Response In Multiple Myeloma Patients Research Articles

Heavy-light chain pairs as an alternative method to monitor isatuximab-based treatment responses in multiple myeloma patients

Heavy-light chain pairs as an alternative method to monitor isatuximab-based treatment responses in multiple myeloma patients

Abstract 3617: Expansion and persistence of anti-BCMA CAR T cells correlates with durability of responses in multiple myeloma patients

Abstract Background: Chimeric antigen receptor (CAR) T cells targeting B-cell maturation antigen (BCMA) can induce >70% response rates in patients with relapsed/refractory multiple myeloma (RRMM). However, most patients ultimately relapse. There are two FDA-approved CAR T products: ciltacabtagene autoleucel (cilta-cel) and idecabtagene vicleucel (ide-cel), the former having much more durable responses. The mechanisms that mediate more durable responses with these CAR T cells is unknown. Previous studies have shown that specific cell states in the apheresis and infusion products are associated with long-term efficacy of anti-BCMA CAR therapy in MM and the relationship between durability of response and CAR T cell persistence remains unclear. Methods: We analyzed serial bone marrow and PBMC samples from 20 MM patients who received BCMA CAR T therapy, including cilta-cel, ide-cel, and JCARH125. Flow cytometry and single-cell RNAseq were used to evaluate the features of CAR T cells that are associated with durable clinical responses. Results: While CAR T cells were detectable but variable among patients at 1-month post infusion, the frequency of CAR T cells in bone marrow at 1-month post-infusion is positively correlated with progression free survival (PFS) in all MM patients (p=0.009). This association was also evident in patients just treated with cilta-cel (p= 0.008). By 6 months, CAR T cells could still be detected by high-throughput flowcytometry in the cilta-cel-treated patients, but CAR T cells were not detectable in most of the patients receiving the other 2 products. Cilta-cel CAR T cells predominantly possessed an effector-like surface phenotype at 1-moth post infusion in both CD8+ and CD4+ compartments in bone marrow. These CAR T cells shifted to effector memory and central memory T cell states by 6 months, respectively. For ide-cel and JCARH125, patients with more durable responses (>6mos) there was a significantly higher proportion of CAR T cells with CD8+ effector memory-like state at 1-month post infusion. Conclusions: Our data demonstrate that distinct anti-BCMA CAR T cell treatments lead to very different cellular outcomes: Cilta-cel CAR T cell treatment leads to greater expansion and persistence compared to other anti-BCMA CAR T cells. Cilta-cel CAR T cells also shift from the initial effector state to a memory phenotype. These results provide insights into features of more efficacious anti-BCMA CAR T cells that can help guide the future development of more durable treatments for MM. Citation Format: Kai Wu, Karen Law, Guy Ledergor, Chang Liu, Zenghua Fan, Vibha Gurunathan, Averey Lea, Matthew Clark, Serena Kwek, Alexander Cheung, Jeffrey Wolf, Ajai Chari, Anupuma Kumar, Justin Eyquem, Thomas Martin, Lawrence Fong. Expansion and persistence of anti-BCMA CAR T cells correlates with durability of responses in multiple myeloma patients [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3617.

PYGO2-MDR1 Axis in Multiple Myeloma Patients with 1q21 Amplification As Promising Target to Overcome Carfilzomib Resistance

Multiple myeloma (MM) is a hematological malignancy characterized by an accumulation of clonal plasma cells (PCs) in the bone marrow (BM). Gain and/or amplification of 1q21 (1q21+) is one of the most frequent secondary cytogenetic abnormalities present in MM patients and in smoldering MM (SMM). The incidence and copy number alteration (CNA) of the 1q21 region increase during the progression and relapse of the disease; in fact, additional copies of 1q21 can be detected in around 40% of newly diagnosed MM (NDMM) and 70% of relapse-refractory MM (RRMM). Recently, 1q21+ has been identified as an adverse prognostic factor in MM patients and its presence has been correlated with a shorter duration of the response in MM patients treated with carfilzomib (CFZ)-based regimens. Thus, the identification of possible target genes in 1q21 region is an emerging unmet medical need in MM patients. PYGOPUS2 (PYGO2) is a gene located in the 1q21 chromosomal region and it is a downstream target of β-catenin, and it has been shown to promote the transcription of gene target of the Wnt-signaling, forming a nuclear complex with β-catenin/BCL9. Different studies have reported that upregulation of PYGO2 is involved in tumorigenesis in breast and lung cancers, showing that overexpression of PYGO2 leads to drug resistance by promoting the activation of the multidrug resistance 1 polypeptide ( MDR1). The expression profile of PYGO2 in1q21+ MM patients and its possible role in CFZ resistance is still unknown and have been investigated in this study. Firstly, we purified CD138 + PCs from BM samples from 18 NDMM and from 11 SMM patients. Fluorescent in situ hybridization (FISH) analysis was performed on purified CD138 + PCs for all patients to access CNA in the region 1q21. A score indicating the number of 1q21 copies was calculated based on the FISH hybridization pattern of each patient. 14/29 (48%) patients presented CNA in the 1q21 region. The expression profile of all 29 samples was generated using GeneChip ClariomD Arrays (Affymetrix Inc., Santa Clara, CA, USA) . The sam package was used to identify differentially expressed genes between 1q21+ and control samples. Our analysis identified PYGO2 to be significantly upregulated in patients with 1q21+ when compared with controls (p= 0.0008). Additionally, we found a positive correlation between gene expression and the 1q21 copy number (p= <0.0001, r= 0.6738). Secondly, we evaluated PYGO2 mRNA expression levels in several human myeloma cell lines (HMCLs) with 1q21 CNA. Our results showed that PYGO2 is overexpressed in HMCLs with 1q21 CNA. Previous studies in solid tumor have shown that PYGO2 is upregulated in drug resistant cancer cells, and this upregulation results in overexpression of MDR1; indeed, we evaluated the mRNA expression of PYGO2 in CFZ-resistant HMCLs. Interestingly our results showed that both PYGO2 and MDR1 expression are upregulated in CFZ-R cells. We next examined the relationship between PYGO2 and MDR1. We generated a PYGO2-knockdown in JJN3 MM cell line using short hairpin RNA (shRNA) lentivectors. Knockdown of PYGO2 resulted in a significant decrease in expression PYGO2, a decrease in cell viability, and a reduction in MDR1 expression. In conclusion, our results show that PYGO2 expression is significantly upregulated in MM patients carrying 1q21+ and that its expression is correlated with 1q21 copy number. Moreover, we found that the PYGO2-MDR1 axis is involved in the CFZ resistance in HMCLs MM cells suggesting that PYGO2 could be a possible future druggable target in 1q21+ MM patients.

