Understanding high-risk smoldering multiple myeloma.

Smoldering multiple myeloma (SMM) is an asymptomatic condition with heterogeneous biology and various risks of progression to symptomatic disease. The best-known risk stratification models are Mayo-2018, and IWWG based on tumor burden. Recently, the personalized risk assessment tool PANGEA was introduced. New markers of SMM progression, including genomic and immune characteristics of plasma cells (PCs) and tumor microenvironment, are under investigation, and some have been incorporated into traditional scoring systems. Only one phase 3 clinical trial demonstrated an overall survival benefit of lenalidomide for high-risk SMM patients. The study has limitations, and most guidelines recommend observation or participation in clinical trials for high-risk SMM. High-intensity time-limited treatment strategies for high-risk SMM demonstrated deep responses in single-arm studies. But these treatments can cause adverse effects in asymptomatic patients.This review aims to understand better the risk of SMM progression from a clinical and biological point of view.

Early Intervention With a Curative Intent Through an Intensive Therapy Versus Immunologic Disease Control Using a Minimal Intensity Approach in the Management of High-risk Smoldering Multiple Myeloma: A Systematic Review of Evidence From Clinical Trials.

A subset of individuals with smoldering myeloma (SMM) are at a high risk of progression to symptomatic myeloma. Current efforts are focused on identifying this high-risk group and intercepting the disease process before its progression. There is no consensus on what the goal of an intervention should be, whether to aim for a cure through a high-intensity intervention or pursue immunologic disease control using the least intense approach. This systematic review summarized current evidence in support of the optimum approach. A database search of Medline/PubMed, Scopus, EMBASE, Web of Science, CINAHL, Wiley Cochrane Library, clinicaltrials.gov, and conference proceedings of ASH, EHA, ASCO, ESMO was performed. Results were presented using narrative synthesis of quantitative data. Of the 2088 identified records, a total of 10 eligible studies made up of 6 minimal-intensity clinical trials, 3 moderate-intensity trials, and 1 high-intensity trial were included in this review with a total demographic population of 588 high-risk SMM patients. Minimal intensity lenalidomide-based regimen demonstrated clinical effectiveness in delaying disease progression and improving overall survival in high-risk SMM. The single-agent monoclonal antibodies did not have any major impact on improving overall survival, although the studies were not powered to do so. There is a marked increase in the depth of response as the intensity of treatment increases without a proportional improvement in overall survival. Moderate- and high-intensity interventions yielded similar minimal residual disease negativity rates and overall survival. The minimal, moderate, and high-intensity approaches all demonstrated clinical benefits in delaying disease progression and improving overall survival in patients with high-risk SMM and increasing intensity of intervention does not necessarily translate to improved overall survival.

Lenalidomide-dexamethasone versus observation in high-risk smoldering myeloma after 12 years of median follow-up time: A randomized, open-label study.

BACKGROUND: Smoldering multiple myeloma (SMM) is a heterogeneous disease in terms of progression to myeloma (MM), but its standard of care continues to be observation. METHODS: The QuiRedex phase 3 trial initiated in 2007 included 119 high-risk patients with SMM randomized to treatment or observation. Treatment consisted of nine 4-week induction cycles (lenalidomide [Rd], 25 mg on days 1-21 plus dexamethasone, 20 mg on days 1-4 and 12-15), followed by maintenance (R, 10 mg on days 1-21) for up to 2 years. The primary end-point was time to progression (TTP) to myeloma based on per protocol population. Secondary end-points were overall survival (OS), response rate, and safety. An update of the trial after a long-term follow-up is presented here. This trial was registered with ClinicalTrials.gov (NCT00480363). FINDINGS: After a median follow-up time of 12.5 years (range: 10.4-13.6), the median TTP to MM was 2.1 years in the observation arm and 9.5 years in the Rd arm (HR: 0.28, 95% CI: 0.18-0.44, p < 0.0001). The median OS was 8.5 years in the abstention arm and not reached in the Rd group (HR: 0.57, 95% CI: 0.34-0.95, p = 0.032). Patients who progressed received optimized treatments according to the standards of care, and the OS from progression was comparable in both arms (p = 0.96). INTERPRETATION: This analysis confirms that early treatment with Rd for high-risk SMM translates into a sustained benefit in both TTP and OS. FUNDING: Pethema (Spanish Program for the Treatment of Hematologic Diseases), Spain.

