The first case of multiple myeloma treated with ASCT followed by Anti-BCMA CAR-T cells using retrovirus vector: A case report.

Chimeric antigen receptor T (CAR-T)-cell therapy targeting B-cell maturation antigen (BCMA) is currently one of the promising treatment methods for relapsed/refractory multiple myeloma (MM). Herein, this study is a case report on a 41-year-old male patient with MM. Unfortunately, he still developed multidrug-resistant, refractory, and bone marrow suppression after receiving multiline high-intensity chemotherapy. After a detailed evaluation, the physician recommended autologous hematopoietic stem cell transplantation (ASCT) support, followed by sequential immunotherapy with autologous anti- BCMA CAR-T cells. The CAR-T product is a novel anti-BCMA CAR-T based on Retrovirus vectors (RV). It was worth noting that the patient achieved VGPR (very good partial remission) one month after infusion of anti-BCMA CAR-T cells. Recent tests have found that the M protein was no longer detectable and the patient has achieved CR (complete response). Although grade 3 cytokine release syndrome (CRS) appeared, the symptom was well controlled and immune effector cell-associated neurotoxicity syndrome (ICANS) did not occur. This was the first case report of RV prepared anti-BCMA CAR-T cells combined with ASCT for the treatment of MM patient in clinical practice, indicating that the RV-based anti-BCMA-CAR-T cells with ASCT have excellent therapeutic efficacy and high safety in triple-refractory MM patients.

Persistent cytopenias after anti-BCMA CAR T-cell therapy are associated with reduced hematopoietic activity in posttreatment bone marrows.

OBJECTIVES: We attempt to analyze bone marrow findings and correlation with cytopenia(s) after anti-B-cell maturation antigen (BCMA) chimeric antigen receptor (CAR) T-cell infusion in this study. METHODS: Relevant clinicopathologic data, including complete blood counts, neutrophil counts, relevant therapy history, and pre- and posttherapy bone marrow evaluations, were studied in 12 patients who received anti-BCMA CAR T-cell therapy. RESULTS: Bone marrow findings after CAR T-cell therapy were available in 6 of 12 cases, 3 of which showed markedly hypocellular marrow with either markedly reduced or essentially absent hematopoiesis. One case showed a hypocellular marrow with trilineage hematopoiesis, while the remaining 2 cases showed persistent involvement by plasma cell myeloma. Reticulin stains did not reveal significant fibrosis. Ten patients had anemia, and 8 patients had leukopenia and thrombocytopenia at day 90 posttherapy. Long-term follow-up showed persistent disease in 10 of 12 cases. CONCLUSIONS: Prolonged cytopenias occur in most patients after BCMA CAR T-cell therapy with bone marrow evaluations demonstrating associated marked hypocellularity with minimal or no hematopoiesis without an increase in fibrosis.

Impact of extramedullary multiple myeloma on outcomes with idecabtagene vicleucel.

Idecabtagene vicleucel (Ide-cel) has demonstrated excellent efficacy and durable responses in patients with relapsed/refractory multiple myeloma (RRMM). However, the outcomes with ide-cel in patients with extramedullary disease (EMD) remain incompletely characterized. We included patients with RRMM treated with ide-cel between May 2021 and April 2023 across 11 US academic institutions. Visceral or soft tissue lesions non-contiguous from bone was classified as EMD. Time-to-event analyses were performed from date of ide-cel infusion. Among 351 patients, 84 (24%) had EMD prior to infusion. The median follow-up from ide-cel infusion was 18.2 months (95% CI: 17-19.3). The day 90 overall response rates (ORR) were 52% vs. 82% for the EMD and non-EMD cohorts, respectively (p < 0.001). The median progression-free survival (PFS) was 5.3 months (95% CI: 4.1-6.9) for the EMD cohort vs. 11.1 months (95% CI: 9.2-12.6; p < 0.0001) for the non-EMD cohort. In a multivariable analysis, EMD was an independent predictor of inferior PFS [hazard ratio 1.5 (1.1-2.2), p = 0.02]. The median overall survival was 14.8 months [95% CI: 9-Not reached (NR)] vs. 26.9 months (26.3 vs. NR, p = 0.006) for the EMD and non-EMD cohorts, respectively. Extramedullary disease represents an independent predictor of inferior day 90 ORR and PFS among patients treated with ide-cel.

