A phase I study of anti-BCMA CAR T cell therapy in relapsed/refractory multiple myeloma and plasma cell leukemia

BCMA CAR-T therapy as salvage therapy in patients with plasmablastic myeloma

OBJECTIVES

Plasmablastic myeloma (PBM) is a variant of multiple myeloma associated with a poor prognosis. We investigated the efficacy and safety of B-cell maturation antigen (BCMA) chimeric antigen receptor T cell (CAR-T) therapy in patients with PBM.

METHODS

The study comprised six patients diagnosed with PBM between January 1, 2023 and December 31, 2023. The patients received BCMA single-target CAR-T therapy or BMCA/CD19 dual-target CAR-T therapy, with some patients undergoing hematopoietic stem cell transplantation before treatment. The median patient age was 55.5 years (range, 41-63). Four patients exhibited high-risk cytogenetic abnormalities.

RESULTS

The objective response rate (ORR) was 83.3%, with four of six patients achieving a complete response or better and three of six achieving a strigent complete response. Two patients exhibited progression-free survival (PFS) of at least 6 months, one of whom succumbed to a pulmonary infection, whereas four patients died of disease progression. Cytokine release syndrome (CRS) was observed in all patients, three of whom experienced grade 3-4 CRS. Two patients experienced grade 1-2 immune effector cell-associated neurotoxicity syndrome. There were no CRS-related deaths.

CONCLUSION

BCMA CAR-T therapy was safe and effective as a salvage treatment for PBM, and its toxicity was controllable. Future research will examine the use of CAR-T therapy as part of combination regimens.

Achieving stringent complete remission in relapsed/refractory multiple myeloma with liver extramedullary disease after CAR‑T cell therapy: A case report

Multiple myeloma (MM) is a clonal plasma cell malignancy characterized by bone marrow infiltration and the presence of monoclonal proteins in the blood and urine. However, despite the advances that have been made in terms of its treatment, relapsed/refractory MM (RRMM) remains a significant challenge. Chimeric antigen receptor (CAR)-T cell therapy, which involves the engineering of T-cells to express CARs targeting specific antigens on tumor cells, has emerged as a promising therapeutic approach for RRMM. The present case report presents a patient with RRMM with liver extramedullary disease (EMD) who achieved stringent complete remission following CAR-T cell therapy. This case report highlights the efficacy of CAR-T cell therapy in treating RRMM, also discussing the patient's clinical course, treatment outcomes and side effects, and moreover, a review of the literature that focuses on the treatment of EMD using CAR-T cell therapy.

European Myeloma Network Group review and consensus statement on primary plasma cell leukemia

BACKGROUND

Primary plasma cell leukemia (PPCL) is the most aggressive disorder among plasma cell malignancies, with new diagnostic criteria recently established by the International Myeloma Working Group. Studies have shown that PPCL patients receiving a combination of novel agents, but not eligible for transplantation, may have a median survival up to 2 years, extended to 3 years or more in those undergoing transplant procedures. These findings remain unsatisfactory, particularly if compared with progresses obtained in multiple myeloma.

DESIGN

A European Myeloma Network (EMN) expert panel reviewed the most recent literature and selected the areas of major concern in the management of PPCL by generating and rank ordering key questions using the criterion of clinical relevance. Multistep procedures were utilized to achieve a consensus on recommendations. The Delphi questionnaire method was used and a consensus of at least 80% was reached for all final statements.

RESULTS

An extended overview of current biological, clinical, prognostic, and therapeutic aspects of PPCL, including ongoing and close to start clinical trials, is presented. Furthermore, updated guidelines for the management of PPCL and practical recommendations are provided, in the context of current knowledge about this disease, also looking at possible future perspectives to ameliorate the outcome of these patients.

CONCLUSIONS

PPCL still remains an unmet clinical need. Notwithstanding, some not negligible progresses have been recently achieved. The European Myeloma Network panel strongly support ongoing and planned clinical trials, as well as biological studies based on novel technologies, strategies, and treatment options that could represent breakthroughs we have been waiting for too long.

Long-term follow-up of BCMA CAR-T cell therapy in patients with relapsed/refractory multiple myeloma

BACKGROUND

B-cell maturation antigen (BCMA)-targeting chimeric antigen receptor (CAR) T-cell immunotherapy has shown promising results in the treatment of relapsed or refractory multiple myeloma (R/RMM). This study presents the updated long-term outcomes from our center.

METHODS

Between July 30, 2018, and September 27, 2023, 141 patients with R/RMM who received BCMA CAR-T therapy were enrolled. Patients underwent conditioning chemotherapy with cyclophosphamide and fludarabine, followed by BCMA CAR-T cell infusion at a median dose of 2.36×106 cells/kg. The study evaluated overall response rates, long-term efficacy, safety profiles, and their associations with clinical and disease characteristics.

RESULTS

At a median follow-up of 20.2 months, the safety profile of the therapy was manageable. Grade 3/4 cytokine release syndrome occurred in 36.2% of patients, with no cases of severe neurotoxicity reported. 1-month post-infusion, grade ≥3 anemia persisted in 39.6% of patients, while neutropenia (43.3%) and thrombocytopenia (52.2%) were observed. The objective response rate (ORR) among evaluable patients was 94.8%, with 50.7% achieving a complete response (CR). The 4-year progression-free survival and overall survival rates were 37.4% (95% CI, 29.1% to 48.1%) and 63.2% (95% CI, 54.8% to 72.8%), respectively, with survival curves showing gradual flattening over time. Patients with a history of autologous stem cell transplantation (ASCT) and those with extramedullary disease demonstrated significantly inferior efficacy and survival outcomes. Peak CAR-T cell expansion was positively correlated with ORR (p<0.001) and CR (p<0.001). Notably, patients with prior ASCT exhibited significantly lower CAR-T cell expansion compared with those without prior ASCT (p<0.001). Immunophenotypic analysis of infused CAR-T cells demonstrated impaired fitness in patients who received ASCT in the past year.

CONCLUSIONS

BCMA CAR-T therapy in patients with R/RMM results in significant and sustained responses, with a manageable safety profile on a large scale. Prior ASCT and extramedullary disease represent adverse prognostic factors. Patients with a history of ASCT demonstrate limited peak CAR-T cell expansion.

Extraosseous Plasmacytoma Confers Poor Outcomes in Primary Plasma Cell Leukemia

BACKGROUND

Primary plasma cell leukemia (PPCL) is one of the most aggressive diseases in oncohematology. Due to its low incidence, there is no established standard treatment, and it is considered an incurable disease.

AIMS

This study presents our experience and outcomes of 92 cases of PPCL between January 2011 and December 2020.

METHODS

Fat pad biopsy was positive for Congo red in six (35 %) of 17 patients, solitary extraosseous plasmacytoma was observed in 30 (32.5 %), and bone marrow fibrosis was identified in 81 (88 %) patients.

RESULTS

While most patients (69.5 %) received conventional chemotherapy combinations, 30.5 % underwent proteasome inhibitor-based treatment and/or autologous stem cell transplantation (auto-SCT). In this series, we report that the presence of extraosseous plasmacytoma, treatment failure, and therapy with classic chemotherapy agents were independent covariates associated with poor survival.

CONCLUSIONS

In PPCL, extraosseous plasmacytoma, treatment failure, and treatment with conventional chemotherapy were associated with poor outcomes.

Extramedullary Multiple Myeloma: Challenges and Opportunities

Extramedullary multiple myeloma (EMM), defined in this review as soft tissue plasmacytomas resulting from hematogenous spread, is characterized by the ability of MM cells to proliferate outside of the bone marrow microenvironment. It is aggressive, often associated with high-risk cytogenetics and early relapse, and independently portends significantly shorter progression-free and overall survival, even in the era of highly effective immunotherapies. The molecular and microenvironmental factors underlying extramedullary MM dissemination continue to be studied to inform the development of better treatments. In this review, we discuss our current understanding of the biology of EMM, focusing on its distinct molecular and microenvironmental characteristics vis-à-vis MM. We also review the current treatment strategies, acknowledging the paucity of large, randomized studies specific to this population.

Role of Chimeric Antigen Receptor T-Cells in the Evolving Therapeutic Landscape of Multiple Myeloma: A Literature Review

Multiple myeloma (MM) is a quotidian malignant disorder of plasma cells. It is hallmarked by the uncontrolled growth of bone marrow plasma cells, leading to multiorgan dysfunction. Despite ongoing advancements in remedies, including chemotherapy, radiotherapy, immunomodulatory drugs, stem cell transplantations, and countless other lines of treatment, the management of MM remains a challenge. Recent studies indicate promising outcomes with chimeric antigen receptor T-cell (CAR-T) therapy, especially in patients who have previously undergone other treatments. This literature review aims to explore various facets of MM and the progress made with CAR-T therapy, emphasizing the mechanism, effectiveness, and safety profile.

A 5-Year Follow-up Clinical Study of the B-cell Maturation Antigen Chimeric Antigen Receptor T-cell Therapy HDS269B in Patients with Relapsed or Refractory Multiple Myeloma

PURPOSE

This study aimed to report the 5-year clinical outcomes of anti-B-cell maturation antigen chimeric antigen receptor (CAR) T-cell (HDS269B) therapy in patients with relapsed/refractory multiple myeloma (RRMM), including those with poor performance status [Eastern Cooperative Oncology Group (ECOG) scores 3 to 4], and to identify factors influencing long-term outcomes.

PATIENTS AND METHODS

Forty-nine patients with RRMM enrolled from 2016 to 2020 received HDS269B (9 × 106 cells/kg) after receiving a conditioning chemotherapy consisting of cyclophosphamide and fludarabine. The overall response, long-term outcomes, and safety were assessed, as were their associations with clinical and disease characteristics.

