CD38 restrains the activity of extracellular cGAMP in a model of multiple myeloma.

2'3'-cyclic guanosine monophosphate-adenosine monophosphate (cGAMP) is the endogenous agonist of STING; as such, cGAMP has powerful immunostimulatory activity, due to its capacity to stimulate type I interferon-mediated immunity. Recent evidence indicates that cancer cells, under certain conditions, can release cGAMP extracellularly, a phenomenon currently considered important for therapeutic responses and tumor rejection. Nonetheless, the mechanisms that regulate cGAMP activity in the extracellular environment are still largely unexplored. In this work, we collected evidence demonstrating that CD38 glycohydrolase can inhibit extracellular cGAMP activity through its direct binding. We firstly used different cell lines and clinical samples to demonstrate a link between CD38 and extracellular cGAMP activity; we then performed extensive in silico molecular modeling and cell-free biochemical assays to show a direct interaction between the catalytic pocket of CD38 and cGAMP. Altogether, our findings expand the current knowledge about the regulation of cGAMP activity.

Severe SARS-CoV-2 and subsequent fungal infections after CAR T-cell therapy for relapsed/refractory multiple myeloma: a challenging and happy ending fight.

Chimeric antigen receptor (CAR) T-cells have unveiled a promising therapeutic horizon for relapsed/refractory multiple myeloma (R/R MM). Nevertheless, immune impairment induced by cellular therapies, previous treatments and MM itself could promote infectious events. COVID-19 could evolve into a life-threating infection in R/R MM patients who often have suboptimal responses to SARS-CoV-2 vaccines. Here, we describe a case of severe and long-lasting COVID-19 pneumonia after CAR T-cell therapy for R/R MM requiring a complex clinical management. Long-term infectious complications in MM patients undergoing CAR T-cells should be taken into consideration as they could counteract the efficacy of this new treatment.

A prospective, multicenter study on hematopoietic stem-cell mobilization with cyclophosphamide plus granulocyte colony-stimulating factor and 'on-demand' plerixafor in multiple myeloma patients treated with novel agents.

High-dose melphalan plus autologous stem-cell transplantation (ASCT) is a standard of care for transplant-eligible patients with newly diagnosed multiple myeloma (NDMM), and adequate hematopoietic stem-cell (HSC) collection is crucial to ensure hematologic recovery after ASCT. In this prospective, observational study we evaluated HSC mobilization with granulocyte colony-stimulating factor (G-CSF), cyclophosphamide, and 'on-demand' plerixafor (in patients with.

Multiparametric Flow Cytometry in Newly Diagnosed Multiple Myeloma Patients: An Italian Monocentric Experience.

Multiple myeloma (MM) is a heterogeneous malignancy characterized by the proliferation of abnormal plasma cells in the bone marrow. Multiparametric flow cytometry (MFC) plays a role in the work-up of the disease in view of the aberrant expression of surface antigens. Our study aimed at describing the antigenic profile detected by MFC in a series of newly diagnosed MM patients to correlate the level of expression with other features of the disease. Between April 2018 and June 2022, 84 consecutive MM patients were studied at presentation. CD56 and CD117 were commonly detected, while CD45, CD28, CD20, CD19, CD13 and CD33 were less recurrent. CD20 expression was associated with the type of secretory MM (p=0.041) and with a higher disease burden (p=0.038). CD28 positivity correlated with a lower platelet count at baseline (p=0.005) and with a lower rate of complete response (p=0.038). Furthermore, CD28 positivity and a lower CD138 expression tended to associate with the high-risk chromosomal translocations t(14;16) and t(4;14). The results of this study indicate that in the diagnostic work-up of MM, MFC may help to identify different patient subsets and improve risk stratification. These observations need to be validated in larger series of patients with a longer follow-up.

NEDD8-activating enzyme inhibition potentiates the anti-myeloma activity of natural killer cells.

