Bortezomib-based graft-versus-host disease prophylaxis in HLA-mismatched unrelated donor transplantation

Comparison of long-term outcomes after first HLA-mismatched unrelated donor transplantation with single unrelated cord blood transplantation using reduced-intensity or reduced-toxicity conditioning

BACKGROUND

No comparative data have shown significant survival differences between HLA-mismatched unrelated donor (MMUD) transplantation and cord blood (CB) transplantation, each with reduced-intensity/reduced-toxicity conditioning (RIC/RTC). However, advances in graft-versus-host disease (GVHD) prophylaxis might help update current strategies.

METHODS

We retrospectively compared the outcomes of first allogeneic hematopoietic cell transplantation from MMUDs (n = 15) or single unrelated CB (n = 35) after RIC/RTC.

RESULTS

The median age was 60 years. The MMUD group had a numerically lower 100-day incidence of grade III-IV acute GVHD (7% vs. 29%, P = 0.079) and non-relapse mortality (0% vs. 40%, P = 0.12). Eight MMUD recipients received anti-thymocyte globulin, bortezomib, or posttransplant cyclophosphamide for GVHD prophylaxis. They did not develop grade III-IV acute GVHD. The MMUD group had significantly better 5-year overall survival than the CB group (62% vs. 31%, P = 0.021), although relapse rates were similar. A multivariable analysis and sensitivity analysis also showed trends toward higher overall survival in the MMUD group.

CONCLUSION

MMUD with better GVHD prophylaxis might be preferred over CB in patients with older age and comorbidities.

The best GVHD prophylaxis: Or at least progress towards finding it

Options for GVHD prophylaxis after allogeneic hematopoietic cell transplantation can best be chosen by understanding the pathophysiology of GVHD. Interventions to limit T cell activation, expansion and subsequent tissue injury can each be utilized in designing successful GVHD prevention strategies Depleting, tolerizing or blunting T cells or host antigen presenting cells (APCs), blocking co-stimulation or more broadly suppressing inflammation have all been used. Interventions which spare regulatory T cells (Tregs) may prevent GVHD and facilitate controlled allo-responses and not compromise subsequent relapse risks. Graft manipulations and pharmacologic interventions each have potential to limit the morbidity of GVHD while permitting the immunocompetence to prevent infection or relapse.

Graft-versus-host disease: teaching old drugs new tricks at less cost

Graft-versus-host disease (GVHD) remains a major cause of morbidity and mortality after allogeneic stem cell transplantation (SCT). Currently, more patients can receive SCT. This is attributed to the use of reduced intensity regimens and the use of different GVHD prophylaxis that breaks the barrier of human leukocyte antigen, allowing an increase in the donor pool. Once an area with relatively few clinical trial options, there has been an increase in interest in GVHD prophylaxis and treatment, which has led to many US Food and Drug Administration (FDA) approvals. Although there is considerable excitement over novel therapies, many patients may not have access to them due to geographical or other resource constraints. In this review article, we summarize the latest evidence on how we can continue to repurpose drugs for GVHD prophylaxis and treatment. Drugs covered by our review include those that have been FDA approved for other uses for at least 15 years (since 2008); thus, they are likely to have generic equivalents available now or in the near future.

A Multicenter Phase II, Double-Blind, Placebo-Controlled Trial of Maintenance Ixazomib After Allogeneic Transplantation for High-Risk Multiple Myeloma: Results of the Blood and Marrow Transplant Clinical Trials Network 1302 Trial

The role of allogeneic hematopoietic cell transplantation (allo-HCT) followed by maintenance therapy in high-risk multiple myeloma (MM) remains controversial. We evaluated the efficacy of ixazomib maintenance therapy after reduced-intensity conditioning allo-HCT from HLA-matched donors in patients with high-risk MM. The primary study endpoint was progression-free survival (PFS) postrandomization, treated as a time to event. Secondary endpoints were grade II-IV and grade II-IV acute graft-versus-host-disease (GVHD), chronic GVHD, best response, disease progression, nonrelapse mortality (NRM), overall survival (OS), toxicity, infection, and health-related quality of life. In this phase 2, double-blinded, prospective multicenter trial, we randomized patients with high-risk MM (ie, those with poor-risk cytogenetics, plasma cell leukemia, or relapsing within 24 months after autologous HCT) to ixazomib (3 mg on days 1, 8, and 15) or placebo after allo-HCT. The conditioning regimen included fludarabine/melphalan/bortezomib with tacrolimus plus methotrexate for GVHD. Fifty-seven patients were enrolled, of whom 52 (91.2%) underwent allo-HCT and 43 (82.7%) were randomized to ixazomib versus placebo. At 21 months postrandomization, the ixazomib and placebo groups had similar PFS (55.3% versus 59.1%; P = 1.00) and OS (94.7% versus 86.4%; P = .17). The cumulative incidences of grade III-IV acute GVHD at 100 days (9.5% versus 0%) and chronic GVHD at 12 months (68.6% versus 63.6%) also were similar in the 2 groups. The secondary analysis showed that at 24 months post-allo-HCT, PFS and OS were 52% and 82%, respectively, with a corresponding NRM of 11.7%. These results demonstrate the safety and durable disease control with allo-HCT in high-risk MM patients. We could not adequately assess the efficacy of ixazomib maintenance because the trial terminated early owing to enrollment delays, but there was no indication of any impact on outcomes.

Maintenance therapy after allogeneic hematopoietic stem cell transplantation for patients with multiple myeloma

In the last two decades, proteasome inhibitors (PIs), immunomodulatory drugs (IMiDs), and monoclonal antibodies have greatly improved the overall survival of patients with multiple myeloma. However, multiple myeloma remains incurable, and high-risk patients have poor long-term survival. Although allogeneic hematopoietic stem cell transplantation (allo-HCT) is not considered standard therapy because of relatively high transplant-related mortality and relapse rates, the graft-versus-myeloma (GVM) effect makes it a potentially curative therapy. Therefore, allo-HCT remains a treatment option for younger patients and those with high-risk myeloma. Maintenance therapy with novel agents has recently been attempted to reduce relapse in patients undergoing allo-HCT, but its effectiveness remains unclear. This review focuses on the role of maintenance therapy after allo-HCT in patients with myeloma. Maintenance therapy using IMiDs and/or PIs after allo-HCT may be effective in reducing relapse or improving response because it may prevent early progression before achievement of the GVM effect or enhance the GVM effect. However, care must be taken to avoid complications, such as graft-versus-host disease. Further studies are necessary to determine the optimal maintenance drugs, drug combinations, dosing, start timing, and number of cycles.

Systematic approach to identify therapeutic targets and functional pathways for the cervical cancer

BACKGROUND

In today's society, cancer has become a big concern. The most common cancers in women are breast cancer (BC), endometrial cancer (EC), ovarian cancer (OC), and cervical cancer (CC). CC is a type of cervix cancer that is the fourth most common cancer in women and the fourth major cause of death.

RESULTS

This research uses a network approach to discover genetic connections, functional enrichment, pathways analysis, microRNAs transcription factors (miRNA-TF) co-regulatory network, gene-disease associations, and therapeutic targets for CC. Three datasets from the NCBI's GEO collection were considered for this investigation. Then, using a comparison approach between the datasets, 315 common DEGs were discovered. The PPI network was built using a variety of combinatorial statistical approaches and bioinformatics tools, and the PPI network was then utilized to identify hub genes and critical modules.

CONCLUSION

Furthermore, we discovered that CC has specific similar links with the progression of different tumors using Gene Ontology terminology and pathway analysis. Transcription factors-gene linkages, gene-disease correlations, and the miRNA-TF co-regulatory network were revealed to have functional enrichments. We believe the candidate drugs identified in this study could be effective for advanced CC treatment.

