Microenvironment immune reconstitution patterns correlate with outcomes after autologous transplant in multiple myeloma

Immune status and selection of patients for immunotherapy in myeloma: a proposal

ABSTRACT

Newer immune-based approaches based on recruitment and redirection of endogenous and/or synthetic immunity such as chimeric antigen receptor T cells or bispecific antibodies are transforming the clinical management of multiple myeloma (MM). Contributions of the immune system to the antitumor effects of myeloma therapies are also increasingly appreciated. Clinical malignancy in MM originates in the setting of systemic immune alterations that begin early in myelomagenesis and regional changes in immunity affected by spatial contexture. Preexisting and therapy-induced changes in immune cells correlate with outcomes in patients with MM including after immune therapies. Here, we discuss insights from and limitations of available data about immune status and outcomes after immune therapies in patients with MM. Preexisting variation in systemic and/or regional immunity is emerging as a major determinant of the efficacy of current immune therapies as well as vaccines. However, MM is a multifocal malignancy. As with solid tumors, integrating spatial aspects of the tumor and consideration of immune targets with the biology of immune cells may be critical to optimizing the application of immune therapy, including T-cell redirection, in MM. We propose 5 distinct spatial immune types of MM that may provide an initial framework for the optimal application of specific immune therapies in MM: immune depleted, immune permissive, immune excluded, immune suppressed, and immune resistant. Such considerations may also help optimize rational patient selection for emerging immune therapies to improve outcomes.

Cellular immunity in the era of modern multiple myeloma therapy

Multiple myeloma (MM) is a relapsing clonal plasma cell malignancy and incurable thus far. With the increasing understanding of myeloma, highlighting the critical importance of the immune system in the pathogenesis of MM is essential. The immune changes in MM patients after treatment are associated with prognosis. In this review, we summarize currently available MM therapies and discuss how they affect cellular immunity. We find that the modern anti-MM treatments enhance antitumour immune responses. A deeper understanding of the therapeutic activity of individual drugs offers more effective treatment approaches that enhance the beneficial immunomodulatory effects. Furthermore, we show that the immune changes after treatment in MM patients can provide useful prognostic marker. Analysing cellular immune responses offers new perspectives for evaluating clinical data and making comprehensive predictions for applying novel therapies in MM patients.

Definers and drivers of functional high-risk multiple myeloma: insights from genomic, transcriptomic, and immune profiling

Traditional prognostic models for newly diagnosed patients with multiple myeloma (MM), including International Staging System criteria and number of high-risk chromosomal abnormalities, are based on disease characteristics at diagnosis. However, the identification of patients at risk of more rapidly progressive MM is inherently a dynamic assessment. In a subset of patients with MM, adverse disease biology only becomes evident after the failure of first-line therapy. We define this entity as functional high-risk MM (FHRMM), encompassing relapse within 18 months of treatment initiation and/or within 12 months of frontline autologous stem cell transplantation. FHRMM is not adequately captured by traditional prognostic models, and there is a need for better understanding of mechanisms or risk factors for early relapse or progression. In this review, we explore potential definitions of FHRMM before delving into its underlying drivers based on genetic, transcriptomic, and immune cell profiling studies. Emerging data suggest that specific features of both myeloma cells and immune cells can enable the FHRMM phenotype. We conclude our review by discussing ongoing and future studies that seek to identify and intervene upon patients with FHRMM preemptively.

High serum miR-223-3p expression level predicts complete response and prolonged overall survival in multiple myeloma patients undergoing autologous hematopoietic stem cell transplantation

Introduction

AHSCT is the treatment of choice for newly diagnosed patients with transplant-eligible multiple myeloma (MM). However, considerable variability in response to autologous hematopoietic stem cell transplantation (AHSCT) results in only 50% of patients achieving complete response (CR) after AHSCT, which is directly associated with improved progression-free and overall survival (OS). In this study, we aimed to investigate the potential predictive role of selected serum miRNAs in MM patients who underwent AHSCT.

Patients and methods

Serum expression level of 6 miRNAs: miR-221-3p, miR-15b-5p, miR-223-3p, miR-320c, miR-361-3p, and miR-150-5p was evaluated in 51 patients who underwent AHSCT. Blood samples were collected at two time points: before conditioning chemotherapy (T1) and fourteen days after transplant (+14) (T2).

