Control of acute myeloid leukemia and generation of immune memory in vivo using AMV564, a bivalent bispecific CD33 x CD3 T cell engager.

Off-the-shelf immunotherapeutics that suppress tumor growth and provide durable protection against relapse could enhance cancer treatment. We report preclinical studies on a CD33 x CD3 bivalent bispecific diabody, AMV564, that not only suppresses tumor growth, but also facilitates memory responses in a mouse model of acute myelogenous leukemia (AML). Mechanistically, a single 5-day treatment with AMV564 seems to reduce tumor burden by redirection of T cells, providing a time window for allogeneic or other T cells that innately recognize tumor antigens to become activated and proliferate. When the concentration of bispecific becomes negligible, the effector: target ratio has also shifted, and these activated T cells mediate long-term tumor control. To test the efficacy of AMV564 in vivo, we generated a CD33+ MOLM13CG bioluminescent human cell line and optimized conditions needed to control these cells for 62 days in vivo in NSG mice. Of note, not only did MOLM13CG become undetectable by bioluminescence imaging in response to infusion of human T cells plus AMV564, but also NSG mice that had cleared the tumor also resisted rechallenge with MOLM13CG in spite of no additional AMV564 treatment. In these mice, we identified effector and effector memory human CD4+ and CD8+ T cells in the peripheral blood immediately prior to rechallenge that expanded significantly during the subsequent 18 days. In addition to the anti-tumor effects of AMV564 on the clearance of MOLM13CG cells in vivo, similar effects were seen when primary CD33+ human AML cells were engrafted in NSG mice even when the human T cells made up only 2% of the peripheral blood cells and AML cells made up 98%. These studies suggest that AMV564 is a novel and effective bispecific diabody for the targeting of CD33+ AML that may provide long-term survival advantages in the clinic.

Immune Adjuvant Therapy With Interleukin-7 in a Lymphopenic Patient With Aplastic Anemia and Mucormycosis.

BACKGROUND: We report the case of a patient with aplastic anemia and pancytopenia on immune-suppressive therapy who developed invasive pulmonary infection with mucormycosis and was treated with immune adjuvant therapy. CASE SUMMARY: Given the patient's profound lymphopenia and progressive invasive mucor despite dual antifungal drug therapy, interleukin (IL)-7, a cytokine that induces lymphocyte activation and proliferation, was instituted and resulted in normalization of absolute lymphocyte counts and was temporally associated with clearance of fungal pathogens and resolution of clinical symptoms. CONCLUSION: Patients with life-threatening fungal infections are frequently immune suppressed and immune adjuvant therapies should be considered in patients who are not responding to antifungal drugs and source control. Well-designed, double-blind, placebo-controlled trials are needed to advance the field. Although a number of immune adjuvants may be beneficial in fungal sepsis, IL-7 is a particularly attractive immune adjuvant because of its broad immunologic effects on key immunologic pathways that mediate enhanced antifungal immune system activity.

Bendamustine/Rituximab Plus Cytarabine/Rituximab, With or Without Acalabrutinib, for the Initial Treatment of Transplant-Eligible Mantle Cell Lymphoma Patients: Pooled Data From Two Pilot Studies.

INTRODUCTION: Mantle cell lymphoma (MCL) is a moderately aggressive lymphoma subtype, generally viewed as incurable. For younger, fit patients, the standard of care remains various high-dose cytarabine-based induction regimens followed by autologous hematopoietic cell transplant and 3 years of rituximab maintenance. Despite reasonably good outcomes, with median progression-free survival in the range of 7 to 9 years, most patients eventually relapse, indicating a need to improve the safety and tolerability of remission induction strategies. METHODS: Given the impressive activity of bendamustine/rituximab (BR) in older patients with MCL, we developed an induction regimen modeled after the Nordic Regimen but substituted BR in place of R-CHOP. In a second pilot study, we incorporated the second-generation Bruton tyrosine kinase inhibitor (BTKi), acalabrutinib, into the regimen. The primary endpoint of both studies was stem cell mobilization success rate. RESULTS: All patients successfully underwent stem cell harvest in both studies. CONCLUSION: The experience from our single institution pilot study suggested that sequential rather than alternating BR and cytarabine/rituximab (CR) was easier to administer from the standpoint of toxicities and subsequent dose modifications. Safety and efficacy data from the 2 pilot studies, FitMCL 1.0 and 2.0, were similar. The pilot studies provided preliminary safety data supporting the development of the NCTN trial EA4181, assessing three different induction regimens with or without acalabrutinib.

