Effectiveness and infectious complications of BCMA T-cell engagers in treating multiple myeloma: Real-world evidence from Sweden.

BACKGROUND: Multiple myeloma (MM), an incurable disease characterized by frequent relapses and a need for multiple treatments, often progresses to a relapse/refractory status resistant to all available drugs and drug classes. Bispecific antibodies, specifically BCMA T-cell engagers, have emerged as effective treatments for MM, demonstrating impressive efficacy. However, these treatments can adversely affect the immune system, increasing vulnerability to infections. METHODS/RESULTS: This study evaluated the efficacy and safety of BCMA T-cell engagers in 58 Swedish patients with poor MM prognosis. The patients exhibited a 69% overall response rate, with 69% survival and 60% progression-free survival at 15 months. CONCLUSIONS: Despite the risk of infectious complications, the prognosis of MM patients can be significantly improved with vigilant monitoring and proactive management of infections. This real-world data highlight the potential of BCMA T-cell engagers in treating MM, emphasizing the need for careful patient monitoring to mitigate infection risks.

Construction of immune-related gene pairs signature to predict the overall survival of multiple myeloma patients based on whole bone marrow gene expression profiling.

Multiple myeloma (MM) is a plasma cell dyscrasia that is characterized by the uncontrolled proliferation of malignant PCs in the bone marrow. Due to immunotherapy, attention has returned to the immune system in MM, and it appears necessary to identify biomarkers in this area. In this study, we created a prognostic model for MM using immune-related gene pairs (IRGPs), with the advantage that it is not affected by technical bias. After retrieving microarray data of MM patients, bioinformatics analyses like COX regression and least absolute shrinkage and selection operator (LASSO) were used to construct the signature. Then its prognostic value is assessed via time-dependent receiver operating characteristic (ROC) and the Kaplan-Meier (KM) analysis. We also used XCELL to examine the status of immune cell infiltration among MM patients. 6-IRGP signatures were developed and proved to predict MM prognosis with a P-value of 0.001 in the KM analysis. Moreover, the risk score was significantly associated with clinicopathological characteristics and was an independent prognostic factor. Of note, the combination of age and ß2-microglobulin with risk score could improve the accuracy of determining patients' prognosis with the values of the area under the curve (AUC) of 0.73 in 5 years ROC curves. Our model was also associated with the distribution of immune cells. This novel signature, either alone or in combination with age and ß2-microglobulin, showed a good prognostic predictive value and might be used to guide the management of MM patients in clinical practice.

A novel T cell-redirecting anti-GPRC5D × CD3 bispecific antibody with potent antitumor activity in multiple myeloma preclinical models.

G-protein-coupled receptor class 5 member D (GPRC5D) is detected in malignant plasma cells in approximately 90% of patients diagnosed with multiple myeloma (MM). Here, we constructed BsAb5003, a novel humanized bispecific monoclonal antibody targeting CD3 and GPRC5D, and evaluated its therapeutic impact on MM. BsAb5003 induced specific cytotoxicity of GPRC5D-positive MM cells with concomitant T cell activation and cytokine release. The efficacy of BsAb5003 was associated with GPRC5D expression levels in MM cell lines. Flow cytometry analysis of bone marrow mononuclear cells (BMMNCs) from 49 MM patients revealed that GPRC5D was expressed in a wide population of MM patients, including heavily treated and high-risk patients. In ex vivo assays using BMMNCs, BsAb5003 induced potent efficacy against CD138 + MM cells in both newly diagnosed and relapsed/refractory patient samples in a GPRC5D expression-dependent manner. BsAb5003 significantly enhanced T cell activation and cytokine production in combination with immunomodulatory drugs (IMiDs) against MM cell lines. BsAb5003 also demonstrated significant inhibition of in vivo tumor growth by recruiting T cells. Taken together, these results suggest that T cell-redirecting bispecific antibody targeting GPRC5D as monotherapy and combination therapy with IMiDs could be a highly potent and effective treatment approach for a wide population of MM patients.

Response to anti-SARS-CoV-2 mRNA vaccines in multiple myeloma and chronic lymphocytic leukemia patients.