An Overview of Autophagy in Hematopoietic Stem Cell Transplantation

Autophagy is a fundamental homeostatic process crucial for cellular adaptation in response to metabolic stress. Autophagy exerts its effect through degrading intracellular components and recycling them to produce macromolecular precursors and energy. This physiological process contributes to cellular development, maintenance of cellular/tissue homeostasis, immune system regulation, and human disease. Allogeneic hematopoietic stem cell transplantation (HSCT) is the only preferred therapy for most bone marrow-derived cancers. Unfortunately, HSCT can result in several serious and sometimes untreatable conditions due to graft-versus-host disease (GVHD), graft failure, and infection. These are the major cause of morbidity and mortality in patients receiving the transplant. During the last decade, autophagy has gained a considerable understanding of its role in various diseases and cellular processes. In light of recent research, it has been confirmed that autophagy plays a crucial role in the survival and function of hematopoietic stem cells (HSCs), T-cell differentiation, antigen presentation, and responsiveness to cytokine stimulation. Despite the importance of these events to HSCT, the role of autophagy in HSCT as a whole remains relatively ambiguous. As a result of the growing use of autophagy-modulating agents in the clinic, it is imperative to understand how autophagy functions in allogeneic HSCT. The purpose of this literature review is to elucidate the established and implicated roles of autophagy in HSCT, identifying this pathway as a potential therapeutic target for improving transplant outcomes.

Translational Clinical Strategies for the Prevention of Gastrointestinal Tract Graft Versus Host Disease

Graft versus host disease (GVHD) is the major non-relapse complication associated with allogeneic hematopoietic stem cell transplantation (HSCT). Unfortunately, GVHD occurs in roughly half of patients following this therapy and can induce severe life-threatening side effects and premature mortality. The pathophysiology of GVHD is driven by alloreactive donor T cells that induce a proinflammatory environment to cause pathological damage in the skin, gastrointestinal (GI) tract, lung, and liver during the acute phase of this disease. Recent work has demonstrated that the GI tract is a pivotal target organ and a primary driver of morbidity and mortality in patients. Prevention of this complication has therefore emerged as an important goal of prophylaxis strategies given the primacy of this tissue site in GVHD pathophysiology. In this review, we summarize foundational pre-clinical studies that have been conducted in animal models to prevent GI tract GVHD and examine the efficacy of these approaches upon subsequent translation into the clinic. Specifically, we focus on therapies designed to block inflammatory cytokine pathways, inhibit cellular trafficking of alloreactive donor T cells to the GI tract, and reconstitute impaired regulatory networks for the prevention of GVHD in the GI tract.

Outcomes in newly diagnosed young or high-risk myeloma patients receiving tandem autologous/allogeneic transplant followed by bortezomib maintenance: a phase II study

Despite novel drugs and autologous HCT, MM remains incurable, with short survival in patients with poor biological characteristics. Allo HCT may be curative in some patients but is hampered by high rates of toxicity and relapse. We hypothesized that bortezomib (BTZ), with its anti-myeloma and immunologic properties, could improve PFS and cGVHD after allo HCT in newly diagnosed MM patients. In this prospective phase II study, we included 39 young (≤50 years) and high-risk patients who received a tandem auto-allo HCT followed by BTZ. Patients had prospective minimal residual disease (MRD) evaluations using Next-Generation Flow cytometry prior to allo HCT, prior BTZ and every 3 months for 2 years. With a median follow-up of 48 months, we report PFS and OS at 5 years of 41% and 80%, with a non-relapse mortality of 12%. Incidences of grade II-IV aGVHD at 12 months and moderate/severe cGVHD at 2 years were 26% and 57%. In a multivariate analysis model including cytogenetics, ISS and MRD status, MRD positivity prior to allo HCT (HR 3.75, p = 0.037), prior BTZ (HR 11.3, p = 0.018) and 3 months post-BTZ initiation (HR 9.7, p = 0.001) was highly predictive of progression. Peritransplant MRD assessment thus strongly predicts disease progression.

Pros and Cons of the Cannabinoid System in Cancer: Focus on Hematological Malignancies

The endocannabinoid system (ECS) is a composite cell-signaling system that allows endogenous cannabinoid ligands to control cell functions through the interaction with cannabinoid receptors. Modifications of the ECS might contribute to the pathogenesis of different diseases, including cancers. However, the use of these compounds as antitumor agents remains debatable. Pre-clinical experimental studies have shown that cannabinoids (CBs) might be effective for the treatment of hematological malignancies, such as leukemia and lymphoma. Specifically, CBs may activate programmed cell death mechanisms, thus blocking cancer cell growth, and may modulate both autophagy and angiogenesis. Therefore, CBs may have significant anti-tumor effects in hematologic diseases and may synergistically act with chemotherapeutic agents, possibly also reducing chemoresistance. Moreover, targeting ECS might be considered as a novel approach for the management of graft versus host disease, thus reducing some symptoms such as anorexia, cachexia, fatigue, anxiety, depression, and neuropathic pain. The aim of the present review is to collect the state of the art of CBs effects on hematological tumors, thus focusing on the essential topics that might be useful before moving into the clinical practice.

Oral Proteasome Inhibitor Ixazomib for Switch-Maintenance Prophylaxis of Recurrent or Late Acute and Chronic Graft-versus-Host Disease after Day 100 in Allogeneic Stem Cell Transplantation

Graft-versus-host disease (GVHD) is a frequent complication in the first year after allogeneic stem cell transplantation (allo-HCT). Recipients of reduced-intensity (RI) or nonmyeloablative (NMA) conditioning combined with calcineurin inhibitor (CNI)-based GVHD prophylaxis frequently develop GVHD in the context of immunosuppression taper. Ixazomib is an oral proteasome inhibitor with a wide safety profile that has demonstrated immunomodulatory properties, inhibition of pro-inflammatory cytokines, and anti-tumor activity. We hypothesized that switch-maintenance GVHD prophylaxis using ixazomib would facilitate CNI taper without increased GVHD frequency and severity while maintaining graft-versus-tumor (GVT) effect and an acceptable safety profile. We conducted an open-label, prospective, single-center pilot study in patients with hematologic malignancies who received an RI or NMA conditioning and CNI-based GVHD prophylaxis that were within day 100 to 150 after HCT (n = 18). Patients were treated with ixazomib once weekly on a 28-day cycle (3 weeks on, 1 week off). Treatment was safe; most adverse events were grade 1 or 2, with cytopenia and elevation in transaminases the most common. Five patients were removed from the study because of toxicity or side effects. Only 5 of 18 patients developed GVHD during the study, and its severity was driven by acute manifestations while chronic involvement was mild. The cumulative incidence of grade II-IV acute and chronic GVHD at 1-year after HCT was 33% (95% confidence interval [CI], 13-55). No patients died during the study, and only 1 had malignant relapse. An additional patient relapsed after completion of the study but within 1 year after HCT. The probability of progression-free survival and GVHD-free/relapse-free survival (composite endpoint) at 1 year were 89% (95% CI, 75-100) and 78% (95% CI, 61-100), respectively. Immune reconstitution analysis showed a rapid and sustained recovery in T-cell subpopulations and B cell reconstitution, and vaccine response in a subset of patients demonstrated continuing or de novo positive protective antibody titers. This study demonstrated low incidence of recurrent and late acute and chronic GVHD within 1 year after HCT possible associated with switch-maintenance GVHD prophylaxis using ixazomib. This approach allowed for CNI taper while preserving GVT effect, without aggravating GVHD. Our findings support further development of this approach and provide a proof-of-concept for switch-maintenance GVHD prophylaxis.