Therapeutic potential of third-generation chimeric antigen receptor T cells targeting B cell maturation antigen for treating multiple myeloma.

Multiple myeloma (MM) is an incurable hematologic malignancy characterized by the rapid proliferation of malignant plasma cells within the bone marrow. Standard therapies often fail due to patient resistance. The US FDA has approved second-generation chimeric antigen receptor (CAR) T cells targeting B-cell maturation antigen (anti-BCMA-CAR2 T cells) for MM treatment. However, achieving enduring clinical responses remains a challenge in CAR T cell therapy. This study developed third-generation T cells with an anti-BCMA CAR (anti-BCMA-CAR3). The CAR incorporated a fully human scFv specific to BCMA, linked to the CD8 hinge region. The design included the CD28 transmembrane domain, two co-stimulatory domains (CD28 and 4-1BB), and the CD3ζ signaling domain (28BBζ). Lentiviral technology generated these modified T cells, which were compared against anti-BCMA-CAR2 T cells for efficacy against cancer. Anti-BCMA-CAR3 T cells exhibited significantly higher cytotoxic activity against BCMA-expressing cells (KMS-12-PE and NCI-H929) compared to anti-BCMA-CAR2 T cells. At an effector-to-target ratio of 10:1, anti-BCMA-CAR3 T cells induced lysis in 75.5 ± 3.8% of NCI-H929 cells, whereas anti-BCMA-CAR2 T cells achieved 56.7 ± 3.4% (p = 0.0023). Notably, after twelve days of cultivation, anti-BCMA-CAR3 T cells nearly eradicated BCMA-positive cells (4.1 ± 2.1%), while anti-BCMA-CAR2 T cells allowed 36.8 ± 20.1% to survive. This study highlights the superior efficacy of anti-BCMA-CAR3 T cells against both low and high BCMA-expressing MM cells, surpassing anti-BCMA-CAR2 T cells. These findings suggest potential for advancing anti-BCMA-CAR3 T cells in chimeric antigen receptor T (CAR-T) therapy for relapsed/refractory MM.

Safety and efficacy of anti-BCMA CAR-T cell therapy in older adults with multiple myeloma: A systematic review and meta-analysis.

INTRODUCTION: Anti-B-cell maturation antigen (BCMA) chimeric antigen receptor T-cell (CAR-T) therapy is transforming the care of patients with relapsed/refractory multiple myeloma (MM). Unfortunately, despite being a disease of older adults these patients remain under-represented in most pivotal clinical trials. We performed a systematic review and proportion meta-analysis of prospective clinical trials and observational studies of anti-BCMA CAR-T therapy in patients with MM with the aim to determine the efficacy and safety of this therapy in older adults (≥65 years). MATERIALS AND METHODS: We searched the Pubmed, Scopus, Web of Science (WOS), Ovid, Embase, CENTRAL, and CINAHL databases through September 9, 2022 and abstracts from the American Society of Hematology (ASH) Annual Meeting 2022. Primary outcome measures included overall response rate (ORR), rates of cytokine release syndrome (CRS), and immune cell-effector-associated neurotoxicity syndrome (ICANS). study was registered with PROSPERO (study number: CRD42022334287). RESULTS: After screening 2218 references, 14 studies were included for data extraction, with a total of 558 patients, 26.2% (n = 146) of whom were older adults. The pooled ORR amongst this population was 93%, which was comparable to the ORR of 86% amongst younger patients. In older adults, the rates of CRS (any grade) and grade ≥ 3 were 95% and 21%, respectively. For younger patients, the pooled rate of CRS (any grade) and grade ≥ 3 CRS was 91% and 20%, respectively. The rate of ICANS (any grade) in older adults was 15%, which was higher than that observed in those <65 years. CONCLUSION: Older adults experience comparable outcomes to younger patients with anti-BCMA CAR-T therapy, albeit with numerically higher rates of neurotoxicity.

Cost-Effectiveness of Anti-BCMA Chimeric Antigen Receptor T Cell Therapy in Relapsed/Refractory Multiple Myeloma.