RESULTS

With a median follow-up of 59.0 months, the overall response rate was 77.55%. The median progression-free survival (PFS) and overall survival (OS) were 9.5 months [95% confidence interval (CI), 5.01-13.99] and 20.0 months (95% CI, 11.26-28.74), respectively. The 5-year PFS and OS rates were 21.3% (95% CI, 12.3%-36.7%) and 34.1% (95% CI, 22.7%-51.3%), respectively. Patients with ECOG 0 to 2 had marked longer survival, with a median PFS of 11.0 months and a median OS of 41.8 months. Early minimal residual disease negativity, higher and persistent CAR T-cell expansion, and the absence of extramedullary disease were associated with better survival outcomes. No new CAR T-cell therapy-associated toxicities were observed. Importantly, ECOG scores 0 to 2, prior therapy lines <4, and CAR T-cell persistence at ≥6 months were independently associated with longer OS.

CONCLUSIONS

HDS269B is effective and safe, especially for patients with ECOG scores 0 to 2. Early CAR T-cell intervention may improve prognosis in patients with RRMM.

Poor outcome despite modern treatments: A retrospective study of 99 patients with primary and secondary plasma cell leukemia

BACKGROUND

Plasma cell leukemia (PCL) is a rare monoclonal gammopathy, associated with short survival. Because of its very low incidence, only a few cohorts have been reported and thus, information on this disease is scarce. The goal of this study was to better understand the clinical features, prognostic factors, and efficacy of modern treatments in both primary PCL (pPCL) and secondary PCL (sPCL).

METHODS

We performed a retrospective, multicenter study of patients diagnosed with PCL, defined as circulating plasma cells ≥20% of total leukocytes and/or ≥2 × 109/L.

RESULTS

We identified 99 eligible PCL patients, of whom 33 were pPCL and 66 were sPCL. The median progression-free survival (PFS) to frontline treatment and overall survival (OS) were, respectively, 4.8 (95% CI, 0.4-9.2) and 18.3 months (95% CI, 0.0-39.0) for pPCL and 0.8 (95% CI, 0.5-1.1) and 1.2 months (95% CI, 0.9-1.5) for sPCL (both p < 0.001). We observed no improvement in OS over time (2005-2012 vs. 2013-2020, p = 0.629 for pPCL and p = 0.329 for sPCL). Finally, our data suggested that sPCL originates from a high-risk multiple myeloma (MM) population with a short OS (median 30.2 months), early relapse after stem cell transplant (median 11.9 months) and a high proportion of patients with multiple cytogenetic abnormalities (36% with ≥2 abnormalities).

CONCLUSIONS

This study is one of the largest PCL cohorts reported. We are also the first to investigate characteristics of MM before its transformation into sPCL and demonstrate that high-risk biologic features already present at the time of MM diagnosis. Moreover, our data highlights the lack of improvement in PCL survival in recent years and the urgent need for better treatment options.

Current Status on Management of Primary Plasma Cell Leukemia

PURPOSEOF REVIEW

Plasma Cell Leukemia (PCL) is a very rare and highly aggressive form of plasma cell dyscrasia. This review seeks to evaluate the outcomes of PCL in the context of combination novel agent therapy and stem cell transplant (SCT) protocols.

RECENT FINDINGS

The diagnostic criteria for PCL have now evolved to include patients with 5% circulating PC. While management remains challenging, the incorporation of novel agent-based induction regimen has significantly improved early mortality and reduced attrition of patients proceeding to SCT. In recent prospective clinical trials, patients with PCL demonstrated an overall response rates of 69% to 86%, with progression-free and overall survival ranging from 13.8 to 15.5 months and 24.8 to 36.3 months, respectively. B-cell lymphoma 2 (BCL2) inhibitors, such as venetoclax present a targeted intervention opportunity for patients with PCL with t(11;14). Dedicated clinical trials tailored to PCL are crucial, integrating newer therapies in the frontline setting to further optimize responses and enhance overall outcomes.

Alliance between titans: combination strategies of CAR-T cell therapy and oncolytic virus for the treatment of hematological malignancies

There have been several clinical studies using chimeric antigen receptor (CAR)-T cell therapy for different hematological malignancies. It has transformed the therapy landscape for hematologic malignancies dramatically. Nonetheless, in acute myeloid leukemia (AML) and T cell malignancies, it still has a dismal prognosis. Even in the most promising locations, recurrence with CAR-T treatment remains a big concern. Oncolytic viruses (OVs) can directly lyse tumor cells or cause immune responses, and they can be manipulated to create therapeutic proteins, increasing anticancer efficacy. Oncolytic viruses have been proven in a rising number of studies to be beneficial in hematological malignancies. There are limitations that cannot be avoided by using either treatment alone, and the combination of CAR-T cell therapy and oncolytic virus therapy may complement the disadvantages of individual application, enhance the advantages of their respective treatment methods and improve the treatment effect. The alternatives for combining two therapies in hematological malignancies are discussed in this article.

A meta-analysis to assess the risk of bleeding and thrombosis following chimeric antigen receptor T-cell therapy: Communication from the ISTH SSC Subcommittee on Hemostasis and Malignancy

BACKGROUND

Chimeric antigen receptor T-cell (CAR T-cell) therapy is increasingly utilized for treatment of hematologic malignancies. Hematologic toxicities including thrombosis and bleeding complications have been reported. Accurate estimates for thrombotic and bleeding outcomes are lacking.

OBJECTIVES

We performed a systematic review and meta-analysis in patients who received CAR T-cell therapy for an underlying hematologic malignancy with the objective to: a) assess the thrombosis and bleeding risk associated with CAR T-cell therapy, b) assess the impact of CRS and ICANS on the risks of thrombosis and bleeding, and c) assess the safety of anticoagulant or antiplatelet use in the period following treatment with CAR T-cell therapy.

METHODS

We searched MEDLINE, EMBASE, and Cochrane CENTRAL up to February 2022 for studies reporting thrombotic or bleeding outcomes in patients receiving CAR T-cell therapy. Pooled event rates were calculated using a random-effects model. We performed subgroup analyses stratified by follow-up duration, CAR T-cell target antigen, and underlying hematologic malignancy.

RESULTS

We included 47 studies with a total of 7040 patients. High heterogeneity between studies precluded reporting of overall pooled rates of thrombotic and bleeding events. In studies with follow-up duration of ≤6 months, the pooled incidence of venous thrombotic events was 2.4% (95% CI, 1.4%-3.4%; I2 = 0%) per patient-month, whereas the rate was 0.1% (95% CI, 0%-0.1%; I2 = 0%) per patient-month for studies with longer follow-up periods (>6 months). The pooled incidences of any bleeding events per patient-month in studies with follow-up duration of ≤6 months and >6 months were 1.9% (95% CI, 0.6%-3.1%; I2 = 78%) and 0.3% (95% CI: 0%-0.8%, I2 = 40%), respectively. Secondary analyses by CAR T-cell target antigen, underlying malignancy, and primary outcome of the studies did not reveal significant differences in the rates of thromboembolism, any bleeding events, or major bleeding events.

CONCLUSION

The risk of both thrombosis and bleeding following CAR T-cell therapy appears to be highest in the initial months following infusion.

A Clinical Perspective on Plasma Cell Leukemia: A Single-Center Experience

Circulating plasma cells (CPCs) are detected in most multiple myeloma (MM) patients, both at diagnosis and on relapse. A small subset, plasma cell leukemia (PCL), represents a different biology and has a poor prognosis. In this retrospective analysis, we evaluated patients with primary (pPCL, n = 35) or secondary (sPCL, n = 49), with ≥5% CPCs and a smaller subset with lower CPCs of 1-4% (n = 20). The median age was 61 years; 45% were men and 54% were Black. High-risk cytogenetics were found in 87% and extramedullary disease in 47%. For the entire cohort, 75% received a proteasome inhibitor, 70% chemotherapy, 54% an immunomodulatory drug, 24% a daratumumab-based regimen and 26% an autologous stem cell transplant (ASCT). The treatments marginally improved the overall survival (OS) for pPCL vs. sPCL (13 vs. 3.5 months p = 0.002). However, the 5-year survival for the whole cohort was dismal at 11%. High-risk cytogenetics, low platelets, extramedullary disease and high LDH were independently associated with poor outcomes. Further research is urgently needed to expand the treatment options and improve the outcomes in PCL.

CAR-T-Cell-Based Cancer Immunotherapies: Potentials, Limitations, and Future Prospects

Cancer encompasses various elements occurring at the cellular and genetic levels, necessitating an immunotherapy capable of efficiently addressing both aspects. T cells can combat cancer cells by specifically recognizing antigens on them. This innate capability of T cells has been used to develop cellular immunotherapies, but most of them can only target antigens through major histocompatibility complexes (MHCs). New gene-editing techniques such as clustered regularly interspaced short palindromic repeat (CRISPR)-associated protein 9 (CRISPR-cas9) can precisely edit the DNA sequences. CRISPR-cas9 has made it possible to generate genetically engineered chimeric antigen receptors (CARs) that can overcome the problems associated with old immunotherapies. In chimeric antigen receptor T (CAR-T) cell therapy, the patient's T cells are isolated and genetically modified to exhibit synthetic CAR(s). CAR-T cell treatment has shown remarkably positive clinical outcomes in cancers of various types. Nevertheless, there are various challenges that reduce CAR-T effectiveness in solid tumors. It is required to address these challenges in order to make CAR-T cell therapy a better and safer option. Combining CAR-T treatment with other immunotherapies that target multiple antigens has shown positive outcomes. Moreover, recently generated Boolean logic-gated advanced CARs along with artificial intelligence has expanded its potential to treat solid tumors in addition to blood cancers. This review aims to describe the structure, types, and various methods used to develop CAR-T cells. The clinical applications of CAR-T cells in hematological malignancies and solid tumours have been described in detail. In addition, this discussion has addressed the limitations associated with CAR-T cells, explored potential strategies to mitigate CAR-T-related toxicities, and delved into future perspectives.