Multiple myeloma (MM) and chronic lymphocytic leukemia (CLL) patients have increased morbidity and mortality rates of COVID-19 due to immunosuppression associated with the disease and ongoing therapy. The same immune impairment accompanying CLL and MM also affects suboptimal vaccine response. The study assessed the effectiveness of the humoral and T cell-mediated immunity following mRNA COVID-19 vaccination (using either BNT162b2 or mRNA-1273) in short-term (2-5 weeks after second dose) and long-term follow-up (12 weeks after vaccination). Between March and August 2021, blood samples were obtained from 62 CLL and 60 MM patients from eight different hematology departments in Poland. Total anti-RBD antibodies were detected in 37% MM patients before vaccination, increased to 91% and 94% in short- and long-term follow-up, respectively. In CLL, serological responses were detectable in 21% of patients before vaccination and increased to 45% in the short-term and 71% in long-term observation. We detected a tendency to higher frequencies of specific CD8+ T cells against SARS-CoV-2 after vaccination compared to samples before vaccination in MM patients and no changes in frequencies of specific T cells in CLL patients. Our study provides novel insights into mRNA vaccination efficacy in immunocompromised MM and CLL patients, and our findings highlight that specific CD8+ T cells against SARS-CoV-2 might be induced by vaccination but do not correlate positively with serological responses.

TIGIT inhibition and lenalidomide synergistically promote antimyeloma immune responses after stem cell transplantation in mice.

Autologous stem cell transplantation (ASCT) with subsequent lenalidomide maintenance is standard consolidation therapy for multiple myeloma, and a subset of patients achieve durable progression-free survival that is suggestive of long-term immune control. Nonetheless, most patients ultimately relapse, suggesting immune escape. TIGIT appears to be a potent inhibitor of myeloma-specific immunity and represents a promising new checkpoint target. Here we demonstrate high expression of TIGIT on activated CD8+ T cells in mobilized peripheral blood stem cell grafts from patients with myeloma. To guide clinical application of TIGIT inhibition, we evaluated identical anti-TIGIT antibodies that do or do not engage FcγR and demonstrated that anti-TIGIT activity is dependent on FcγR binding. We subsequently used CRBN mice to investigate the efficacy of anti-TIGIT in combination with lenalidomide maintenance after transplantation. Notably, the combination of anti-TIGIT with lenalidomide provided synergistic, CD8+ T cell-dependent, antimyeloma efficacy. Analysis of bone marrow (BM) CD8+ T cells demonstrated that combination therapy suppressed T cell exhaustion, enhanced effector function, and expanded central memory subsets. Importantly, these immune phenotypes were specific to the BM tumor microenvironment. Collectively, these data provide a logical rationale for combining TIGIT inhibition with immunomodulatory drugs to prevent myeloma progression after ASCT.

Talquetamab, a T-Cell-Redirecting GPRC5D Bispecific Antibody for Multiple Myeloma.

BACKGROUND: G protein-coupled receptor, family C, group 5, member D (GPRC5D) is an orphan receptor expressed in malignant plasma cells. Talquetamab, a bispecific antibody against CD3 and GPRC5D, redirects T cells to mediate killing of GPRC5D-expressing myeloma cells. METHODS: In a phase 1 study, we evaluated talquetamab administered intravenously weekly or every other week (in doses from 0.5 to 180 µg per kilogram of body weight) or subcutaneously weekly, every other week, or monthly (5 to 1600 µg per kilogram) in patients who had heavily pretreated relapsed or refractory multiple myeloma that had progressed with established therapies (a median of six previous lines of therapy) or who could not receive these therapies without unacceptable side effects. The primary end points - the frequency and type of dose-limiting toxic effects (study part 1 only), adverse events, and laboratory abnormalities - were assessed in order to select the recommended doses for a phase 2 study. RESULTS: At the data-cutoff date, 232 patients had received talquetamab (102 intravenously and 130 subcutaneously). At the two subcutaneous doses recommended for a phase 2 study (405 µg per kilogram weekly [30 patients] and 800 µg per kilogram every other week [44 patients]), common adverse events were cytokine release syndrome (in 77% and 80% of the patients, respectively), skin-related events (in 67% and 70%), and dysgeusia (in 63% and 57%); all but one cytokine release syndrome event were of grade 1 or 2. One dose-limiting toxic effect of grade 3 rash was reported in a patient who had received talquetamab at the 800-µg dose level. At median follow-ups of 11.7 months (in patients who had received talquetamab at the 405-µg dose level) and 4.2 months (in those who had received it at the 800-µg dose level), the percentages of patients with a response were 70% (95% confidence interval [CI], 51 to 85) and 64% (95% CI, 48 to 78), respectively. The median duration of response was 10.2 months and 7.8 months, respectively. CONCLUSIONS: Cytokine release syndrome, skin-related events, and dysgeusia were common with talquetamab treatment but were primarily low-grade. Talquetamab induced a substantial response among patients with heavily pretreated relapsed or refractory multiple myeloma. (Funded by Janssen Research and Development; MonumenTAL-1 ClinicalTrials.gov number, NCT03399799.).