Current and Emerging Targeted Therapies for Acute Graft-Versus-Host Disease

Acute graft-versus-host disease (GVHD), the major complication after allogeneic hematopoietic cell transplant (HCT), develops in approximately 50% of patients. The primary treatment is high-dose systemic steroids, but treatment failure is common, and steroid-refractory (SR) GVHD is the leading cause of non-relapse mortality after allogeneic HCT. Ruxolitinib became the first treatment for SR GVHD to obtain US Food and Drug Administration approval, and other new treatments are actively being studied. We searched the literature using the PubMed database and clinical trials using ClinicalTrials.gov to identify the most promising new treatments for GVHD. In this review, we categorize potential new treatments for GVHD by their mechanism of action (e.g., antibodies that deplete T cells or prevent their trafficking to target tissues, proteasome inhibitors, tyrosine kinase inhibitors, and other agents) and summarize the results from clinical trials.

Graft-versus-host disease prophylaxis: Pathophysiology-based review on current approaches and future directions

Graft-versus-host disease (GvHD) was first described in 1959, since then major efforts have been made in order to understand its physiopathology and animal models have played a key role. Three steps, involving different pathways, have been recognised in either acute and chronic GvHD, identifying them as two distinct entities. In order to reduce GvHD incidence and severity, prophylactic measures were added to transplant protocols. The combination of a calcineurin inhibitor (CNI) plus an antimetabolite remains the standard of care. Better knowledge of GvHD pathophysiology has moved this field forward and nowadays different drugs are being used on a daily basis. Improving GvHD prophylaxis is a major goal as it would translate into less non-relapse mortality and better overall survival. As compared to CNI plus methotrexate the combination of CNI plus mycophenolate mophetil (MMF) allows us to obtain similar results in terms of GvHD incidence but a lower toxicity rate in terms of neutropenia or mucositis. The use of ATG has been related to a lower risk of acute and chronic GvHD in prospective randomized trials as well as the use of posttransplant Cyclophosphamide, with no or marginal impact on overall survival but with an improvement in GvHD-relapse free survival (GRFS). The use of sirolimus has been related to a lower risk of acute GvHD and significantly influenced overall survival in one prospective randomized trial. Other prospective trials have evaluated the use of receptors such as CCR5 or α4β7 to avoid T-cells trafficking into GvHD target organs, cytokine blockers or immune check point agonists. Also, epigenetic modifiers have shown promising results in phase II trials. Attention should be paid to graft-versus-leukemia, infections and immune recovery before bringing new prophylactic strategies to clinical practice. Although the list of novel agents for GvHD prophylaxis is growing, randomized trials are still lacking for many of them.

Ixazomib for Chronic Graft-versus-Host Disease Prophylaxis following Allogeneic Hematopoietic Cell Transplantation

Chronic graft-versus-host disease (cGVHD) is major cause of morbidity and mortality following allogeneic hematopoietic cell transplantation (HCT). Ixazomib is an oral, second-generation, proteasome inhibitor that has been shown in preclinical models to prevent GVHD. We conducted a phase I/II trial in 57 patients to evaluate the safety and efficacy of ixazomib administration for cGVHD prophylaxis in patients undergoing allogeneic HCT. Oral ixazomib was administered on a weekly basis for a total of 4 doses, beginning days +60 through +90, to recipients of matched related donor (MRD, n = 25) or matched unrelated donor (MUD, n = 26) allogeneic HCT in phase II portion of the study, once the recommended phase II dose of 4 mg was identified in phase I (n = 6). All patients received peripheral blood graft and standard GVHD prophylaxis of tacrolimus and methotrexate. Ixazomib administration was safe and well tolerated, with thrombocytopenia, leukopenia, gastrointestinal complaints, and fatigue the most common adverse events (>10%). In phase II (n = 51), the cumulative incidence of cGVHD at 1 year was 36% (95% confidence interval [CI], 19% to 54%) in the MRD cohort and 39% (95% CI, 21% to 56%) in the MUD cohort. One-year cumulative incidence of nonrelapse mortality (NRM) and relapse was 0% and 20% (95% CI, 8% to 36%) in the MRD cohort, respectively. In the MUD cohort, the respective NRM and relapse rates were 4% (0% to 16%) and 34% (17% to 52%). The outcomes on the study were compared post hoc with contemporaneous matched Center for International Blood and Marrow Transplant Research (CIBMTR) controls. This post hoc analysis showed no significant improvement in cGVHD rates in both the MRD (hazard ratio [HR] = 0.85, P = .64) or MUD cohorts (HR = 0.68, P = .26) on the study compared with CIBMTR controls. B cell activating factor plasma levels were significantly higher after ixazomib dosing in those who remained cGVHD free compared with those developed cGVHD. This study shows that the novel strategy of short-course oral ixazomib following allogeneic HCT is safe but did not demonstrate significant improvement in cGVHD incidence in recipients of MRD and MUD transplantation compared with matched CIBMTR controls. This study is registered at www.clinicaltrials.gov as NCT02250300.

Carfilzomib combined with cyclosporine and methotrexate for the prevention of graft-versus-host disease after allogeneic stem-cell transplantation from unrelated donors

Acute graft-versus-host disease (aGVHD) is the major treatment-related complication after stem-cell transplantation (SCT) from unrelated donors. The proteasome-inhibitor bortezomib was added to GVHD prevention regimens with initial promise. However, two randomized studies failed to show efficacy. We explored the addition of carfilzomib, s second-generation proteasome inhibitor (20 mg/m², intravenously on days +1 and +2) to cyclosporine/methotrexate backbone in 26 patients after SCT from unrelated donors. We compared outcomes to historical group of 100 patients given cyclosporine/methotrexate alone. Median follow-up was 34 months. There was no difference between the groups in engraftment or toxicities. The cumulative incidence of aGVHD grade II-IV, 6 months post transplant was 11% (95% CI, 4-32) and 39% (95% CI, 30-50), respectively (P = 0.01). The cumulative incidence of chronic GVHD, 2 years post transplant, was 49% (95% CI, 32-75) and 41% (95% CI, 33-52), respectively (P = 0.98). Three-year non-relapse mortality was 11% (95% CI, 4-33) and 18% (95% CI, 12-27, P = 0.45) while 3-year relapse rates were 8% (95% CI, 2-29) and 26% (95% CI, 18-36), respectively (P = 0.06). Three-year survival was 81% (95%CI, 66-96) and 56% (95% CI, 46-66), respectively (P = 0.05). In conclusion, carfilzomib with cyclosporine/methotrexate is safe, may reduce aGVHD, and possibly improve survival after unrelated donor SCT. These initial observations merit further study in larger comparative studies. ClinicalTrial.gov NCT01991301.

Prospective phase 2 trial of ixazomib after nonmyeloablative haploidentical peripheral blood stem cell transplant

Proteasome inhibition results in extensive immunomodulatory effects that augment natural killer cell cytotoxicity and inhibit aspects of T-cell, B-cell, and dendritic cell function. We performed a phase 2 study that examined the effects of ixazomib for graft-versus-host disease (GVHD) prophylaxis (up to 12 cycles) with posttransplant cyclophosphamide and tacrolimus after standard nonmyeloablative haploidentical donor transplantation (HIDT). Ixazomib was started on day +5 (4 mg on days 1, 8, and 15 of a 28-day cycle), with dose reductions allowed in future cycles for toxicity. All patients received peripheral blood stem cells. Twenty-five patients were enrolled with a median age of 62 years (range, 35-77 years) who had acute leukemia (4), myelodysplastic syndrome (7), non-Hodgkin lymphoma/Hodgkin lymphoma/chronic lymphocytic leukemia (8), and myeloma (6). The hematopoietic cell transplant comorbidity index was ≥3 in 68% of the patients. After a median follow-up of 33.5 months, the cumulative incidence of relapse/progression at 1 year was 24% and 44% at 3 years, which failed to meet the statistically predefined goal of decreasing 1-year risk of relapse. Engraftment occurred in all patients with no secondary graft failure, and 3-year nonrelapse mortality (NRM) was 12%. Cumulative incidence of grade 3 to 4 acute GVHD was 8%, whereas moderate-to-severe chronic GVHD occurred in 19%. Nineteen patients survive with an estimated 1-year overall survival (OS) of 84% and 3-year OS of 74%. Hematologic and cutaneous toxicities were common but manageable. The substitution of ixazomib for mycophenolate mofetil (MMF) post-HIDT results in reliable engraftment, comparable rates of clinically significant GVHD, relapse and NRM, and favorable OS. This trial was registered at www.clinicaltrials.gov as # NCT02169791.

