EVIDENCE meta-analysis: evaluating minimal residual disease as an intermediate clinical endpoint for multiple myeloma.

Estimating progression-free survival (PFS) and overall survival (OS) superiority during clinical trials of multiple myeloma (MM) has become increasingly challenging as novel therapeutics have improved patient outcomes. Thus, it is imperative to identify earlier endpoint surrogates that are predictive of long-term clinical benefit to expedite development of more effective therapies. Minimal residual disease (MRD)-negativity is a common intermediate endpoint that has shown prognostic value for clinical benefit in trials of patients with multiple myeloma (MM). This meta-analysis was based on the FDA guidance for considerations for a meta-analysis of MRD as a clinical endpoint and evaluates MRD-negativity as an early endpoint reasonably likely to predict long-term clinical benefit. Eligible studies were phase 2 or 3 randomized controlled clinical trials measuring MRD negativity as an endpoint in patients with MM, with follow-up of ≥6 months following an a priori defined time point of 12±3 months post-randomization. Eight newly diagnosed MM-(NDMM)-studies evaluating 4,907 patients were included. Trial-level associations between MRD-negativity and PFS were R2WLSiv (95% CI) 0.67 (0.43-0.91) and R2copula 0.84 (0.64->0.99) at the 12-month timepoint. The individual-level association between 12-month MRD negativity and PFS resulted in a global odds ratio of 4.02 (95% CI: 2.57-5.46). For relapse/refractory MM-(RRMM), there were four studies included, and the individual-level association between 12-month MRD negativity and PFS resulted in a global odds ratio of 7.67 (4.24-11.10). A clinical trial demonstrating a treatment effect on MRD is reasonably likely to eventually demonstrate a treatment effect on PFS, suggesting that MRD may be an early clinical endpoint reasonably likely to predict clinical benefit in MM, that may be used to support accelerated approval and thereby expedite the availability of new drugs to patients with MM.

Minimal Residual Disease-Adapted Therapy in Multiple Myeloma: Current Evidence and Opinions.

PURPOSE OF REVIEW: Multiple myeloma (MM) is a biologically heterogeneous malignancy with relatively uniform treatment paradigms. This review aims to assess the growing role of Minimal Residual Disease (MRD) assessment in facilitating response-adapted therapeutic decision making to individualize therapy in MM. RECENT FINDINGS: MRD has been repeatedly demonstrated to provide strong prognostic information, superseding traditional IMWG response criteria. The use of MRD to modulate therapy remains controversial. Here, we review the existing landscape of MRD-adapted trial designs in both induction/consolidation and maintenance settings, including recent data from influential studies and retrospective analyses. We navigate existing data, leverage the increased resolution of longitudinal MRD assessments, and comment on trials in progress to explain our current utilization of MRD in the clinic. MRD transcends traditional response assessments by providing a window into disease-treatment interaction over time. As a strong patient-level surrogate, MRD has limited current use in individualizing treatment, but is poised to comprehensively shape treatment strategies at many key points in a patient's MM course.

Genomic Profiling to Contextualize the Results of Intervention for Smoldering Multiple Myeloma.

PURPOSE: Early intervention for High-Risk Smoldering Multiple Myeloma (HR-SMM) achieves deep and prolonged responses. It is unclear if beneficial outcomes are due to treatment of less complex, susceptible disease or inaccuracy in clinical definition of cases entered. EXPERIMENTAL DESIGN: Here, we interrogated whole genome and whole exome sequencing for 54 patients across two HR-SMM interventional studies (NCT01572480, NCT02279394). RESULTS: We reveal that the genomic landscape of treated HR-SMM is generally simple as compared to Newly Diagnosed (ND)MM counterparts with less inactivation of tumor suppressor genes, RAS pathway mutations, MYC disruption, and APOBEC contribution. The absence of these events parallels that of indolent precursor conditions, possibly explaining overall excellent outcomes. However, some patients harboring genomic complexity fail to sustain response and experience resistant, progressive disease. Overall, clinical risk scores do not effectively discriminate between genomically indolent and aggressive disease. CONCLUSIONS: Genomic profiling can contextualize the advantage of early intervention in SMM and guide personalization of therapy.

Emerging Strategies for the Prevention of Immune Toxicities Associated with T cell-Engaging Cancer Therapies.