Identification of CD8+ T-cell epitope from multiple myeloma-specific antigen AKAP4.

Multiple myeloma (MM) is a malignant plasma cell disorder affecting mainly the elderly population. Revolutionary progress in immunotherapy has been made recently, including monoclonal antibodies and chimeric antigen receptor T cell (CAR-T) therapies; however, the high relapse rate remains problematic. Therefore, combination therapies against different targets would be a reasonable strategy. In this study, we present a new X-chromosome encoded testis-cancer antigen (CTA) AKAP4 as a potential target for MM. AKAP4 is expressed in MM cell lines and MM primary malignant plasma cells. HLA-A*0201-restricted cytotoxic T lymphocytes (CTLs) induced by dendritic cells (DCs) transduced with an adenovirus vector encoding the full-length AKAP4 gene were demonstrated to lyse AKAP4+ myeloma cells. Seven of the 12 candidate epitopes predicated by the BIMAS and SYFPEITH algorithms were able to bind HLA-A*0201 in the T2 binding assay, of which only two peptides were able to induce CTL cytotoxicity in the co-culture of peptide-loaded human mature dendritic cells and the autologous peripheral blood mononuclear cells (PBMCs) from the same HLA-A*0201 donor. The AKAP4 630-638 VLMLIQKLL was identified as the strongest CTL epitope by the human IFN-γ ELISPOT assay. Finally, the VLMLIQKLL-specific CTLs can lyse the HLA-A*0201+AKAP4+ myeloma cell line U266 in vitro, and inhibit tumor growth in the mice bearing U266 tumors in vivo. These results suggest that the VLMLIQKLL epitope could be used to develop cancer vaccine or T-cell receptor transgenic T cells (TCR-T) to kill myeloma cells.

Changes in Bone Marrow Tumor and Immune Cells Correlate with Durability of Remissions Following BCMA CAR T Therapy in Myeloma.

Chimeric antigen-receptor (CAR) T cells lead to high response rates in myeloma, but most patients experience recurrent disease. We combined several high-dimensional approaches to study tumor/immune cells in the tumor microenvironment (TME) of myeloma patients pre- and post-B-cell maturation antigen (BCMA)-specific CAR T therapy. Lower diversity of pretherapy T-cell receptor (TCR) repertoire, presence of hyperexpanded clones with exhaustion phenotype, and BAFF+PD-L1+ myeloid cells in the marrow correlated with shorter progression-free survival (PFS) following CAR T therapy. In contrast, longer PFS was associated with an increased proportion of CLEC9A+ dendritic cells (DC), CD27+TCF1+ T cells with diverse T-cell receptors, and emergence of T cells expressing marrow-residence genes. Residual tumor cells at initial response express stemlike genes, and tumor recurrence was associated with the emergence of new dominant clones. These data illustrate a dynamic interplay between endogenous T, CAR T, myeloid/DC, and tumor compartments that affects the durability of response following CAR T therapy in myeloma. SIGNIFICANCE: There is an unmet need to identify determinants of durable responses following BCMA CAR T therapy of myeloma. High-dimensional analysis of the TME was performed to identify features of immune and tumor cells that correlate with survival and suggest several strategies to improve outcomes following CAR T therapy. See related commentary by Graham and Maus, p. 478. This article is highlighted in the In This Issue feature, p. 476.