Ixazomib for Treatment of Refractory Chronic Graft-versus-Host Disease: A Chronic GVHD Consortium Phase II Trial

New interventions are needed in advanced chronic graft-versus-host disease (GVHD). In a phase II, single-arm, multicenter trial, we examined the efficacy of ixazomib in patients with chronic GVHD who had progressed after at least 1 previous line of systemic immunosuppressive (IS) therapy. Ixazomib was given as a 4 mg oral dose weekly on days 1, 8, and 15 of a 28-day cycle for up to 6 total cycles. The primary endpoint was 6-month treatment failure, a composite endpoint including death, relapse, and requirement for an additional line of systemic IS therapy. A total of 50 subjects were enrolled at 6 institutions. The median time from the onset of chronic GVHD to enrollment was 2.8 years (interquartile range, 1.5 to 4.3 years). The degree of chronic GVHD at enrollment was National Institutes of Health (NIH)-defined moderate (16%) or severe (84%), predominantly classic (80% versus 20% overlap), with 52% of patients having involvement of 4 or more organs. The patients were heavily pretreated, with 39 (78%) receiving 3 or more previous lines of systemic therapy for chronic GVHD. Of the 50 patients treated, 26 completed 6 months of planned therapy. The 6-month treatment failure rate was significantly lower than the historical benchmark (28% versus 44%; P = .01) previously established in second-line therapy for chronic GVHD. No patient, transplantation, or chronic GVHD variables were significantly associated with 6-month treatment failure. NIH-defined overall response rate was 40% at 6 months. Overall survival was 92% at 6 months and 90% at 12 months. Ixazomib met the primary endpoint of low treatment failure at 6 months in the setting of advanced chronic GVHD. At 6 months, the NIH-defined rate of complete/partial response was 40%, and 52% of patients remained on ixazomib therapy, suggesting that the low treatment failure rate was due in part due to prevention of progressive disease that would have required additional treatment.

Targeting Signal 3 Extracellularly and Intracellularly in Graft-Versus-Host Disease

Allogeneic hematopoietic stem cell transplantation (allo-HCT) holds curative potential for many hematological disorders. However, the pathophysiology of the desired graft-versus-tumor effect is linked to life-threatening complications of acute graft-versus-host disease (GVHD). Allogeneic donor T lymphocytes are essential for causing GVHD, and their activation relies on the coordination of TCR engagement and co-stimulation, also known as Signal 1 and Signal 2. In addition to these signals, a network of secreted cytokines by immune cells provides a third signal, Signal 3, that is critical for the initiation and maintenance of GVHD. Strategies to target Signal 3 in human diseases have shown therapeutic benefit for inflammatory disorders such as Rheumatoid Arthritis and Inflammatory Bowel Disease. However, despite our growing understanding of their role in GVHD, the success of targeting individual cytokines has been modest with some notable exceptions. This review aims to describe current approaches toward targeting Signal 3 in clinical GVHD, and to highlight emerging studies in immune cell biology that may be harnessed for better clinical translation.

Dissecting the biology of allogeneic HSCT to enhance the GvT effect whilst minimizing GvHD

Allogeneic haematopoietic stem cell transplantation (allo-HSCT) was the first successful therapy for patients with haematological malignancies, predominantly owing to graft-versus-tumour (GvT) effects. Dramatic methodological changes, designed to expand eligibility for allo-HSCT to older patients and/or those with comorbidities, have led to the use of reduced-intensity conditioning regimens, in parallel with more aggressive immunosuppression to better control graft-versus-host disease (GvHD). Consequently, disease relapse has become the major cause of death following allo-HSCT. Hence, the prevention and treatment of relapse has come to the forefront and remains an unmet medical need. Despite >60 years of preclinical and clinical studies, the immunological requirements necessary to achieve GvT effects without promoting GvHD have not been fully established. Herein, we review learnings from preclinical modelling and clinical studies relating to the GvT effect, focusing on mechanisms of relapse and on immunomodulatory strategies that are being developed to overcome disease recurrence after both allo-HSCT and autologous HSCT. Emphasis is placed on discussing current knowledge and approaches predicated on the use of cell therapies, cytokines to augment immune responses and dual-purpose antibody therapies or other pharmacological agents that can control GvHD whilst simultaneously targeting cancer cells.

Advances in understanding the pathogenesis of graft-versus-host disease

Acute graft-versus-host disease (GVHD) remains a major complication after allogeneic haematopoietic stem cell transplantation (allo-HSCT). The emergence of different immuno-prophylaxis strategies, such as post-transplant cyclophosphamide or anti-thymocyteglobulin has reduced the incidence of acute GVHD in recent years. The biology of the acute GVHD we observe in the clinic may change due to the use of novel immuno-stimulatory agents, including immune checkpoint inhibitors or anti-neoplastic immune-modifiers, like lenalidomide, given before or after allo-HSCT. Here we discuss the recent advances in our understanding of acute GVHD with a focus on early events of the disease, including tissue damaging factors, innate immune cells, costimulatory pathways, immune cell signalling, immuno-regulatory cell types, biomarkers of GVHD and regenerative approaches. New insight in the pathogenesis of acute GVHD has revealed the role of pro-inflammatory intracellular signalling, defects in intestinal tissue regeneration and anti-bacterial defence, as well as a reduced diversity of the microbiome, which will be the basis for the development of novel therapies.

Phase I study of graft-versus-host disease prophylaxis including bortezomib for allogeneic hematopoietic cell transplantation from unrelated donors with one or two HLA loci mismatches in Japanese patients

This phase I study was designed for graft-versus-host disease (GVHD) prophylaxis including bortezomib in allogeneic hematopoietic cell transplantation (allo-HCT) from human leukocyte antigen (HLA)-mismatched unrelated donors in Japanese patients. Patients were administered bortezomib on days 1, 4, and 7, with short-term methotrexate and tacrolimus. Three bortezomib dose levels were prepared (1.0, 1.3, and 1.5 mg/m²). A dose of 1.3 mg/m² was planned for administration to the initial six patients, and was adjusted if dose-limiting toxicity developed. Five of six patients enrolled for the initial dose had bone marrow donors. Two cases had single-antigen and single-allele mismatches; four had single-antigen mismatch at the A, B, C, and/or DRB1 loci in the GVH direction. All patients achieved neutrophil engraftment and complete donor chimerism. Three patients developed grade II acute GVHD, and none developed grade III-IV GVHD or any dose-limiting toxicity attributable to bortezomib by day 100. Two patients developed late-onset acute GVHD, and two developed chronic GVHD, but all cases were manageable. All patients were alive without relapse after a median follow-up period of 52 months. The optimal dose of bortezomib was determined to be 1.3 mg/m². Prophylaxis against GVHD using a regimen including bortezomib thus seems feasible for HLA-mismatched unrelated allo-HCT.