Natural Killer (NK) cells act as important regulators in the development and progression of hematological malignancies and their suppressor activity against Multiple Myeloma (MM) cells has been confirmed in many studies. Significant changes in the distribution of NK cell subsets and dysfunctions of NK cell effector activities were described in MM patients and correlated with disease staging. Thus, restoring or enhancing the functionality of these effectors for the treatment of MM represents a critical need. Neddylation is a post-translational modification that adds a ubiquitin-like molecule, NEDD8, to the substrate protein. One of the outcomes is the activation of the Cullin Ring Ligases (CRLs), a class of ubiquitin-ligases that controls the degradation of about 20% of proteasome-regulated proteins. Overactivation of CRLs has been described in cancer and can lead to tumor growth and progression. Thus, targeting neddylation represents an attractive approach for cancer treatment. Our group has recently described how pharmacologic inhibition of neddylation increases the expression of the NKG2D activating receptor ligands, MICA and MICB, in MM cells, making these cells more susceptible to NK cell degranulation and killing. Here, we extended our investigation to the direct role of neddylation on NK cell effector functions exerted against MM. We observed that inhibition of neddylation enhanced NK cell-mediated degranulation and killing against MM cells and improved Daratumumab/Elotuzumab-mediated response. Mechanistically, inhibition of neddylation increased the expression of Rac1 and RhoA GTPases in NK cells, critical mediators for an efficient degranulation at the immunological synapse of cytotoxic lymphocytes, and augmented the levels of F-actin and perforin polarization in NK cells contacting target cells. Moreover, inhibition of neddylation partially abrogated TGFß-mediated repression of NK cell effector activity. This study describes the role of neddylation on NK cell effector functions and highlights the positive immunomodulatory effects achieved by the inhibition of this pathway in MM.

Cross-Dressing of Multiple Myeloma Cells Mediated by Extracellular Vesicles Conveying MIC and ULBP Ligands Promotes NK Cell Killing.

Natural Killer (NK) cells are innate cytotoxic lymphoid cells that play a crucial role in cancer immunosurveillance. NKG2D is an activating receptor that binds to MIC and ULBP molecules typically induced on damaged, transformed, or infected cells. The secretion of NKG2D ligands (NKG2DLs) through protease-mediated cleavage or in an extracellular vesicle (EV) is a mode to control their cell surface expression and a mechanism used by cancer cells to evade NKG2D-mediated immunosurveillance. EVs are emerging as important players in mediating cell-to-cell communication due to their ability to transfer biological material to acceptor cells. Herein, we investigated the spreading of NKG2DLs of both MIC and ULBP molecules through the EV-mediated cross-dressing on multiple myeloma (MM) cells. We focused our attention on two MICA allelic variants, namely MICA*008 and MICA*019, representing the prototype of short and long MICA alleles, respectively, and on ULBP-1, ULBP-2, and ULBP-3. Our findings demonstrate that both ULBP and MICA ligands can be acquired from tumor cells through EVs enhancing NK cell recognition and killing. Moreover, besides MICA, EVs expressing ULBP-1 but not ULBP-2 and 3 were detected in bone marrow aspirates derived from a cohort of MM patients. Our findings shed light on the role of EV-associated MICA allelic variants and ULBP molecules in the modulation of NKG2D-mediated NK cell immunosurveillance in the tumor microenvironment. Moreover, the EV-mediated transfer of NKG2DLs could suggest novel therapeutic approaches based on the usage of engineered nanoparticles aimed at increasing cancer cell immunogenicity.

Belantamab Mafodotin: From Clinical Trials Data to Real-Life Experiences.

Despite the recent approval of novel immunotherapies, such as immunomodulatory drugs, proteasome inhibitors and anti-CD38 monoclonal antibodies, Multiple Myeloma (MM) remains incurable, and the acquisition of triple-refractoriness leads to really dismal outcomes in even earlier lines of therapy. More recently, innovative therapeutic strategies targeting B cell maturation antigen (BCMA), highly expressed on the plasma cell surface, are drawing different future landscapes in terms of effectiveness and outcomes. Belantamab Mafodotin, a first-in-class anti-BCMA antibody-drug conjugate, demonstrated good efficacy and safety profile in triple-refractory patients in the phase 2 DREAMM-2 trial, and it was approved for the treatment of MM triple-exposed patients with >4 prior lines of therapy. Here, starting from Belantamab Mafodotin clinical trials and also exploring combination studies and different schedules in order to improve its efficacy and toxicity, we focused on real-life experiences all over the world, which have confirmed clinical trial data and encourage further Belantamab Mafodotin investigations.

Sialofucosylation Enables Platelet Binding to Myeloma Cells via P-Selectin and Suppresses NK Cell-Mediated Cytotoxicity.

Multiple myeloma (MM) is a plasma cell disorder that develops in the bone marrow (BM) and is characterized by uncontrolled proliferation and the ability to disseminate to different sites of the skeleton. Sialofucosylated structures, particularly Sialyl Lewis a/x (SLea/x), facilitate the homing of MM cells into the BM, leading to resistance to bortezomib in vivo. Platelets have been shown to play an important role in tumor metastasis. Platelets can bind to the surface of cancer cells, forming a "cloak" that protects them from the shear stress of the bloodstream and natural killer (NK) cell-mediated cytotoxicity. In this study, we showed that the presence of SLea/x induced a strong binding of MM cells to P-selectin, leading to specific and direct interactions with platelets, which could be inhibited by a P-selectin-blocking antibody. Importantly, platelets surrounded SLea/x-enriched MM cells, protecting them from NK cell-mediated cytotoxicity. The interactions between the platelets and MM cells were also detected in BM samples obtained from MM patients. Platelet binding to SLea/x-enriched MM cells was increased in patients with symptomatic disease and at relapse. These data suggest an important role of SLea/x and platelets in MM disease progression and resistance to therapy.