SUMMARY: Immune-related toxicities including cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS) are common side effects of bispecific antibody and chimeric antigen receptor (CAR) T-cell therapies of hematologic malignancies. As anti-inflammatory therapy (the standard of care) is variably effective in mitigating these toxicities after onset, here we discuss emerging evidence for shifting the strategy from mitigation to prevention.

Genomic Classification and Individualized Prognosis in Multiple Myeloma.

PURPOSE: Outcomes for patients with newly diagnosed multiple myeloma (NDMM) are heterogenous, with overall survival (OS) ranging from months to over 10 years. METHODS: To decipher and predict the molecular and clinical heterogeneity of NDMM, we assembled a series of 1,933 patients with available clinical, genomic, and therapeutic data. RESULTS: Leveraging a comprehensive catalog of genomic drivers, we identified 12 groups, expanding on previous gene expression-based molecular classifications. To build a model predicting individualized risk in NDMM (IRMMa), we integrated clinical, genomic, and treatment variables. To correct for time-dependent variables, including high-dose melphalan followed by autologous stem-cell transplantation (HDM-ASCT), and maintenance therapy, a multi-state model was designed. The IRMMa model accuracy was significantly higher than all comparator prognostic models, with a c-index for OS of 0.726, compared with International Staging System (ISS; 0.61), revised-ISS (0.572), and R2-ISS (0.625). Integral to model accuracy was 20 genomic features, including 1q21 gain/amp, del 1p, TP53 loss, NSD2 translocations, APOBEC mutational signatures, and copy-number signatures (reflecting the complex structural variant chromothripsis). IRMMa accuracy and superiority compared with other prognostic models were validated on 256 patients enrolled in the GMMG-HD6 (ClinicalTrials.gov identifier: NCT02495922) clinical trial. Individualized patient risks were significantly affected across the 12 genomic groups by different treatment strategies (ie, treatment variance), which was used to identify patients for whom HDM-ASCT is particularly effective versus patients for whom the impact is limited. CONCLUSION: Integrating clinical, demographic, genomic, and therapeutic data, to our knowledge, we have developed the first individualized risk-prediction model enabling personally tailored therapeutic decisions for patients with NDMM.

Genomic and immune signatures predict clinical outcome in newly diagnosed multiple myeloma treated with immunotherapy regimens.

Despite improving outcomes, 40% of patients with newly diagnosed multiple myeloma treated with regimens containing daratumumab, a CD38-targeted monoclonal antibody, progress prematurely. By integrating tumor whole-genome and microenvironment single-cell RNA sequencing from upfront phase 2 trials using carfilzomib, lenalidomide and dexamethasone with daratumumab ( NCT03290950 ), we show how distinct genomic drivers including high APOBEC mutational activity, IKZF3 and RPL5 deletions and 8q gain affect clinical outcomes. Furthermore, evaluation of paired bone marrow profiles, taken before and after eight cycles of carfilzomib, lenalidomide and dexamethasone with daratumumab, shows that numbers of natural killer cells before treatment, high T cell receptor diversity before treatment, the disappearance of sustained immune activation (that is, B cells and T cells) and monocyte expansion over time are all predictive of sustained minimal residual disease negativity. Overall, this study provides strong evidence of a complex interplay between tumor cells and the immune microenvironment that is predictive of clinical outcome and depth of treatment response in patients with newly diagnosed multiple myeloma treated with highly effective combinations containing anti-CD38 antibodies.

Immunophenotypic correlates of sustained MRD negativity in patients with multiple myeloma.

The role of the immune microenvironment in maintaining disease remission in patients with multiple myeloma (MM) is not well understood. In this study, we comprehensively profile the immune system in patients with newly diagnosed MM receiving continuous lenalidomide maintenance therapy with the aim of discovering correlates of long-term treatment response. Leveraging single-cell RNA sequencing and T cell receptor ß sequencing of the peripheral blood and CyTOF mass cytometry of the bone marrow, we longitudinally characterize the immune landscape in 23 patients before and one year after lenalidomide exposure. We compare patients achieving sustained minimal residual disease (MRD) negativity to patients who never achieved or were unable to maintain MRD negativity. We observe that the composition of the immune microenvironment in both the blood and the marrow varied substantially according to both MRD negative status and history of autologous stem cell transplant, supporting the hypothesis that the immune microenvironment influences the depth and duration of treatment response.