Deep Characterization of Immune Dysfunction in Patients with Multiple Myeloma (MM) and Identification of Cellular Biomarkers for Tailored Vaccination Strategies

Background: Infection is the leading cause of death in MM. However, the extent of immune dysfunction compared to other B-cell lymphoproliferative disorders (B-CLPD) and healthy adults remains poorly studied. Greater knowledge is needed for tailored vaccination strategies and to improve outcomes upon new pathogens or breakthrough infections. Aim: Generate an atlas of the basal immune status and its response to vaccination in MM vs B-CLPD patients and age-matched health care practitioners (HCP), using the COVID-19 mRNA vaccines as a case study. Methods: A total of 1,099 blood and serum samples were collected from 177 individuals: 28 MM, 53 B-CLPD and 96 HCP older than 50. They were studied before COVID-19 mRNA vaccination, at days 7 and 14 after the first dose, at days 7 and 62 after the second dose, as well as before and at day 17 after the booster. Immune profiling was performed using multidimensional and computational flow cytometry that systematically analyzed 56 immune cell types per sample and time point: 17 B, 30 T, 6 antigen-presenting cell (APC) and 3 granulocytic subsets. Serum levels of IgM, IgG and IgA against the receptor-binding domain (RBD) of the spike (S) glycoprotein, S glycoprotein, nucleocapsid (N) and main protease were quantified using a multiplex-microsphere-based flow cytometry assay. SARS-CoV-2-specific CD8 T cells were quantified using a dextramer panel of S, N, membrane, and ORF3 proteins. Results: When compared to HCP and/or B-CLPD, MM patients showed abnormal distribution of 17/17 B, 22/30 T, 4/6 APC and 1/3 granulocytic cell subsets prior to vaccination. The most deviated cell types in MM were naïve CD21+ B-cells, naïve CD4 T-cells, PD1- and PD1+CD127low effector memory (EM) CD8 T cells, classical monocytes and neutrophils. The B cell compartment of MM patients showed impaired response to COVID-19 mRNA vaccination. While B-CLPD patients and HCP displayed significant expansions of naïve CD21-, IgM+IgD+CD27+CD21-, IgG+CD27-CD21-, and IgG+CD27+CD21- B-cell subsets, as well as of IgA+ circulating plasma cells, such expansions were not observed in MM patients. Accordingly, anti-RBD IgM, IgA and IgG titers were significantly reduced in MM compared to B-CLPD and HCP after the second dose ( P ≤.002). Importantly, the booster increased anti-RBD IgG levels in HCP (20,184 to 186,629 IU/mL, P <.001) but not in MM (1,991 to 5,998 IU/mL, P =.14) and B-CLPD (33,548 to 41,288 IU/mL, P =.19) patients. The immune response of the T-cell compartment was also altered in MM patients. The significant expansion of CD127lowPD1+ and CD127+CD25+ EM CD4, naïve CD4 and CD127lowPD1+ EM CD8 subsets observed in HCP was unnoted in MM and B-CLPD patients. Accordingly, the percentage of virus-specific CD8 T cells after the second dose did not increase in MM and B-CLPD patients. The booster increased virus-specific CD8 T cells in HCP (0.08 to 0.14%, P =.02), but not in MM (0.08 to 0.09%, P =.94) and B-CLPD (0.23 to 0.16%, P =.85). Furthermore, the booster induced virus-specific CD8 T cell differentiation into an EM phenotype in HCP but not in MM and B-CLPD patients. In addition to the dysfunctional B and T cell response to vaccination, MM patients showed abnormal kinetics of APC such as intermediateclassical and non-classical SLAN- and SLAN+ monocytes, as well as of granulocytic subsets such as basophils and neutrophils. Based on differences in immune-cell distribution using HCP as a reference, we calculated an immune dysregulation longitudinal cumulative score in each individual that included 48,496 immune parameters. Compared with HCP, up to 34% MM and 17% B-CLPD patients showed high immune dysregulation scores. Among them, 75% and 33%, respectively, had low seroconversion after the second dose. We found 7/30 T and 14/17 B-cell subsets associated with poor vaccine response in MM patients, namely CD127lowPD1+CXCR5+ EM CD8 T cells, as well as CD21- and CD21+ naïve, transitional, IgM+IgD+CD27+CD21+, IgM+CD27-CD21+, and IgG+CD27-CD21+ B cells. Conclusion: We provide an atlas of the immune dysfunction in MM patients and how it affects the efficacy of vaccination strategies such as for COVID-19. The schedule of vaccine doses may thus benefit from individualization according to patients' immune status, which could act as a surrogate of host, tumor and treatment-related immune dysfunction. Accordingly, we have identified key cell types for readily monitoring of patients' immune status using routinely available flow cytometry.