Lenalidomide-based triplet regimens in first relapsed multiple myeloma patients: real-world evidence from a propensity score matched analysis.

Lenalidomide and dexamethasone (Rd)-based triplets, in particular carfilzomib-Rd (KRd) and daratumumab-Rd (DaraRd), represent a standard of care in lenalidomide-sensitive multiple myeloma (MM) patients in first relapse. Meta-analysis of randomized clinical trials (RCT), suggested better outcome with DaraRd. Trying to address this issue in clinical practice, we collected data of 430 consecutive MM patients addressed to Rd-based triplets in first relapse between January 2017 and March 2021. Overall, the most common used regimen was DaraRd, chosen in almost half of the cases (54.4%), followed by KRd (34.6%). Different triplets were used much less commonly. In an attempt to limit the imbalance of a retrospective analysis, we conducted a propensity score matching (PSM) comparison between DaraRd and KRd. After PSM, efficacy of DaraRd versus KRd was similar in terms of overall-response rate (ORR) (OR: 0.9, P=0.685) as well as of very good partial response (VGPR) or better (OR: 0.9, P=0.582). The median progression-free survival (PFS) was significantly longer for DaraRd (29.8 vs. 22.5 months; P=0.028). DaraRd was tolerated better, registering a lower rate of grade 3-4 non-hematological toxicity (OR: 0.4, P<0.001). With the limitations of any retrospective analysis, our real-life PSM comparison between DaraRd and KRd, in first-relapse MM patients, showed better tolerability and prolonged PFS of DaraRd, although with some gaps of performance, in particular of DaraRd, with respect to RCT. Carfilzomib-containing regimens, like KRd, still remain a valid second-line option in the emerging scenario of first-line daratumumab-based therapy.

Immunogenicity of SARS-CoV-2 vaccination in patients undergoing autologous stem cell transplantation. A multicentric experience.

COVID-19 disease has a strong impact on hematological patients; those receiving autologous hematopoietic stem cell transplantation (aHSCT) represent a particularly vulnerable group, in which the effectiveness of vaccination is very variable. Chiarucci et al. showed that patients affected by non-Hodgkin lymphoma (NHL) and treated with rituximab experienced a lower rate of immunization against SARS-CoV-2 (54%), as well as significantly lower IgG antibody titers. In our multicenter retrospective observational study, we included 82 patients who underwent aHSCT, divided into two groups: 58 patients vaccinated after aHSCT (group A) and 24 vaccinated before getting transplantation (group B). In group A, 39 (67%) patients had positive serology, and the rate of positivity increased with time after aHSCT. In the subgroup of patients with NHL, the administration of rituximab predicted negative serology, particularly when administered in the 6 months before vaccination (13% response rate). Patients affected by plasma cells had a higher rate of positivity (83% overall), independently of the time to aHSCT. In group B, no patient who initially showed positive serology became negative after transplantation, so the aHSCT did not affect the response to the vaccination. Our study confirmed the role of rituximab as a negative predictor of response to SARS-CoV-2 vaccination, whereas the conditioning and transplantation procedure itself seemed to be less important.

GAS6/TAM signaling pathway controls MICA expression in multiple myeloma cells.

NKG2D ligands play a relevant role in Natural Killer (NK) cell -mediated immune surveillance of multiple myeloma (MM). Different levels of regulation control the expression of these molecules at cell surface. A number of oncogenic proteins and miRNAs act as negative regulators of NKG2D ligand transcription and translation, but the molecular mechanisms sustaining their basal expression in MM cells remain poorly understood. Here, we evaluated the role of the growth arrest specific 6 (GAS6)/TAM signaling pathway in the regulation of NKG2D ligand expression and MM recognition by NK cells. Our data showed that GAS6 as well as MERTK and AXL depletion in MM cells results in MICA downregulation and inhibition of NKG2D-mediated NK cell degranulation. Noteworthy, GAS6 derived from bone marrow stromal cells (BMSCs) also increases MICA expression at both protein and mRNA level in human MM cell lines and in primary malignant plasma cells. NF-kB activation is required for these regulatory mechanisms since deletion of a site responsive for this transcription factor compromises the induction of mica promoter by BMSCs. Accordingly, knockdown of GAS6 reduces the capability of BMSCs to activate NF-kB pathway as well as to enhance MICA expression in MM cells. Taken together, these results shed light on molecular mechanism underlying NKG2D ligand regulation and identify GAS6 protein as a novel autocrine and paracrine regulator of basal expression of MICA in human MM cells.