Single-Center Experience of Patients with Plasma Cell Leukemia in the Era of New Therapeutics

INTRODUCTION

Plasma cell leukemia (PCL) can occur de novo as primary PCL (pPCL), or in patients with prior diagnosis of multiple myeloma (MM) as secondary PCL (sPCL). In 2021, the diagnostic criteria have been revised, establishing a new cut-off of ≥5% plasma cells in the peripheral blood. Lacking specific clinical trials, PCL is treated similarly to MM; however, outcome for patients with PCL remains poor. Here, we report outcomes for patients with pPCL and sPCL in the era of novel agents.

METHODS

We performed a retrospective analysis and identified 19 patients (11 pPCL, 8 sPCL) who have been treated for PCL between 2010 and 2022 at University Hospital Essen.

RESULTS

Patients with pPCL had a median overall survival (OS) of 37.8 months (95% CI: [15.4; 52.3] months) from diagnosis, with a median time to next treatment (TTNT) of 18.4 (2.0; 22.9) months. All patients were treated with a proteasome-inhibitor (PI)-based induction therapy, and the majority was consolidated with an autologous stem cell transplantation (SCT). Five of these patients received a tandem transplantation. Patients with sPCL had a median OS of only 1.5 months after diagnosis of PCL. Only 1 patient achieved a remission with daratumumab and subsequent allogenic SCT.

CONCLUSION

With our study, we add evidence for a PI-based induction therapy followed by a consolidating autologous SCT for patients with pPCL and give further evidence that a tandem transplant concept might be beneficial. The diagnosis of sPCL remains devastating and needs new therapeutic approaches.

The new era of immunological treatment, last updated and future consideration of CAR T cell-based drugs

Cancer treatment is one of the fundamental challenges in clinical setting, especially in relapsed/refractory malignancies. The novel immunotherapy-based treatments bring new hope in cancer therapy and achieve various treatment successes. One of the distinguished ways of cancer immunotherapy is adoptive cell therapy, which utilizes genetically modified immune cells against cancer cells. Between different methods in ACT, the chimeric antigen receptor T cells have more investigation and introduced a promising way to treat cancer patients. This technology progressed until it introduced six US Food and Drug Administration-approved CAR T cell-based drugs. These drugs act against hematological malignancies appropriately and achieve exciting results, so they have been utilized widely in cell therapy clinics. In this review, we introduce all CAR T cells-approved drugs based on their last data and investigate them from all aspects of pharmacology, side effects, and compressional. Also, the efficacy of drugs, pre- and post-treatment steps, and expected side effects are introduced, and the challenges and new solutions in CAR T cell therapy are in the last speech.

Functional CRISPR screens in T cells reveal new opportunities for cancer immunotherapies

T cells are fundamental components in tumour immunity and cancer immunotherapies, which have made immense strides and revolutionized cancer treatment paradigm. However, recent studies delineate the predicament of T cell dysregulation in tumour microenvironment and the compromised efficacy of cancer immunotherapies. CRISPR screens enable unbiased interrogation of gene function in T cells and have revealed functional determinators, genetic regulatory networks, and intercellular interactions in T cell life cycle, thereby providing opportunities to revamp cancer immunotherapies. In this review, we briefly described the central roles of T cells in successful cancer immunotherapies, comprehensively summarised the studies of CRISPR screens in T cells, elaborated resultant master genes that control T cell activation, proliferation, fate determination, effector function, and exhaustion, and highlighted genes (BATF, PRDM1, and TOX) and signalling cascades (JAK-STAT and NF-κB pathways) that extensively engage in multiple branches of T cell responses. In conclusion, this review bridged the gap between discovering element genes to a specific process of T cell activities and apprehending these genes in the global T cell life cycle, deepened the understanding of T cell biology in tumour immunity, and outlined CRISPR screens resources that might facilitate the development and implementation of cancer immunotherapies in the clinic.

Pomalidomide improves the effectiveness of CAR-T treatment in the relapsed and refractory multiple myeloma or B-cell leukemia/lymphoma with extramedullary disease

Relapsed and refractory multiple myeloma (RRMM) and B-cell leukemia/lymphoma with extramedullary disease (EMD) have poor prognosis and high mortality, lack of effective therapeutic approaches. We reported for the first time that 6 patients with malignant hematological diseases with EMD received chimeric antigen receptor (CAR)-T treatment combined with pomalidomide, and CAR-T cells were treated with pomalidomide in vitro to determine its killing activity and cytokine secretion. Three patients with RRMM were given B cell maturation antigen (BCMA)-CAR-T therapy. All 3 patients with B-cell leukemia/lymphoma received CD19/22-CAR-T sequential infusion. There were no treatment-related deaths. The maximum overall response rate (ORR) was 100%. Median follow-up was 211.5 days (75-407 days). Three patients (50%) experienced cytokine release syndrome, all of which were grade 1, and no neurotoxicity was observed. In vitro experiments showed that the killing activity did not differ significantly between BCMA-CAR-T cells with and without pomalidomide (10, 25, or 50 μg/mL) in 8226/U266 cell cocultures (P > .05). Tumor necrosis factor (TNF)-α and interferon (IFN)-γ secretion was significantly higher from 8226 and Raji cells cocultured with BCMA-CAR-T and cluster of differentiation (CD)19-CAR-T cells (P < .05). Based on the cocultures, adding pomalidomide significantly promoted IFN-γ and TNF-α secretion (P < .05). Based on the above clinical and in vitro studies demonstrating the co-administration of pomalidomide with CAR-T cell treatment demonstrated favorable tolerability and therapeutic effectiveness in RRMM or B-cell leukemia/lymphoma.

Exploring cellular immunotherapy platforms in multiple myeloma

Despite major advances in therapeutic platforms, most patients with multiple myeloma (MM) eventually relapse and succumb to the disease. Among the novel therapeutic options developed over the past decade, genetically engineered T cells have a great deal of potential. Cellular immunotherapies, including chimeric antigen receptor (CAR) T cells, are rapidly becoming an effective therapeutic modality for MM. Marrow-infiltrating lymphocytes (MILs) derived from the bone marrow of patients with MM are a novel source of T cells for adoptive T-cell therapy, which robustly and specifically target myeloma cells. In this review, we examine the recent innovations in cellular immunotherapies, including the use of dendritic cells, and cellular tools based on MILs, natural killer (NK) cells, and CAR T cells, which hold promise for improving the efficacy and/or reducing the toxicity of treatment in patients with MM.

Exploring the efficacy and safety of anti-BCMA chimeric antigen receptor T-cell therapy for multiple myeloma: Systematic review and meta-analysis

Objective

Multiple myeloma (MM) is a bone marrow cancer that profoundly affects plasma cells involved in the immune response. Myeloma cells alter the average production of cells in the bone marrow. Anti-B-cell maturation antigen (BCMA) chimeric antigen receptor (CAR) T-cell therapy allows genetic modifications of an individual's T-cells to increase the expression of CARs used to identify and attach BCMA proteins to the malignant cells. Our main objective is to perform a systematic review and meta-analysis to explore the efficacy and safety of anti-BCMA CAR T-cell therapy for MM.

Material and Methods

We searched five databases, PubMed, CNKI, EMBASE, Cochrane, Web of Science, and CNKI, for studies published on anti-BCMA,CAR-T-cell treatment for MM. Inclusion criteria involved prospective single-arm studies either single or multi-center, in various MM phases and studies that reported anti-BCMA,CAR-T-cell treatment for MM. We excluded non-English publications and conference papers. All statistical analyses were performed in R software and Review Manager 5.4.1.

Results

Thirteen articles were included in the analysis. We found that the overall response survival complete response increase was statistically significant. Similarly, the reduction in cytokine release syndrome grades 3 and 4 and neurotoxicity after follow-up was statistically significant. However, the reduction in minimal residual disease negativity (MRDN) was not statistically significant.

Conclusion

Using anti-BCMA CAR T-cell therapy in MM was highly efficacious and safe in lowering the adverse outcomes and improving the survival outcomes, complete response, and overall response.

Neosetophomone B induces apoptosis in multiple myeloma cells via targeting of AKT/SKP2 signaling pathway

Multiple myeloma (MM) is a hematologic malignancy associated with malignant plasma cell proliferation in the bone marrow. Despite the available treatments, drug resistance and adverse side effects pose significant challenges, underscoring the need for alternative therapeutic strategies. Natural products, like the fungal metabolite neosetophomone B (NSP-B), have emerged as potential therapeutic agents due to their bioactive properties. Our study investigated NSP-B's antitumor effects on MM cell lines (U266 and RPMI8226) and the involved molecular mechanisms. NSP-B demonstrated significant growth inhibition and apoptotic induction, triggered by reduced AKT activation and downregulation of the inhibitors of apoptotic proteins and S-phase kinase protein. This was accompanied by an upregulation of p21Kip1 and p27Cip1 and an elevated Bax/BCL2 ratio, culminating in caspase-dependent apoptosis. Interestingly, NSP-B also enhanced the cytotoxicity of bortezomib (BTZ), an existing MM treatment. Overall, our findings demonstrated that NSP-B induces caspase-dependent apoptosis, increases cell damage, and suppresses MM cell proliferation while improving the cytotoxic impact of BTZ. These findings suggest that NSP-B can be used alone or in combination with other medicines to treat MM, highlighting its importance as a promising phytoconstituent in cancer therapy.