Despite its promising outcomes, anti-BCMA chimeric antigen receptor T cell therapy (CAR-T) is the most expensive myeloma treatment developed to date, and its cost-effectiveness is an important issue. This study aimed to assess the cost-effectiveness of anti-BCMA CAR-T compared to standard antimyeloma therapy in patients with relapsed/refractory multiple myeloma. The model included myeloma patients in Japan and the United States who have received ≥3 prior lines of antimyeloma therapy, including immunomodulatory drugs, proteasome inhibitors, and anti-CD38 monoclonal antibodies. A Markov model was constructed to compare the CAR-T strategy, in which patients receive either idecabtagene vicleucel (ide-cel) or ciltacabtagene autoleucel (cilta-cel) followed by 3 lines of multiagent chemotherapy after relapse, and the no CAR-T strategy, in which patients receive only chemotherapy. Data from the LocoMMotion, KarMMa, and CARTITUDE-1 trials were extracted. Several assumptions were made regarding long-term progression-free survival (PFS) with CAR-T. Extensive scenario analyses were made regarding regimens for no CAR-T strategies. The outcome was an incremental cost-effectiveness ratio (ICER) with willingness-to-pay thresholds of ¥7,500,000 in Japan and $150,000 in the United States. When a 5-year PFS of 40% with cilta-cel was assumed, the ICER of the CAR-T strategy versus the no CAR-T strategy was ¥7,603,823 per QALY in Japan and $112,191 per QALY in the United States over a 10-year time horizon. When a 5-year PFS of 15% with ide-cel was assumed, the ICER was ¥20,388,711 per QALY in Japan and $261,678 per QALY in the United States over a 10-year time horizon. The results were highly dependent on the PFS assumption with CAR-T and were robust to changes in most other parameters and scenarios. Although anti-BCMA CAR-T can be cost-effective even under current pricing, a high long-term PFS is necessary.

PD1+TIGIT+2B4+KLRG1+ Cells Might Underlie T Cell Dysfunction in Patients Treated with BCMA-Directed Chimeric Antigen Receptor T Cell Therapy.

Chimeric antigen receptor T cell (CAR-T) therapy has shown rapid, frequent, and deep responses in patients with relapsed/refractory multiple myeloma (RRMM). However, relapse frequently occurs following CAR-T therapy, and the cause of this resistance is not well defined. Among the potential mechanisms of resistance, T cell intrinsic factors may be an important source of failure. Here we used spectral flow cytometry to identify the changes in T cell phenotypes in bone marrow aspirates at different stages of multiple myeloma progression, including cases that relapsed after anti-BCMA CAR-T therapy. We identified completely different T cell phenotypes in RRMM and post CAR-T relapse cases compared to healthy donors and earlier stages of multiple myeloma, novel double-negative CD3+ T cells in RRMM and CAR-T relapsed cases, and differences in CD8 T cell phenotype at the baseline between peripheral blood and bone marrow from healthy donors. We found that the majority of T cells in RRMM patients and significant T cell subsets in post-CAR-T relapsed patients expressed multiple coinhibitory markers, including PD1, TIGIT, 2B4, and KLRG1.

Single-cell transcriptomic atlas throughout anti-BCMA CAR-T therapy in patients with multiple myeloma.

Introduction: The emergence of chimeric antigen receptor (CAR)-T therapy targeting B cell maturation antigen (BCMA) has improved the prognosis of patients with multiple myeloma (MM); however, the majority of patients eventually experience relapse. Methods: In this study, employing the latest single-cell RNA sequencing technology, we examined 24 bone marrow or peripheral blood samples collected throughout the course of anti-BCMA CAR-T therapy, analyzing a total of 59,725 bone marrow cells and 72,479 peripheral blood cells. Results: Our findings reveal that tumor cells in relapsed patient exhibit higher expression levels of HSP90B1 and HSPA5, and demonstrate significantly enriched pathways regarding endoplasmic reticulum stress and unfolded protein response. In the analysis of T cells, we observed that patient with impaired effector function and increased expression of immune checkpoints in endogenous T cell are more susceptible to relapse. Notably, T cells from both the bone marrow microenvironment and peripheral blood share highly similar biological characteristics. Discussion: Overall, this study provides a comprehensive atlas of endogenous immune cells, particularly in the relatively long term, after CAR-T therapy. It offers clinical evidence for a deeper understanding of the internal environment post CAR-T treatment and for identifying mechanisms underlying relapse.