Acute Graft-versus-Host Disease: An Update on New Treatment Options.

Acute graft-versus-host disease (GVHD) occurs in approximately 50% of patients and remains a primary driver of non-relapse and transplant-related mortality. The best treatment remains prevention with either in vivo or ex vivo T-cell depletion, with multiple strategies used worldwide based on factors such as institution preference, ability to perform graft manipulation, and ongoing clinical trials. Predicting patients at high risk for developing severe acute GVHD based on clinical and biomarker-based criteria allows for escalation or potential de-escalation of therapy. Modern therapies for treatment of the disease include JAK/STAT pathway inhibitors, which are standard of care in the second-line setting and are being investigated for upfront management of non-severe risk based on biomarkers. Salvage therapies beyond the second-line remain suboptimal. In this review, we will focus on the most clinically used GVHD prevention and treatment strategies, including the accumulating data on JAK inhibitors in both settings.

Top advances in lymphoma for 2021.

Chimeric antigen receptor (CAR) T-cell therapy, antibody-drug conjugates, bispecific T-cell redirectors, and agents targeting tonic B-cell receptor signaling have altered the paradigm for three of the most common lymphomas in the year 2021. For diffuse large B-cell lymphoma, the POLARIX study has shown improvement on the standard backbone of rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone in the frontline setting, a feat that had not been achieved despite great efforts over the past 20 years. In the relapsed and refractory setting, two unique CAR T-cell products have displaced autologous transplantation to the third line, and they allow patients with chemotherapy-resistant disease to receive approved therapy earlier. CAR T-cell products, once used exclusively in the aggressive lymphoma arena, are now showing high response rates and durable activity against indolent lymphomas. The investigation of mosunetuzumab in indolent lymphomas offers another option for patients who have received multiple lines of cytotoxic drugs. On the basis of these trends, PI3K inhibitors are being displaced in favor of safer and more durable constructs. In addition, within the past year, the approval and implementation of zanubrutinib for marginal zone lymphoma have filled a need for later line therapy, especially for less fit and elderly patients.

Mouse models of graft-versus-host disease.

Transplantation of allogeneic hematopoietic stem and progenitor cells (allo-HCT) allows for cure of life-limiting malignant and non-malignant hematologic diseases. Crossing the human leukocyte antigen (HLA) barrier, however, comes at the cost of graft-versus-host disease (GVHD), a life-threatening syndrome mediated in part by the same donor T-lymphocytes that eliminate malignant cells. Acute GVHD occurs in the skin, gut, and/or liver in 25-55% of patients with a mortality rate of 15-40%, while chronic GVHD develops in 30-65% of patients who survive at least 3 months following allo-HCT and is highly debilitating in its extensive form, with a 30-50% 5year mortality rate stemming in part from immune dysregulation and opportunistic infections. Knowledge gaps remain in understanding the pathogenesis and in developing novel and effective treatments for the acute and chronic GVHD, which have distinct biology and yet are both treated with front line systemic corticosteroids. Novel and informative mouse models remain the primary means by which these diseases are studied and drugs initially developed prior to testing in humans. In this chapter, we describe allo-HCT mouse models and protocols using these mouse models by which to study acute and chronic GVHD with the goal of improving prevention and therapy.

Haploidentical bone marrow transplant with posttransplant cyclophosphamide for sickle cell disease: An update.

Hematopoietic cell transplant (HCT) can cure both children and adults with sickle cell disease. Outcomes have historically been poor for the vast majority of patients who lack a matched sibling donor. However, the development of haploidentical HCT (haplo-HCT) with high doses of posttransplant cyclophosphamide (PTCy) has allowed for curative long-term potential with favorable transplant-related outcomes, though this has not obviated the potential for graft rejection from human leukocyte antigen mismatch and repeated red blood cell transfusions. Accordingly, multiple strategies have been developed to improve outcomes, the majority of which are based on the Johns Hopkins platform from 2012. Presently, we aim to discuss results from pertinent studies and compare outcomes with the two most recent approaches involving either thiotepa plus 200-cGy total body irradiation or 400-cGy total body irradiation. Direct comparisons are required to determine the optimized curative potential. Transplant-eligible patients must be referred to tertiary medical centers for consideration of haplo-HCT.