Clinical and cytogenetic characteristics of primary and secondary plasma cell leukemia under the new IMWG definition criteria: a retrospective study

BACKGROUND

Plasma cell leukemia (PCL) is a rare and aggressive plasma cell disorder, exhibiting a more unfavorable prognosis than multiple myeloma. PCL is classified into pPCL and sPCL. Recently, the IMWG has recommended new PCL definition criteria, which require the presence of ≥5% circulating plasma cells in peripheral blood smears. Due to its low incidence, research on pPCL and sPCL is limited.

METHODS

We conducted a retrospective study and analyzed clinical and cytogenetic data of pPCL and sPCL patients. Overall survival (OS) and progression-free survival (PFS) were assessed by the Kaplan-Meier method, and survival distributions were compared using the log-rank test.

RESULTS

This is a small cohort comprising 23 pPCL and 9 sPCL patients. Notably, sPCL patients showed a higher incidence of extramedullary infiltration and a higher percentage of bone marrow plasma cells (p = 0.015 and 0.025, respectively). Although no significant difference was found between the two groups in OS and PFS, a trend emerged suggesting a superior survival outcome for pPCL patients, with a higher cumulative 1-year PFS rate (38.3% vs. 13.3%) and a lower early mortality rate (mortality rate at 3 months: 15% vs. 33%). We also suggested that pPCL patients carrying t(11;14) may have a longer median survival time than individuals with other cytogenetic abnormalities, but this was not confirmed due to the small sample size.

CONCLUSION

Our study revealed clinical and cytogenetic features of pPCL and sPCL patients according to the new diagnostic criteria. The findings suggested a generally better prognosis for pPCL than sPCL and the likelihood of t(11;14) translocation acting as a favorable prognostic factor in pPCL. It is important to note that our study had a limited sample size, which may lead to bias. We hope well-designed studies can be conducted to provide more results.

Treatment of primary plasma cell leukaemia with carfilzomib and lenalidomide-based therapy (EMN12/HOVON-129): final analysis of a non-randomised, multicentre, phase 2 study

BACKGROUND

Primary plasma cell leukaemia is a rare and aggressive plasma cell disorder with a poor prognosis. The aim of the EMN12/HOVON-129 study was to improve the outcomes of patients with primary plasma cell leukaemia by incorporating carfilzomib and lenalidomide in induction, consolidation, and maintenance therapy.

METHODS

The EMN12/HOVON-129 study is a non-randomised, phase 2, multicentre study conducted at 19 academic centres and hospitals in seven European countries (Belgium, Czech Republic, Denmark, Italy, Norway, The Netherlands, and the UK) for previously untreated patients with primary plasma cell leukaemia aged 18 years or older. Inclusion criteria were newly diagnosed primary plasma cell leukaemia (defined as >2 ×109 cells per L circulating monoclonal plasma cells or plasmacytosis >20% of the differential white cell count) and WHO performance status 0-3. Patients aged 18-65 years (younger patients) and 66 years or older (older patients) were treated in age-specific cohorts and were analysed separately. Younger patients were treated with four 28-day cycles of carfilzomib (36 mg/m2 intravenously on days 1, 2, 8, 9, 15, and 16), lenalidomide (25 mg orally on days 1-21), and dexamethasone (20 mg orally on days 1, 2, 8, 9, 15, 16, 22, and 23). Carfilzomib-lenalidomide-dexamethasone (KRd) induction was followed by double autologous haematopoietic stem-cell transplantation (HSCT), four cycles of KRd consolidation, and then maintenance with carfilzomib (27 mg/m2 intravenously on days 1, 2, 15, and 16 for the first 12 28-day cycles, and then 56 mg/m2 on days 1 and 15 in all subsequent cycles) and lenalidomide (10 mg orally on days 1-21) until progression. Patients who were eligible for allogeneic HSCT, could also receive a single autologous HSCT followed by reduced-intensity conditioning allogeneic HSCT and then carfilzomib-lenalidomide maintenance. Older patients received eight cycles of KRd induction followed by maintenance therapy with carfilzomib and lenalidomide until progression. The primary endpoint was progression-free survival. The primary analysis population was the intention-to-treat population, irrespective of the actual treatment received. Data from all participants who received any study drug were included in the safety analyses. The trial was registered at www.trialregister.nl (until June 2022) and https://trialsearch.who.int/ as NTR5350; recruitment is complete and this is the final analysis.

FINDINGS

Between Oct 23, 2015, and Aug 5, 2021, 61 patients were enrolled and received KRd induction treatment (36 patients aged 18-65 years [20 (56%) were male and 16 (44%) female], and 25 aged ≥66 years [12 (48%) were male and 13 (52%) female]). With a median follow-up of 43·5 months (IQR 27·7-67·8), the median progression-free survival was 15·5 months (95% CI 9·4-38·4) for younger patients. For older patients, median follow-up was 32·0 months (IQR 24·7-34·6), and median progression-free survival was 13·8 months (95% CI 9·2-35·5). Adverse events were most frequently observed directly after treatment initiation, with infections (two of 36 (6%) younger patients and eight of 25 (32%) older patients) and respiratory events (two of 36 [6%] younger patients and four of 25 [16%] older patients) being the most common grade 3 or greater events during the first four KRd cycles. Treatment-related serious adverse events were reported in 26 (72%) of 36 younger patients and in 19 (76%) of 25 older patients, with infections being the most common. Treatment-related deaths were reported in none of the younger patients and three (12%) of the older patients (two infections and one unknown cause of death).

INTERPRETATION

Carfilzomib and lenalidomide-based therapy provides improved progression-free survival compared with previously published data. However, results remain inferior in primary plasma cell leukaemia compared with multiple myeloma, highlighting the need for new studies incorporating novel immunotherapies.

FUNDING

Dutch Cancer Society, Celgene (a BMS company), and AMGEN.

Bilateral orbital plasmacytomas as first sign of extramedullary progression post CAR-T therapy: case report and literature review

Background

Plasma cell leukemia (PCL) is an aggressive and rare form of plasma cell dyscrasia characterized by peripheral blood expression, poor prognosis, and high relapse rates. Extramedullary plasmacytomas are common in this entity and can affect various organs and soft tissues. Chimeric antigen receptor-T-cell (CAR-T) therapy is a novel immunotherapy for hematological malignancies with promising results. However, it is not indicated for PCL, and experience in this condition is limited. This case is a rare presentation of bilateral orbital plasmacytomas after CAR-T therapy in a patient with PCL history.

Case presentation

We present the case of a 51-year-old female patient with a history of previous primary PCL treated with CAR-T therapy achieving complete response and without evidence of systemic progression. Six months after the treatment, she developed subacute proptosis and ptosis on the left eye.An orbital CT scan was performed and showed an orbital tumor in both eyes. A surgical biopsy with histological examination revealed plasma cells, consistent with a plasmacytoma. PET-CT and MRI confirmed the presence of tumors in both orbits. The patient was treated with dexamethasone and chemotherapy along with palliative radiation therapy to the left orbit which had a good response.

Conclusion

Orbital involvement in multiple myeloma and PCL is rare, with plasmacytomas being more common in other parts of the body. In this report, we present a case of a patient with PCL history, treated with multiple therapeutic lines including CAR-T therapy, who presented bilateral orbital plasmacytomas as the first sign of extramedullary progression after the treatment. This case should be considered by specialist to be aware that the orbits are a possible location of extramedullary progression.

Effectiveness and safety of anti-BCMA chimeric antigen receptor T-cell treatment in relapsed/refractory multiple myeloma: a comprehensive review and meta-analysis of prospective clinical trials

Background: Chimeric antigen receptor T cells treatment targeting B cell maturation antigen (BCMA) is an emerging treatment option for relapsed/refractory multiple myeloma (RRMM) and has demonstrated outstanding outcomes in clinical studies. Objective: The aim of this comprehensive review and meta-analysis was to summarize the effectiveness and safety of anti-BCMA CAR-T treatment for patients with relapsed/refractory multiple myeloma (RRMM). Our research identifies variables influencing outcome measures to provide additional evidence for CAR-T product updates, clinical trial design, and clinical treatment guidance. Methods: The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) standard was followed for conducting this comprehensive review and meta-analysis, which was submitted to PROSPERO (CRD42023390037). From the inception of the study until 10 September 2022, PubMed, Web of Science, EMBASE, the Cochrane Library, CNKI, and WanFang databases were searched for eligible studies. Stata software (version 16.0) was used to assess effectiveness and safety outcomes. Results: Out of 875 papers, we found 21 relevant trials with 761 patients diagnosed as RRMM and were given anti-BCMA CAR-T treatment. The overall response rate (ORR) for the entire sample was 87% (95% CI: 80-93%) complete response rate (CRR) was 44% (95% CI: 34-54%). The minimal residual disease (MRD) negativity rate within responders was 78% (95% CI: 65-89%). The combined incidence of cytokine release syndrome was 82% (95% CI: 72-91%) and neurotoxicity was 10% (95% CI: 5%-17%). The median progression-free survival (PFS) was 8.77 months (95% CI: 7.48-10.06), the median overall survival (OS) was 18.87 months (95% CI: 17.20-20.54) and the median duration of response (DOR) was 10.32 months (95% CI: 9.34-11.31). Conclusion: According to this meta-analysis, RRMM patients who received anti-BCMA CAR-T treatment have demonstrated both effectiveness and safety. Subgroup analysis confirmed the anticipated inter-study heterogeneity and pinpointed potential factors contributing to safety and efficacy, which may help with the development of CAR-T cell studies and lead to optimized BCMA CAR-T-cell products. Systematic Review Registration: Clinicaltrials.gov, PROSPERO, CRD42023390037.