Results

All selected miRNAs significantly changed their expression level across the procedure- two were up-regulated after AHSCT: hsa-miR-320c (FC 1.42, p<0.0001) and hsa-miR-361-3p (FC 1.35, p=0.0168); four were down-regulated: hsa-miR-15b-5p (FC 0.53, p<0.0001), hsa-miR-221-3p (FC 0.78, p=0.0004), hsa-miR-223-3p (FC 0.74, p=0.0015) and hsa-miR-150-5p (FC 0.75, p=0.0080). Notably, before AHSCT, hsa-miR-223-3p was down-regulated in International Staging System (ISS) III patients (FC=0.76, p=0.0155), and hsa-miR-320c was up-regulated (FC=1.27, p=0.0470). These differences became non-significant after AHSCT. Eight (15.69%) patients achieved CR before AHSCT and 17 patients (33.33%) at +100 days after AHSCT. In multivariate logistic regression analysis, achievement of CR after induction and hsa-miR-223-3p at T1 were independent predictors of CR after AHSCT. In multivariate Cox regression analysis, hsa-miR-223-3p at T1 expression level was associated with prolonged OS (HR 0.06, 95%CI: 0.00 - 0.99, p=0.0488).

Conclusion

Serum expression of has-miR-223-3p is a predictor of CR and prolonged OS in MM patients undergoing AHSCT.

The immunome of mobilized peripheral blood stem cells is predictive of long-term outcomes and therapy-related myeloid neoplasms in patients with multiple myeloma undergoing autologous stem cell transplant

Upfront autologous stem cell transplant (ASCT) is the standard of care for newly diagnosed multiple myeloma (MM) patients. However, relapse is ubiquitous and therapy-related myeloid neoplasms (t-MN) post-ASCT are commonly associated with poor outcomes. We hypothesized that the enrichment of abnormal myeloid progenitors and immune effector cells (IEC) in the peripheral blood stem cells (PBSCs) is associated with a higher risk of relapse and/or development of t-MN. We performed a comprehensive myeloid and lymphoid immunophenotyping on PBSCs from 54 patients with MM who underwent ASCT. Median progression-free (PFS), myeloid neoplasm-free (MNFS), and overall survival (OS) from ASCT were 49.6 months (95% CI: 39.5-Not Reached), 59.7 months (95% CI: 55-74), and 75.6 months (95% CI: 62-105), respectively. Abnormal expression of CD7 and HLA-DR on the myeloid progenitor cells was associated with an inferior PFS, MNFS, and OS. Similarly, enrichment of terminally differentiated (CD27/CD28-, CD57/KLRG1+) and exhausted (TIGIT/PD-1+) T-cells, and inhibitory NK-T like (CD159a+/CD56+) T-cells was associated with inferior PFS, MNFS, and OS post-transplant. Our observation of abnormal myeloid and IEC phenotype being present even before ASCT and maintenance therapy suggests an early predisposition to t-MN and inferior outcomes for MM, and has the potential to guide sequencing of future treatment modalities.

Immunophenotypic correlates of sustained MRD negativity in patients with multiple myeloma

The role of the immune microenvironment in maintaining disease remission in patients with multiple myeloma (MM) is not well understood. In this study, we comprehensively profile the immune system in patients with newly diagnosed MM receiving continuous lenalidomide maintenance therapy with the aim of discovering correlates of long-term treatment response. Leveraging single-cell RNA sequencing and T cell receptor β sequencing of the peripheral blood and CyTOF mass cytometry of the bone marrow, we longitudinally characterize the immune landscape in 23 patients before and one year after lenalidomide exposure. We compare patients achieving sustained minimal residual disease (MRD) negativity to patients who never achieved or were unable to maintain MRD negativity. We observe that the composition of the immune microenvironment in both the blood and the marrow varied substantially according to both MRD negative status and history of autologous stem cell transplant, supporting the hypothesis that the immune microenvironment influences the depth and duration of treatment response.

Hemophagocytic lymphohistiocytosis after autologous stem cell transplantation in angioimmunoblastic T-cell lymphoma: A case report

BACKGROUND

Angioimmunoblastic T-cell lymphoma (AITL), a unique subtype of peripheral T-cell lymphoma, has relatively poor outcomes. High-dose chemotherapy with autologous stem cell transplantation (ASCT) can achieve complete remission and improve outcomes. Unfortunately, subsequent T-cell lymphoma-triggered hemophagocytic lymphohistiocytosis (HLH) has a worse prognosis than B-cell lymphoma-triggered HLH.