Smoldering multiple myeloma: Reviewing the rationale for intervention.

Smoldering multiple myeloma has been recognized for over 40 years and represents a pre-symptomatic phase of the 2nd most common hematologic malignancy. 1/3 of patients will remain asymptomatic at 10 years. There is an identifiable subset of patients that will develop CRAB within 2 years of recognition and these patients are considered for therapeutic intervention before the development of potentially irreversible complications. Obstacles to widespread implementation of therapeutic guidelines are limited by the variable definitions associated with this high-risk group as well as the poor concordance between classification schemes. Analysis of clinical trial outcomes as well as uniform eligibility helps determine whether a given patient should be considered for therapeutic intervention outside of a clinical trial.

Smoldering multiple myeloma: biology, clinical manifestations and management.

Smoldering multiple myeloma (SMM) is a heterogeneous group of asymptomatic plasma cell disorder characterized by the presence of monoclonal protein ≥ 30 g/L and/or 10-60% of bone marrow plasma cells and no evidence of SLiM-CRAB criteria according to the 2014 International Myeloma Working Group (IMWG) recommendations. Once the effort to reclassify SMM with active disease as MM requiring treatment was completed, the need to redefine new high-risk SMM arose. The 20/2/20 and the IMWG risk model with the add-on high-risk cytogenetic abnormalities allow to identify high-risk SMM with 50% risk of progression to MM within 2 years, and therefore might help to propose a better therapeutic approach, either with the goal to « cure ¼ by profoundly debulk the MM with aggressive therapies, or alternatively to restore the immune surveillance like a « delay ¼ strategy with immune-based therapies. The debate is still ongoing but clearly challenges the watch-and-wait standard of care.

Smoldering multiple myeloma - Past, present, and future.

Smoldering multiple myeloma (SMM) routinely precedes the development of multiple myeloma. While some patients experience aggressive disease, others have more indolent courses akin to those with monoclonal gammopathy of undetermined significance. Much effort has been made to understand the pathobiological basis of this heterogeneity. Scientific advancements have led to the emergence of various clinical and genomic markers of relevance, translating into evolution of disease definitions over time. More recently, the interest in manipulation of biological pathways has intensified in a bid to stall or halt disease progression. Studies with lenalidomide have exemplified the promise of early intervention, whereas numerous therapeutic approaches remain the subject of ongoing clinical investigation. This review summarizes the historic progress made in defining SMM as a distinct clinicopathologic entity, provides a critical appraisal of the evidence guiding risk assessment, and suggests a pragmatic approach to its modern-day management. Finally, an overview of developments on the horizon is also provided.

Smoldering multiple myeloma: evolving diagnostic criteria and treatment strategies.

The adage for smoldering myeloma (SMM) has been to observe without treatment, until criteria for active multiple myeloma were satisfied. Definitions and risk stratification models have become more sophisticated, with prognostication tailored to include high-risk cytogenetics as per the most recent International Myeloma Working Group 2020 risk model. Moreover, progress in defining genomic evolution and changes in the bone marrow microenvironment through the monoclonal continuum have given insight into the complexities underlying the different patterns of progression observed in SMM. Given recent data showing improved progression-free survival with early intervention in high-risk SMM, the current dilemma is focused on how these patients should be treated. This case-based article maps the significant advancements made in the diagnosis and risk stratification of SMM. Data from landmark clinical trials will also be discussed, and ongoing trials are summarized. Ultimately, we outline our approach to SMM and hope to impart to the reader a sound concept of the current clinical management of SMM.

Rare Association between Sarcoidosis and Smoldering Multiple Myeloma: A Case Report.