Laryngeal edema as a symptom of local cytokine release syndrome after BCMA-targeting CAR-T therapy for relapsed and refractory multiple myeloma.

Cytokine release syndrome (CRS) can be a major side effect of chimeric antigen receptor T-cell (CAR-T) therapy, and may occasionally become life-threatening in patients with factors such as high tumor burden or poor performance status. Among the many CRS events observed in B-cell maturation antigen (BCMA)-targeting CAR-T therapy, local symptoms (also called local CRS) are poorly understood due to their low frequency. Here, we present the case of a 54-year-old woman with refractory multiple myeloma exhibiting laryngeal edema as a local CRS. Before CAR-T therapy, she was diagnosed with progressive disease indicated by a left thyroid mass. After local irradiation, she received the BCMA-targeting CAR-T agent idecabtagene vicleucel (ide-cel). On day 2, the patient developed CRS, which resolved on treatment with tocilizumab. However, on day 4, laryngeal edema worsened, and was judged to be a local CRS. Intravenous dexamethasone rapidly reduced this edema. In conclusion, laryngeal edema rarely occurs as a local CRS, and to the best of our knowledge, has never been reported after ide-cel infusion. Dexamethasone was effective for reducing the local reaction that persisted after treatment of systemic symptoms with tocilizumab.

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

BACKGROUND: BCMA-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. METHODS: Data 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. RESULTS: At 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). CONCLUSIONS: These 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.

Identification of potential resistance mechanisms and therapeutic targets for the relapse of BCMA CAR-T therapy in relapsed/refractory multiple myeloma through single-cell sequencing.

BACKGROUND: BCMA CAR-T is highly effective for relapsed/refractory multiple myeloma(R/R-MM) and significantly improves the survival of patients. However, the short remission time and high relapse rate of MM patients treated with BCMA CAR-T remain bottlenecks that limit long-term survival. The immune microenvironment of the bone marrow (BM) in R/R-MM may be responsible for this. The present study aims to present an in-depth analysis of resistant mechanisms and to explore potential novel therapeutic targets for relapse of BCMA CAR-T treatment via single-cell RNA sequencing (scRNA-seq) of BM plasma cells and immune cells. METHODS: This study used 10X Genomic scRNA-seq to identify cell populations in R/R-MM CD45+ BM cells before BCMA CAR-T treatment and relapse after BCMA CAR-T treatment. Cell Ranger pipeline and CellChat were used to perform detailed analysis. RESULTS: We compared the heterogeneity of CD45+ BM cells before BCMA CAR-T treatment and relapse after BCMA CAR-T treatment. We found that the proportion of monocytes/macrophages increased, while the percentage of T cells decreased at relapse after BCMA CAR-T treatment. We then reclustered and analyzed the alterations in plasma cells, T cells, NK cells, DCs, neutrophils, and monocytes/macrophages in the BM microenvironment before BCMA CAR-T treatment and relapse after BCMA CAR-T treatment. We show here that the percentage of BCMA positive plasma cells increased at relapse after BCMA CAR-T cell therapy. Other targets such as CD38, CD24, SLAMF7, CD138, and GPRC5D were also found to be expressed in plasma cells of the R/R-MM patient at relapse after BCMA CAR-T cell therapy. Furthermore, exhausted T cells, TIGIT+NK cells, interferon-responsive DCs, and interferon-responsive neutrophils, increased in the R/R-MM patient at relapse after BCMA CAR-T cell treatment. Significantly, the proportion of IL1ßhi Mφ, S100A9hi Mφ, interferon-responsive Mφ, CD16hi Mφ, MARCO hi Mφ, and S100A11hi Mφ significantly increased in the R/R-MM patient at relapse after BCMA CAR-T cell therapy. Cell-cell communication analysis indicated that monocytes/macrophages, especially the MIF and APRIL signaling pathway are key players in R/R-MM patient at relapse after BCMA CAR-T cell therapy. CONCLUSION: Taken together, our data extend the understanding of intrinsic and extrinsic relapse of BCMA CAR-T treatment in R/R-MM patient and the potential mechanisms involved in the alterations of antigens and the induced immunosuppressive microenvironment, which may provide a basis for the optimization of BCMA CAR-T strategies. Further studies should be performed to confirm these findings.