CASE SUMMARY

We here report a 50-year-old woman with AITL who achieved a favorable outcome after developing HLH 2 mo after receiving high-dose chemotherapy/ ASCT. The patient was initially admitted to our hospital because of multiple enlarged lymph nodes. The final pathologic diagnosis, made on biopsy of a left axillary lymph node was AITL (Stage IV, Group A). Four cycles of the following chemotherapy regimen were administered: Cyclophosphamide 1.3 g, doxorubicin 86 mg, and vincristine 2 mg on day 1; prednisone 100 mg on days 1-5; and lenalidomide 25 mg on days 1-14. The interval between each cycle was 21 d. The patient received a conditioning regimen (busulfan, cyclophosphamide, and etoposide) followed by peripheral blood stem cell infusion. Unfortunately, she developed sustained fever and a low platelet count 17 d after ACST, leading to a diagnosis of HLH after ASCT. During treatment, she experienced thrombocytopenia and Pneumocystis carinii pneumonia. The patient was successfully treated with etoposide and glucocorticoids.

CONCLUSION

It is possible that development of HLH is related to immune reconstitution after ASCT.

Tracking the evolution of therapy-related myeloid neoplasms using chemotherapy signatures

Patients treated with cytotoxic therapies, including autologous stem cell transplantation, are at risk for developing therapy-related myeloid neoplasms (tMN). Preleukemic clones (ie, clonal hematopoiesis [CH]) are detectable years before the development of these aggressive malignancies, although the genomic events leading to transformation and expansion are not well defined. Here, by leveraging distinctive chemotherapy-associated mutational signatures from whole-genome sequencing data and targeted sequencing of prechemotherapy samples, we reconstructed the evolutionary life-history of 39 therapy-related myeloid malignancies. A dichotomy was revealed, in which neoplasms with evidence of chemotherapy-induced mutagenesis from platinum and melphalan were hypermutated and enriched for complex structural variants (ie, chromothripsis), whereas neoplasms with nonmutagenic chemotherapy exposures were genomically similar to de novo acute myeloid leukemia. Using chemotherapy-associated mutational signatures as temporal barcodes linked to discrete clinical exposure in each patient's life, we estimated that several complex events and genomic drivers were acquired after chemotherapy was administered. For patients with prior multiple myeloma who were treated with high-dose melphalan and autologous stem cell transplantation, we demonstrate that tMN can develop from either a reinfused CH clone that escapes melphalan exposure and is selected after reinfusion, or from TP53-mutant CH that survives direct myeloablative conditioning and acquires melphalan-induced DNA damage. Overall, we revealed a novel mode of tMN progression that is not reliant on direct mutagenesis or even exposure to chemotherapy. Conversely, for tMN that evolve under the influence of chemotherapy-induced mutagenesis, distinct chemotherapies not only select preexisting CH but also promote the acquisition of recurrent genomic drivers.

Deep Immune Profiling of Multiple Myeloma at Diagnosis and under Lenalidomide Maintenance Therapy

The bone marrow microenvironment interacts with malignant cells and regulates cancer survival and immune evasion in multiple myeloma (MM). We investigated the immune profiles of longitudinal bone marrow samples from patients with newly diagnosed MM (n = 18) using cytometry by time-of-flight. The results before and during treatment were compared between patients with good (GR, n = 11) and bad (BR, n = 7) responses to lenalidomide/bortezomib/dexamethasone-based treatment. Before treatment, the GR group had a lower tumor cell burden and a higher number of T cells with a phenotype shifted toward CD8+ T cells expressing markers attributed to cytotoxicity (CD45RA and CD57), a higher abundance of CD8+ terminal effector cells, and a lower abundance of CD8+ naïve T cells. On natural killer (NK) cells, increased expression of CD56 (NCAM), CD57, and CD16 was seen at baseline in the GR group, indicating their maturation and cytotoxic potential. During lenalidomide-based treatment, the GR patients showed an increase in effector memory CD4+ and CD8+ T-cell subsets. These findings support distinct immune patterns in different clinical contexts, suggesting that deep immune profiling could be used for treatment guidance and warrants further exploration.