Clinical characteristics and outcomes of IgD myeloma: experience across UK national trials.

Immunoglobulin D (IgD) myeloma is a subtype often considered to have adverse features and inferior survival, but there is a paucity of data from large clinical studies. We compare the clinical characteristics and outcomes of patients with IgD myeloma from UK phase 3 myeloma trials analyzed in 2 groups: old (1980-2002) and recent (2002-2016) clinical trials, based on the time of adoption of novel myeloma therapies. Patients with IgD myeloma comprised 44 of 2789 (1.6%) and 70 of 5773 (1.2%) of the old and recent trials, respectively. Overall, IgD myeloma was associated with male predominance, low-level paraproteinemia (<10g/L), and λ light chain preference. The frequency of ultra-high-risk cytogenetics was similar in IgD myeloma compared with other subtypes (4.3% vs 5.3%, P > .99). Despite the old trial series being a younger group (median age: 59 vs 63 years, P = .015), there was a higher frequency of bone lesions, advanced stage at diagnosis, worse performance status, and severe renal impairment compared with the recent trials. Furthermore, the early mortality rate was significantly higher for the old trial series (20% vs 4%, P = .01). The overall response rate following induction therapy was significantly higher in the recent trials (89% vs 43%, P < .0001), and this was consistent with improved median overall survival (48 months; 95% confidence interval [CI] 35-67 months vs 22 months; 95% CI, 16-29 months). Survival outcomes for IgD myeloma have significantly improved and are now comparable to other myeloma types because of earlier diagnosis, novel therapies, and improved supportive care. This trial was registered at clinicaltrials.gov as # NCT01554852.

Teclistamab in Relapsed or Refractory Multiple Myeloma.

BACKGROUND: Teclistamab is a T-cell-redirecting bispecific antibody that targets both CD3 expressed on the surface of T cells and B-cell maturation antigen expressed on the surface of myeloma cells. In the phase 1 dose-defining portion of the study, teclistamab showed promising efficacy in patients with relapsed or refractory multiple myeloma. METHODS: In this phase 1-2 study, we enrolled patients who had relapsed or refractory myeloma after at least three therapy lines, including triple-class exposure to an immunomodulatory drug, a proteasome inhibitor, and an anti-CD38 antibody. Patients received a weekly subcutaneous injection of teclistamab (at a dose of 1.5 mg per kilogram of body weight) after receiving step-up doses of 0.06 mg and 0.3 mg per kilogram. The primary end point was the overall response (partial response or better). RESULTS: Among 165 patients who received teclistamab, 77.6% had triple-class refractory disease (median, five previous therapy lines). With a median follow-up of 14.1 months, the overall response rate was 63.0%, with 65 patients (39.4%) having a complete response or better. A total of 44 patients (26.7%) were found to have no minimal residual disease (MRD); the MRD-negativity rate among the patients with a complete response or better was 46%. The median duration of response was 18.4 months (95% confidence interval [CI], 14.9 to not estimable). The median duration of progression-free survival was 11.3 months (95% CI, 8.8 to 17.1). Common adverse events included cytokine release syndrome (in 72.1% of the patients; grade 3, 0.6%; no grade 4), neutropenia (in 70.9%; grade 3 or 4, 64.2%), anemia (in 52.1%; grade 3 or 4, 37.0%), and thrombocytopenia (in 40.0%; grade 3 or 4, 21.2%). Infections were frequent (in 76.4%; grade 3 or 4, 44.8%). Neurotoxic events occurred in 24 patients (14.5%), including immune effector cell-associated neurotoxicity syndrome in 5 patients (3.0%; all grade 1 or 2). CONCLUSIONS: Teclistamab resulted in a high rate of deep and durable response in patients with triple-class-exposed relapsed or refractory multiple myeloma. Cytopenias and infections were common; toxic effects that were consistent with T-cell redirection were mostly grade 1 or 2. (Funded by Janssen Research and Development; MajesTEC-1 ClinicalTrials.gov numbers, NCT03145181 and NCT04557098.).