While several case reports suggest an association between sarcoidosis and multiple myeloma (MM), few cases involve smoldering MM. We report a case of sarcoidosis and smoldering MM discovered simultaneously in a patient admitted for hypercalcemia. Initial tests raised suspicion for sarcoidosis and MM, prompting invasive testing. Surgical lung biopsy revealed necrotizing granulomas, which could represent sarcoidosis in the appropriate setting. Thus, sarcoidosis was diagnosed following a negative infectious workup. Bone marrow biopsy revealed 13% plasma cells leading to subsequent diagnosis of smoldering MM. This case demonstrates the challenge of determining disease activity when other causes of CRAB symptoms are present.

Smoldering Myeloma Treatment: Who, What, and When.

ABSTRACT: Smoldering multiple myeloma (MM) is a clonal plasma cell disorder characterized by excess marrow involvement and immunoglobulin production. It is the precursor of MM, differing by the lack of end-organ damage. Smoldering MM encompasses a heterogeneous group of patients, with a median risk of progression to active disease of 50% in the first 5 years. Until recently, the standard of care would dictate observation off therapy until the development of end-organ damage. The recognition of high-risk and ultrahigh-risk subgroups of smoldering MM, with more likely evolution to MM, has led to earlier initiation of therapy in the disease course. Ongoing studies to define the ideal timing and patient population are underway, as well as identification of which agents would be of greatest benefit, as the armamentarium for MM continues to grow.

Testing Mayo Clinic's New 20/20/20 Risk Model in Another Cohort of Smoldering Myeloma Patients: A Retrospective Study.

Background-smoldering multiple myeloma (SMM) risk of progression to multiple myeloma (MM) is highly heterogeneous and several models have been suggested to predict this risk. Lakshman et al. recently proposed a model based on three biomarkers: bone marrow plasma cell (BMPC) percentage > 20%, free light chain ratio (FLCr) > 20 and serum M protein > 20 g/L. The goal of our study was to test this "20/20/20" model in our population and to determine if similar results could be obtained in another cohort of SMM patients. Method-we conducted a retrospective, single center study with 89 patients diagnosed with SMM between January 2008 and December 2019. Results-all three tested biomarkers were associated with an increased risk of progression: BMPC percentage ≥ 20% (hazard ratio [HR]: 4.28 [95%C.I., 1.90-9.61]; p < 0.001), serum M protein ≥ 20 g/L (HR: 4.20 [95%C.I., 1.90-15.53]; p = 0.032) and FLCr ≥ 20 (HR: 3.25 [95%C.I., 1.09-9.71]; p = 0.035). The estimated median time to progression (TTP) was not reached for the low and intermediate risk groups and was 29.1 months (95%C.I., 3.9-54.4) in the high-risk group (p = 0.006). Conclusions-the 20/20/20 risk stratification model adequately predicted progression in our population and is easy to use in various clinical settings.

Progress in the Management of Smoldering Multiple Myeloma.

PURPOSE OF REVIEW: Smoldering multiple myeloma (SMM) is defined as an asymptomatic clonal proliferation of pre-malignant plasma cells and an increased risk of progression to multiple myeloma (MM) relative to monoclonal gammopathy of undetermined significance. Whether patients with SMM should be treated prior to development of symptomatic disease is fiercely debated and is a highly active area of research. RECENT FINDINGS: The ECOG E3A06 study demonstrated that early treatment with lenalidomide significantly reduced the risk of progression to MM compared to observation in patients with high risk SMM. The IMWG recently validated a risk stratification model to include cytogenetics and a personalized risk calculator for individual patients. Beyond this, molecular genomic aberrations and immunological phenomena that promote progression from asymptomatic disease to MM have been recently characterized and may help to more precisely identify patients who are most suitable for early intervention. As highly effective and tolerable therapies for plasma cell disorders evolve, the field is approaching a paradigm shift that involves the adoption of intervention for patients with SMM who are at high risk for progression to symptomatic myeloma in order to prevent morbidity and mortality. This review highlights our current understanding of the biology of patients with SMM, clarifies the rationale for early intervention, and summarizes early results of various treatment strategies for patients with high-risk smoldering myeloma.