P-398 Dynamic immune response in multiple myeloma patients infected with SARS-CoV-2 omicron BA.4/5 subvariant in China

P-398 Dynamic immune response in multiple myeloma patients infected with SARS-CoV-2 omicron BA.4/5 subvariant in China

The CAR-HEMATOTOX score as a prognostic model of toxicity and response in patients receiving BCMA-directed CAR-T for relapsed/refractory multiple myeloma

BackgroundBCMA-directed CAR T-cell therapy (CAR-T) has altered the treatment landscape of relapsed/refractory (r/r) multiple myeloma, but is hampered by unique side effects that can lengthen hospital stays and increase morbidity. Hematological toxicity (e.g. profound and prolonged cytopenias) represents the most common grade ≥ 3 toxicity and can predispose for severe infectious complications. Here, we examined the utility of the CAR-HEMATOTOX (HT) score to predict toxicity and survival outcomes in patients receiving standard-of-care idecabtagene vicleucel and ciltacabtagene autoleucel.MethodsData were retrospectively collected from 113 r/r multiple myeloma patients treated between April 2021 and July 2022 across six international CAR-T centers. The HT score—composed of factors related to hematopoietic reserve and baseline inflammatory state—was determined prior to lymphodepleting chemotherapy.ResultsAt lymphodepletion, 63 patients were HTlow (score 0–1) and 50 patients were HThigh (score ≥ 2). Compared to their HTlow counterparts, HThigh patients displayed prolonged severe neutropenia (median 9 vs. 3 days, p < 0.001), an increased severe infection rate (40% vs. 5%, p < 0.001), and more severe ICANS (grade ≥ 3: 16% vs. 0%, p < 0.001). One-year non-relapse mortality was higher in the HThigh group (13% vs. 2%, p = 0.019) and was predominantly attributable to fatal infections. Response rates according to IMWG criteria were higher in HTlow patients (≥ VGPR: 70% vs. 44%, p = 0.01). Conversely, HThigh patients exhibited inferior progression-free (median 5 vs. 15 months, p < 0.001) and overall survival (median 10.5 months vs. not reached, p < 0.001).ConclusionsThese data highlight the prognostic utility of the CAR-HEMATOTOX score for both toxicity and treatment response in multiple myeloma patients receiving BCMA-directed CAR-T. The score may guide toxicity management (e.g. anti-infective prophylaxis, early G-CSF, stem cell boost) and help to identify suitable CAR-T candidates.

Clinical Features and Risk Stratification of Multiple Myeloma Patients with COVID-19.

SARS-CoV-2 infection often results in a more severe COVID-19 disease course in multiple myeloma (MM) patients compared to immunocompetent individuals. The aim of this report is to summarize the clinical features of the MM patients with COVID-19 and the impact of MM treatment on outcomes to guide risk stratification and ensure the appropriate management of the patients. Serological responses in MM patients post-infection or -vaccination are also reviewed to better understand the strategy of prevention. Along with reports from the literature, we presented findings from a retrospective analysis of the clinical characteristics and outcomes of COVID-19 infection in MM patients in our institution. Study population includes 34 MM patients with a median age of 61 (range: 35-82 years) who tested positive for SARS-CoV-2 between 1 March 2020-15 August 2021. We examined the effect of chemotherapy, the benefit of neutralizing monoclonal antibody (Bamlanivimab) and the impact of anti-CD38 antibody (daratumumab) on the hospitalization and mortality of the patients, as well as the efficacy of native antibody production. Our results showed that MM patients have increased hospitalization and mortality rates from COVID-19 compared with that of general population, especially those on active chemotherapy. Advanced age, high-risk myeloma, renal disease, and suboptimal disease control are independent predictors of adverse outcomes. The use of daratumumab does not increase the disease severity/hospitalization or the post-infection/vaccination seropositivity of SARS-CoV-2. The neutralizing antibody decreases overall mortality. Evidence from the current study and previous publications suggest that testing of neutralizing antibody post-SARS-CoV-2 vaccination in MM patients may be needed in reducing COVID-19 risk.