Race for the Cure: From the Oldest to the Newest Monoclonal Antibodies for Multiple Myeloma Treatment.

Multiple myeloma is characterized by a wide clinical heterogeneity due to an intricate network of interactions between bone marrow-resident clonal plasma cells and the microenvironment. Over the last years, dramatic improvement in the understanding of these pathways led to the introduction of novel drugs with immune-mediated mechanisms of action. Some of these compounds, such as the anti-cd38 daratumumab and isatuximab, the anti-slamf-7 elotuzumab, and the antibody-drug conjugate belantamab-mafodotin, have been tested in large clinical trials and have now fully entered the real-life management. The bispecific T-cell engagers are under investigation with promising results, and other satisfactory data is expected from the application of nanotechnologies. The perfect timing to introduce these drugs in the sequence of treatment and their adverse events represent new challenges to be addressed, and further experience is required to improve their use.

Daratumumab combined with dexamethasone and lenalidomide or bortezomib in relapsed/refractory multiple myeloma (RRMM) patients: Report from the multiple myeloma GIMEMA Lazio group.

The multiple myeloma (MM) treatment has changed over the last years due to the introduction of novel drugs. Despite improvements in the MM outcome, MM remains an incurable disease. Daratumumab is a human IgGK monoclonal antibody targeting CD38 with tumor activity associated with immunomodulatory mechanism. In combination with standard of care regimens, including bortezomib (Vd) or lenalidomide (Rd), daratumumab prolonged progression-free survival (PFS) in patients (pts) with relapsed/refractory multiple myeloma (RRMM) and in new diagnosis MM. We report the data of the MM GIMEMA Lazio group in 171 heavily treated pts who received daratumumab, lenalidomide and dexamethasone (DRd) or daratumumab, velcade and dexamethasone (DVd). The overall response rate was 80%, and the overall survival (OS) and PFS were 84% and 77%, respectively. In addition, pts treated with DRd showed a better median PFS compared to pts treated with DVd, at 12 and 24 months, respectively. The most common hematologic treatment-emergent adverse events (TAEs) were neutropenia, thrombocytopenia, and anemia. The most common nonhematologic TAEs were peripheral sensory neuropathy and infections. Our data confirmed that DRd or DVd therapy is effective and safe in RRMM pts, and our real-life analysis could support the physicians regarding the choice of optimal therapy in this setting of pts.

High Levels of Circulating Tumor Plasma Cells as a Key Hallmark of Aggressive Disease in Transplant-Eligible Patients With Newly Diagnosed Multiple Myeloma.

PURPOSE: High levels of circulating tumor plasma cells (CTC-high) in patients with multiple myeloma are a marker of aggressive disease. We aimed to confirm the prognostic impact and identify a possible cutoff value of CTC-high for the prediction of progression-free survival (PFS) and overall survival (OS), in the context of concomitant risk features and minimal residual disease (MRD) achievement. METHODS: CTC were analyzed at diagnosis with two-tube single-platform flow cytometry (sensitivity 4 × 10-5) in patients enrolled in the multicenter randomized FORTE clinical trial (ClinicalTrials.gov identifier: NCT02203643). MRD was assessed by second-generation multiparameter flow cytometry (sensitivity 10-5). We tested different cutoff values in series of multivariate (MV) Cox proportional hazards regression analyses on PFS outcome and selected the value that maximized the Harrell's C-statistic. We analyzed the impact of CTC on PFS and OS in a MV analysis including baseline features and MRD negativity. RESULTS: CTC analysis was performed in 401 patients; the median follow-up was 50 months (interquartile range, 45-54 months). There was a modest correlation between the percentage of CTC and bone marrow plasma cells (r = 0.38). We identified an optimal CTC cutoff of 0.07% (approximately 5 cells/µL, C-index 0.64). In MV analysis, CTC-high versus CTC-low patients had significantly shorter PFS (hazard ratio, 2.61; 95% CI, 1.49 to 2.97, P < .001; 4-year PFS 38% v 69%) and OS (hazard ratio, 2.61; 95% CI, 1.49 to 4.56; P < .001; 4-year OS 68% v 92%). The CTC levels, but not the bone marrow plasma cell levels, affected the outcome. The only factor that reduced the negative impact of CTC-high was the achievement of MRD negativity (interaction P = .039). CONCLUSION: In multiple myeloma, increasing levels of CTC above an optimal cutoff represent an easy-to-assess, robust, and independent high-risk factor. The achievement of MRD negativity is the most important factor that modulates their negative prognostic impact.