Efficacy of bortezomib to intensify the conditioning regimen and the graft-versus-host disease prophylaxis for high-risk myeloma patients undergoing transplantation

This multicenter phase I trial was designed to evaluate the safety and efficacy of bortezomib (Bz) as part of both the conditioning regimen and the graft-versus-host disease (GvHD) prophylaxis. Patients received fludarabine, melphalan and Bz (days -9 and -2). GVHD prophylaxis consisted of Bz (days +1, +4, and +7), sirolimus (Siro) from day -5 and tacrolimus (Tk) from -3 (except the first five patients that did not receive Tk). Twenty-five patients with poor prognostic multiple myeloma were included. Eleven out of the 19 patients had high-risk features. Out of the 21 patients evaluable at day +100, 14 were in CR (67%) and 7 (33%) in PR. Cumulative incidence (CI) of nonrelapse mortality at 1 year was 24%. CI of grades 2-4 and 3-4 acute GvHD was 35% and 10%, respectively; CI of chronic GvHD was 35% and 55% at 1 and 2 years, respectively. Overall and event free survival at 2 years were 64% and 31%, respectively. Bz as part of the conditioning regimen and in the combination with Siro/tacrolimus for GvHD prophylaxis is safe and effective allowing an optimal disease control early after transplant and reducing the risk of GvHD.

Acute Graft-Versus-Host Disease: A Brief Review

Graft‐versus‐host disease (GvHD) is an important complication that can be observed after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Acute GvHD (aGvHD) is seen after allo-HSCT and the incidence of aGvHD is around 30%-50%. aGvHD prophylaxis is essential in patients undergoing allo-HSCT. Initial therapy for aGvHD is steroids. Prognosis is poor in aGvHD patients not responding to steroids. In this article, the pathobiology, clinical findings, prophylaxis, and treatment of aGvHD will be summarized.

Progress in research on paclitaxel and tumor immunotherapy

Paclitaxel is a well-known anticancer agent with a unique mechanism of action. It is considered to be one of the most successful natural anticancer drugs available. This study summarizes the recent advances in our understanding of the sources, the anticancer mechanism, and the biosynthetic pathway of paclitaxel. With the advancement of biotechnology, improvements in endophytic fungal strains, and the use of recombination techniques and microbial fermentation engineering, the yield of extracted paclitaxel has increased significantly. Recently, paclitaxel has been found to play a large role in tumor immunity, and it has a great potential for use in many cancer treatments.

Three prophylaxis regimens (tacrolimus, mycophenolate mofetil, and cyclophosphamide; tacrolimus, methotrexate, and bortezomib; or tacrolimus, methotrexate, and maraviroc) versus tacrolimus and methotrexate for prevention of graft-versus-host disease with haemopoietic cell transplantation with reduced-intensity conditioning: a randomised phase 2 trial with a non-randomised contemporaneous control group (BMT CTN 1203)

BACKGROUND

Prevention of graft-versus-host disease (GvHD) without malignant relapse is the overall goal of allogeneic haemopoietic cell transplantation (HCT). We aimed to evaluate regimens using either maraviroc, bortezomib, or post-transplantation cyclophosphamide for GvHD prophylaxis compared with controls receiving the combination of tacrolimus and methotrexate using a novel composite primary endpoint to identify the most promising intervention to be further tested in a phase 3 trial.

METHODS

In this prospective multicentre phase 2 trial, adult patients aged 18-75 years who received reduced-intensity conditioning HCT were randomly assigned (1:1:1) by random block sizes to tacrolimus, mycophenolate mofetil, and post-transplantation cyclophosphamide (cyclophosphamide 50 mg/kg on days 3 and 4, followed by tacrolimus starting on day 5 and mycophenolate mofetil starting on day 5 at 15 mg/kg three times daily not to exceed 1 g from day 5 to day 35); tacrolimus, methotrexate, and bortezomib (bortezomib 1·3 mg/m2 intravenously on days 1, 4, and 7 after HCT); or tacrolimus, methotrexate, and maraviroc (maraviroc 300 mg orally twice daily from day -3 to day 30 after HCT). Methotrexate was administered as a 15 mg/m2 intravenous bolus on day 1 and 10 mg/m2 intravenous bolus on days 3, 6, and 11 after HCT; tacrolimus was given intravenously at a dose of 0·05 mg/kg twice daily (or oral equivalent) starting on day -3 (except the post-transplantation cyclophosphamide, as indicated), with a target level of 5-15 ng/mL. Tacrolimus was continued at least until day 90 and was tapered off by day 180. Each study group was compared separately to a contemporary non-randomised prospective cohort of patients (control group) who fulfilled the same eligibility criteria as the trial, but who were treated with tacrolimus and methotrexate at centres not participating in the trial. The primary endpoint (GvHD-free, relapse-free survival [GRFS]) was defined as the time from HCT to onset of grade 3-4 acute GvHD, chronic GvHD requiring systemic immunosuppression, disease relapse, or death. The study was analysed by modified intention to treat. The study is closed to accrual and this is the planned analysis. This trial is registered with ClinicalTrials.gov, number NCT02208037.

FINDINGS

Between Nov 17, 2014, and May 18, 2016, 273 patients from 31 US centres were randomly assigned to the three study arms: 89 to tacrolimus, methotrexate, and bortezomib; 92 to tacrolimus, methotrexate, and maraviroc; 92 to tacrolimus, mycophenolate mofetil, and post-transplantation cyclophosphamide; and six were excluded. Between Aug 1, 2014, and Sept 14, 2016, 224 controls received tacrolimus and methotrexate. Controls were generally well matched except for more frequent comorbidities than the intervention groups and a different distribution of types of conditioning regimens used. Compared with controls, the hazard ratio for GRFS was 0·72 (90% CI 0·54-0·94; p=0·044) for tacrolimus, mycophenolate mofetil, and post-transplantation cyclophosphamide, 0·98 (0·76-1·27; p=0·92) for tacrolimus, methotrexate, and bortezomib, and 1·10 (0·86-1·41; p=0·49) for tacrolimus, methotrexate, and maraviroc. 238 patients experienced grade 3 or 4 toxicities: 12 (13%) had grade 3 and 67 (73%) grade 4 events with tacrolimus, mycophenolate mofetil, and post-transplantation cyclophosphamide; ten (11%) had grade 3 and 68 (76%) had grade 4 events with tacrolimus, methotrexate, and bortezomib; and 18 (20%) had grade 3 and 63 (68%) had grade 4 events with tacrolimus, methotrexate, and maraviroc. The most common toxicities were haematological (77 [84%] for tacrolimus, mycophenolate mofetil, and post-transplantation cyclophosphamide; 73 [82%] for tacrolimus, methotrexate, and bortezomib; and 78 [85%] for tacrolimus, methotrexate, and maraviroc) and cardiac (43 [47%], 44 [49%], and 43 [47%], respectively).

INTERPRETATION

Tacrolimus, mycophenolate mofetil, and post-transplantation cyclophosphamide was the most promising intervention, yielding the best GRFS; this regimen is thus being prospectively compared with tacrolimus and methotrexate in a phase 3 randomised trial.

FUNDING

US National Health, Lung, and Blood Institute; National Cancer Institute; National Institute of Allergy and Infectious Disease; and Millennium Pharmaceuticals.