Clinical outcome of SARS-CoV-2 infections occurring in multiple myeloma patients after vaccination and prophylaxis with tixagevimab/cilgavimab.

Patients with multiple myeloma (MM) frequently reported immune impairment with an increased risk for infection-related mortality. We aimed to evaluate the immune response in MM patients vaccinated for SARS-CoV-2 during active treatment. We enrolled 158 patients affected by active MM or smoldering MM (SMM) and 40 healthy subjects. All subjects received 2 or 3 doses of the BNT162b2 (Pfizer/BioNTech) vaccine, and the anti-spike IgG values were evaluated after every dose. We applied the Propensity Score Matching (PSM) as a consequence of the limited sample size and its heterogeneity to adjust for differences in baseline clinical variables between MM patients who achieved or not a vaccine response after 2 or 3 doses. At 30 days from the second dose, the median antibodies level in MM was 25.2 AU/mL, lower than in SMM and in the control group. The same results were confirmed after the third dose, with lower median anti-spike IgG levels in MM, compared to SMM and control group. Following PSM, lack of response to SARS-CoV-2 complete vaccination plus boost was associated with age more than 70 years old and use of high-dose of steroids. We failed to identify an association between specific treatment types and reduced vaccine response. The use of prophylaxis with tixagevimab/cilgavimab for 40 non-responder patients after 3 doses of vaccine has proven to be an effective and safe approach in reducing the risk of serious illness in the event of a breakthrough SARS-CoV-2 infection, faced with a mild symptomatic course, and in providing protection instead of long-term humoral immune vaccine responses. Following PSM, only the high-risk cytogenetic abnormalities were associated with an increased risk of developing a breakthrough SARS-CoV-2 infection. Monitoring the immune response is fundamental in MM patients that remain highly vulnerable to SARS-CoV-2 despite the vaccine. The use of prophylaxis with tixagevimab/cilgavimab can guarantee better protection from the severe form of the disease.

Can urine studies be replaced by serum free light chains measurements to assign responses in multiple myeloma patients?

Serum and urine protein electrophoresis and immunofixation are the preferred techniques for monitoring monoclonal proteins and evaluating treatment response in multiple myeloma (MM) patients with measurable disease. However, urine studies are subjected to limitations that may lead to inaccuracies or prevent guidelines compliance. We retrospectively studied if the substitution of urine studies by measuring serum free light chains (sFLCs) results in a comparable disease monitoring, both in intact immunoglobulin (II) and light chain (LC) MM patients. In our cohort, equal or higher percentages of disease were identified by sFLCs at baseline and maximum response as compared to urine studies. Achieving very good partial response or better (≥VGPR) according to the response criteria proposed by the French group (evaluating sFLCs instead of urine) and the IMWG response criteria were associated to a 62% and 63% reduced risk of progression, respectively. A similar prognostic value for reaching ≥VGPR was also observed among LCMM patients when the French group and the IMWG response criteria were applied. Overall, these results support the replacement of urine studies by the sFLCs assay in IIMM. In LCMM, sFLCs could be used for monitoring and urine studies could be performed only to confirm complete remissions and progressions.

Cellular Immune Composition in Multiple Myeloma Patients Associated with Variable Humoral Responses to Sars-Cov-2 Vaccination