Overcoming Proteasome Inhibitor-Refractory Multiple Myeloma With Elotuzumab, Bortezomib, Nelfinavir, and Dexamethasone.

Multiple myeloma is a common plasma cell malignancy with a median overall survival of fewer than 10 years. Proteasome inhibitors comprise an important part of the treatment regimen for this disease. The present study reports the case of a 57-year-old man who experienced a second relapse of multiple myeloma 6 years after initial treatment with bortezomib, lenalidomide, dexamethasone (VRD) followed by autologous hematopoietic cell transplant. The first relapse had been successfully treated with VRD, but this approach failed to control his second relapse. Given the lack of response to VRD therapy and relapse while on bortezomib maintenance, the patient was deemed proteasome inhibitor-refractory and received a new treatment of elotuzumab, lenalidomide, and dexamethasone. Four and a half cycles were completed before the treatment was stopped due to grade 4 cytopenias. The patient received a novel combination of elotuzumab, bortezomib, nelfinavir, and dexamethasone. After six cycles, the serum M-protein level was improved to 0.6 g/dL and the kappa light chains dropped from 3.49 to 1.04 mg/dL. A bone marrow biopsy conducted after five treatment cycles demonstrated < 1% plasma cells by immunohistochemistry and achievement of minimal residual disease status. Overall, this case study suggests that proteasome inhibitor-refractory multiple myeloma may be successfully re-treated with proteasome inhibitors when co-administered with nelfinavir.

Minimal residual disease negativity and lenalidomide maintenance therapy are associated with superior survival outcomes in multiple myeloma.

Modern combinations of therapies for multiple myeloma have led to improvement in survival outcomes with near 100% overall response rate and 25% complete response rates, particularly with autologous hematopoietic cell transplant (AHCT). Minimal residual disease (MRD) assessment with multiparameter flow cytometry is a valid prognostic biomarker for progression-free survival (PFS) and overall survival (OS). However, few data exist regarding whether MRD positivity or negativity will meaningfully influence treatment decisions. We evaluated 433 patients who received induction therapy, followed by AHCT. Participants had MRD assessment by multiparameter flow cytometry before and at days +100 and +365 following AHCT. They also received either lenalidomide, bortezomib, or no maintenance therapy following AHCT. Maintenance treatment with lenalidomide improved MRD negativity at day +365 compared to bortezomib (92.9% vs 41.6%, p = 0.01), or no maintenance therapy (92.9% vs 24.4%, p = 0.012). The median PFS for patients who were MRD negative at day + 365 was 42 vs 17.5 months (p < 0.001) and median OS was 80.6 vs 59 months (p = 0.02). Maintenance therapy following AHCT for multiple myeloma improves the depth of response as assessed by MRD.

Early viral reactivation despite excellent immune reconstitution following haploidentical Bone marrow transplant with post-transplant cytoxan for sickle cell disease.

BACKGROUND: Haploidentical bone marrow transplant (haplo-BMT) offers near universal donor availability as a curative modality for individuals with severe sickle cell disease (SCD). However, the required intense immunodepletion is associated with increased infectious complications. A paucity of data exists on immune reconstitution following haplo-BMT for SCD. METHODS: A multi-institution learning collaborative was developed in the context of a phase II clinical trial of a non-myeloablative, related haplo-BMT with post-transplant cyclophosphamide for SCD. We report results from a cohort of 23 patients for whom immune reconstitution data up to one year were available. RESULTS: Median age was 14.8 years. Out of 23, 18 participants received pre-conditioning with azathioprine, hydroxyurea, and hypertransfusions. 70% (16/23) of participants had multiple indications for haplo-BMT. We observed excellent immune reconstitution of CD4, CD8, CD19, and CD56 cellular subsets by 6 months post transplant. Engraftment rate and event-free survival in this cohort were 100% and 96%, respectively. 70% (16/23) of patients had at least one viral reactivation or infection, including CMV 35% (8/23), HHV-6 22% (5/23), and polyoma virus 17% (4/23), with no cases of post-transplant lymphoproliferative disease. CONCLUSION: Further prospective studies are needed to better characterize immune reconstitution and the immunologic basis for increased viral reactivation following haplo-BMT with post-transplant cyclophosphamide for SCD.

Implication of Rituximab Infusion Reactions on Clinical Outcomes in Patients With Diffuse Large B-cell Lymphoma: A Single Institution Experience.