MRD and Plasma Cell Dynamics after CAR T-cell Therapy in Myeloma.

SUMMARY: In this issue, Paiva and colleagues characterize the dynamics of minimal residual disease (MRD) and clinical responses during chimeric antigen receptor (CAR) T-cell therapy of relapsed/refractory multiple myeloma. Although both correlate with prolonged progression-free survival, MRD is reached faster in the bone marrow than complete response in peripheral blood; consequently, the study addresses the need for future guidelines to explore new MRD-negative definitions that are independent of the monoclonal (M) protein to overcome this limitation, particularly in clinical trials using early depth of response as an endpoint. See related article by Paiva et al., p. 365 (1).

Monoclonal gammopathies of clinical significance (MGCS): In pursuit of optimal treatment.

Monoclonal gammopathy of clinical significance (MGCS) represents a new clinical entity referring to a myriad of pathological conditions associated with the monoclonal gammopathy of undetermined significance (MGUS). The establishment of MGCS expands our current understanding of the pathophysiology of a range of diseases, in which the M protein is often found. Aside from the kidney, the three main organ systems most affected by monoclonal gammopathy include the peripheral nervous system, skin, and eye. The optimal management of these MGUS-related conditions is not known yet due to the paucity of clinical data, the rarity of some syndromes, and limited awareness among healthcare professionals. Currently, two main treatment approaches exist. The first one resembles the now-established therapeutic strategy for monoclonal gammopathy of renal significance (MGRS), in which chemotherapy with anti-myeloma agents is used to target clonal lesion that is thought to be the culprit of the complex clinical presentation. The second approach includes various systemic immunomodulatory or immunosuppressive options, including intravenous immunoglobulins, corticosteroids, or biological agents. Although some conditions of the MGCS spectrum can be effectively managed with therapies aiming at the etiology or pathogenesis of the disease, evidence regarding other pathologies is severely limited to individual patient data from case reports or series. Future research should pursue filling the gap in knowledge and finding the optimal treatment for this novel clinical category.

Combination venetoclax and selinexor effective in relapsed refractory multiple myeloma with translocation t(11;14).

Patients with multiple myeloma-bearing translocation t(11;14) have recently been shown to benefit from the apoptosis-inducing drug venetoclax; however, the drug lacks FDA approval in multiple myeloma thus far due to a potential safety signal in the overall patient population. Selinexor is an inhibitor of nuclear export that is FDA-approved for patients with multiple myeloma refractory to multiple lines of therapy. Here, we report that in four patients with multiple myeloma with t(11;14), the concomitant administration of venetoclax and selinexor was safe and associated with disease response. Moreover, the combination was synergistic in t(11;14) multiple myeloma cell lines and caused decreased levels of Cyclin D1 (which is overexpressed due to the CCND1-IGH fusion) when given in combination as compared to single agents. These data suggest that the combination of venetoclax and selinexor is effective and t(11;14) may serve as a therapeutic marker for response and target for future clinical trials.

T cell redirecting bispecific antibodies for multiple myeloma: emerging therapeutic strategies in a changing treatment landscape.

In recent years, the treatment landscape of multiple myeloma has continued to evolve with the introduction of novel immunotherapies. This progress has translated to improved overall survival for patients, but an unmet need remains in the heavily pretreated and high-risk subsets of patients. Emerging immunotherapies in the form of CAR-T cell therapies have been approved for multiple myeloma. However, CAR-T cell therapy has logistical limitations and there is a need for immunotherapies that are readily available, safe, and effective in RRMM. Currently, pending approval, there are many "off the shelf" bispecific antibodies being developed that target BCMA, GPRC5D, FcRH5 and other cell surface proteins. Preliminary efficacy data has suggested that these bispecific antibody therapies have similar response rates (∼50-80%) in heavily pretreated patients. Similarly, to CAR-T cell therapy, cytokine release syndrome and immune effector cell associated neurotoxicity syndrome are adverse events of key interest and incidence range from ∼40 to 90% and 3 to 20%, respectively. In this review, we highlight the various bispecific immunotherapies under development in the treatment of multiple myeloma with a focus on the data from clinical phase I and II studies.

Oncogenic RAS commandeers amino acid sensing machinery to aberrantly activate mTORC1 in multiple myeloma.