Allogeneic Transplantation after Myeloablative Rituximab/BEAM ± Bortezomib for Patients with Relapsed/Refractory Lymphoid Malignancies: 5-Year Follow-Up Results

Although bortezomib and rituximab have synergistic activity in patients with lymphoma and both can attenuate graft-versus-host disease (GVHD), the drugs have not been used together in patients undergoing allogeneic stem cell transplantation (alloSCT). In this phase I/II trial, we assessed the safety and activity of bortezomib added to the rituximab (R) plus BEAM (carmustine, etoposide, cytarabine, melphalan) regimen in patients with relapsed lymphoma undergoing alloSCT. Primary GVHD prophylaxis consisted of tacrolimus and methotrexate. Bortezomib (1 to 1.3 mg/m² per dose) was administered i.v. on days -13, -6, -1, and +2. We performed inverse probability weighting analysis to compare GVHD and survival results with an historical control group that received R-BEAM without bortezomib. Thirty-nine patients were assessable for toxic effects and response. The median age was 54 years. The most common diagnosis was diffuse large B cell lymphoma (41%). Twenty-two patients (56%) and 17 patients (44%) received their transplants from matched related and matched unrelated donors, respectively. The maximum tolerated bortezomib dose was 1 mg/m². The weighted cumulative incidences of grades II to IV and III or IV acute GVHD were 50% and 34%, respectively; these incidences and survival rates were not significantly different from those of the control group. Median survival was not reached in patients age ≤ 50 years and with a long follow-up time of 60.7 months. The R-BEAM regimen has a survival benefit in lymphoma patients age ≤ 50 years undergoing alloSCT. The addition of bortezomib has no impact on survival or incidence of GVHD.

αβ T Cell-Depleted Haploidentical Hematopoietic Stem Cell Transplantation without Antithymocyte Globulin in Children with Chemorefractory Acute Myelogenous Leukemia

We evaluated the outcome of αβ T cell-depleted haploidentical hematopoietic stem cell transplantation (HSCT) in a cohort of children with chemorefractory acute myelogenous leukemia (AML). Twenty-two patients with either primary refractory (n = 10) or relapsed refractory (n = 12) AML in active disease status received a transplant from haploidentical donors. The preparative regimen included cytoreduction with fludarabine and cytarabine and subsequent myeloablative conditioning with treosulfan and thiotepa. Antithymocyte globulin was substituted with tocilizumab in all patients and also with abatacept in 10 patients. Grafts were peripheral blood stem cells engineered by αβ T cell and CD19 depletion. Post-transplantation prophylactic therapy included infusion of donor lymphocytes, composed of a CD45RA-depleted fraction with or without a hypomethylating agent. Complete remission was achieved in 21 patients (95%). The cumulative incidence of grade II-IV acute graft-versus-host disease (GVHD) was 18%, and the cumulative incidence of chronic GVHD was 23%. At 2 years, transplantation-related mortality was 9%, relapse rate was 42%, event-free survival was 49%, and overall survival was 53%. Our data suggest that αβ T cell-depleted haploidentical HSCT provides a reasonable chance of long-term survival in a cohort of children with chemorefractory AML and creates a solid basis for further improvement.

On the role of the immunoproteasome in transplant rejection

The immunoproteasome is expressed in cells of hematopoietic origin and is induced during inflammation by IFN-γ. Targeting the immunoproteasome with selective inhibitors has been shown to be therapeutically effective in pre-clinical models for autoimmune diseases, colitis-associated cancer formation, and transplantation. Immunoproteasome inhibition prevents activation and proliferation of lymphocytes, lowers MHC class I cell surface expression, reduces the expression of cytokines of activated immune cells, and curtails  T helper 1 and 17 cell differentiation. This might explain the in vivo efficacy of immunoproteasome inhibition in different pre-clinical disease models for autoimmunity, cancer, and transplantation. In this review, we summarize the effect of immunoproteasome inhibition in different animal models for transplantation.

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

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

Bortezomib-based immunosuppression after reduced-intensity conditioning hematopoietic stem cell transplantation: randomized phase II results

Aprior phase I/II trial of bortezomib/tacrolimus/methotrexate prophylaxis after human leukocyte antigen (HLA)-mismatched reduced intensity conditioning allogeneic hematopoietic stem cell transplantation documented low acute graft-versus-host disease incidence, with promising overall and progression-free survival. We performed an open-label three-arm 1:1:1 phase II randomized controlled trial comparing grade II–IV acute graft-versus-host disease between conventional tacrolimus/methotrexate (A) versus bortezomib/tacrolimus/methotrexate (B), and versus bortezomib/sirolimus/tacrolimus (C), in reduced intensity conditioning allogeneic transplantation recipients lacking HLA-matched related donors. The primary endpoint was grade II–IV acute graft-versus-host disease incidence rate by day +180. One hundred and thirty-eight patients (A 46, B 45, C 47) with a median age of 64 years (range: 24–75), varying malignant diagnoses and disease risk (low 14, intermediate 96, high/very high 28) received 7–8/8 HLA-mismatched (40) or matched unrelated donor (98) grafts. Median follow up in survivors was 30 months (range: 14–46). Despite early immune reconstitution differences, day +180 grade II-IV acute graft-versus-host disease rates were similar (A 32.6%, B 31.1%, C 21%; P=0.53 for A vs. B, P=0.16 for A vs. C). The 2-year non-relapse mortality incidence was similar (A 14%, B 16%, C 6.4%; P=0.62), as were relapse (A 32%, B 32%, C 38%; P=0.74), chronic graft-versus-host disease (A 59%, B 60% C 55%; P=0.66), progression-free survival (A 54%, B 52%, C 55%; P=0.95), and overall survival (A 61%, B 62%, C 62%; P=0.98). Overall, the bortezomib-based regimens evaluated did not improve outcomes compared with tacrolimus/methotrexate therapy. clinicaltrials.gov Identifier: 01754389

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

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

Allograft for Myeloma: Examining Pieces of the Jigsaw Puzzle

Multiple myeloma (MM) cure remains elusive despite the availability of newer anti-myeloma agents. Patients with high-risk disease often suffer from early relapse and short survival. Allogeneic hematopoietic cell transplantation (allo-HCT) is an “immune-based” therapy that has the potential to offer long-term remission in a subgroup of patients, at the expense of high rates of transplant-related morbidity and mortality. Donor lymphocyte infusion (DLI) upon disease relapse after allo-HCT is able to generate an anti-myeloma response suggestive of a graft-versus-myeloma effect. Allo-HCT provides a robust platform for additional immune-based therapy upon relapse including DLI and, maintenance with immunomodulatory drugs and immunosuppressive therapy. There have been conflicting findings from randomized prospective trials questioning the role of allo-HCT. However, to this date, allo-HCT remains the only potential curable treatment for MM and its therapeutic role needs to be better defined especially for patients with high-risk disease. This review examines different aspects of this treatment and summarizes ongoing attempts at improving its therapeutic index.

The Role of B Cell Targeting in Chronic Graft-Versus-Host Disease

Chronic graft-versus-host disease (cGVHD) is a leading cause of late morbidity and mortality following allogeneic stem cell transplantation. Current therapies, including corticosteroids and calcineurin inhibitors, are only effective in roughly 50% of cases; therefore, new treatment strategies are under investigation. What was previously felt to be a T cell disease has more recently been shown to involve activation of both T and B cells, as well as a number of cytokines. With a better understanding of its pathophysiology have come more expansive preclinical and clinical trials, many focused on B cell signaling. This report briefly reviews our current understanding of cGVHD pathophysiology and reviews clinical and preclinical trials with B cell-targeted agents.