Non-Conventional Allogeneic Anti-BCMA Chimeric Antigen Receptor-Based Immune Cell Therapies for Multiple Myeloma Treatment.

MM, characterized by the progressive accumulation of clonal plasma cells in bone marrow, remains a severe medical problem globally. Currently, almost all MM patients who have received standard treatments will eventually relapse. Autologous anti-BCMA CAR-T cells are one of the FDA-approved immunotherapy cell-based products for treating adults with relapsed or refractory (r/r) multiple myeloma. However, this type of CAR-T cell product has several limitations, including high costs, long manufacturing times, and possible manufacturing failure, which significantly hinder its wider application for more patients. In this review, we summarized the current development stage of applying other types of immune cells to bring the anti-BCMA CAR-T therapy from autologous to allogeneic. In general, anti-BCMA CAR gene-edited αß T cells and CAR-Natural Killer (NK) cells are at the forefront, with multiple clinical trials ongoing, while CAR-γδ T cells and CAR-invariant Natural Killer T (iNKT) cells are still in pre-clinical studies. Other immune cells such as macrophages, B cells, and dendritic cells have been mainly developed to target other antigens and have the potential to be used to target BCMA. Nevertheless, additional regulatory requirements might need to be taken into account in developing these non-conventional allogenic anti-BCMA CAR-based cell products.

Innovation in BCMA CAR-T therapy: Building beyond the Model T.

Autologous chimeric antigen receptor T-cell (CAR-T) therapies targeting B-cell maturation antigen (BCMA) have revolutionized the field of multiple myeloma in the same way that the Ford Model T revolutionized the original CAR world a century ago. However, we are only beginning to understand how to improve the efficacy and usability of these cellular therapies. In this review, we explore three automotive analogies for innovation with BCMA CAR-T therapies: stronger engines, better mileage, and hassle-free delivery. Firstly, we can build stronger engines in terms of BCMA targeting: improved antigen binding, tools to modulate antigen density, and armoring to better reach the antigen itself. Secondly, we can improve "mileage" in terms of response durability through ex vivo CAR design and in vivo immune manipulation. Thirdly, we can implement hassle-free delivery through rapid manufacturing protocols and off-the-shelf products. Just as the Model T set a benchmark for car manufacturing over 100 years ago, idecabtagene vicleucel and ciltacabtagene autoleucel have now set the starting point for BCMA CAR-T therapy with their approvals. As with any emerging technology, whether automotive or cellular, the best in innovation and optimization is yet to come.

Triple MAPK inhibition salvaged a relapsed post-BCMA CAR-T cell therapy multiple myeloma patient with a BRAF V600E subclonal mutation.

BACKGROUND: Multiple Myeloma (MM) is a progressive plasma cell neoplasm characterized by heterogeneous clonal expansion. Despite promising response rates achieved with anti-BCMA CAR-T cell therapy, patients may still relapse and there are currently no clear therapeutic options in post-CAR-T settings. In this report, we present a case of a post-BCMA CAR-T relapsed/refractory (RR) MM patient with skin extramedullary disease (EMD) in which a novel MAPK inhibition combinatorial strategy was implemented based on next-generation sequencing and in vitro experiments. CASE PRESENTATION: A 61-year-old male with penta-refractory MM penta- (IgA lambda), ISS stage 3 with hyperdiploidy, gain of 1q21 and del13 was treated with anti-BCMA CAR-T cell therapy, achieving a best response of VGPR. He progressed after 6 months and was salvaged for a short period with autologous stem cell transplantation. Eventually, he progressed with extramedullary disease manifested as subcutaneous nodules. Based on whole-exome sequencing, we identified a BRAF (V600E) dominant subclone in both bone marrow and cutaneous plasmacytoma. Following in vitro experiments, and according to our previous studies, we implemented a triple MAPK inhibition strategy under which the patient achieved a very good partial response for 110 days, which allowed to bridge him to subsequent clinical trials and eventually achieve a stringent complete response (sCR). CONCLUSION: Here, we show the applicability, effectiveness, and tolerability the triple MAPK inhibition strategy in the context of post-BCMA CAR-T failure in specific subset of patients. The triple therapy could bridge our hospice bound RRMM patient with BRAF (V600E) to further therapeutic options where sCR was achieved. We will further evaluate triple MAPK inhibition in patients with BRAF V600E in a precision medicine clinical trial launching soon.

sBCMA Plasma Level Dynamics and Anti-BCMA CAR-T-Cell Treatment in Relapsed Multiple Myeloma.