Background: Multiple Myeloma (MM) patients are immune-deficient and mount suboptimal immune responses to SARS-CoV-2 mRNA vaccine, making them more susceptible to severe COVID-19 manifestations. We have previously described that MM patients undergoing certain therapies have compromised humoral immune responses even after receiving multiple doses of the SARS-CoV-2 mRNA vaccine (Aleman, et al. Cancer Cell 2022). However, the mechanisms underlying the suboptimal antibody responses observed in these patients are not understood. Emerging research suggests that specific cell populations within the immune milieu, such as Follicular helper (TFH) CD4+ T cells, help B cells mount a robust serological response (Cui, et al. 2021). In addition, Natural Killer (NK) cells have been known to play a protective role in SARS-CoV-2 infection (Fuentes-Villalobos, et al. 2022). We report here on the cellular immune composition highly associated with suboptimal humoral immune responses in MM patients. Methods: We longitudinally followed 31 MM patients with variable serological responses after receiving SARS-CoV-2 vaccination, as determined by quantification of anti-spike IgG antibody titers, and compared to 13 age matched healthy donors. We categorized patients based on their production of anti-spike IgG post full vaccination of two doses. Of our selected cohort, 14 patients had failed to produce detectable anti-spike IgG (MM sub-optimal), whereas the other 17 MM patients had detectable anti-spike IgG (MM within detectable range). We analyzed samples collected post second dose and post third dose of COVID-19 vaccine using high dimensional spectral flow cytometry to elucidate immune phenotypic differences. Data and sample collection for this study was approved by the institutional review board (IRB) and follows the Declaration of Helsinki and International Conference on Harmonization Guidelines for Good Clinical Practice (IRB: GCO#: 16-00791 (MM patients) & GCO #: 20-03374 (PARIS). Results: We compared spike binding antibody responses pre and post third vaccine dose in our MM and control cohorts. While the third dose of mRNA vaccine resulted in a robust increase in anti-spike IgG for the majority of patients, the serological response in MM patients remained significantly lower (p<0.05) as compared to healthy controls (Figure 1A). The sub-optimal MM patient group had the lowest serological response, with 28% (4/14) of the patients showing no detectable anti-spike IgG levels post third booster vaccination. MM patients with sub-optimal responses did not have an increased incidence of lymphopenia or difference of absolute B cell and T cell counts. Further examination, however, revealed noticeable differences in TFH and NK cell populations. Sub-optimal MM patients showed a significantly lower prevalence of PD1+CXCR5+ TFH cells (p<0.01), as compared to MM patients within detectable serological range both pre and post third vaccination (Figure 1B). PD1+CXCR5+ TFH cells are associated with higher levels of anti-spike IgG neutralizing antibodies (Cui, et al. 2021). In addition, sub-optimal MM patients showed significantly fewer NK cells (p<0.05) when compared to MM patients within detectable serological range and healthy donors (Figure 1B). NK cell subset analysis in the sub-optimal MM patient group revealed a high prevalence of immature NK cell subsets (CD16-/dimCD56hi) (p<0.01), whereas MM patients within serological range and healthy donors showed a dominant mature cytolytic NK cell subset (CD16hiCD56dim). Half of the sub-optimal MM patients were on anti-CD38 monoclonal antibody therapy (7/14) compared to those mounting efficient responses (11%, 2/17), which we have previously described as affecting anti-spike IgG production and depleting NK populations. Conclusion: We describe here that significantly reduced numbers of CD4+ TFH and NK cells is associated with sub-optimal serological responses to SARS-COV-2 mRNA vaccination in MM patients. The distinct phenotype observed in our sub-optimal MM patient cohort could be a product of their pre-existing immune composition, the nature of their disease progression, or in response to ongoing therapies. Our data suggests that longitudinal immunophenotyping may identify vulnerable MM patients that may need additional vaccinations or prophylactic intervention, such as monoclonal antibody therapies. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Assessing Pretransplant and Posttransplant Therapy Response in Multiple Myeloma Patients.

Multiple myeloma (MM) is a hematologic cancer defined by an abnormal development of clonal plasma cells in the bone marrow, releasing vast quantities of immunoglobulins and different proteins. In the majority of patients, MM remains incurable despite decades of medical improvement and a number of treatment breakthroughs. Frontline standard-of-care has little long-term success, with the majority of patients eventually relapsing, although the overall progression-free survival (PFS) has improved significantly in the last ten years. Patients who are eligible for a transplant have the highest PFS rate at 5 years, depending on medication response and other various factors that are yet to be discovered. Therefore, the current study aimed to evaluate the response to VCD (bortezomib, cyclophosphamide, dexamethasone) and VTD (bortezomib, thalidomide, dexamethasone) used as pretransplant regimens, as well as to compare responses between thalidomide and lenalidomide used as maintenance therapy posttransplant. This retrospective study was performed on a group of 105 hospitalized patients in the Hematology Department of the Timisoara Municipal Emergency Clinical Hospital between January 2016 and December 2021. Data was collected from the paper records of patients with MM who were under-followed. The treatment regimens used as induction therapy were either VCD or VTD if cyclophosphamide was contraindicated. Of the 105 patients, 27 became eligible for bone marrow transplantation. Furthermore, they received maintenance therapy which was based on either lenalidomide with dexamethasone or thalidomide with dexamethasone. Of the 62 patients treated with VTD, 17.7% were in complete remission before stem cell transplantation. Of the 43 patients treated with VCD, 37.2% were in complete remission. The 5-year mean progression-free survival (PFS) in the entire cohort was better in the group treated with the VTD regimen (31.6 vs. 27.2 months). However, in the 27 patients undergoing maintenance after ASCT, the PFS with thalidomide was 35.5 months (95% CI = 27-42), while the PFS rate in those receiving maintenance treatment with lenalidomide was 46.1 months (95% CI = 20-73). VCD proved to be superior to VTD in inducing complete pretransplant responses. Regarding maintenance therapy, patients from the lenalidomide group had superior responses compared with those under thalidomide.

Metabolic features of myeloma cells in the context of bone microenvironment: Implication for the pathophysiology and clinic of myeloma bone disease.