HLA-mismatched unrelated donor transplantation using TLI-ATG conditioning has a low risk of GVHD and potent antitumor activity

Many patients lack a fully HLA-matched donor for hematopoietic cell transplantation (HCT), and HLA mismatch is typically associated with inferior outcomes. Total lymphoid irradiation and antithymocyte globulin (TLI-ATG) is a nonmyeloablative conditioning regimen that is protective against graft-versus-host disease (GVHD), and we hypothesized that the protective effect would extend beyond HLA-matched donors. We report outcomes for all consecutively transplanted patients at Stanford University from December 2001 through May 2015 who received TLI-ATG conditioning and HCTs from 8 to 9 out of 10 HLA-mismatched unrelated donors (MMUDs, N = 72) compared with 10 out of 10 HLA-matched unrelated donors (MUDs, N = 193). The median age of the patients was 60 years with a median follow-up of 2 years, and there was a similar distribution of lymphoid and myeloid malignancies in both cohorts. There were no significant differences between MMUD and MUD cohorts in overall survival (46% vs 46% at 5 years, P = .86), disease-free survival (38% vs 28% at 5 years, P = .25), nonrelapse mortality (17% vs 12% at 2 years, P = .34), acute GVHD grades III-IV (6% vs 3% at day +100, P = .61), or chronic GVHD (39% vs 35% at 5 years, P = .49). There was a trend toward less relapse in the MMUD cohort (45% vs 60% at 5 years, hazard ratio: 0.71, P = .094), which was significant for patients with lymphoid malignancies (29% vs 57% at 5 years, hazard ratio: 0.55, P = .044). Achieving full donor chimerism was strongly associated with lower relapse rates. TLI-ATG conditioning may overcome the traditionally poorer outcome associated with HLA-mismatched donors and may be particularly well suited for patients with lymphoid malignancies who lack HLA-matched donors.

Alternative Donor Graft Sources for Adults with Hematologic Malignancies: A Donor for All Patients in 2017!

Hematopoietic stem cell transplant (HSCT) is potentially curative for a wide variety of malignant diseases, including acute and leukemias, lymphoma, and myelodysplasia. Choice of a stem cell donor is dependent on donor availability, donor compatibility and health, recipient disease type, and recipient condition. Current sources of stem cell donation for HSCT are matched sibling donors (MSDs), matched unrelated donors (MUDs), 1-antigen mismatched unrelated donors (MMUDs), haploidentical donors (haplo), and umbilical cord blood (UCB) units. Historically, preferred donors for HSCT have been human leukocyte antigen (HLA)-matched sibling donors; however, only about 30% of U.S. patients will have a MSD available. The majority of patients referred for HSCT will require an alternative donor graft: MUD, MMUD, UCB, or haplo. The likelihood of finding a MUD varies depending on the ethnicity of the recipient. White Caucasians of European descent have the greatest chance of finding a MUD. Chances of finding a MUD are significantly less for African-American or Hispanic recipients due to HLA polymorphisms. Therefore, MMUD, UCB, and haplo donor graft sources expand the donor pool for recipients who do not have a MSD or MUD available. Given the variety of different donor stem cell sources available today, nearly every patient who needs an allogeneic HSCT has a potential donor in 2017. All transplant-eligible patients with hematologic malignancies should be evaluated by a transplant center to determine if HSCT is a viable treatment option for their underlying disease process.

IMPLICATIONS FOR PRACTICE

The goal of this review is to increase the awareness of oncology practitioners to the availability of alternative donor stem cell transplants for patients with hematologic malignancies. Despite new agents, stem cell transplant remains the only curative therapy for many patients with acute and chronic leukemia, myelodysplasia, and lymphoma. Given the variety of different donor stem cell sources available today, nearly every patient who needs an allogeneic stem cell transplant will have a donor.

Calcineurin and mTOR Inhibitor-Free Post-Transplantation Cyclophosphamide and Bortezomib Combination for Graft-versus-Host Disease Prevention after Peripheral Blood Allogeneic Hematopoietic Stem Cell Transplantation: A Phase I/II Study

Graft-versus-host disease (GVHD) hampers the utility of allogeneic hematopoietic stem cell transplantation (AHSCT). The purpose of this study was to determine the feasibility, safety, and efficacy of a novel combination of post-transplantation cyclophosphamide (PTC) and bortezomib for the prevention of GVHD. Patients undergoing peripheral blood AHSCT for hematological malignancies after reduced-intensity conditioning with grafts from HLA-matched related or unrelated donors were enrolled in a phase I/II clinical trial. Patients received a fixed dose of PTC and an increasing dose of bortezomib in 3 cohorts, from .7 to 1 and then to 1.3 mg/m², administered 6 hours after graft infusion and 72 hours thereafter, during phase I. The study was then extended at the higher dose in phase II for a total of 28 patients. No graft failure and no unexpected grade ≥3 nonhematologic toxicities were encountered. The median times to neutrophil and platelet engraftment were 16 and 27 days, respectively. Day +100 treatment-related mortality was 3.6% (95% confidence interval [CI], .2% to 15.7%). The cumulative incidences of grades II to IV and grades III and IV acute GVHD were 35.9% (95% CI, 18.6% to 53.6%) and 11.7% (95% CI, 2.8% to 27.5%), respectively. The incidence of chronic GVHD was 27% (95% CI, 11.4% to 45.3%). Progression-free survival, overall survival, and GVHD and relapse-free survival rates were 50% (95% CI, 30.6% to 66.6%), 50.8% (95% CI, 30.1% to 68.2%), and 37.7% (95% CI, 20.1% to 55.3%), respectively. Immune reconstitution, measured by CD3, CD4, and CD8 recovery, was prompt. The combination of PTC and bortezomib for the prevention of GVHD is feasible, safe, and yields promising results. The combination warrants further examination in a multi-institutional trial.

New drugs and allogeneic hematopoietic stem cell transplantation for hematological malignancies: do they have a role in bridging, consolidating or conditioning transplantation treatment?

INTRODUCTION

Novel targeted therapies and monoclonal antibodies can be combined with allogeneic stem cell transplantation (allo-SCT) at different time-points: 1) before the transplant to reduce tumour burden, 2) as part of the conditioning in place of or in addition to conventional agents 3) after the transplant to allow long-term disease control. Areas covered: This review focuses on the current integration of new drugs with allo-SCT for the treatment of major hematological malignancies for which allo-SCT has been a widely-adopted therapy. Expert opinion: After having been used as single agent salvage treatments in relapsed patients after allo-SCT or in combination with donor lymphocyte infusions, many new drugs have also been safely employed before allo-SCT as a bridge to transplantation or after it as planned consolidation/maintenance. This era of new drugs has opened new important opportunities to 'smartly' combine 'targeted drugs and cell therapies' in new treatment paradigms that may lead to higher cure rates or longer disease control in patients with hematological malignancies.

Allogeneic Stem Cell Transplantation for Relapsed/Refractory B Cell Lymphomas: Results of a Multicenter Phase II Prospective Trial including Rituximab in the Reduced-Intensity Conditioning Regimen

The treatment of patients with refractory/relapsed B cell non-Hodgkin lymphoma (NHL) is evolving because of the availability of novel drugs. Allogeneic stem cell transplantation (alloSCT) can be curative, but its morbidity and mortality remain a matter of concern. We conducted a multicenter prospective phase II trial to evaluate the benefit of including only 1 dose of rituximab in the conditioning regimen before alloSCT. The primary endpoint was progression-free survival. The study enrolled 121 patients with relapsed/refractory B cell lymphomas. The conditioning regimen consisted of thiotepa, cyclophosphamide, fludarabine, and rituximab (500 mg/m²). Rabbit antithymocyte globulin was administered only in case of unrelated donors. Sixty-seven (55%) and 54 (45%) patients received grafts from related and unrelated donors, respectively. The crude cumulative incidence (CCI) of nonrelapse mortality (NRM) was 21% at 3 years. The CCIs of chronic graft-verus-host disease (GVHD) at 3 years were 54% and 31% in recipients of matched sibling and unrelated grafts, respectively. At a median follow-up of 41 months, the estimated 3-year progression-free and overall survival were 50% and 61%, respectively. Long-term outcome was also evaluated with the composite endpoint of GVHD-free and relapse-free survival (GRFS). This is the first work evaluating the GRFS in a prospective trial of lymphoma patients: the 1-year and 3-year GRFS were 40% and 34%, respectively. AlloSCT can cure a fraction of patients with rather low NRM and an encouraging PFS and GRFS.