An N-glycosylation hotspot in immunoglobulin κ light chains is associated with AL amyloidosis.

Immunoglobulin light chain (AL) amyloidosis is caused by a small, minimally proliferating B-cell/plasma-cell clone secreting a patient-unique, aggregation-prone, toxic light chain (LC). The pathogenicity of LCs is encrypted in their sequence, yet molecular determinants of amyloidogenesis are poorly understood. Higher rates of N-glycosylation among clonal κ LCs from patients with AL amyloidosis compared to other monoclonal gammopathies indicate that this post-translational modification is associated with a higher risk of developing AL amyloidosis. Here, we exploited LC sequence information from previously published amyloidogenic and control clonal LCs and from a series of 220 patients with AL amyloidosis or multiple myeloma followed at our Institutions to define sequence and spatial features of N-glycosylation, combining bioinformatics, biochemical, proteomics, structural and genetic analyses. We found peculiar sequence and spatial pattern of N-glycosylation in amyloidogenic κ LCs, with most of the N-glycosylation sites laying in the framework region 3, particularly within the E strand, and consisting mainly of the NFT sequon, setting them apart with respect to non-amyloidogenic clonal LCs. Our data further support a potential role of N-glycosylation in determining the pathogenic behavior of a subset of amyloidogenic LCs and may help refine current N-glycosylation-based prognostic assessments for patients with monoclonal gammopathies.

Autologous stem cell transplantation in multiple myeloma patients over 70 years: A GIMEMA Lazio Working Group experience in a retrospective case-control study.

High-dose chemotherapy followed by autologous stem cell transplantation (auto-SCT) is the standard treatment for young patient ≤65 years with multiple myeloma (MM). The role of auto-SCT in elderly patients older than 70 years remains controversial in the era of novel agents and especially since the recent introduction of monoclonal antibodies (AbMo). In this study, we evaluated 12 patients with MM over 70 years old undergoing auto-SCT (elderly graft cohort) in seven centers of GIMEMA Working Group Lazio. We compared the baseline characteristics, treatment and outcome with 97 MM elderly patients who did not receive auto-SCT (nontransplant patients) from the same registry who were ≥ 70 years old, but did not undergo auto-SCT. The median progression free survival (PFS) for graft versus no-graft cohort was 56.4 versus 26.1 months, respectively. There was a trend for better PFS among graft compared to nontransplant patient (p = .1). On the other hand, the median overall survival for transplant versus nontransplant cohort was 107.6 versus 49.5 months (p = .02). Despite the small number of patients aged ≥70 years and ≤74 years, it seems that auto-SCT is well tolerated, safe and effective. Therefore, we propose that it should be considered an important treatment option in the era of new drugs in elderly fit patients with MM.

Physicians' Perceptions of Clinical Utility of a Digital Health Tool for Electronic Patient-Reported Outcome Monitoring in Real-Life Hematology Practice. Evidence From the GIMEMA-ALLIANCE Platform.

Digital health tools are increasingly being used in cancer care and may include electronic patient-reported outcome (ePRO) monitoring systems. We examined physicians' perceptions of usability and clinical utility of a digital health tool (GIMEMA-ALLIANCE platform) for ePRO monitoring in the real-life practice of patients with hematologic malignancies. This tool allows for the collection and assessment of ePROs with real-time graphical presentation of results to medical staff. Based on a predefined algorithm, automated alerts are sent to medical staff. Participating hematologists completed an online survey on their experience with the platform. Of the 201 patients invited to participate between December 2020 and June 2021 (cut-off date for current analysis), 180 (90%) agreed to enter the platform and had a median age of 57 years. Twenty-three hematologists with a median age of 42 years and an average of 17 years of experience in clinical practice were surveyed. All hematologists agreed or strongly agreed that the platform was easy to use, and 87%, agreed or strongly agreed that ePROs data were useful to enhance communication with their patients. The majority of physicians (78%) accessed the platform at least once per month to consult the symptom and health status profile of their patients. The frequency of access was independent of physician sex (p=0.393) and years of experience in clinical practice (p=0.404). In conclusion, our preliminary results support the clinical utility, from the perspective of the treating hematologist, of integrating ePROs into the routine cancer care of patients with hematologic malignancies.