Minimal residual disease in multiple myeloma: why, when, where

Key predictors of long-term outcomes in BCMA-targeted CAR-T therapy for relapsed/refractory multiple myeloma

BACKGROUND

B-cell maturation antigen (BCMA)-directed chimeric antigen receptor T-cell (CAR-T) therapy exhibits high response rates in patients with relapsed/refractory multiple myeloma (r/r MM). However, the specific factors that influence the response duration remain poorly understood.

METHODS

This single-centre, retrospective observational study included 56 patients with r/r MM who received BCMA CAR-T therapy (equecabtagene autoleucel) at Tongji Hospital, China. We analysed response rates and long-term clinical outcomes and identified key factors contributing to the long-term efficacy of BCMA CAR-T therapy.

RESULTS

At a median follow-up of 39.6 months, the overall response rate (ORR) was 96.4%. Among the patients, 96.4% (54 of 56) achieved minimal residual disease (MRD) negativity, whereas 80.4% (45 of 56) achieved complete response (CR) or stringent complete response (sCR). Poorer outcomes were observed in patients with triple exposure, high cytogenetic risk, or failure to achieve CR. Better outcomes were associated with a CAR-T cell persistence of at least six months and sustained MRD negativity. Prolonged MRD negativity was strongly correlated with longer progression-free survival (PFS), with median PFS durations of 58 months, 64 months, and not reached (NR) for patients who maintained MRD negativity for 12, 24, and 36 months, respectively. Patients who remained MRD-negative and progression-free exhibited higher CAR-T cell expansion peaks. Additionally, CAR-T cell persistence was positively correlated with the duration of MRD negativity duration, PFS, and overall survival (OS).

CONCLUSIONS

BCMA CAR-T therapy provides durable responses in a subset of patients with r/r MM. Early intervention may improve patient prognosis by promoting sustained MRD negativity, thus improving overall treatment outcomes.

TRIAL REGISTRATION

Trial registration Chinese Clinical Trial Registry, ChiCTR2000033946 ( https://www.chictr.org.cn/showproj.html?proj=53503 ), Registered June 18, 2020. Trial registration Chinese Clinical Trial Registry, ChiCTR1800018137 ( https://www.chictr.org.cn/showproj.html?proj=30653 ), Registered August 31, 2018.

The efficacy of new drug regimens in treating newly diagnosed high-risk cytogenetic multiple myeloma patients: a systematic literature review and meta-analysis

Introduction

Multiple myeloma (MM) is a plasma cell malignancy comprising 10% of hematologic cancers, associated with bone marrow dysfunction and organ damage. High-risk cytogenetic MM patients, identified by specific genetic abnormalities, face poor outcomes despite recent advancements. Traditional treatments often prove inadequate, necessitating novel regimens. This review assesses the efficacy of emerging therapies-next-generation proteasome inhibitors, immunomodulatory drugs, and CD38-targeting agents-aimed at improving outcomes for this patient subset.

Methods

A systematic review and meta-analysis were performed, analyzing data from 18 randomized controlled trials (RCTs) involving high-risk MM patients treated with new drug combinations. Data extraction, quality assessment, and meta-analysis were conducted using a Bayesian fixed-effects model.

Results

For transplant-eligible patients, CD38-based therapies reduced progression or death risk by 33% during induction and 48% during maintenance. They improved progression-free survival (PFS) by 38% in induction and 57% in maintenance and increased minimal residual disease (MRD) negativity by 38%. Dual novel drug regimens also enhanced MRD negativity, but Elotuzumab and Ixazomib regimens showed limited impact. Carfilzomib-based therapies showed varying PFS and survival benefits.

Conclusion

CD38-targeted regimens notably improve outcomes in high-risk cytogenetic MM, especially for transplant-eligible patients, by reducing disease progression, enhancing PFS, and increasing MRD negativity. Dual novel regimens show promise in MRD improvements. These findings support the potential of tailored therapeutic strategies to optimize patient care.

Cytogenetic risk stratification combined with minimal residual disease status influences the therapeutic outcome and prognosis of multiple myelomas

To explore the value of cytogenetic risk stratification combined with minimal residual disease (MRD) status in predicting the therapeutic efficacy and prognosis for multiple myeloma (MM). From January 2017 to December 2023, 73 cases of newly diagnosed MM were recruited. Cytogenetic risks were stratified according to the results of fluorescence in situ hybridization (FISH); MRD status and clinical data were analyzed. The progression-free survival (PFS) and overall survival (OS), and their influencing factors were evaluated. During the median follow-up period of 30 (4-65) months, the median progression-free survival (PFS) and overall survival (OS) were 38 (95% CI 29.7, 46.3) months and 55 (95% CI 45.9, 64.1) months, respectively. In our cohort, the 3-year PFS rate was 51.0% and the 3-year OS rate was 71.0%. According to the MRD status, 31 MM patients were assigned to the MRD-positivity group and 42 to the MRD-negativity group. Significant differences were detected in the median PFS (30 months vs. 45 months, χ2 = 7.747, P = 0.005) and OS (34 months vs. 59 months, χ2 = 8.683, P = 0.003) between groups. Subgroup analyses based on the cytogenetic risk stratification (standard risk [SR] and high risk [HR]) showed that MM patients in the SR/MRD-negativity subgroup did not reach the median PFS and OS, and the median PFS (42 months vs. 33 months, P = 0.093) and OS (59 months vs. 42 months, P = 0.703) were similar between the SR/MRD-positivity and HR/MRD-negativity subgroups. In comparison to the HR/MRD-negativity subgroup, the median PFS (20 months vs. 33 months, P = 0.031) and OS (33 months vs. 42 months, P = 0.032) were significantly shorter in the HR/MRD-positivity group. Multivariate analysis showed that MRD-positivity was an independent risk factor for PFS (HR 2.874, 95% CI 1.452, 5.689; P = 0.008) and OS (HR 3.504, 95% CI 1.599, 7.676; P = 0.002) of MM. MRD status is a powerful prognostic indicator of PFS and OS in MM, but its performance is inferior to cytogenetic risk stratification. More high-risk cytogenetic abnormalities (HRCAs) indicate a worse prognosis of MM, while MRD-negativity improves HRCA-associated prognosis of MM. We recommend a risk stratification by assessing MRD status combined with HRCAs in MM patients, thus favoring the design of individualized treatment.

Multiple Myeloma: Improved Outcomes Resulting from a Rapidly Expanding Number of Therapeutic Options

Multiple myeloma (MM) is a bone-marrow-based cancer of plasma cells. Over the last 2 decades, marked treatment advances have led to improvements in the overall survival (OS) of patients with this disease. Key developments include the use of chemotherapy, immunomodulatory drugs, proteasome inhibitors, and monoclonal antibodies. MM remains incurable, with outcomes influenced by many factors, including age, sex, genetics, and treatment response. This review summarizes recent studies regarding monitoring and treatment of MM, emphasizing the efficacy of new therapies, the impact of maintenance treatments, and approaches for managing relapsed or refractory MM. The role of specific drug classes used to treat MM, including immunomodulatory drugs, proteasome inhibitors, monoclonal antibodies, and newer treatments such as chimeric antigen receptor T-cell therapies and bispecific antibodies are discussed. Combination therapies have significantly improved outcomes. Maintenance therapies, particularly with lenalidomide, have been effective in extending OS but lead to an increased risk of secondary cancers. Venetoclax, selinexor, and ruxolitinib have shown potential as new therapeutic options for patients with relapsed or refractory MM. Immune-based treatments, such as chimeric antigen receptor T-cell therapy and bispecific antibodies, mark a major advancement for heavily pretreated patients, although challenges remain related to cost, availability, and side effects. The treatment landscape for patients with MM has seen significant progress, with current therapies providing a longer OS and better quality of life. Future research should focus on optimizing these strategies, personalizing therapies, and exploring new therapeutic targets.

Multiple Myeloma Insights from Single-Cell Analysis: Clonal Evolution, the Microenvironment, Therapy Evasion, and Clinical Implications

Multiple myeloma (MM) is a complex and heterogeneous hematologic malignancy characterized by clonal evolution, genetic instability, and interactions with a supportive tumor microenvironment. These factors contribute to treatment resistance, disease progression, and significant variability in clinical outcomes among patients. This review explores the mechanisms underlying MM progression, including the genetic and epigenetic changes that drive clonal evolution, the role of the bone marrow microenvironment in supporting tumor growth and immune evasion, and the impact of genomic instability. We highlight the critical insights gained from single-cell technologies, such as single-cell transcriptomics, genomics, and multiomics, which have enabled a detailed understanding of MM heterogeneity at the cellular level, facilitating the identification of rare cell populations and mechanisms of drug resistance. Despite the promise of advanced technologies, MM remains an incurable disease and challenges remain in their clinical application, including high costs, data complexity, and the need for standardized bioinformatics and ethical considerations. This review emphasizes the importance of continued research and collaboration to address these challenges, ultimately aiming to enhance personalized treatment strategies and improve patient outcomes in MM.