Multiple myeloma (MM) is a hematological malignancy characterized by the accumulation of malignant plasma cells (PCs) into the bone marrow (BM). The complex interaction between the BM microenvironment and MM PCs can lead to severe impairment of bone remodeling. Indeed, the BM microenvironment exerts a critical role in the survival of malignant PCs. Growing evidence indicates that MM cells have several metabolic features including enhanced glycolysis and an increase in lactate production through the upregulation of glucose transporters and enzymes. More recently, it has been reported that MM cells arehighly glutamine addicted. Interestingly, these metabolic changes in MM cells may affect BM microenvironment cells by altering the differentiation process of osteoblasts from mesenchymal stromal cells. The identification of glutamine metabolism alterations in MM cells and bone microenvironment may provide a rationale to design new therapeutic approaches and diagnostic tools. The osteolytic lesions are the most frequent clinical features in MM patients, often characterized by pathological fractures and acute pain. The use of the newer imaging techniques such as Magnetic Resonance Imaging (MRI) and combined Positron Emission Tomography (PET) and Computerized Tomography (CT) has been introduced into clinical practice to better define the skeletal involvement. Currently, the PET/CT with 18F-fluorodeoxyglucose (FDG) is the diagnostic gold standard to detect active MM bone disease due to the high glycolytic activity of MM cells. However, new tracers are actively under investigation because a portion of MM patients remains negative at the skeletal level by 18F-FDG. In this review, we will summarize the existing knowledge on the metabolic alterations of MM cells considering their impact on the BM microenvironment cells and particularly in the subsequent formation of osteolytic bone lesions. Based on this, we will discuss the identification of possible new druggable targets and the use of novel metabolic targets for PET imaging in the detection of skeletal lesions, in the staging and treatment response of MM patients.

Dendritic Cell-Based Immunotherapy in Multiple Myeloma: Challenges, Opportunities, and Future Directions.

Immunotherapeutic approaches, including adoptive cell therapy, revolutionized treatment in multiple myeloma (MM). As dendritic cells (DCs) are professional antigen-presenting cells and key initiators of tumor-specific immune responses, DC-based immunotherapy represents an attractive therapeutic approach in cancer. The past years, various DC-based approaches, using particularly ex-vivo-generated monocyte-derived DCs, have been tested in preclinical and clinical MM studies. However, long-term and durable responses in MM patients were limited, potentially attributed to the source of monocyte-derived DCs and the immunosuppressive bone marrow microenvironment. In this review, we briefly summarize the DC development in the bone marrow niche and the phenotypical and functional characteristics of the major DC subsets. We address the known DC deficiencies in MM and give an overview of the DC-based vaccination protocols that were tested in MM patients. Lastly, we also provide strategies to improve the efficacy of DC vaccines using new, improved DC-based approaches and combination therapies for MM patients.

Early Dynamics and Depth of Response in Multiple Myeloma Patients Treated With BCMA CAR-T Cells.

Chimeric antigen receptor T-cell (CAR-T) therapy targeted against B-cell maturation antigen (BCMA) in multiple myeloma (MM) has produced rapid responses but many eventually relapse. In light of this new treatment, novel predictors of progression-free survival (PFS) are needed. We performed a single institution analysis of 54 BCMA-CAR-T patients. We analyzed patient’s overall response rate (ORR) by the IMWG criteria, involved serum-free light chains (iFLC), and minimal residual disease testing by next-generation sequencing (MRD-NGS). Between patients who achieved a ≤SD and those who achieved a ≥PR, PFS differed significantly (p < 0.0001); though there was no difference between patients who achieved a ≥CR vs. VGPR/PR (p = 0.2). In contrast, patients who achieved a nonelevated iFLC at 15 days (p < 0.0001, HR = 6.8; 95% CI, 2.7–17.3) or 30 days (p < 0.001, HR = 16.7; 95% CI, 3.9–71.7) had a prolonged PFS compared with those with an elevated iFLC. Patients achieving MRD-NGS less than the detectable limit at a sensitivity of 10−6 had a better PFS than those with detectable disease at 1 month (p = 0.02) and 3 months (p = 0.02). In conclusion, achieving a nonelevated iFLC and an undetectable MRD-NGS quickly were factors that were strongly associated with improved PFS. Further studies are needed to confirm the role of these markers in MM patients receiving CAR-T therapies.

Impact of Autologous Hematopoietic Cell Transplant (HCT) Followed By Dendritic Cell/Myeloma Fusion Vaccine with Lenalidomide Maintenance in Increasing Multiple Myeloma (MM) Immunity (BMT CTN 1401)

Impact of Autologous Hematopoietic Cell Transplant (HCT) Followed By Dendritic Cell/Myeloma Fusion Vaccine with Lenalidomide Maintenance in Increasing Multiple Myeloma (MM) Immunity (BMT CTN 1401)

CD19+ B Lymphocytes Are Predictive for Anti-Sars-Cov-2 Vaccination Response in Multiple Myeloma Patients

CD19+ B Lymphocytes Are Predictive for Anti-Sars-Cov-2 Vaccination Response in Multiple Myeloma Patients

Predictive Value of CD229, CD319 and c-Maf Overexpression for Treatment Response in Multiple Myeloma Patients