Targeting the Canonical Nuclear Factor-κB Pathway with a High-Potency IKK2 Inhibitor Improves Outcomes in a Mouse Model of Idiopathic Pneumonia Syndrome

Idiopathic pneumonia syndrome (IPS) is a noninfectious inflammatory disorder of the lungs that occurs most often after fully myeloablative allogeneic hematopoietic stem cell transplantation (HSCT). IPS can be severe and is associated with high 1-year mortality rates despite existing therapies. The canonical nuclear factor-(NF) κB signaling pathway has previously been linked to several inflammatory disorders of the lung, including asthma and lung allograft rejection. It has never been specifically targeted as a novel IPS treatment approach, however. Here, we report that the IκB kinase 2 (IKK2) antagonist BAY 65-5811 or "compound A," a highly potent and specific inhibitor of the NF-κB pathway, was able to improve median survival times and recipient oxygenation in a well-described mouse model of IPS. Compound A impaired the production of the proinflammatory chemokines CCL2 and CCL5 within the host lung after transplantation. This resulted in significantly lower numbers of donor lung infiltrating CD4⁺ and CD8⁺ T cells and reduced pulmonary inflammatory cytokine production after allograft. Compound A's beneficial effects appeared to be specific for limiting pulmonary injury, as the drug was unable to improve outcomes in a B6 into B6D2 haplotype-matched murine HSCT model in which recipient mice succumb to lethal acute graft-versus-host disease of the gastrointestinal tract. Collectively, our data suggest that the targeting of the canonical NF-κB pathway with a small molecule IKK2 antagonist may represent an effective and novel therapy for the specific management of acute lung injury that can occur after allogeneic HSCT.

Prospective study of nonmyeloablative, HLA-mismatched unrelated BMT with high-dose posttransplantation cyclophosphamide

Allogeneic blood or marrow transplantation (BMT) candidates may lack HLA-matched, related haploidentical, and unrelated umbilical cord options. Barriers to partially HLA-mismatched, unrelated donor (mMUD) BMT include excess graft-versus-host disease (GVHD), graft failure, and death. We prospectively studied nonmyeloablative (NMA) mMUD BMT with high-dose posttransplantation cyclophosphamide (PTCy) for patients with hematologic malignancies. Three transplants were performed with busulfan/fludarabine conditioning, with subsequent change to fludarabine/Cy/total body irradiation (flu/Cy/TBI). Twenty mMUD transplants are reported using flu/Cy/TBI, T-cell replete bone marrow grafts, and PTCy, mycophenolate mofetil, and sirolimus or tacrolimus (1 patient) for GVHD prophylaxis. The median patient age was 56. Ofthese unrelated grafts, 45% had ≥2 mismatched HLA loci, 25% had ≥3 mismatched loci, and 50% had HLA-C mismatches. No graft failure or grades 3-4 acute GVHD occurred. The median times to neutrophil recovery (≥500/μL) and platelet recovery (≥20 000/μL) were 19 days and 31 days, respectively. Full-donor chimerism was achieved in 95% of evaluable patients by day 60. The 180-day probability of grades 2-4 acute GVHD (all grade 2) was 25%, and the 1-year probability of any chronic GVHD was 16% (none severe). The 2-year nonrelapse mortality probability was 6%. With 4-year median follow-up, the 1-year progression-free and overall survival probabilities were 65% and 75%, respectively. NMA, T-cell replete mMUD BMT is thus a potentially viable option for patients without other suitable donors. This trial was registered at www.clinicaltrials.gov as #NCT01203722.

Ex Vivo CD34+-Selected T Cell-Depleted Peripheral Blood Stem Cell Grafts for Allogeneic Hematopoietic Stem Cell Transplantation in Acute Leukemia and Myelodysplastic Syndrome Is Associated with Low Incidence of Acute and Chronic Graft-versus-Host Disease and High Treatment Response

Ex vivo CD34⁺-selected T cell depletion (TCD) has been developed as a strategy to reduce the incidence of graft-versus-host disease (GVHD) after allogeneic (allo) hematopoietic stem cell transplantation (HSCT). Clinical characteristics, treatment responses, and outcomes of patients developing acute (aGVHD) and chronic GVHD (cGVHD) after TCD allo-HSCT have not been well established. We evaluated 241 consecutive patients (median age, 57 years) with acute leukemia (n = 191, 79%) or myelodysplastic syndrome (MDS) (n = 50, 21%) undergoing CD34⁺-selected TCD allo-HSCT without post-HCST immunosuppression in a single institution. Cumulative incidences of grades II-IV and III-IV aGVHD at 180 days were 16% (95% confidence interval [CI], 12 to 21) and 5% (95% CI, 3 to 9), respectively. The skin was the most frequent organ involved, followed by the gastrointestinal tract. Patients were treated with topical corticosteroids, poorly absorbed corticosteroids (budesonide), and/or systemic corticosteroids. The overall day 28 treatment response was high at 82%. The cumulative incidence of any cGVHD at 3 years was 5% (95% CI, 3 to 9), with a median time of onset of 256 days (range, 95 to 1645). The 3-year transplant-related mortality, relapse, overall survival, and disease-free survival were 24% (95% CI, 18 to 30), 22% (95% CI, 17 to 27), 57% (95% CI, 50 to 64), and 54% (95% CI, 47 to 61), respectively. The 1-year and 3-year probabilities of cGVHD-free/relapse-free survival were 65% (95% CI, 59 to 71) and 52% (95% CI, 45 to 59), respectively. Our findings support the use of ex vivo CD34⁺-selected TCD allograft as a calcineurin inhibitor-free intervention for the prevention of GVHD in patients with acute leukemia and MDS.

Novel targets in the treatment of chronic graft-versus-host disease

Despite advances that have improved survival after allogeneic hematopoietic stem cell transplantation (HCT), chronic graft-versus-host disease (GVHD) remains a leading cause of late morbidity and mortality after transplant. Current treatment options show limited efficacy in steroid-refractory disease, and there exists a paucity of robust data to guide management decisions. Lack of United States Food and Drug Administration (FDA)- or European Medicines Agency (EMA)-approved agents in GVHD underscore the importance of developing novel therapies. Better understanding of the biology of chronic GVHD has provided novel targets for treatment, and structured guidelines in diagnosis and in clinical trial design have provided a common language and pathways for research in this area. These, combined with the surge of drug development in Oncology and Immunology, are factors that have contributed to the accelerating field of drug development and clinical research in chronic GVHD. In these exciting times, it is possible to foresee long awaited advances in the treatment of this devastating complication of HCT. This review will summarize the ongoing clinical development for novel therapies in chronic GVHD.

Mechanistic approaches for the prevention and treatment of chronic GVHD

Clinical outcomes for patients undergoing allogeneic hematopoietic stem cell transplantation continue to improve, but chronic graft-versus-host disease (GVHD) remains a common toxicity and major cause of nonrelapse morbidity and mortality. Treatment of chronic GVHD has previously relied primarily on corticosteroids and other broadly immune suppressive agents. However, conventional immune suppressive agents have limited clinical efficacy in chronic GVHD, and prolonged immune suppressive treatments result in additional toxicities that further limit clinical recovery from transplant and return to normal daily function. Recent advances in our understanding of the immune pathology of chronic GVHD offer the possibility that new therapeutic approaches can be directed in more precise ways to target specific immunologic mechanisms and pathways. In this review, we briefly summarize current standard treatment options and present new therapeutic approaches that are supported by preclinical studies and early-phase clinical trials suggesting that these approaches may have clinical utility for treatment or prevention of chronic GVHD. Further evaluation of these new therapeutic options in well-designed prospective multicenter trials are needed to identify the most effective new agents and improve outcomes for patients with chronic GVHD.