New Approaches to Smoldering Myeloma

Monoclonal Antibodies in Smoldering Multiple Myeloma and Monoclonal Gammopathy of Undetermined Significance: Current Status and Future Directions

Monoclonal antibodies (MoAbs) targeting several cellular receptors have significantly improved the prognosis of multiple myeloma (MM). Their high effectiveness and safety raise the question of whether earlier therapeutic intervention in monoclonal gammopathy of undetermined significance (MGUS) and smoldering multiple myeloma (SMM) influences the natural course of the disease. MM is preceded by clinically recognized conditions such as MGUS and SMM. Numerous studies are investigating the disease biology and immune profile of SMM and MGUS to unravel the intricate relationship between immunosurveillance and disease progression. The standard approach to MGUS and SMM remains close observation. Early studies indicate benefits in terms of progression or even survival for promptly treating high-risk SMM patients. Ongoing debates are focused on which patients with SMM and MGUS to treat, as well as on determining the optimal therapeutic approach. The first approach aims to cure by attempting to eliminate the pathological clone, while the second approach is preventive, aiming to manage disease progression to active MM and restore the immune system. In this review, we focus on the available and emerging data on early treatment, particularly with MoAbs alone or in combination with other therapies, in SMM and MGUS patients.

A population-based cohort study of the epidemiology of light-chain amyloidosis in Taiwan

The incidence rate of AL (light-chain) amyloidosis is not known in Asia. We conducted a retrospective cohort study using the Taiwan National Healthcare Insurance Research database and Death Registry to estimate incidence and all-cause case fatality rates, and characteristics of patients with AL amyloidosis in Taiwan. All patients with confirmed, newly diagnosed AL amyloidosis from 01-Jan-2016 until 31-Dec-2019 were enrolled and followed up until dis-enrolment, death or study end (31-Dec-2019). There were 841 patients with newly diagnosed AL amyloidosis with median age of 61.4 years and 58.7% were men. At diagnosis, cardiac, renal and liver-related diseases were present in 28.54%, 23.19% and 2.14% of patients, respectively. AL amyloidosis age-adjusted annual incidence was 5.73 per million population in 2016 and 5.26 per million population in 2019. All-cause case fatality ranged from 1.7 to 2.9% over the study period and was highest (~10%) in patients ≥ 80 years. Survival was significantly lower in patients with co-morbid cardiac, renal, or liver-related diseases which could indicate organ involvement. The incidence of AL amyloidosis in Taiwan appears to be similar to Western countries. The poor prognosis in patients with co-morbid diseases highlights the need for earlier diagnosis.

Recovery of polyclonal immunoglobulins during treatment in patients ineligible for autologous stem-cell transplantation is a prognostic marker of longer progression-free survival and overall survival

Immunoparesis is the suppression of normal polyclonal immunoglobulins and is present in most patients with newly diagnosed multiple myeloma (MM). The association of immunoparesis at diagnosis, and particularly its recovery along with treatment, with survival in patients ineligible for autologous stem-cell transplantation (ASCT) has not been well established. This retrospective study evaluated the impact of immunoparesis in 431 patients diagnosed with MM, ineligible for ASCT, with a median overall survival of 36 months [95% confidence interval (CI): 31-40]. Immunoparesis was present in 81.2% of patients at diagnosis and was associated with a trend to a worse overall response rate (ORR: 84.8% vs. 74.9%; OR 1.88 (95% CI: 0.97-3.63), shorter progression-free survival (PFS) [22.0 vs. 18.2 months; hazard ratio (HR) 0.775; 95%CI: 0.590-1.018; p = 0.066], and overall survival (OS) (45.9 vs. 34.2 months; HR 0.746; 95% CI: 0.551-1.010; p = 0.057). Twenty-four per cent of patients who had immunoparesis at diagnosis recovered polyclonal immunoglobulins in the follow-up period. Interestingly, these patients had a better ORR (96.3% vs. 68.2%; OR 12.29 (95% CI: 3.77-40.06), PFS (HR 0.703; 95CI%: 0.526-0.941; p = 0.018) and OS (HR 0.678; 95 CI%: 0.503-0.913; p = 0.011) than patients who did not recover it. In summary, restoring a healthy immune system along with first-line treatment in patients with MM, not receiving ASCT, is associated with better outcomes.