BACKGROUND: The addition of the anti-CD20 monoclonal antibody rituximab to chemotherapy for diffuse large B-cell lymphoma (DLBCL) has led to improvements in progression-free survival and overall survival, although the exact mechanism of rituximab is not known. Rituximab administration often results in transient, non-life-threatening infusion reactions (IRs). We report a retrospective cohort of patients with DLBCL who received rituximab to determine the significance of IRs on clinical outcomes. PATIENTS AND METHODS: We identified and analyzed a retrospective cohort of 229 patients with DLBCL. They were stratified into 2 cohorts; those who did and did not have an IR. Univariate and multivariate analyses were performed to evaluate the prognostic significance of rituximab-related IRs relative to DLBCL subtype, International Prognostic Index score, c-Myc translocations or amplifications, chemotherapy regimen, and Ki-67 proliferative index. RESULTS: Baseline characteristics did not differ significantly between the 2 groups. Rituximab was included as initial treatment in all patients. Patients with an IR had a significantly higher overall survival (hazard ratio, 0.26; 95% confidence interval, 0.07-0.95) at 5 years. In addition, subgroup analysis showed a significantly higher progression-free survival in patients with the germinal center subtype of disease and c-Myc alterations who had a rituximab-related IR (log-rank P < .0001). CONCLUSIONS: The presence of a rituximab-related IR is associated with a better overall survival in patients with DLBCL. Although limited by the small sample size and retrospective nature, these results provide rationale for further investigation into the mechanism of action of rituximab in order to optimize the efficacy of CD20 monoclonal antibodies.

T-cell deplete versus T-cell replete haploidentical hematopoietic stem cell transplantation for sickle cell disease: where are we?

Introduction: Severe sickle cell disease is associated with progressive end-organ damage and early mortality in adults. While allogeneic hematopoietic cell transplant from a matched related donor is curative, the vast majority of patients do not have a compatible sibling. Accordingly, platforms using haploidentical donors have been developed, which provide near-universal availability. Areas covered: This review focuses on the two commonly used approaches for haploidentical hematopoietic transplants, namely T-cell deplete and T-cell replete, each of which is associated with unique benefits and drawbacks. The purpose of this paper is to facilitate individualized decision-making for patients and providers by reviewing the pros- and cons of these differing approaches. Expert opinion: Individuals with sickle cell disease eligible for a hematopoietic cell transplant can be considered based on recent results. Comparable outcomes are seen with T-cell deplete and T-cell replete approaches. The choice depends largely on institutional preference.

Haploidentical Stem Cell Transplantation With Post-Transplantation Cyclophosphamide for Aggressive Lymphomas: How Far Have We Come and Where Are We Going?

Haploidentical hematopoietic stem cell transplantation (haplo-HSCT) with post-transplant cyclophosphamide (PTCy) offers universal donor availability and can potentially cure relapsed or primary refractory Hodgkin lymphoma (HL) and non-Hodgkin lymphoma (NHL). However, a conditioning regimen intensity that balances the graft-versus-lymphoma (GvL) effect with regimen-related toxicities (RRTs) has not yet been optimized. Limited data exist on the management of relapse, which is common post-transplant. Few prospective or randomized control trials have been conducted on lymphoma patients undergoing haplo-HSCT. Therefore, the current review aims to summarize published retrospective data in the field to help guide clinical decision making for high-risk patients. Retrospective studies in the field are characterized by variability in patient population and sample sizes, eligibility criteria, number of prior treatments (e.g., chemotherapy, radiation therapy, and autologous transplant), graft source (bone marrow or peripheral blood), as well as choice and intensity of the conditioning regimen (non-myeloablative, reduced intensity, or myeloablative). Nonetheless, common themes that emerge from the literature include: 1) Enhanced donor availability and selection with haplo-HSCT with success in heterogeneous patient populations; 2) Outcomes that are comparable if not superior to matched related (MRD) or unrelated (MUD) donor transplants; 3) The benefit of PTCy for reducing incidence of relapse and chronic graft-versus-host disease (GvHD); 4) Presence of co-morbidities leading to poorer transplant-related outcomes; and 5) The need for novel approaches to address disease relapse, particularly for patients with active disease at the time of transplant. Excellent transplant-related outcomes with haplo-HSCT with PTCy have been seen for HL and NHL based on retrospective data. Further studies are needed to determine integration with advanced cellular therapy techniques, such as chimeric antigen receptor (CAR) T-cell, antibody drug conjugates, and checkpoint inhibitors. Graft manipulation may be another avenue for future research.