Oncogenic RAS mutations are common in multiple myeloma (MM), an incurable malignancy of plasma cells. However, the mechanisms of pathogenic RAS signaling in this disease remain enigmatic and difficult to inhibit therapeutically. We employ an unbiased proteogenomic approach to dissect RAS signaling in MM. We discover that mutant isoforms of RAS organize a signaling complex with the amino acid transporter, SLC3A2, and MTOR on endolysosomes, which directly activates mTORC1 by co-opting amino acid sensing pathways. MM tumors with high expression of mTORC1-dependent genes are more aggressive and enriched in RAS mutations, and we detect interactions between RAS and MTOR in MM patient tumors harboring mutant RAS isoforms. Inhibition of RAS-dependent mTORC1 activity synergizes with MEK and ERK inhibitors to quench pathogenic RAS signaling in MM cells. This study redefines the RAS pathway in MM and provides a mechanistic and rational basis to target this mode of RAS signaling.

Global Myeloma Trial Participation and Drug Access in the Era of Novel Therapies.

PURPOSE: The globalization of clinical trials has accelerated recent advances in multiple myeloma (MM). However, it is unclear whether trial enrollment locations are reflective of the global burden of MM and whether access to novel therapies is timely and equitable for countries that participate in those trials. METHODS: To assess this, we characterized where MM trials that led to US Food and Drug Administration (FDA) approvals were conducted and determined how often and quickly these drug regimens received approval in their participating trial countries on the basis of country income level and geographic region. RESULTS: A systematic review was conducted to identify all MM clinical trials that met their primary endpoint, enrolled patients outside the United States, and resulted in FDA approval from 2005 to 2019. A total of 18 pivotal MM clinical trials were identified. High-income countries enrolled patients in 100% (18/18) of the trials identified, whereas upper-middle and lower-middle-income countries were represented in 61% (11/18) and 28% (5/18) of trials, respectively. No patients from low-income countries were enrolled. One trial enrolled patients in sub-Saharan Africa, and no trials enrolled patients in South Asia/Caribbean. For drugs/regimens that were approved in their participating countries, the median time from FDA approval to approval was 10.9 months. There were no drugs approved in lower-middle-income trial countries. MM trials leading to FDA approval are generally run in high-income, European, and Central Asian countries. CONCLUSION: There are substantial disparities in where novel therapies are evaluated and where they are ultimately approved for use on the basis of income level and geography.

Efficacy and safety of carfilzomib-lenalidomide-dexamethasone in newly diagnosed multiple myeloma: pooled analysis of four single-arm studies.

Pooled analyses of four single-arm phase 1 and 2 studies (NCT01816971, NCT02405364, NCT01029054, NCT01402284) investigated the clinical effectiveness of carfilzomib-lenalidomide-dexamethasone (KRd) in newly diagnosed multiple myeloma (NDMM). Patients who did (Cohort 1; n = 122) and did not (Cohort 2; n = 99) undergo autologous stem cell transplant (high-dose melphalan [HDM]-ASCT) were included. Patients received a 28-day cycle of induction KRd. The rate of very good partial response or better, the primary endpoint, was 93% in Cohort 1 and 90% in Cohort 2. Two-year progression-free survival and overall survival rates were 88% and 96% for Cohort 1, and 85% and 97% for Cohort 2. At least 90% of patients in each cohort reported ≥1 grade 3 or 4 treatment-emergent adverse events. Subgroup analyses by age, International Staging System stage, and cytogenetic risk were consistent with the overall population. KRd is an effective and tolerable treatment option for patients with NDMM regardless of HDM-ASCT eligibility.

Daratumumab: A review of current indications and future directions.

Daratumumab, a human IgG1 kappa monoclonal antibody targeting CD38 has transformed the treatment paradigm of multiple myeloma (MM). With the identification of CD38 as a crucial receptor involved in immune system function, it became an ideal target for monoclonal antibody (mAb) drug development in MM. Daratumumab's unique multifaceted mechanism of action has led to great success in the treatment of relapsed refractory multiple myeloma (RRMM) as well as newly diagnosed multiple myeloma (NDMM) patients. Along with its efficacy comes a low toxicity profile, improved further with the introduction of subcutaneous daratumumab. With such success within MM, daratumumab is now being explored in other disease states. This article will review daratumumab's drug development, practical use, and future potential indications.