Smoldering multiple myeloma 40 years later: a story of unintended disease.

Introduction: Smoldering multiple myeloma (SMM) is a clonal plasma cell (PC) disorder considered a prelude to MM due to its greater malignant potential compared to monoclonal gammopathy of undetermined significance (MGUS). Despite tectonic changes in the SMM landscape that occurred since it was first distinguished four decades ago, SMM continues to represent a complex and controversial entity causing a great deal of diagnostic and management turmoil.Areas covered: Author addresses increasingly complicated, ambiguous, as well as some overlooked and misjudged aspects of SMM such as the disease identity, relationship to its counterparts, MGUS and overt MM, its niche in the modern classification of monoclonal gammopathies and management. The PubMed search (1980-2020) was conducted and the current NCCN guidelines reviewed in reference to the diagnosis and treatment of smoldering multiple myeloma.Expert opinion: A plethora of clinical and biological evidence points to SMM as a source of the ongoing and expanding uncertainty of this condition and calls into question its authenticity as a discrete entity. Until comprehensive testing can predict the progression of pre-myeloma conditions with the utmost precision, attempts at preemptive treatments will fail to answer the basic question of who will benefit from the early treatment and who will not.

Renal and pulmonary thrombotic microangiopathy triggered by proteasome-inhibitor therapy in patient with smoldering myeloma: A renal biopsy and autopsy case report.

RATIONALE: Thrombotic microangiopathy (TMA) is a group of clinical syndromes characterized by excessive platelet activation and endothelial injury that leads to acute or chronic microvascular obliteration by intimal mucoid and fibrous thickening, with or without associated thrombi. It frequently involves the kidney but may involve any organ or system at variable frequencies depending on the underlying etiology. Among its numerous causes, drug toxicities and complement regulation abnormalities stand out as some of the most common. A more recently described association is with monoclonal gammopathy. Lung involvement by TMA is infrequent, but has been described in Cobalamin C deficiency and post stem-cell transplantation TMA. PATIENT CONCERNS: This is the case of a patient with smoldering myeloma who received proteasome-inhibitor therapy due to retinopathy and developed acute renal failure within one week of therapy initiation. DIAGNOSES: A renal biopsy showed thrombotic microangiopathy. At the time, mild pulmonary hypertension was also noted and presumed to be idiopathic. INTERVENTIONS: Given the known association of proteasome-inhibitor therapy with thrombotic microangiopathy, Bortezomib was discontinued and dialysis was initiated. OUTCOMES: Drug withdrawal failed to prevent disease progression and development of end-stage renal disease, as well as severe pulmonary hypertension that eventually lead to the patient's death. LESSONS: To our knowledge, this is the first reported case of pulmonary involvement by TMA associated with monoclonal gammopathy which appears to have been triggered by proteasome-inhibitor therapy. Clinicians should be aware of this possibility to allow for more prompt recognition of pulmonary hypertension as a potential manifestation of monoclonal gammopathy-associated TMA, especially in patients also receiving proteasome-inhibitors, so that treatment aiming to slow disease progression can be instituted.

Smoldering multiple myeloma: the role of different scoring systems in identifying high-risk patients in real-life practice.

We explore the predictive role of 2014-updated International Myeloma Working Group (IMWG) diagnostic criteria and of some of currently available risk models for progression to symptomatic myeloma when applied in our unselected population of 75 smoldering multiple myeloma (SMM) patients observed between 2000 and 2015. Risk scores including routinely used clinical parameters such as bone marrow plasmacell infiltration rate, immunoparesis, serum monoclonal component (sMC) value, and altered free light chain ratio (FLCr), were clinically useful to identify SMM patients at higher risk of progression. Time to myeloma progression in our ultra-high risk SMM according to IMWG diagnostic update criteria was very short (12.4 months). Our analysis identified as independent reliable predictors of progression altered FLCr as well as increasing plasma cell infiltration which are part of most commonly applied risk models. Waiting for new scoring systems, bone marrow evaluation and complete laboratory screening are still milestones for SMM management.