Immune dysregulation in multiple myeloma: the current and future role of cell-based immunotherapy

Immune dysregulation is a hallmark of clinically active multiple myeloma (MM). Interactions between malignant clonal cells and immune cells within the bone marrow microenvironment are associated with the formation of a milieu favorable to tumor progression. IL-10, TGF-β and other immunoregulatory pathways are upregulated, promoting angiogenesis, tumor cell survival and inhibition of the native immune response. Transcriptomic evaluation of the bone marrow microenvironment reveals polarization of the T cell repertoire towards exhaustion and predominance of accessory cells with immunosuppressive qualities. These changes facilitate the immune escape of tumor cells and functional deficiencies that manifest as an increased risk of infection and a reduction in response to vaccinations. Immunotherapy with Chimeric Antigen Receptor (CAR) T cells and other cellular-based approaches have transformed outcomes for patients with advanced MM. Characterization of the immune milieu and identification of biomarkers predictive of treatment response are essential to increasing durability and allowing for the incorporation of novel strategies such as cancer vaccines. This paper will review the current use of cancer vaccines and CAR T cell therapy in MM as well as potential opportunities to expand and improve the application of these platforms.

Immune Reconstitution and Vaccinations in Multiple Myeloma: A Report From the 19th International Myeloma Society Annual Workshop

Given the significance of the immune system and the important role of therapies within the context of the immune system in plasma cell disorders, the International Myeloma Society annual workshop convened a session dedicated to this topic. A panel of experts covered various aspects of immune reconstitution and vaccination. The top oral presentations were highlighted and discussed. This is a report of the proceedings.

The immune system in multiple myeloma and precursor states: Lessons and implications for immunotherapy and interception

Multiple myeloma (MM) and its precursor monoclonal gammopathy of undetermined significance (MGUS) are distinct disorders that likely originate in the setting of chronic immune activation. Evolution of these lesions is impacted by cross-talk with both innate and adaptive immune systems of the host. Harnessing the immune system may, therefore, be an attractive strategy to prevent clinical malignancy. While clinical MM is characterized by both regional and systemic immune suppression and paresis, immune-based approaches, particularly redirecting T cells have shown remarkable efficacy in MM patients. Optimal application and sequencing of these new immune therapies and their integration into clinical MM management may depend on the underlying immune status, in turn impacted by host, tumor, and environmental features. Immune therapies carry the potential to achieve durable unmaintained responses and cures in MM.

Therapy-selected clonal hematopoiesis and its role in myeloid neoplasms

Therapy-related myeloid neoplasms (t-MN) account for approximately 10-15% of all myeloid neoplasms and are associated with poor prognosis. Genomic characterization of t-MN to date has been limited in comparison to the considerable sequencing efforts performed for de novo myeloid neoplasms. Until recently, targeted deep sequencing (TDS) or whole exome sequencing (WES) have been the primary technologies utilized and thus limited the ability to explore the landscape of structural variants and mutational signatures. In the past decade, population-level studies have identified clonal hematopoiesis as a risk factor for the development of myeloid neoplasms. However, emerging research on clonal hematopoiesis as a risk factor for developing t-MN is evolving, and much is unknown about the progression of CH to t-MN. In this work, we will review the current knowledge of the genomic landscape of t-MN, discuss background knowledge of clonal hematopoiesis gained from studies of de novo myeloid neoplasms, and examine the recent literature studying the role of therapeutic selection of CH and its evolution under the effects of antineoplastic therapy. Finally, we will discuss the potential implications on current clinical practice and the areas of focus needed for future research into therapy-selected clonal hematopoiesis in myeloid neoplasms.

Blasts in context: the impact of the immune environment on acute myeloid leukemia prognosis and treatment

Acute myeloid leukemia (AML) is a cancer that originates from the bone marrow (BM). Under physiological conditions, the bone marrow supports the homeostasis of immune cells and hosts memory lymphoid cells. In this review, we summarize our present understanding of the role of the immune microenvironment on healthy bone marrow and on the development of AML, with a focus on T cells and other lymphoid cells. The types and function of different immune cells involved in the AML microenvironment as well as their putative role in the onset of disease and response to treatment are presented. We also describe how the immune context predicts the response to immunotherapy in AML and how these therapies modulate the immune status of the bone marrow. Finally, we focus on allogeneic stem cell transplantation and summarize the current understanding of the immune environment in the post-transplant bone marrow, the factors associated with immune escape and relevant strategies to prevent and treat relapse.