High level of circulating cell-free tumor DNA at diagnosis correlates with disease spreading and defines multiple myeloma patients with poor prognosis

Multiple myeloma (MM) is a plasma cell (PC) disorder characterized by skeletal involvement at the time of diagnosis. Recently, cell-free DNA (cfDNA) has been proven to recapitulate the heterogeneity of bone marrow (BM) disease. Our aim was to evaluate the prognostic role of cfDNA at diagnosis according to disease distribution, and to investigate the role of the MM microenvironment inflammatory state in supplying the release of cfDNA. A total of 162 newly diagnosed MM patients were screened using 18F-FDG PET/CT and assessed by ultra low-pass whole genome sequencing (ULP-WGS). High cfDNA tumor fraction (ctDNA) levels were correlated with different tumor mass markers, and patients with high ctDNA levels at diagnosis were more likely to present with metabolically active paraskeletal (PS) and extramedullary (EM) lesions. Moreover, we demonstrated that microenvironment cancer-associated fibroblast (CAFs)-mediated inflammation might correlate with high ctDNA levels. Indeed, a high cfDNA TF level at diagnosis predicted a poorer prognosis, independent of R-ISS III and 1q amplification; the inclusion of >12% ctDNA in the current R-ISS risk score enables a better identification of high-risk patients. ctDNA can be a reliable and less invasive marker for disease characterization, and can refine patient risk.

Dynamics of minimal residual disease and its clinical implications in multiple myeloma: A retrospective real-life analysis

BACKGROUND

Minimal residual disease (MRD) testing is a promising approach to tailor the treatment of multiple myeloma (MM). However, several major concerns remain to be addressed before moving it into daily practice, most of which stem from the dynamic nature of the MRD status. Thus, it is crucial to understand the MRD dynamics and propose its clinical implications.

METHODS

We retrospectively analysed the data of patients with newly diagnosed MM (NDMM) who had flow cytometry-based MRD tests at multiple time points after initiation of therapy. The impact of undetectable MRD (including attainment, duration and loss) on clinical outcomes was analysed.

RESULTS

In a cohort of 220 patients with NDMM, attainment of MRD- offered favourable outcomes (P < 0.0001 for both progression-free survival (PFS) and overall survival (OS)), regardless of baseline risk factors. Notably, MRD- duration ≥12 months was associated with an 83 % (95 % confidence interval (CI), 0.09-0.34; P < 0.0001) or 69 % (95 % CI, 0.13-0.76; P = 0.0098) reduction in risk of progression/death or death, while the longer MRD- was sustained, the better the outcome was. Loss of MRD- led to poor PFS (hazard ratio (HR) 0.01, 95 % CI 0-0.06, P < 0.0001) and OS (HR 0.03, 95 % CI 0-0.24, P = 0.0008). Most patients (70 %) who lost MRD- status carried high-risk cytogenetic abnormalities (HRCAs). While MRD- was temporally inconsistent with conventional therapeutic responses (eg ≥ complete remission or very good partial response), it predicted disease progression or recurrence more robustly than the latter. Last, the predictive value of the MRD status was independent of baseline risk factors (eg high-risk cytogenetic abnormality, International Staging System (ISS) or Revised (R-)ISS staging).

CONCLUSIONS

Longitudinal assessment of MRD during the treatment course and follow-up is required for monitoring disease progression or relapse, to guide treatment decisions. Accordingly, a prospective study is currently ongoing to investigate the feasibility and benefit of the MRD-tailored therapy according to the longitudinal changes of the MRD status.

Impact of pretransplant minimal residual disease in patients with multiple myeloma and a very good partial response or better receiving autologous hematopoietic stem cell transplantation

BACKGROUND

The prognostic significance of minimal residual disease (MRD) status before autologous hematopoietic stem cell transplantation (autoHCT) in patients with multiple myeloma (MM) has not been clearly elucidated.

METHODS

Retrospective single-center study of adult MM patients who achieved ≥very good partial response (VGPR) after induction therapy from 2015 to 2021 received upfront autoHCT and had available pretransplant MRD status by next-generation flow cytometry. The cohort was divided into pretransplant MRD-negative (MRDneg) and MRD-positive (MRDpos) groups.

RESULTS

A total of 733 patients were included in our analysis; 425 were MRDneg and 308 MRDpos at autoHCT. In the MRDpos group, more patients had high-risk cytogenetic abnormalities (48% vs. 38%, respectively; p = .025), whereas fewer patients achieved ≥CR before autoHCT (14% vs. 40%; p < .001). At day 100 after autoHCT, 37% of the MRDpos versus 71% of the MRDneg achieved ≥CR, and at best posttransplant response 65% versus 88% achieved ≥CR, respectively. After a median follow-up of 27.6 months (range, 0.7-82.3), the median PFS was significantly shorter for patients in the MRDpos group compared to the MRDneg group: 48.2 months (95% confidence interval [CI], 0.3-80.5) versus 80.1 months (95% CI, 0.5-80.1), respectively (p < .001). There was no significant difference in overall survival between the two groups (p = .41). Pretransplant MRDpos status was predictive of shorter PFS in multivariate analysis (hazard ratio, 1.80; 95% CI, 1.31-2.46; p < .001). The impact of pretransplant MRD status was retained in most of the examined subgroups.

CONCLUSIONS

In patients achieving ≥VGPR to induction, pretransplant MRDpos status was associated with a lower CR rate after autoHCT and a shorter PFS.

The burden of myeloma: novel approaches to disease assessment

Novel therapies in multiple myeloma (MM) have increased the rates of conventional complete remission (CR) in patients. However, patients in CR can have highly heterogeneous outcomes. Novel and more sensitive methods of assessing residual disease burden after therapy will help prognosticate this group better and, ideally, allow individualized therapy adjustments based on response depth in the future. Here, we review novel bone marrow, peripheral blood, and imaging methods for assessing myeloma burden and discuss the opportunities and limitations of incorporating these in everyday clinical practice.

Roadmap for new practitioners to navigate the multiple myeloma landscape

Multiple myeloma (MM) is a blood cancer in which monoclonal plasma cells cause end organ damage resulting in hypercalcemia, renal failure, anemia, and bone lesions. MM is considered incurable, however, recent advances in treatment have improved survival. Historically, MM has been treated with immunomodulatory drugs (IMiDs), proteosome inhibitors (PIs), and corticosteroids. While newer therapeutic approaches such as monoclonal antibodies and cellular therapies have broadened the treatment horizon, the selection and sequencing of these therapies has become more complex. This review aims to help advanced practice providers navigate through the diagnosis, staging, treatment, and supportive care considerations in the MM space.

Recent advances in the management of older adults with newly diagnosed multiple myeloma in Japan

Multiple myeloma is a cancer of plasma cells; the incidence rate of multiple myeloma is high among older adults. Although significant advances have been made in the clinical management of multiple myeloma driven by the introduction of novel drugs, such as proteasome inhibitors, immuno- modulators and antibodies, multiple myeloma remains incurable. Hence, the current therapeutic goal for multiple myeloma is to achieve long-term survival while maintaining a good quality of life. In this context, personalized treatment to balance the efficacy and safety of therapies is important, especially for older adults as they display diverse physical, cognitive or organ functioning. Furthermore, old age is also often associated with frailty. Several tools for evaluating frailty in older adults with multiple myeloma are now available, and frail patients defined by these tools have shown a poor prognosis and more treatment-related toxicities. In addition, it is important to evaluate other factors, such as the International Staging System, high-risk chromosomal abnormalities and treatment response, to predict the clinical course of patients. Further investigations are required to determine how these factors can optimize the treatment for multiple myeloma. In this review, we present a detailed account on the developments and issues related to the current treatment approaches for older adults with newly diagnosed multiple myeloma. We also discuss the ongoing phase III clinical study conducted by the lymphoma study group of the Japan Clinical Oncology Group, which targeted older adults with newly diagnosed multiple myeloma.

Real-world study on adoption of standard of care (SoC) for transplant-eligible newly diagnosed multiple myeloma (TE-NDMM) patients between 2017 and 2020/2021 across France, Germany, Spain, and Italy

OBJECTIVES

This non-interventional observational study described the current standard-of-care (SoC) for transplant-eligible newly diagnosed multiple myeloma (TE-NDMM) patients in France, Germany, Spain, and Italy, and recorded the evolution in regimen adoption in distinct elements of frontline treatment during 2017-2020/2021.

METHODS

Clinical information on ongoing (I) or previous (II) TE-NDMM patients was extracted from the Cancerology database. Proportions of patients receiving regimens in each element and the evolution in regimen adoption were determined for the entire population and each country.

RESULTS

Most common induction regimens among I patients were VRd in France (75.3%) and Spain (44.1%), VTd in Italy (65.2%), and regimens other than VRd/VTd/VCd in Germany. Maintenance was ongoing/planned for 78.3%, 62.3%, 65.2%, and 61.4% patients in France, Germany, Spain, and Italy, respectively. Among II patients, VRd induction increased from 27.0% in 2017 to 65.7% in 2019 in France, remained relatively low in Spain and Germany, and not present in Italy. In Italy and Spain, VTd induction declined from 72.4% and 58.3% in 2017 to 52.8% and 17.3% in 2019, respectively. VCd induction in Germany declined from 85.2% in 2017 to 64.1% in 2019.

CONCLUSION

The use of bortezomib triplets in induction varied markedly over time and between selected countries.

Real-world data on prognostic value of measurable residual disease assessment by fragment analysis or next-generation sequencing in multiple myeloma

Measurable residual disease (MRD) negativity is a strong prognostic indicator in multiple myeloma (MM). However, the optimal use of MRD in daily clinical practice has been hampered by the limited feasibility of MRD testing. Therefore, we examined the clinical relevance of commercially available MRD modalities based on clonality assays by fragment analysis with IdentiClone® (n = 73 patients) and next-generation sequencing (NGS) with LymphoTrack® (n = 116 patients) in newly diagnosed patients with MM who received autologous stem cell transplantation (ASCT). MRD was assessed at the end of induction (pre-ASCT) and/or at 100 days after ASCT (post-ASCT). MRD could not predict survival when assessed by fragment analysis. However, NGS-based MRD negativity at pre- or post-ASCT was beneficial in terms of progression-free and overall survival. Moreover, NGS-based MRD negativity was independently associated with improved progression-free and overall survival, and MRD-positive patients both pre- and post-ASCT had worst outcome. Indeed, initial adverse prognostic features by high-risk cytogenetics could be mitigated upon achieving MRD negativity by NGS. We demonstrate the feasibility and clinical benefit of achieving MRD negativity by commercially available clonality-based MRD assays in MM and support incorporating NGS, but not fragment analysis, to tailor therapeutic strategies in real-world practice.

Monitoring multiple myeloma in the peripheral blood based on cell-free DNA and circulating plasma cells

With the advent of novel, highly effective therapies for multiple myeloma (MM), classical serologic monitoring appears insufficient for response assessment and prediction of relapse. Moreover, serologic studies in MM are hampered by interference of therapeutic antibodies. The detection of malignant plasma cell clones by next generation sequencing (NGS) or multiparameter flow cytometry (MFC) circumvents these difficulties and can be performed in the peripheral blood (pB) by targeting circulating cell-free DNA (cfDNA) or circulating plasma cells (CPCs), thus also avoiding an invasive sampling procedure. Here, we applied NGS of VJ light chain (LC) rearrangements in cfDNA and MFC of magnetically-enriched CD138-positive CPCs (me-MFC) to investigate disease burden in unselected MM patients. Sequencing was successful for 114/130 (87.7%) cfDNA samples and me-MFC results were analyzable for 196/205 (95.6%) samples. MM clones were detectable in 38.9% of samples taken at initial diagnosis or relapse (ID/RD), but only in 11.8% of samples taken during complete remission (CR). Circulating MM plasma cells were present in 83.3% of ID/RD samples and 9.9% of CR samples. Residual disease assessment by NGS or me-MFC in samples taken during very good partial remission or CR was 80% concordant. Notably, 4/4 (NGS) and 5/8 (me-MFC) positive CR samples were from patients with oligo- or non-secretory myeloma. The time to progression was shorter if there was evidence of residual myeloma in the pB. Together, our findings indicate that our two novel analytical approaches accurately indicate the course of MM and may be particularly valuable for monitoring patients with serologically non-trackable disease.