Multiple Myeloma: Clinical Updates From the American Society of Hematology Annual Meeting 2018.

Herein, we summarize the novel clinical data for multiple myeloma (MM) that were presented in the 2019 Annual Meeting of the American Society of Hematology. Triplet regimens including lenalidomide-dexamethasone for high-risk smoldering MM are effective but longer follow-up data are needed. Among transplant-eligible, newly diagnosed MM (NDMM) patients, carfilzomib- and daratumumab-based combinations are promising as effective and safe induction regimens and do not impair stem cell collection. Maintenance with ixazomib results in prolonged progression-free survival (PFS) compared with placebo. Regarding transplant-ineligible NDMM patients, large phase III studies showed that the additional use of daratumumab in backbone first-line regimens provides deep responses and PFS prolongation, whereas dose-/schedule-adjusted lenalidomide-dexamethasone has similar efficacy and is more tolerable than continuous lenalidomide-dexamethasone. In the relapsed/refractory setting carfilzomib- and daratumumab-based regimens remain highly effective and safe treatments, whereas the introduction of venetoclax, isatuximab, atezolizumab, and oprozomib broadens the therapeutic options. Among heavily pretreated MM patients, selinexor and melflufen showed particularly encouraging results. Novel immunotherapeutic approaches including chimeric antigen receptor T cells against B-cell maturation antigen and bispecific antibodies constitute a promising alternative that remains to be evaluated in later-phase studies.

Randomized, Double-Blind, Placebo-Controlled, Multicenter Study of Siltuximab in High-Risk Smoldering Multiple Myeloma.

PURPOSE: IL6 is important for the growth and survival of myeloma cells. This study evaluated blocking IL6 with siltuximab to delay the transition from high-risk smoldering multiple myeloma (SMM) to multiple myeloma. PATIENTS AND METHODS: In a randomized, double-blind, placebo-controlled, multicenter study, 85 patients with high-risk SMM were randomized to 15 mg/kg siltuximab (43 patients) or placebo (42 patients). The primary endpoint was 1-year progression-free survival (PFS) rate, based on IMWG CRAB criteria. Secondary endpoints included progressive disease indicator rate, PFS, and safety. RESULTS: Median age was 62 years (range: 21-84); 57% were male and 87% had a baseline Eastern Cooperative Oncology Group score of 0. The 1-year PFS rate was 84.5% (siltuximab) and 74.4% (placebo). After a median follow-up of 29.2 months, 32.6% of PFS events occurred with siltuximab and 42.9% with placebo. Median PFS was not reached with siltuximab but was 23.5 months with placebo [HR 0.50 (95% confidence interval, 0.24-1.04); P = 0.0597]. The safety profile of siltuximab was comparable with placebo. Most adverse events in the siltuximab group were grade 2/3; the most common serious adverse events were infections/infestations, and renal/urinary disorders. Mortality was low in both groups (3 deaths in the siltuximab group and 4 in the placebo group). CONCLUSIONS: Although this study did not meet the prespecified protocol hypothesis criteria, data suggest that siltuximab may delay the progression of high-risk SMM.

Diagnosis and management of smoldering multiple myeloma: the razor's edge between clonality and cancer.

Smoldering multiple myeloma (SMM) is a rare plasma cell disorder, and as the disease is asymptomatic, diagnosis is often incidental. SMM is characterized by increased marrow infiltration by clonal plasma cells and/or elevated serum M-protein in the absence of a myeloma-defining event (MDE). In recent years, SMM has gained increased attention owing to a broadening of the criteria for MDE, which include apart from the CRAB criteria, three additional parameters. Survival advantage may be offered by early treatment in the high-risk subset, based on a single trial. In this review, we assess the risk factors and models for progression to multiple myeloma. A review of our diagnostic and management approaches to SMM is presented.