Anti-CD19 and anti-BCMA CAR T cell therapy followed by lenalidomide maintenance after autologous stem-cell transplantation for high-risk newly diagnosed multiple myeloma

Few prospective studies have examined posttransplant chimeric antigen receptor (CAR) T cell infusion as candidates for front-line consolidation therapy for high-risk multiple myeloma (MM) patients. This single-arm exploratory clinical trial is the first to evaluate the safety and efficacy of sequential anti-CD19 and anti-BCMA CAR-T cell infusion, followed by lenalidomide maintenance after autologous stem cell transplantation (ASCT), in 10 high-risk newly diagnosed multiple myeloma (NDMM) patients. The treatment was generally well tolerated, with hematologic toxicities being the most common grade 3 or higher adverse events. All patients had cytokine release syndrome (CRS), which was grade 1 in 5 patients (50%) and grade 2 in 5 patients (50%). No neurotoxicity was observed after CAR-T cell infusion. The overall response rate was 100%, with the best response being 90% for a stringent complete response (sCR), and 10% for a complete response (CR). At a median follow-up of 42 (36-49) months, seven (70%) of 10 patients showed sustained minimal residual disease (MRD) negativity for more than 2 years. The median progression-free survival (PFS) and overall survival (OS) were not reached. Although the sample size was small and there was a lack of control in this single-arm study, the clinical benefits observed warrant ongoing randomized controlled trials.

Langerhans dendritic cell vaccines bearing mRNA-encoded tumor antigens induce anti-myeloma immunity after autotransplant

Triple antigen–bearing mRNA-electroporated autologous LC vaccines after ASCT for MM are safe and immunogenic.

Posttransplant vaccination targeting residual disease is an immunotherapeutic strategy to improve antigen-specific immune responses and prolong disease-free survival after autologous stem cell transplantation (ASCT) for multiple myeloma (MM). We conducted a phase 1 vaccine trial to determine the safety, toxicity, and immunogenicity of autologous Langerhans-type dendritic cells (LCs) electroporated with CT7, MAGE-A3, and Wilms tumor 1 (WT1) messenger RNA (mRNA), after ASCT for MM. Ten patients received a priming immunization plus 2 boosters at 12, 30, and 90 days, respectively, after ASCT. Vaccines contained 9 × 10⁶ mRNA-electroporated LCs. Ten additional patients did not receive LC vaccines but otherwise underwent identical ASCT and supportive care. At 3 months after ASCT, all patients started lenalidomide maintenance therapy. Vaccinated patients developed mild local delayed-type hypersensitivity reactions after booster vaccines, but no toxicities exceeded grade 1. At 1 and 3 months after vaccines, antigen-specific CD4 and CD8 T cells increased secretion of proinflammatory cytokines (interferon-γ, interleukin-2, and tumor necrosis factor-α) above prevaccine levels, and also upregulated the cytotoxicity marker CD107a. CD4 and CD8 T-cell repertoire analysis showed a trend for increased clonal expansion in the vaccine cohort, which was more pronounced in the CD4 compartment. Although not powered to assess clinical efficacy, treatment responses favored the vaccine arm. Triple antigen–bearing mRNA-electroporated autologous LC vaccination initiated at engraftment after ASCT, in conjunction with standard lenalidomide maintenance therapy for MM, is safe and induces antigen-specific immune reactivity. This trial was registered at www.clinicaltrials.gov as #NCT01995708.

Novel Cell and Immune Engagers in Optimizing Tumor- Specific Immunity Post-Autologous Transplantation in Multiple Myeloma

Autologous stem cell transplantation (ASCT) is an important component of treatment of multiple myeloma (MM). The post-ASCT setting offers a unique opportunity to increase myeloma specific immunity through enhancement of T and NK cell responses. The vast array of therapeutics being developed for MM, including cell-based therapies, dendritic vaccines, bispecific antibodies, and IL-15 agonists, provide the opportunity to increase tumor-specific immunity. Maintenance therapies, including immunomodulatory drugs, proteasome inhibitors, and daratumumab, exhibit a significant anti-myeloma response by modulating the immune system. Lenalidomide promotes an antitumoral immune microenvironment, whereas daratumumab can potentially cause NK cell fratricide. Thus, understanding the effects of commonly used maintenance drugs on the immune system is important. In this review, we look at current and emerging therapeutics and their integration post-ASCT in the context of immune reconstitution to improve clinical responses in patients with MM. © 2021 American Society for Transplantation and Cellular Therapy. Published by Elsevier Inc.