Recovery-model: A model for CAR T-cell-related thrombocytopenia in relapsed/refractory multiple myeloma

BACKGROUND

Patients with multiple myeloma (MM) treated with anti-B cell maturation antigen (BCMA) and chimeric antigen receptor (CAR) T-cell therapy tend to show delayed platelet recovery.

PATIENTS AND METHODS

This single-center retrospective observational study included a cohort of patients with MM treated with anti-BCMA CAR-T cells in ChiCTR-OPC-16009113, ChiCTR1800018137, and ChiCTR1900021153.

RESULTS

Fifty-eight patients with MM treated with anti-BCMA CAR-T cells were included. Delayed platelet recovery (platelet count not recovering to 50 × 10⁹/L within 28 days) was observed in 36 % of patients. Regression analysis identified several factors that influenced platelet recovery, and accordingly, a Recovery-Model was developed. A high Recovery-Model score indicates a greater risk of delayed platelet recovery after CAR-T cell infusion and reflects the risk of hematologic toxicity. The model's predictive biomarkers included baseline platelet count, baseline hemoglobin level, logarithm of baseline Ferritin level, and cytokine release syndrome grade. Finally, survival analysis showed a significant relationship between overall survival, delayed platelet recovery (p = 0.0457), and a high Recovery-Model score (p = 0.0011).

CONCLUSIONS

Inflammation-related factors and bone marrow reserves are associated with delayed platelet recovery. Therefore, we developed a model to predict the risk of delayed platelet recovery and hematological toxicity in relapsed/refractory patients with MM after anti-BCMA CAR-T cell treatment.

Cancer-cell-derived fumarate suppresses the anti-tumor capacity of CD8+ T cells in the tumor microenvironment

Metabolic alterations in the microenvironment significantly modulate tumor immunosensitivity, but the underlying mechanisms remain obscure. Here, we report that tumors depleted of fumarate hydratase (FH) exhibit inhibition of functional CD8⁺ T cell activation, expansion, and efficacy, with enhanced malignant proliferative capacity. Mechanistically, FH depletion in tumor cells accumulates fumarate in the tumor interstitial fluid, and increased fumarate can directly succinate ZAP70 at C96 and C102 and abrogate its activity in infiltrating CD8⁺ T cells, resulting in suppressed CD8⁺ T cell activation and anti-tumor immune responses in vitro and in vivo. Additionally, fumarate depletion by increasing FH expression strongly enhances the anti-tumor efficacy of anti-CD19 CAR T cells. Thus, these findings demonstrate a role for fumarate in controlling TCR signaling and suggest that fumarate accumulation in the tumor microenvironment (TME) is a metabolic barrier to CD8⁺ T cell anti-tumor function. And potentially, fumarate depletion could be an important strategy for tumor immunotherapy.

Long-term outcomes following CAR T cell therapy: what we know so far

Chimeric antigen receptors (CAR) are engineered fusion proteins designed to target T cells to antigens expressed on cancer cells. CAR T cells are now an established treatment for patients with relapsed and/or refractory B cell lymphomas, B cell acute lymphoblastic leukaemia and multiple myeloma. At the time of this writing, over a decade of follow-up data are available from the initial patients who received CD19-targeted CAR T cells for B cell malignancies. Data on the outcomes of patients who received B cell maturation antigen (BCMA)-targeted CAR T cells for multiple myeloma are more limited owing to the more recent development of these constructs. In this Review, we summarize long-term follow-up data on efficacy and toxicities from patients treated with CAR T cells targeting CD19 or BCMA. Overall, the data demonstrate that CD19-targeted CAR T cells can induce prolonged remissions in patients with B cell malignancies, often with minimal long-term toxicities, and are probably curative for a subset of patients. By contrast, remissions induced by BCMA-targeted CAR T cells are typically more short-lived but also generally have only limited long-term toxicities. We discuss factors associated with long-term remissions, including the depth of initial response, malignancy characteristics predictive of response, peak circulating CAR levels and the role of lymphodepleting chemotherapy. We also discuss ongoing investigational strategies designed to improve the length of remission following CAR T cell therapy.

Phase II, Open-Label Study of Ciltacabtagene Autoleucel, an Anti-B-Cell Maturation Antigen Chimeric Antigen Receptor-T-Cell Therapy, in Chinese Patients With Relapsed/Refractory Multiple Myeloma (CARTIFAN-1)

PURPOSE

CARTIFAN-1 aimed to evaluate the efficacy and safety of ciltacabtagene autoleucel (cilta-cel), a B-cell maturation antigen-targeting chimeric antigen receptor T-cell therapy, in Chinese patients with relapsed/refractory multiple myeloma (RRMM).

METHODS

This pivotal phase II, open-label study (ClinicalTrials.gov identifier: NCT03758417), conducted across eight sites in China, enrolled adult patients with RRMM who had received ≥ 3 lines of prior therapy, including a proteasome inhibitor and immunomodulatory drug. Patients received a single infusion of cilta-cel (target dose 0.75 × 10⁶ chimeric antigen receptor-positive viable T cells/kg). The primary end point was overall response rate. Secondary end points included progression-free survival (PFS), overall survival (OS), and incidence and severity of adverse events (AEs).

RESULTS

As of the clinical cutoff of July 19, 2021, 48 patients received a cilta-cel infusion. At an 18-month median follow-up, the overall response rate was 89.6% (95% CI, 77.3 to 96.5), with a median time to first response of approximately 1 month; 77.1% of patients (95% CI, 62.7 to 88.0) achieved complete response or better. Medians for duration of response, PFS, and OS were not reached. The 18-month PFS and OS rates were 66.8% (95% CI, 49.4 to 79.4) and 78.7% (95% CI, 64.0 to 88.0), respectively. Hematologic AEs were common, including anemia (100%), neutropenia (97.9%), lymphopenia (95.8%), and thrombocytopenia (87.5%). Cytokine release syndrome occurred in 97.9% of patients (35.4% grade 3/4); the median time to onset was 7 days, and the median duration was 5 days. Infections occurred in 85.4% of patients (37.5% grade 3/4). Ten deaths occurred after cilta-cel infusion, eight of which were due to treatment-related AEs.

CONCLUSION

These data demonstrate a favorable risk-benefit profile for a single infusion of cilta-cel, resulting in early, deep, and durable responses in heavily pretreated patients with RRMM in China.

A systematic review on performance analysis of critical time points in multiple myeloma treated by CAR-T cell immunotherapy

BACKGROUND

Multiple myeloma (MM) is the second most common hematological malignancy without cure, and Chimeric Antigen Receptor T Cell (CAR-T) therapy has been shown great promising in MM. Unlike previous published studies mainly focusing on efficacy and safety, this study aims to summarize time points in the process of CAR-T therapy in MM and establish a standardized time-related CAR-T therapy platform to provide a reference for CAR-T treatment in MM.

METHODS

All the literatures were retrieved from PubMed, Web of Science, Embase, American Society of Hematology (ASH), American Society of Clinical Oncology (ASCO) and European Hematology Association (EHA). Relevant median detection time of efficacy and safety-related indicators of CAR-T therapy in MM were extracted from included literatures, and median values were applied to represent detection time points of indicators. Notably, the median values were not the certain and optimal detection time points, while the significance is that indicators could be detected more frequently around the median values to obtain the ideal results.

RESULTS

This review presented the median detection time points of efficacy and safety-related indicators of CAR-T therapy in MM according to the chronological order. For short-term effects on inflammation status within 1 month after CAR-T initiation, the median time points of cytokine release syndrome onset, immune effector cell-associated neurotoxicity syndrome onset, neutrophils recovery and CAR-T expansion peak were 4.5, 8, 10 and 12 days, respectively. For medium-term effects on clinical response in MM beyond 1 month and up to 3 months following CAR-T infusion, the median time points of minimal residual disease negativity, the reduction of serum light chain to minimum, platelet recovery and the reduction of M protein to minimum were 30, 30, 44 and 90 days, respectively.

CONCLUSIONS

This systematic review summarized the median detection time points of efficacy and safety-related indicators of CAR-T therapy in MM and constructed the time-related CAR-T therapy platform, providing an evidence-based standard for establishment of CAR-T treatment regimen in MM.

Dose-response correlation for CAR-T cells: a systematic review of clinical studies

The potential of chimeric antigen receptor (CAR) T cells to successfully treat hematological cancers is widely recognized. Multiple CAR-T cell therapies are currently under clinical development, with most in early stage, during which dose selection is a key goal. The objective of this review is to address the question of dose-dependent effects on response and/or toxicity from available CAR-T cell clinical trial data. For that purpose, systematic literature review of studies published between January 2010 and May 2022 was performed on PubMed and Embase to search clinical studies that evaluated CAR-T cells for hematological cancers. Studies published in English were considered. Studies in children (age <18 years), solid tumors, bispecific CAR-T cells and CAR-T cell cocktails were excluded. As a result, a total of 74 studies met the inclusion criteria. Thirty-nine studies tested multiple dose levels of CAR-T cells with at least >1 patient at each dose level. Thirteen studies observed dose-related increase in disease response and 23 studies observed dose-related increase in toxicity across a median of three dose levels. Optimal clinical efficacy was seen at doses 50-100 million cells for anti-CD19 CAR-T cells and >100 million cells for anti-BCMA CAR-T cells in majority of studies. The findings suggest, for a given construct, there exists a dose at which a threshold of optimal efficacy occurs. Dose escalation may reveal increasing objective response rates (ORRs) until that threshold is reached. However, when ORR starts to plateau despite increasing dose, further dose escalation is unlikely to result in improved ORR but is likely to result in higher incidence and/or severity of mechanistically related adverse events.