Neutrophil-to-lymphocyte ratio as a predictor of survival in patients with triple-negative breast cancer.

PURPOSE: Peripheral blood lymphopenia and elevated neutrophil-to-lymphocyte ratio (NLR) have been associated with poor outcomes in various malignancies. However, existing literature has largely focused on baseline parameters. The aim of this study is to assess the impact of radiation therapy (RT) and chemotherapy on absolute lymphocyte counts (ALC) and NLR in relation to survival outcomes in patients with triple-negative breast cancer (TNBC). METHODS: A retrospective analysis was performed on 126 patients with TNBC treated at Washington University between 2005 and 2010. Cox proportional hazard model with time-varying covariates was applied to estimate the effect of time-varying ALC and NLR separately on overall survival (OS) and disease-free survival (DFS). RESULTS: All patients received RT and 112 patients received either neoadjuvant chemotherapy or adjuvant chemotherapy, or both. Patients deceased had lower ALC and higher NLR compared to patients alive throughout the treatment course, even 1 year after treatment completion (ALC, 1 vs. 1.3, P = 0.03 and NLR, 3.9 vs. 2.6, P = 0.03). High ALC was associated with superior OS on both continuous and binary scales (cutoff of 1 K/ul) (HR 0.14; 95% CI 0.05-0.34; P < 0.001 and HR 0.28; 95% CI 0.13-0.61; P = 0.01, respectively). Additionally, high NLR was weakly associated with inferior OS on continuous scales (HR 1.1; 95% CI 1.06-1.15; P < 0.001). CONCLUSIONS: Post-treatment lymphopenia and NLR elevation can persist until 1 year after treatment completion. Both portend shorter survival for patients with TNBC. Our data support the use of ALC and NLR to identify high risk patients who may benefit from clinical trials rather than standard of care therapy.

Diagnostic and Therapeutic Strategies for Patients with Malignant Epidural Spinal Cord Compression.

OPINION STATEMENT: Malignant epidural spinal cord compression (MESCC) is an oncologic emergency with the potential for devastating consequences for patients if not promptly diagnosed and treated. MESCC is diagnosed by imaging. MRI is by far the most sensitive test, preferably with gadolinium. Once the diagnosis of MESCC is suspected, patients with neurologic deficits should receive prompt administration of dexamethasone with a 10-mg IV loading dose followed by 4 mg every 6 h. Quick taper is recommended once the definitive treatment is established. Consultation with medical oncology, radiation oncology, and neurosurgery is imperative in order to facilitate a multidisciplinary approach. Although spine surgery is the most effective method for relief of cord compression and is necessary if there is spinal instability, surgery is only used in selected patients because most patients have a poor overall condition and short life expectancy. Radiation therapy, therefore, is the most commonly used therapy for patients with MESCC after surgical decompression or in patients who are not surgical candidates. Conventional fractionated radiation alone can achieve modest neurologic outcomes in selected radiosensitive tumors. Radiosurgery techniques which deliver intense focal irradiation to a delimited area with imaging guidance and contoured radiation delivery to the shape of the tumor have recently emerged as increasing effective treatments in MESCC, especially in radioresistant tumors. Stereotactic radiosurgery and different radiation technologies have been studied in recent clinical trials.

Matrix metalloproteinase-7 and premalignant host responses in Helicobacter pylori-infected mice.

Helicobacter pylori-induced gastritis is the strongest singular risk factor for gastric adenocarcinoma. Matrix metalloproteinase-7 (MMP-7) is a proteolytic enzyme that can modify the intestinal microbial replicative niche as well as affect tumorigenesis, and H. pylori stimulates expression of MMP-7 in gastric epithelial cells in vitro. Utilizing a transgenic murine model of H. pylori-mediated injury, our experiments now show that gastric inflammation is increased within the context of MMP-7 deficiency, which involves both Th1- and Th17-mediated pathways. Enhanced gastritis in H. pylori-infected mmp-7-/- mice is strongly linked to accelerated epithelial cellular turnover. However, more severe inflammation and heightened proliferation and apoptosis are not dependent on MMP-7-mediated bacterial eradication. Collectively, these studies indicate that H. pylori-mediated induction of MMP-7 may serve to protect the gastric mucosa from pathophysiologic processes that promote carcinogenesis.