The 2020 BMT CTN Myeloma Intergroup Workshop on Immune Profiling and Minimal Residual Disease Testing in Multiple Myeloma

The fifth annual Blood and Marrow Transplant Clinical Trials Network Myeloma Intergroup Workshop on Immune Profiling and Minimal Residual Disease Testing in Multiple Myeloma was conducted as one of the American Society of Hematology Annual Meeting Scientific Workshops on Thursday December 3, 2020. This workshop focused on four main topics: (1) integrating minimal residual disease into clinical trial design and practice; (2) the molecular and immunobiology of disease evolution and progression in myeloma; (3) adaptation of next-generation sequencing, next-generation flow cytometry, and cytometry by time of flight techniques; and (4) chimeric antigen receptor T-cell and other cellular therapies for myeloma. In this report, we provide a summary of the workshop presentations and discuss future directions in the field.

Treatment Strategy for Multiple Myeloma to Improve Immunological Environment and Maintain MRD Negativity

Improving the immunological environment and eradicating minimal residual disease (MRD) are the two main treatment goals for long-term survival in patients with multiple myeloma (MM). Immunomodulatory drugs (IMiDs), monoclonal antibody drugs (MoAbs), and autologous grafts for autologous stem cell transplantation (ASCT) can improve the immunological microenvironment. ASCT, MoAbs, and proteasome inhibitors (PIs) may be important for the achievement of MRD negativity. An improved immunological environment may be useful for maintaining MRD negativity, although the specific treatment for persistent MRD negativity is unknown. However, whether the ongoing treatment should be continued or changed if the MRD status remains positive is controversial. In this case, genetic, immunophenotypic, and clinical analysis of residual myeloma cells may be necessary to select the effective treatment for the residual myeloma cells. The purpose of this review is to discuss the MM treatment strategy to "cure MM" based on currently available therapies, including IMiDs, PIs, MoAbs, and ASCT, and expected immunotherapies, such as chimeric antigen receptor T cell (CAR-T) therapy, via improvement of the immunological environment and maintenance of MRD negativity.

Treatment Induced Cytotoxic T-Cell Modulation in Multiple Myeloma Patients

The biology of plasma cell dyscrasias (PCD) involves both genetic and immune-related factors. Since genetic lesions are necessary but not sufficient for Multiple Myeloma (MM) evolution, several authors hypothesized that immune dysfunction involving both B and T cell counterparts plays a key role in the pathogenesis of the disease. The aim of this study is to evaluate the impact of cornerstone treatments for Multiple Myeloma into immune system shaping. A large series of 976 bone marrow samples from 735 patients affected by PCD was studied by flow analysis to identify discrete immune subsets. Treated MM samples displayed a reduction of CD4+ cells (p<0.0001) and an increase of CD8+ (p<0.0001), CD8+/DR+ (p<0.0001) and CD3+/CD57+ (p<0.0001) cells. Although these findings were to some extent demonstrated also following bortezomib treatment, a more pronounced cytotoxic polarization was shown after exposure to autologous stem cell transplantation (ASCT) and Lenalidomide (Len) treatment. As a matter of fact, samples of patients who received ASCT (n=110) and Len (n=118) were characterized, towards untreated patients (n=138 and n=130, respectively), by higher levels of CD8+ (p<0.0001 and p<0.0001, respectively), CD8+/DR+ (p=0.0252 and p=0.0001, respectively) and CD3+/CD57+ cells (p<0.0001 and p=0.0006, respectively) and lower levels of CD4+ lymphocytes (p<0.0001 and p=0.0005, respectively). We demonstrated that active MM patients are characterized by a relevant T cell modulation and that most of these changes are therapy-related. Current Myeloma treatments, notably ASCT and Len treatments, polarize immune system towards a dominant cytotoxic response, likely contributing to the anti-Myeloma effect of these regimens.