The adverse impact of a gain in chromosome 1q on the prognosis of multiple myeloma treated with bortezomib-based regimens: A retrospective single-center study in China

Background

Multiple myeloma is genetically heterogeneous, and chromosome abnormalities play a pivotal role in prognosis. A gain in chromosome 1q (+1q) is among the most common cytogenetic abnormalities; however, its relationship with overall survival (OS) and progression-free survival (PFS) in patients with multiple myeloma is still unclear. We aim to clarify the impact of +1q on the clinical characteristics and survival outcomes of patients treated with bortezomib-based combination regimes.

Materials and methods

We retrospectively analyzed 258 patients first diagnosed with myeloma who underwent bortezomib-based therapy at the bone marrow transplantation department of a multiple myeloma treatment center in the first affiliated hospital of Zhejiang University, China.

Results

We identified 258 newly diagnosed patients with multiple myeloma in our department from July 2013 to September 2018. We observed that 127 (49.2%) of the patients acquired +1q at diagnosis, and +1q strongly correlated with the occurrence of del(13q) and IgH rearrangement (P < 0.001). In the patients with +1q, the PFS was 22.2 months (95% CI 15.8-28.5 months), and the three-year and five-year PFS was 35.1% and 15.3%, respectively. Univariate analysis revealed that albumin, lactate dehydrogenase (LDH), and the percentage of plasma cells significantly affected PFS. Multivariate analysis showed that LDH and the percentage of plasma cells significantly affected PFS in the +1q patients. In terms of OS, the median OS for the +1q patients was 47.4 months (95% CI 34.7-59.5), while the OS of the non-+1q patients was not reached (P = 0.048). The univariate and multivariate analyses revealed that age, platelet count, and extramedullary lesions were significant adverse factors for OS in the +1q patients. There were no statistical differences between PFS and OS when there were other chromosomal abnormalities, but there was a decreased tendency in PFS. LDH and +1q also had a synergistic adverse effect on survival.

Conclusion

+1q is associated with a higher tumor burden and correlated with the occurrence of del(13q) and IgH rearrangement at diagnosis. In the era of novel agents, +1q still significantly affects PFS and OS.

Five-year remission without disease progression in a patient with relapsed/refractory multiple myeloma with extramedullary disease treated with LCAR-B38M chimeric antigen receptor T cells in the LEGEND-2 study: a case report

BACKGROUND

Multiple myeloma remains incurable despite treatment advancements over the last 20 years. LCAR-B38M Cells in Treating Relapsed/Refractory Multiple Myeloma was a phase 1, first-in-human, investigator-initiated study in relapsed/refractory multiple myeloma conducted at four sites in China. The study used LCAR-B38M chimeric antigen receptor-T cells expressing two B-cell maturation antigen-targeting single-domain antibodies designed to confer avidity, and a CD3ζ signaling domain with a 4-1BB costimulatory domain to optimize T-cell activation and proliferation. This chimeric antigen receptor construct is identical to ciltacabtagene autoleucel. In the LEGEND-2 study (n = 57, Xi'an site), overall response rate was 88%; median (95% CI) progression-free survival and overall survival were 19.9 (9.6-31.0) and 36.1 (26.4-not evaluable) months, respectively; and median follow-up was 25 months. This case study reports on a patient with relapsed/refractory multiple myeloma (λ light chain type) who was treated with LCAR-B38M chimeric antigen receptor T cells in the LEGEND-2 study (Xi'an site); he had received five prior lines of treatment and had extensive extramedullary lesions.

CASE PRESENTATION

The patient, a 56-year-old Asian male, received cyclophosphamide (500 mg daily × 3 days) as lymphodepletion therapy and a total dose of 0.5 × 10⁶ chimeric antigen receptor + T cells/kg split into three infusions (days 1, 24, and 84 from June to August 2016). He experienced grade 2 cytokine release syndrome after the first infusion; all symptoms resolved with treatment. No cytokine release syndrome occurred following the second and third infusions. His λ light chain levels decreased and normalized 20 days after the first infusion, and extramedullary lesions were healed as of January 2018. He has sustained remission for 5 years and received no other multiple myeloma treatments after LCAR-B38M chimeric antigen receptor T cell infusion. As of 30 October 2020, the patient is still progression-free and has maintained minimal residual disease-negative (10^-4) complete response status for 52 months.

CONCLUSIONS

This case provides support that treatment with LCAR-B38M chimeric antigen receptor T cells can result in long-term disease remission of 5 or more years without disease progression in a heavily pretreated patient with extensive extramedullary disease and no other treatment options.

Phase I CAR-T Clinical Trials Review

BACKGROUND/AIM

Chimeric antigen receptor (CAR) T cells with tumor specificity are being increasingly investigated. Phase I trials are the first step of testing for safety of novel CAR-T therapy to determine the maximum tolerated dose (MTD). Several dose escalation methods have been developed over time including rule-based, model-based, and model-assisted designs. The goal of this project is to overview the phase I designs used in current CAR-T trials.

MATERIALS AND METHODS

We searched PubMed for peer-reviewed literature published between January 1, 2015 and December 31, 2021. The search was limited to human studies in the English language using the keywords "CAR-T phase I", "clinical trials", and "full text".

RESULTS

One hundred nine papers with at least partial phase I components were included for analysis. 31.2% of the trials used the traditional 3+3 or a variation of said design, and 60.6% did not mention the dose escalation design. The majority of the manuscripts (59.6%) did not report cohort size while 19.3% did not specify the timing of evaluation. Although most of the studies were registered with CT.gov, only 33.9% had any results submitted or posted to CT.gov These trends persisted even in manuscripts published in journals with high impact factors.

CONCLUSION

Standardizing the publication criteria and providing basic elements of phase I clinical trials are critical to ensure high quality of manuscripts. With the quick development and high costs of CAR-T cell therapy, adoption of advanced designs such as model-based and model-assisted should increase to improve efficiency of clinical trials.

Guggulsterone Induces Apoptosis in Multiple Myeloma Cells by Targeting High Mobility Group Box 1 via Janus Activated Kinase/Signal Transducer and Activator of Transcription Pathway

Multiple myeloma (MM) is a hematological disorder characterized by the abnormal expansion of plasma cells in the bone marrow. Despite great advances over the past three decades in discovering the efficacious therapies for MM, the disease remains incurable for most patients owing to emergence of drug-resistant cancerous cells. Guggulsterone (GS), a phytosteroid, extracted from the gum resin of guggul plant, has displayed various anticancer activities in vitro and in vivo; however, the molecular mechanisms of its anticancer activity have not been evaluated in MM cells. Therefore, in this study, we investigated the anticancer activity of GS in various MM cell lines (U266, MM.1S, and RPMI 8226) and the mechanisms involved. GS treatment of MM cells caused inhibition of cell proliferation and induction of apoptotic cell death as indicated by increased Bax protein expression, activation of caspases, and cleavage of poly (ADP-ribose) polymerase. This was associated with the downregulation of various proliferative and antiapoptotic gene products, including cyclin D, Bcl-2, Bcl-xL, and X-linked inhibitor of apoptosis protein. GS also suppressed the constitutive and interleukin 6-induced activation of STAT3. Interestingly, the inhibition of Janus activated kinase or STAT3 activity by the specific inhibitors or by siRNA knockdown of STAT3 resulted in the downregulation of HMGB1, suggesting an association between GS, STAT3, and HMGB1. Finally, GS potentiated the anticancer effects of bortezomib (BTZ) in MM cells. Herein, we demonstrated that GS could be a potential therapeutic agent for the treatment of MM, possibly alone or in combination with BTZ.

Risk of infection in patients with hematological malignancies receiving CAR T-cell therapy: systematic review and meta-analysis

BACKGROUND

Chimeric antigen receptor (CAR) T-cell therapy has emerged as a promising treatment option for relapsed or refractory B-cell malignancies and multiple myeloma. Underlying and treatment-related variables may contribute to the development of infectious complications.

RESEARCH DESIGN AND METHODS

We conducted a systematic review and meta-analysis on the incidence of overall and severe (grade ≥3) infection in patients with hematological malignancies receiving CAR T-cells. Secondary outcomes included the specific rates of bacterial, viral and invasive fungal infection (IFI), and infection-related mortality. PubMed, Embase and Web of Science databases were searched from inception to 27 May 2022. Sensitivity analysis were performed according to the type of malignancy and study design (randomized clinical trials [RCTs] or observational studies).

RESULTS

Forty-five studies (34 RCTs) comprising 3,591 patients were included. The pooled incidence rates of overall and severe infection were 33.8% (I² = 96.31%) and 16.2% (I² = 74.41%). The respiratory tract was the most common site of infection. Most events were bacterial or viral, whereas the occurrence of IFI was rare. The pooled attributable mortality was 1.8% (I² = 43.44%).

CONCLUSIONS

Infection is a frequent adverse event in patients receiving CAR T-cell therapy. Further research should address specific risk factors in this population.

B cell deficiency promotes the initiation and progression of lung cancer

Currently commercialized CAR-T cell therapies targeting CD19 and BCMA show great efficacy to cure B cell malignancies. However, intravenous infusion of these CAR-T cells severely destroys both transformed and normal B cells in most tissues and organs, in particular lung, leading to a critical question that what the impact of normal B cell depletion on pulmonary diseases and lung cancer is. Herein, we find that B cell frequency is remarkably reduced in both smoking carcinogen-treated lung tissues and lung tumors, which is associated with advanced cancer progression and worse patient survival. B cell depletion by anti-CD20 antibody significantly accelerates the initiation and progression of lung tumors, which is mediated by repressed tumor infiltration of T cells and macrophage elimination of tumor cells. These findings unveil the overall antitumor activity of B cells in lung cancer, providing novel insights into both mechanisms underlying lung cancer pathogenesis and clinical prevention post CAR-T cell therapy.

Case report: Plasma cell leukemia secondary to multiple myeloma successfully treated with anti-BCMA CAR-T cell therapy

Chimeric antigen receptor (CAR)-T cell therapy provides an effective salvage treatment for relapsed/refractory multiple myeloma (RRMM) patients. End-stage RRMM with plasma cell leukemia (PCL) transformation is highly aggressive and resistant to conventional therapy. There is an urgent need for new therapeutics and CAR-T therapy may play an important role. We report a case of PCL secondary to RRMM successfully treated with CAR-T cell therapy targeting B-cell maturation antigen (BCMA). A woman was diagnosed as having MM 4 years ago and progressed to secondary PCL (sPCL) of five prior lines of treatment including proteasome inhibitors, an immunomodulatory agent, cytotoxic drugs, and an anti-CD38 monoclonal antibody. After receiving a BCMA CAR-T therapy, she achieved a stringent complete response that lasted 9 months. Then, the patient irregularly took venetoclax 10 mg per day due to a slightly higher λ FLC concentration, which did not meet the criteria for progression. She maintained a complete response for the following 7 months. In conclusion, BCMA CAR-T therapy may be a promising therapeutic approach in PCL patients. More studies are needed to evaluate the benefit of anti-BCMA CAR-T therapy in PCL patients.

Clinical Trial Registration:www.chictr.org.cn, ChiCTR1900024388, Registered 9 July 2019.

Phase 1 study of C-CAR088, a novel humanized anti-BCMA CAR T-cell therapy in relapsed/refractory multiple myeloma

BACKGROUND

Anti-B-cell maturation antigen (BCMA) chimeric antigen receptor T-cell (CAR T) therapy showed remarkable efficacy in patients with relapsed or refractory multiple myeloma (RRMM). This phase 1 dose-escalation and expansion study developed C-CAR088, a novel second-generation humanized anti-BCMA CAR T-cell therapy, and assessed the safety and efficacy of three dosages of C-CAR088 in patients with RRMM.

METHODS

Patients received lymphodepletion with three doses of cyclophosphamide (300 mg/m2) and three doses of fludarabine (30 mg/m2) on days -5, -4, and -3, followed by an infusion of C-CAR088 on day 0. Doses of 1.0×106, 3.0×106, and 6.0×106 CAR T cells/kg (±20%) were tested in the dose-escalation cohorts and expansion cohorts. The primary endpoint was treatment safety, including the rate of treatment-emergent adverse events after cell infusion. Secondary endpoints were the overall response rate and progression-free survival. The exploratory endpoints were the quantification of C-CAR088 CAR T cells, selection of cytokines and chemokines in blood, and measurement of tumor BCMA expression.

RESULTS

As of July 2, 2021, 31 patients had been infused with C-CAR088. Any grade cytokine release syndrome (CRS) occurred in 29 patients (93.5%), and grade 3 CRS occurred in 3 patients (9.7%). One patient from the high-dose group (4.5-6.0×106 CAR T cells/kg) developed grade 1 neurotoxicity. No dose-limiting toxicities were observed in any dose group, and all adverse events were reversible after proper management. The overall response, stringent complete response, complete response (CR), and very good partial response rates were 96.4%, 46.4%, 10.7%, and 32.1%, respectively. The CR rate in the medium-dose (3.0×106 CAR T cells/kg) and high-dose (4.5-6.0×106 CAR T cells/kg) groups was 54.5% and 71.4%, respectively. In the CR group, 15 (93.7%) patients achieved minimal residual disease (MRD) negativity (test sensitivity >1/10-5). All seven patients with double-hit or triple-hit multiple myeloma achieved MRD-negative CR.

CONCLUSIONS

The present study demonstrated that C-CAR088 had a good safety profile and high antitumor activity in patients with RRMM, constituting a promising treatment option for RRMM.

TRIAL REGISTRATION NUMBER

NCT03815383, NCT03751293, NCT04295018, and NCT04322292.

Impact of glucocorticoids on short-term and long-term outcomes in patients with relapsed/refractory multiple myeloma treated with CAR-T therapy

Background

Glucocorticoids (GCs) are often used to treat cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS). The effects of GCs on the efficacy of CAR-T cell treatment in relapsed/refractory multiple myeloma (RRMM) have not been fully established. We evaluated the impact of GCs on clinical outcomes of RRMM patients treated with CAR-T cells.

Methods

This study involved RRMM patients treated with CAR-T cells at our center between June 2017 and December 2020. Patients were stratified into GC-used group (GC-group) and non-GC-used group (NGC-group). CRS or ICANS was graded on the basis of the American Society of Transplantation and Cellular Therapy consensus grading system. Response status was evaluated by the IMWG Uniform Response Criteria. The duration of response (DOR), progression-free survival (PFS), and overall survival (OS) were calculated.

Result

A total of 71 patients were included in this study. In the NGC group (40 patients), 34 (85%) had responses to CAR-T cell therapy, including 16 (40%) stringent complete response (sCR), seven (17.5%) complete response (CR), five (12.5%) very good partial response (VGPR), and six (15%) partial response (PR). The overall response rate (ORR) and complete response rate (CRR) in the NGC group were 85% and 57.5%. In the GC group (31 patients), 29 (93.5%) had responses, including 11 (35.5%) sCR, nine (29%) CR, two (6.4%) VGPR, and seven (22.6%) PR. Differences in ORR and CRR between the two groups were insignificant. The dose, duration, and timing of GCs did not affect ORR and CRR. At a median follow-up of 28.2 months, the median PFS was 20.4 months (95% CI, 7.9 to 32.9) while the median OS was 36.6 months (95% CI, 25.9 to 47.2) for the GC group. The median PFS and OS for the NGC group were 13.7 months (95% CI, 8.8 to 18.6) and 27.5 months (95% CI, 14.1 to 41.0). There were no significant differences in either PFS or OS between the GC group and the NGC group. Differences in median DOR for the patients with CR or better in the GC group and NGC group were not significant (p = 0.17). Earlier, prolonged use and high dose of GCs were not associated with any effects on either PFS or OS. Additionally, GCs had no effects on CAR-T cell proliferation.

Conclusion

Administration of GCs, dose, timing, and duration does not influence the clinical efficacy of CAR-T cells in RRMM in this study.

CAR-T Cell Therapy in Hematological Malignancies: Current Opportunities and Challenges

Chimeric antigen receptor T (CAR-T) cell therapy represents a major breakthrough in cancer treatment, and it has achieved unprecedented success in hematological malignancies, especially in relapsed/refractory (R/R) B cell malignancies. At present, CD19 and BCMA are the most common targets in CAR-T cell therapy, and numerous novel therapeutic targets are being explored. However, the adverse events related to CAR-T cell therapy might be serious or even life-threatening, such as cytokine release syndrome (CRS), CAR-T-cell-related encephalopathy syndrome (CRES), infections, cytopenia, and CRS-related coagulopathy. In addition, due to antigen escape, the limited CAR-T cell persistence, and immunosuppressive tumor microenvironment, a considerable proportion of patients relapse after CAR-T cell therapy. Thus, in this review, we focus on the progress and challenges of CAR-T cell therapy in hematological malignancies, such as attractive therapeutic targets, CAR-T related toxicities, and resistance to CAR-T cell therapy, and provide some practical recommendations.

Update on primary plasma cell leukemia

Plasma cell leukemia (PCL) is a rare and highly aggressive plasma cell neoplasm developing in 0.5?4% of patients with multiple myeloma (MM). The diagnostic criteria were recently revised from 20% to ≥5% of circulating plasma cells in peripheral blood smears. PCL is classified as primary or secondary; primary PCL is when it presents in patients with no MM. Primary PCL shows clinical and laboratory features at presentation that differ from MM and exhibits a dismal prognosis even with the use of effective agents against MM. Therefore, intensive chemotherapy should be initiated immediately after diagnosis, and autologous stem cell transplantation is recommended for transplant-eligible patients. Maintenance therapy after transplantation may reduce the rate of early relapses. We reviewed the definitions of PCL, revised diagnostic criteria, clinical features, and appropriate initial treatments for primary PCL.

New and emerging pharmacotherapies for management of multiple myeloma

DISCLAIMER

In an effort to expedite the publication of articles related to the COVID-19 pandemic, AJHP is posting these manuscripts online as soon as possible after acceptance. Accepted manuscripts have been peer-reviewed and copyedited, but are posted online before technical formatting and author proofing. These manuscripts are not the final version of record and will be replaced with the final article (formatted per AJHP style and proofed by the authors) at a later time.

PURPOSE

The pharmacology, efficacy, safety, and dosing/administration of new and emerging therapies for the treatment of multiple myeloma are summarized.

SUMMARY

There have been significant advancements in the treatment of multiple myeloma in recent years, with an expansion of available drug therapies. Newer therapies for multiple myeloma include the anti-CD38 monoclonal antibodies daratumumab and isatuximab, the exportin 1 inhibitor selinexor, the anti-B-cell maturation antigen (BCMA) antibody-drug conjugate belantamab mafodotin, and the chimeric antigen receptor (CAR) T-cell therapy idecabtagene vicleucel. These agents have unique toxicity profiles, specific monitoring parameters, and operational considerations that clinicians treating multiple myeloma should be aware of. There is likely to be continued rapid expansion of new agents for patients with multiple myeloma, as there are many novel investigational agents in the drug development pipeline, such as bispecific antibodies and additional CAR T-cell therapies.

CONCLUSION

Several therapeutic agents have been recently approved by the Food and Drug Administration for the treatment of multiple myeloma. There are many novel agents in the pipeline, including bispecific antibodies and CAR T-cell therapies that have the potential to continue to change the treatment landscape of multiple myeloma.

Risk Factors Associated with Durable Progression-Free Survival in Patients with Relapsed or Refractory Multiple Myeloma Treated with Anti-BCMA CAR T-cell Therapy

PURPOSE

B-cell maturation antigen (BCMA) chimeric antigen receptor (CAR) T-cell therapy results in high remission rates in patients with relapsed/refractory (R/R) multiple myeloma. However, the factors associated with prognosis following CAR T-cell therapy are unknown.

PATIENTS AND METHODS

Between July 1, 2018 and July 31, 2020, 61 patients with R/R multiple myeloma received anti-BCMA CAR T-cell therapy (Chictr.org number, ChiCTR1800017404). Step-wise multivariate Cox regression and competing risk analyses were conducted to identify poor prognosis-associated risk factors.

RESULTS

Sixty patients (98.4%) experienced cytokine release syndrome (CRS), including 33, 23, and 4 cases of CRS grades 1 to 2, 3, and 4, respectively. The objective response rate (ORR) was 98.3%, and the complete remission (CR) rate was 70.3%. With a median follow-up period of 21.1 months, the 1-year overall survival (OS) and progression-free survival (PFS) rates were 78.0% and 50.2%, respectively. The median PFS was 12.7 months. Cox modeling revealed that poor PFS was associated with extramedullary disease [HR = 2.59, 95% confidence interval (95% CI) = 1.29-5.21, P = 0.008], light chain multiple myeloma (HR = 2.53, 95% CI = 1.03-5.97, P = 0.035), high-risk cytogenetics (HR = 2.80, 95% CI = 1.27-6.14, P = 0.01), and prior treatment with more than 3 therapeutic lines (HR = 3.14, 95% CI = 1.34-7.34, P = 0.008). Among the 41 CR cases, competing risk analyses demonstrated higher relapse predispositions in those with extramedullary disease (HR = 4.51, 95% CI = 1.86-10.9, P = 0.001), light chain multiple myeloma (HR = 4.89, 95% CI = 1.52 - 15.7, P = 0.008), or high-risk cytogenetics (HR = 5.09, 95% CI = 1.63-15.9, P = 0.005).

CONCLUSIONS

Anti-BCMA CAR T-cell therapy is safe and effective for R/R multiple myeloma. For patients with high-risk factors, improvements to extend remission and more specific individualized therapies are needed.

Absolute Lymphocyte Count Prior to Lymphodepletion Impacts Outcomes in Multiple Myeloma Patients Treated with Chimeric Antigen Receptor T Cells

Chimeric antigen receptor (CAR) T cell therapy has shown unprecedented response rates in patients with relapsed/refractory (R/R) multiple myeloma (MM). However, the factors associated with immediate response and durable remission have not been fully elucidated. This study aimed to investigate the impact of prelymphodepletion (pre-LD) absolute lymphocyte count (ALC) on the outcomes of CAR T cell therapy and cytokine release syndrome (CRS). A receiver operating characteristic curve was used to determine the optimal cutoff value of pre-LD ALC. The correlation of pre-LD ALC with deep response (defined as very good partial response or better), CRS, and long-term outcomes was analyzed in 85 patients with R/R MM who received CAR T cell treatment. The median pre-LD ALC was 1.0 × 10⁹/L (range, 0.1 to 2.9× 10⁹/L). The optimal cutoff value of pre-LD ALC was 0.75 × 10⁹/L. Twenty-two patients (26%) had a low pre-LD ALC (<0.75 × 10⁹/L), and 63 patients (74%) had a high pre-LD ALC (≥0.75 × 10⁹/L). The deep response rate was significantly higher in patients with a high pre-LD ALC compared with patients with a low pre-LD ALC (76% versus 41%; P = .002). Patients with a low pre-LD ALC had significantly inferior overall survival (OS) and progression-free survival (PFS) compared with those with a high pre-LD ALC (median OS, 15.4 months versus not reached [P < .001]; median PFS, 8.4 months versus 27.3 months [P < .001]). No correlation between pre-LD ALC and CRS was observed. Our data indicate that pre-LD ALC may be a useful indicator to predict the outcomes of CAR T cell therapy in patients with R/R MM. © 2021 American Society for Transplantation and Cellular Therapy. Published by Elsevier Inc.

Annotating BCMA Expression in Multiple Myelomas

B cell maturation antigen (BCMA) is a promising theranostic target for multiple myeloma (MM). BCMA-targeted therapeutics, such as antibody-drug conjugates and chimeric antigen receptor T-cell immunotherapies, are rapidly reshaping the treatment landscape of MM. Along with the progress, a critical challenge is to noninvasively visualize the dynamic change of BCMA for a better-personalized prescription of the above-mentioned therapeutics. We aim to develop immuno-positron emission tomography (immunoPET) imaging strategies to visualize BCMA expression and realize target-specific diagnosis of MM in the work. A series of BCMA-targeting nanobodies were produced and two of them were successfully labeled with gallium-68 (⁶⁸Ga). MM models were established using MM.1S cell line and NOD-Prkdc^em26Cd52Il2rg^em26Cd22/Nju mice. The diagnostic efficacies of the developed probes (i.e., [⁶⁸Ga]Ga-NOTA-MMBC2 and [⁶⁸Ga]Ga-NOTA-MMBC3) were investigated in disseminated MM models by immunoPET imaging, region of interest analysis on PET images, biodistribution study, and histopathological staining study. [⁶⁸Ga]Ga-NOTA-MMBC2 and [⁶⁸Ga]Ga-NOTA-MMBC3 were developed with radiochemical purities of >99%. ImmunoPET imaging with either [⁶⁸Ga]Ga-NOTA-MMBC2 or [⁶⁸Ga]Ga-NOTA-MMBC3 precisely visualized BCMA expression and delineated MM lesions throughout the bone marrows. Moreover, [⁶⁸Ga]Ga-NOTA-MMBC3 immunoPET successfully detected remnant MM after treatment with daratumumab, a prescription medicine used to treat MM. The immunoPET imaging data correlated well with the biodistribution and immunohistochemistry staining results. The work successfully developed two state-of-the-art BCMA-targeted radiotracers for annotating BCMA expression and diagnosing MM. Translational studies interpreting the diagnostic efficacies of the immunoPET radiotracers are warranted.

Anti-BCMA CAR-T Cell Therapy in Relapsed/Refractory Multiple Myeloma Patients With Extramedullary Disease: A Single Center Analysis of Two Clinical Trials

Background

The prognosis of relapsed/refractory multiple myeloma (RRMM) patients with the extramedullary disease was significantly poor. Extramedullary multiple myeloma (EMM) patients gained limited benefits from traditional drugs. Anti-B cell maturation antigen (BCMA) chimeric antigen receptor (CAR) T-cell therapy seems to be a promising approach to treat RRMM patients. However, very few clinical studies are designed for EMM. Our study aimed to compare and assess the safety, efficacy, and pharmacokinetics of anti-BCMA CAR-T cell therapy in EMM and non-EMM.

Methods

The results from published anti-BCMA CAR-T clinical trials, in which raw data of EMM patients were available, were reviewed and summarized. Two trials conducted in our clinical centers were analyzed and presented with detailed data.

Results

According to published anti-BCMA CAR-T clinical trials, the ORR of EMM ranged from 57% to 100%, with the complete remission (CR) rate of 29% to 60%. Between February 22, 2017, and September 26, 2019, a total of 61 subjects (EMM 25; non-EMM 36) received anti-BCMA CAR-T cell infusion. The data-cutoff date was April 1, 2021. There were no statistical differences between EMM and non-EMM groups in adverse events (AEs), including cytokine release syndrome (CRS). The most common AEs of grade ≥ 3 in both groups were hematologic toxicities. There was no significant difference in the objective response rate (ORR) and ≥ complete remission (CR) rate between both groups. However, the ≥ CR rate of the EMM group was lower than the non-EMM group receiving the fully human anti-BCMA CAR-T cell therapy (p = 0.026). The median progression-free survival (PFS) for EMM and the non-EMM group was 121 days and 361 days, respectively (p = 0.001). The median overall survival (OS) for EMM and the non-EMM group was 248 days and 1024 days, respectively (p = 0.005). The C_max and AUC_0-28d for EMM group were lower than non-EMM group (C_max, p = 0.016; AUC_0-28d, p = 0.016). Extramedullary disease was an independent prognostic risk factor for PFS (hazard ratio, 2.576; 95% CI, 1.343 to 4.941; p = 0.004) and OS (hazard ratio, 2.312; 95% CI, 1.165 to 4.592; p = 0.017) in RRMM patients receiving anti-BCMA CAR-T cell therapy.

Conclusions

Based on our results, EMM patients could benefit from the two anti-BCMA CAR products, although they had a shorter PFS and OS compared with non-EMM patients.

Clinical Trial Registration

http://www.chictr.org.cn, identifier ChiCTR-OPC-16009113 and ChiCTR1800018137.

A Recurring Chemogenetic Switch for Chimeric Antigen Receptor T Cells

As a revolutionary cancer treatment, the chimeric antigen receptor (CAR) T cell therapy suffers from complications such as cytokine release syndromes and T cell exhaustion. Their mitigation desires controllable activation of CAR-T cells that is achievable through regulatory display of CARs. By embedding the hepatitis C virus NS3 protease (HCV-NS3) between the single-chain variable fragment (scFv) and the hinge domain, we showed that the display of anti-CD19 scFv on CAR-T cells was positively correlated to the presence of a clinical HCV-NS3 inhibitor asunaprevir (ASV). This novel CAR design that allows the display of anti-CD19 scFv in the presence of ASV and its removal in the absence of ASV creates a practically recurring chemical switch. We demonstrated that the intact CAR on T cells can be repeatedly turned on and off by controlling the presence of ASV in a dose dependent manner both in vitro and in vivo, which enables delicate modulation of CAR-T activation during cancer treatment.