Background: Ly-9 (CD229) and SLAMF7 (CD319) are more stable markers that could be used to replace the less stable conventional markers CD138 and CD38 in multiple myeloma (MM) patient follow-up. In those patients, the correlation between these markers and the histopathologic marker c-Maf has not been well investigated. Objective: To assess the predictive value of CD229, CD319, and c-MAF overexpression on outcome of treatment in MM patients. Patients and Methods: 61 newly diagnosed multiple myeloma patients were involved in this prospective study. Flow cytometric analysis of bone marrow (BM) samples for CD229 PE, CD319 PE, CD138 PerCP and CD38FITC as well as BM biopsy immunohistochemically were analyzed for c-Maf expression Results: CD229 and CD319 were highly expressed in (≥93.95%) and (≥95.6%) of MM patients respectively. c-Maf was positive in (29.5%) of patients. In MM patients with high expression of CD229 and CD319 as well as those with c-Maf positivity showed high serum Ca++, β2M, CD138 and CD38. CD229 was significantly correlated with CD319, CD38, CD138, β2M and serum Ca (p-values were< 0.001,0.01, 0.01, 0.009, and 0.02 respectively). Patients with overexpression of CD 229, CD319 and c-Maf were more refractory to treatment (p-values were <0.001,<0.001 and <0.001 respectively). Conclusion: We detected that both CD229 and CD319 were significantly overexpressed on MM cells and correlated significantly with CD138 and CD38, suggesting their use as alternative markers for MM diagnosis as well as follow-up. Patients with CD229,CD319, and c-Maf overexpression were associated with a significant poor response to therapy.

MM-219: Outcome of COVID-19 Among Patients with Multiple Myeloma at the Armenian Hematology Center

The effect of COVID-19 on patients with multiple myeloma (MM), the second most common hematological malignancy, is of particularly great concern due to immunosuppression associated with the disease, and at this time remains incompletely understood. The aim of the current study was the analysis of the characteristics of COVID-19 infection and serological response in MM patients in Armenia for the period of 2020-2021.MethodsWe performed a retrospective study (epidemiological, clinical, and laboratory characteristics) on a cohort of 125 patients with MM, 42 in which developed COVID-19 between March 1, 2020, and May 30, 2021.ResultsOf the 42 (33.6%) patients diagnosed with COVID-19, 19 (45.2%) were hospitalized and 23 (66.4%) were managed at home. The median age was 60 years; 40.5% of patients were male. Hypertension (39%), hyperlipidemia (42%), obesity (33%), diabetes mellitus (18%), chronic kidney disease (14%), and lung disease (18%) were the most common comorbidities. In the total cohort, 8 patients (19%) died. The most common initial symptoms were fever (63%), cough (50%), dyspnea (43%), and hypoxemia (28%). Clinical status was considered as mild in 24 (57%), severe in 10 (24%), or critical in 8 (19%), with lung infiltrates reported on imaging in 12 (29%) and multiple organ failure in 4 (10%). Older age, male sex, cardiovascular risk, and patients with noncomplete remission were significantly (p<0.02) associated with hospitalization. Among hospitalized patients, laboratory findings demonstrated elevation of traditional inflammatory markers and a significant (p<0.01) association between elevated inflammatory markers, severe hypogammaglobulinemia and mortality. Hospitalization was required in 16 patients for a median of 10-12 days (range, 3–32), 2 needing mechanical ventilation. Most patients required O2 administration, in addition to antibiotics and hydroxychloroquine.ConclusionOur limited experience of COVID-19 emphasizes the severity of this condition in MM patients, with a high mortality incidence (19%). However, based on these preliminary data, in a country where about 62 new MM are diagnosed each year and where 222 000 cases of COVID-19 have been reported so far, this complication remains very rare. Further investigations are mandatory in order to assess the impact of this new viral infection on MM patients.

MiR-22 Modulates Lenalidomide Activity by Counteracting MYC Addiction in Multiple Myeloma.

Simple SummaryMYC-driven deregulation of microRNAs represents a critical event in human malignancies, including multiple myeloma (MM). Although the introduction of new therapeutic strategies has prolonged survival of patients, MM remains an incurable disease, often due to the onset of drug resistance. MYC hyperactivation is involved in the development of resistance to immunomodulatory imide drugs (IMiDs), but the mechanism is still unclear. Here, we report that MYC represses the transcription of tumor suppressor miR-22 in MM, and that low miR-22 expression is associated with IMiD resistance in MM patients. By in silico and in vitro analysis, we show that miR-22 mimics affect MYC signaling, leading to MM cell death in MYC proficient cells. Furthermore, we demonstrate here that lenalidomide treatment enhances miR-22 activity by reducing the MYC inhibitory effect, and that the combination of lenalidomide with miR-22 mimics restores drug sensitivity, leading to synergistic anti-MM activity.Background: MYC is a master regulator of multiple myeloma (MM) by orchestrating several pro-tumoral pathways, including reprograming of the miRNA transcriptome. MYC is also involved in the acquirement of resistance to anti-MM drugs, including immunomodulatory imide drugs (IMiDs). Methods: In silico analysis was performed on MM proprietary and on public MMRF-CoMMpass datasets. Western blot and chromatin immunoprecipitation (ChIP) experiments were performed to validate miR-22 repression induced by MYC. Cell viability and apoptosis assays were used to evaluate lenalidomide sensitization after miR-22 overexpression. Results: We found an inverse correlation between MYC and miR-22 expression, which is associated with poor outcome in IMiD-treated MM patients. Mechanistically, we showed that MYC represses transcription of miR-22, which, in turn, targets MYC, thus establishing a feed-forward loop. Interestingly, we found that IMiD lenalidomide increases miR-22 expression by reducing MYC repression and, most importantly, that the combination of lenalidomide with miR-22 mimics results in a synergistic direct and NK-mediated cytotoxic activity. Conclusions: Taken together, our findings indicate that: (1) low miR-22 expression could represent a potential predictive biomarker of poor lenalidomide response in MM patients; and (2) miR-22 reduces MYC oncogenic activity, thus triggering a novel synthetic lethality loop, which sensitizes MM cells to lenalidomide.