GPRC5D-Directed CAR Yields 100% Response Rate.

Patients with refractory or relapsed multiple myeloma usually develop resistance to the two approved BCMA-targeting chimeric antigen receptor (CAR) T cells. A preliminary study of a new CAR T-cell therapy that zeroes in on the GPRC5D protein on multiple myeloma cells suggests that this approach is safe and effective. All 10 patients treated with the GPRC5D-targeting cells showed responses.

Monoclonal antibody Daratumumab promotes macrophage-mediated anti-myeloma phagocytic activity via engaging FC gamma receptor and activation of macrophages.

Daratumumab (DAR) is novel human anti-CD38 IgG1, high-affinity human monoclonal antibody having broad-spectrum killing activity. The antibody is recommended to treat multiple myeloma. Recently Antibody-dependent cellular phagocytosis (ADCP) have been identified as the potential mechanism of DAR in addition to complement-dependent cytotoxicity (CDC) and antibody-dependent cell-mediated cytotoxicity (ADCC). In the present study we evaluated the effect of Daratumumab on other effector cells of multiple myeloma. Luciferase+ MM.1R GFP cells were selected for the study. For immune-compromised multiple myeloma tumour xenograft mouse model we used severe combined immunodeficient beige (SCID-beige), NOD SCID gamma (NSG) and C57Bl/6j mice. Bioluminescence imaging was carried by injecting luciferin, and in vivo confocal microscopy was done for tracing bone marrow niches. Spleen and tumours were submitted to immunophenotypic analysis. MTT assay was done for cell proliferation studies. We established tumour xenograft mouse model. It was found that DAR showed significant anti-tumour effect in tumour xenograft multiple myeloma mice. We found that DAR showed anti-tumour activity via Fc-FcγR interaction with macrophages. DAR induced phenotypic activation of macrophages in mice and resulted in ADCP of cancerous cells via interacting Fc-FcγR in vitro. The study suggested that DAR exerted anti-tumour activity in multiple myeloma by interacting with Fc-FcγR.

Effect of Autologous Stem Cell Transplantation Combined with Modified VTD Regimen on Elderly Patients with Multiple Myeloma and Its Influence on miRNA Cytokines.

OBJECTIVE: To explore the effect of autologous stem cell transplantation combined with modified VTD regimen on elderly patients with multiple myeloma and its influence on miRNA cytokines. METHODS: The data of 42 elderly patients with multiple myeloma who were treated in our hospital from May 2010 to June 2018 were retrospectively analyzed, and they were divided into the combined group (autologous stem cell transplantation combined with improved VTD scheme, n = 25) and the control group (improved VTD scheme, n = 17) according to different treatment schemes, and the clinical efficacy of the two groups was compared. The levels of CD3+, CD4+, CD4+/CD8+, and Treg were measured in the two groups. The expression levels of miRNA-15a, miRNA-16, and miRNA-21 in the bone marrow fluid of the two groups were measured before and after treatment. The levels of M protein and myeloma cells in the two groups were detected. Comparing the incidence of adverse reactions between the two groups, the Kaplan-Meier method was used for survival analysis. RESULTS: The total effective rate of the combined group (84.00%) was higher than that of the control group (52.94%), and the difference was statistically significant (P < 0.05). After treatment, the levels of CD3+, CD4+, CD4+/CD8+, Treg, miRNA-15a, and miRNA-16 in the combined group were higher than those in the control group, and the levels of miRNA-21, M protein, and myeloma cells were lower than those in the control group, with statistical significance (P < 0.05). There was no significant difference in adverse reactions between the two groups (P > 0.05). The first, second, and third year survival rates of group A (96.00%, 88.00%, and 80.00%) were significantly higher than those of the control group (70.59%, 58.82%, and 47.06%), and the difference was statistically significant (P < 0.05). CONCLUSION: Autologous stem cell transplantation combined with a modified VTD regimen can effectively improve the immune function and survival rate of elderly patients with multiple myeloma, which is safe and effective.

Inflammation and infection in plasma cell disorders: how pathogens shape the fate of patients.

The role of infection and chronic inflammation in plasma cell disorders (PCD) has been well-described. Despite not being a diagnostic criterion, infection is a common complication of most PCD and represents a significant cause of morbidity and mortality in this population. As immune-based therapeutic agents are being increasingly used in multiple myeloma, it is important to recognize their impact on the epidemiology of infections and to identify preventive measures to improve outcomes. This review outlines the multiple factors attributed to the high infectious risk in PCD (e.g. the underlying disease status, patient age and comorbidities, and myeloma-directed treatment), with the aim of highlighting future prophylactic and preventive strategies that could be implemented in the clinic. Beyond this, infection and pathogens as an entity are believed to also influence disease biology from initiation to response to treatment and progression through a complex interplay involving pathogen exposure, chronic inflammation, and immune response. This review will outline both the direct and indirect role played by oncogenic pathogens in PCD, highlight the requirement for large-scale studies to decipher the precise implication of the microbiome and direct pathogens in the natural history of myeloma and its precursor disease states, and understand how, in turn, pathogens shape plasma cell biology.

Impact on NK cell functions of acute versus chronic exposure to extracellular vesicle-associated MICA: Dual role in cancer immunosurveillance.

Natural killer (NK) cells are innate cytotoxic lymphocytes that play a key role in cancer immunosurveillance thanks to their ability to recognize and kill cancer cells. NKG2D is an activating receptor that binds to MIC and ULBP molecules typically induced on damaged, transformed or infected cells. The release of NKG2D ligands (NKG2DLs) in the extracellular milieu through protease-mediated cleavage or by extracellular vesicle (EV) secretion allows cancer cells to evade NKG2D-mediated immunosurveillance. In this work, we investigated the immunomodulatory properties of the NKG2D ligand MICA*008 associated to distinct populations of EVs (i.e., small extracellular vesicles [sEVs] and medium size extracellular vesicles [mEVs]). By using as model a human MICA*008-transfected multiple myeloma (MM) cell line, we found that this ligand is present on both vesicle populations. Interestingly, our findings reveal that NKG2D is specifically involved in the uptake of vesicles expressing its cognate ligand. We provide evidence that MICA*008-expressing sEVs and mEVs are able on one hand to activate NK cells but, following prolonged stimulation induce a sustained NKG2D downmodulation leading to impaired NKG2D-mediated functions. Moreover, our findings show that MICA*008 can be transferred by vesicles to NK cells causing fratricide. Focusing on MM as a clinically and biologically relevant model of tumour-NK cell interactions, we found enrichment of EVs expressing MICA in the bone marrow of a cohort of patients. All together our results suggest that the accumulation of NKG2D ligands associated to vesicles in the tumour microenvironment could favour the suppression of NK cell activity either by NKG2D down-modulation or by fratricide of NK cell dressed with EV-derived NKG2D ligands.

A BAFF ligand-based CAR-T cell targeting three receptors and multiple B cell cancers.

B cell-activating factor (BAFF) binds the three receptors BAFF-R, BCMA, and TACI, predominantly expressed on mature B cells. Almost all B cell cancers are reported to express at least one of these receptors. Here we develop a BAFF ligand-based chimeric antigen receptor (CAR) and generate BAFF CAR-T cells using a non-viral gene delivery method. We show that BAFF CAR-T cells bind specifically to each of the three BAFF receptors and are effective at killing multiple B cell cancers, including mantle cell lymphoma (MCL), multiple myeloma (MM), and acute lymphoblastic leukemia (ALL), in vitro and in vivo using different xenograft models. Co-culture of BAFF CAR-T cells with these tumor cells results in induction of activation marker CD69, degranulation marker CD107a, and multiple proinflammatory cytokines. In summary, we report a ligand-based BAFF CAR-T capable of binding three different receptors, minimizing the potential for antigen escape in the treatment of B cell cancers.