BACKGROUND: Novel chimeric antigen receptor T-cells (CAR-T) target the B-cell maturation antigen (BCMA) expressed on multiple myeloma cells. Assays monitoring CAR-T cell expansion and treatment response are being implemented in clinical routine. METHODS: Plasma levels of soluble BCMA (sBCMA) and anti-BCMA CAR-T cell copy numbers were monitored in the blood, following CAR-T cell infusion in patients with relapsed multiple myeloma. sBCMA peptide concentration was determined in the plasma, applying a human BCMA/TNFRS17 ELISA. ddPCR was performed using probes targeting the intracellular signaling domains 4-1BB und CD3zeta of the anti-BCMA CAR-T construct. RESULTS: We report responses in the first five patients who received anti-BCMA CAR- T cell therapy at our center. Four patients achieved a complete remission (CR) in the bone marrow one month after CAR-T infusion, with three patients achieving stringent CR, determined by flow cytometry techniques. Anti-BCMA CAR-T cells were detectable in the peripheral blood for up to 300 days, with copy numbers peaking 7 to 14 days post-infusion. sBCMA plasma levels started declining one to ten days post infusion, reaching minimal levels 30 to 60 days post infusion, before rebounding to normal levels. CONCLUSIONS: Our data confirm a favorable response to treatment in four of the first five patients receiving anti-BCMA CAR-T at our hospital. Anti-BCMA CAR-T cell expansion seems to peak in the peripheral blood in a similar pattern compared to the CAR-T cell products already approved for lymphoma treatment. sBCMA plasma level may be a valid biomarker in assessing response to BCMA-targeting therapies in myeloma patients.

A combination of humanized anti-BCMA and murine anti-CD38 CAR-T cell therapy in patients with relapsed or refractory multiple myeloma.

Chimeric antigen receptor T (CAR-T) cells are a promising approach in hematopoietic malignancies. We evaluated the safety and efficacy of a combination of humanized anti-BCMA and murine anti-CD38 CAR-T cell therapy in patients with relapsed or refractory multiple myeloma (R/RMM). Twenty-two R/RMM patients, with a median age of 56 years and a median number of previous therapies of 8, were included in the study. Both CAR-T cells infusion doses were 2.0 × 106/kg. The overall response rate (ORR) was 90.9%, with 12 patients (54.5%) achieving a strict complete response/complete response (sCR/CR). The 24-month overall survival (OS) rate was 56.6%, and the progression-free survival (PFS) rate was 48.7%. Cytokine release syndrome (CRS) of grades 1-2 occurred in 16 patients (72.7%) and of grade ≥3 in six patients (27.3%). Immune effector cell-associated neurotoxic syndrome (ICANS) of grades 1-2 occurred in three patients (13.6%). The combination therapy is potential in R/RMM patients.Trial registration: The patients were enrolled in clinical trials registered as ChiCTR1800017051.

Harnessing natural killer cells for the treatment of multiple myeloma.

Multiple myeloma (MM) is hematologic malignancy that is associated with profound immune alterations. Myeloma cells are susceptible to killing by natural killer (NK) cells but acquire the ability to elude NK cell surveillance by avoiding recognition and suppressing NK cell function. Major advances in the treatment of multiple myeloma have been achieved by effective new drugs that redirect NK cells and enhance their function. Despite significant progress, myeloma remains incurable and novel treatment approaches are required. Strategies to take advantage of the intrinsic antitumor properties of NK cells to treat MM represent a novel immunotherapeutic approach. One such strategy is adoptive NK cell therapy that consist of infusions of NK cells that have been propagated ex vivo. Adoptive NK cell therapy encompasses contemporary genetic engineering strategies such as chimeric antigen receptor (CAR)-engineered NK cells. An alternative approach involves the use of pharmacologic agents to enhance NK cell activity against myeloma. NK cell-modulating therapies can be used to bolster the function of endogenous NK cells or to enhance the efficacy of adoptively infused NK cells. Here, we review the mechanistic complexities influencing NK cell activity in MM and highlight a variety of innovative NK cell-based strategies being developed for the treatment of MM.