Single Cell Resolution Profiling Defines the Innate and Adaptive Immune Repertoires Modulated By Daratumumab and IMiDs Treatment in Multiple Myeloma (MM)

Background: The combination of immunomodulatory (IMiDs) drugs with monoclonal antibodies targeting the transmembrane glycoprotein CD38 induces deep and durable responses in MM patients. IMiDs mediated degradation of the transcription factors IKZF1/3 attenuates myeloma cells proliferation and releases IKZF1 transcriptional repression of IL-2 and type I/II interferon response genes promoting T, NK and NKT cells proliferation and activation. Similarly targeting the non-lineage restricted molecule CD38 with daratumumab also exerts direct and indirect tumoricidal effects. Mechanisms implicated in daratumumab-mediated killing include a direct apoptotic effect and activation of cytotoxic immune effector functions, including antibody-dependent cellular cytotoxicity (ADCC), antibody-dependent cellular phagocytosis, and complement dependent cytotoxicity (CDC). Therefore, the synergistic effects observed with daratumumab and IMiDs are postulated to derive from their co-modulation of the host adaptive and innate immunity. A systematic unsupervised interrogation of the bone marrow immune cells of daratumumab and IMiDs treated MM patients is key for the prediction of their clinical responses and the understanding of underlying mechanisms of resistance.Methods and Results: Bone marrow (BM) aspirates and matching peripheral blood were collected from 20 myeloma patients treated with daratumumab in combination with IMiDs (lenalidomide or pomalidomide) prior to initiation of therapy and at the time of disease response (n=10) or progression (n=10). Bone marrow mononuclear cells were isolated through Ficoll density gradients coupled with magnetic sorting of CD138pos and CD138neg cells. Unbiased mRNA profiling of BM CD138neg cells was performed by single-cell RNA-seq (scRNA-seq) using the GemCode system (10x Genomics), a droplet-based method enabling high cell throughput and efficient single-cell capture. Sequencing was performed on Illumina NEXTseq platform in a paired-end format. Cell Ranger Single Cell Software Suite was used to perform sample de-multiplexing, barcode processing, and single-cell 3′ gene counting. Sequencing data from 30,074 CD138neg single cells (12,908 cells from responding (S) and 17,166 cells from progressing (R) patients) were kept for analysis by the Seurat R package and analyzed by principal component analysis (PCA) and clusteringand then visualized by t -distributed stochastic neighbour embedding (t -SNE) projection. Shown in Fig 1 a representative t -SNE and heatmap plot of 9 immune clusters typically identified in individual samples including terminal effector T cells (KLRG1hi, IL7Rlow), memory T cells (central memory TCM: SELLhi CCR7hi and effector memory TEM: SELLlow CCR7low), CD4 T cells, NK and NKT cells (NKG7, GNLY), B cells (MS4A1), monocytes (CD14, LYZ), macrophages (CD68) and dendritic cells (FCER1A, CST3). Transcriptome profiling of immune cells pre- and post-treatments in S and R patients revealed the following key findings: 1) T cells (CD8Apos and CD3pos) were largely senescent in myeloma patients lacking CD28 expression; 2) amongst checkpoint inhibitory genes LAG3 had the highest expression on activated T cells followed by PDCD1 and to a much lesser extent by HAVCR2 and TIGIT; 3) exposure to daratumumab and IMiDs resulted in the expansion of activated effector CD8 cyctotoxic and effector memory T cells and depletion of CD38pos T and B cells; 4) compared to resistant or progressing patients, responders were characterized by higher CD28 expression in T cells, a significantly larger clusters of central memory T cells (TCM: IL7Rpos, SELLpos, CCR7pos, CD27pos, KLRG1neg) and a M1 activated macrophage signature (IL1Bpos, CCL3pos). Of note no significant difference was noted in CD38 transcript amongst S and R patients. Single cell profiling of CD138pos cells will be updated at the meeting as well as further characterization of the immune repertoire and TCR clonality status of R and S patients.Conclusion: Anunbiased single cell profiling of bone marrow immune cells in MM patients exposed to Daratumumab and IMiDs demonstrated that LAG3 targeting and restoration of co-stimulatory genes expression (CD28) should be studied as means to reverse immunoparesis. Central memory T cells (TCM) expansion and M1 macrophage signature in responders to Daratumumab and IMiDs combinations represent potential biomarkers of response. [Display omitted] DisclosuresNeri:Celgene: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding. Jimenez-Zepeda:Janssen: Honoraria; Amgen: Honoraria; Celgene: Honoraria; Takeda: Honoraria. Boise:Eli Lilly and Company: Research Funding; Abbvie: Consultancy. Thakurta:Celgene Corporation: Employment, Equity Ownership. Bahlis:Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau.