who received a transplant more than 21 months after their initial lymphoma diagnosis (5-year cumulative incidence, 20%).

CONCLUSION

Our study defines a subset of relapsed or refractory lymphoma patients who should be closely monitored for development of s-MDS/AML after high-dose chemotherapy and ASCT.

Dual PI3K/ERK inhibition induces necroptotic cell death of Hodgkin Lymphoma cells through IER3 downregulation

PI3K/AKT and RAF/MEK/ERK pathways are constitutively activated in Hodgkin lymphoma (HL) patients, thus representing attractive therapeutic targets. Here we report that the PI3K/ERK dual inhibitor AEZS-136 induced significant cell proliferation inhibition in L-540, SUP-HD1, KM-H2 and L-428 HL cell lines, but a significant increase in necroptotic cell death was observed only in two out of four cell lines (L-540 and SUP-HD1). In these cells, AEZS-136-induced necroptosis was associated with mitochondrial dysfunction and reactive oxygen species (ROS) production. JNK was activated by AEZS-136, and AEZS-136-induced necroptosis was blocked by the necroptosis inhibitor necrostatin-1 or the JNK inhibitor SP600125, suggesting that JNK activation is required to trigger necroptosis following dual PI3K/ERK inhibition. Gene expression analysis indicated that the effects of AEZS-136 were associated with the modulation of cell cycle and cell death pathways. In the cell death-resistant cell lines, AEZS-136 induced the expression of immediate early response 3 (IER3) both in vitro and in vivo. Silencing of IER3 restored sensitivity to AEZS-136-induced necroptosis. Furthermore, xenograft studies demonstrated a 70% inhibition of tumor growth and a 10-fold increase in tumor necrosis in AEZS-136-treated animals. Together, these data suggest that dual PI3K/ERK inhibition might be an effective approach for improving therapeutic outcomes in HL.

Bendamustine in Combination With Gemcitabine and Vinorelbine Is an Effective Regimen As Induction Chemotherapy Before Autologous Stem-Cell Transplantation for Relapsed or Refractory Hodgkin Lymphoma: Final Results of a Multicenter Phase II Study

PURPOSE

This multicenter, open-label, phase II study evaluated the combination of bendamustine, gemcitabine, and vinorelbine (BeGEV) as induction therapy before autologous stem-cell transplantation (ASCT) in patients with relapsed or refractory Hodgkin lymphoma (HL).

PATIENTS AND METHODS

Patients with HL who were refractory to or had relapsed after one previous chemotherapy line were eligible. The primary end point was complete response (CR) rate after four cycles of therapy. Secondary end points were: overall response rate, stem-cell mobilization activity, and toxicity. Progression-free and overall survival were also evaluated.

RESULTS

In total, 59 patients were enrolled. After four cycles of therapy, 43 patients (73%) achieved CR, and six (10%) achieved partial response, for an overall response rate of 83%. The most common grade 3 to 4 nonhematologic toxicities included febrile neutropenia (n = 7) and infection (n = 4). Regarding hematologic toxicities, grade 3 to 4 thrombocytopenia and neutropenia were each experienced by eight patients (13.5%). CD34+ cells were successfully harvested in 55 of 57 evaluable patients, and 43 of 49 responding patients underwent ASCT. With a median follow-up of 29 months, the 2-year progression-free and overall survival rates for the total population were 62.2% and 77.6%, respectively. The same figures for patients undergoing autograft were 80.8% and 89.3%, respectively.

CONCLUSION

This phase II study demonstrates that BeGEV is an effective salvage regimen able to induce CR in a high proportion of patients with relapsed or refractory HL before ASCT. These data provide a strong rationale for further development of the BeGEV regimen.

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.