Comparison of FACS and PCR for Detection of BCMA-CAR-T Cells.

Chimeric-antigen-receptor (CAR)-T-cell therapy is already widely used to treat patients who are relapsed or refractory to chemotherapy, antibodies, or stem-cell transplantation. Multiple myeloma still constitutes an incurable disease. CAR-T-cell therapy that targets BCMA (B-cell maturation antigen) is currently revolutionizing the treatment of those patients. To monitor and improve treatment outcomes, methods to detect CAR-T cells in human peripheral blood are highly desirable. In this study, three different detection reagents for staining BCMA-CAR-T cells by flow cytometry were compared. Moreover, a quantitative polymerase chain reaction (qPCR) to detect BCMA-CAR-T cells was established. By applying a cell-titration experiment of BCMA-CAR-T cells, both methods were compared head-to-head. In flow-cytometric analysis, the detection reagents used in this study could all detect BCMA-CAR-T cells at a similar level. The results of false-positive background staining differed as follows (standard deviation): the BCMA-detection reagent used on the control revealed a background staining of 0.04% (±0.02%), for the PE-labeled human BCMA peptide it was 0.25% (±0.06%) and for the polyclonal anti-human IgG antibody it was 7.2% (±9.2%). The ability to detect BCMA-CAR-T cells down to a concentration of 0.4% was similar for qPCR and flow cytometry. The qPCR could detect even lower concentrations (0.02-0.01%). In summary, BCMA-CAR-T-cell monitoring can be reliably performed by both flow cytometry and qPCR. In flow cytometry, reagents with low background staining should be preferred.

Innovative Anti-CD38 and Anti-BCMA Targeted Therapies in Multiple Myeloma: Mechanisms of Action and Resistance.

CD38 and B-cell maturation antigens (BCMAs) are prevalently expressed on neoplastic plasma cells in multiple myeloma (MM), making them ideal therapeutic targets. Anti-CD38 monoclonal antibodies, such as approved daratumumab and isatuximab, are currently the milestone in MM treatment because they induce plasma cell apoptosis and kill through several mechanisms, including antibody-dependent cellular cytotoxicity or phagocytosis. BCMA is considered an excellent target in MM, and three different therapeutic strategies are either already available in clinical practice or under investigation: antibody-drug conjugates, such as belantamab-mafodotin; bispecific T cell engagers; and chimeric antigen receptor-modified T cell therapies. Despite the impressive clinical efficacy of these new strategies in the treatment of newly diagnosed or multi-refractory MM patients, several mechanisms of resistance have already been described, including antigen downregulation, the impairment of antibody-dependent cell cytotoxicity and phagocytosis, T- and natural killer cell senescence, and exhaustion. In this review, we summarize the current knowledge on the mechanisms of action and resistance of anti-CD38 and anti-BCMA agents and their clinical efficacy and safety.

Efficacy and follow-up of humanized anti-BCMA CAR-T cell therapy in relapsed/refractory multiple myeloma patients with extramedullary-extraosseous, extramedullary-bone related, and without extramedullary disease.

The prognosis of patients with multiple myeloma (MM) with extramedullary disease (EMD) remains poor. A high overall response rate (ORR) has been reported following anti-B-cell maturation antigen (BCMA) chimeric antigen receptor (CAR)-T cell therapy in relapsed/refractory (R/R) patients with MM; however, data on patients with EMD remain limited. Herein, we compared and analyzed the efficacy and long-term follow-up of anti-BCMA CAR-T cell therapy in R/R MM patients with extramedullary-extraosseous (EM-E), extramedullary-bone related (EM-B), and without extramedullary disease. No difference in the ORR was observed between the three groups. The long-term efficacy of anti-BCMA CAR-T cell therapy in the EM-E group was worse than that in patients without EMD and with EM-B. In the EM-E group, disease progression was the reappearance of extramedullary lesions without an increase in the MM cell percentage or M protein level. Although no difference in the proportion of CAR-T cells was detected among the three groups, the EM-E group might exhibit a relatively high grade of cytokine release syndrome following anti-BCMA CAR-T therapy. Interleukin-6 levels in the without EMD group were lower than those in the EM-E and EM-B groups. However, given the small number of cases in the three groups, statistical analysis was not performed.(ChiCTR1800017051 and ChiCTR2000033925).