Recent Advances in the Management of Smoldering Multiple Myeloma

There is remarkable progress in the treatment of multiple myeloma (MM) with significant improvement in survival in the past 10 years. Monoclonal gammopathy of undetermined significance (MGUS) and smoldering multiple myeloma (SMM) can evolve into symptomatic multiple myeloma (sy-MM) with organ involvement. SMM has associated with a much higher progression to MM compared to MGUS. In 2014, International Myeloma Working Group (IMWG) reclassified ultra-high-risk smoldering myeloma patients with bone marrow plasma cells > 60% or serum-free light chain ratio (FLCr) > 100 or > 1 focal bone lesion on the magnetic resonance imaging as MM. SMM is a heterogeneous disorder with probability for progression to myeloma up to 50% in the first 5 years. Several risk models and clinical features have been identified to stratify the risk of progression to MM. Thanks to advances in our understanding of the genomic profile of MM, there are several ongoing clinical trials, and genomic studies are being done to assess the risk of progression to MM and early intervention. There is still no standard criterion regarding when to start therapy. This review discusses identifying SMM patients who are at high risk of progression to sy-MM and recent development of new and early treatment strategies and ongoing clinical trials for these high-risk SMM patients.

Smoldering Multiple Myeloma: To Treat or Not to Treat

Smoldering multiple myeloma (SMM) is an asymptomatic, intermediate stage positioned between the plasma cell disorders of monoclonal gammopathy of undermined significance and overt multiple myeloma (MM). Although the patients with SMM have a higher risk of progression to MM in comparison to their counterparts with monoclonal gammopathy of undermined significance, their clinical course can be highly variable. The standard of care for SMM, irrespective of the risk status, continues to be observation due to paucity of high-level evidence demonstrating survival or quality-of-life benefit with early intervention. With the expanded 2014 criteria for MM utilizing biomarkers, the subset of SMM patients with 70% to 80% risk of progression at 2 years (ultra-high risk SMM) is now categorized as active MM and treated prior to the development of end-organ damage. After exclusion of this group, patients with approximately 50% risk of progression in 2 years are now considered high-risk SMM, and the value of early treatment in this subset can be established only through clinical trials. Despite its limitations, a recent phase III trial (QuiRedex) has shown survival advantage to using lenalidomide and dexamethasone doublet over observation in high-risk SMM. In this article, we review the evolving concepts in the diagnosis, risk stratification, and management of SMM.

Elotuzumab monotherapy in patients with smouldering multiple myeloma: a phase 2 study

Smouldering multiple myeloma (SMM) is associated with increased risk of progression to multiple myeloma within 2 years, with no approved treatments. Elotuzumab has been shown to promote natural killer (NK) cell stimulation and antibody-dependent cellular cytotoxicity (ADCC) in vitro. CD56^dim (CD56^dim /CD16⁺ /CD3^- /CD45⁺ ) NK cells represent the primary subset responsible for elotuzumab-induced ADCC. In this phase II, non-randomized study (NCT01441973), patients with SMM received elotuzumab 20 mg/kg intravenously (cycle 1: days 1, 8; monthly thereafter) or 10 mg/kg (cycles 1, 2: weekly; every 2 weeks thereafter). The primary endpoint was the relationship between baseline proportion of bone marrow-derived CD56^dim NK cells and maximal M protein reduction; secondary endpoints included overall response rate (ORR) and progression-free survival (PFS). Fifteen patients received 20 mg/kg and 16 received 10 mg/kg; combined data arepresented. At database lock (DBL, September 2014), no association was found between baseline CD56^dim NK cell proportion and maximal M protein reduction. With minimum 28 months' follow-up (DBL: January 2016), ORR (90% CI) was 10% (2·7-23·2) and 2-year PFS rate was 69% (52-81%). Upper respiratory tract infections occurred in 18/31 (58%) patients. Four (13%) patients experienced infusion reactions, all grade 1-2. Elotuzumab plus lenalidomide/dexamethasone is under investigation for SMM.

Smoldering Multiple Myeloma: Who and When to Treat

Smoldering multiple myeloma (SMM) is an asymptomatic plasma cell disorder characterized by the presence of ≥ 3 g/dL serum M-protein and/or 10% to 60% bone marrow plasma cell infiltration with no myeloma-defining event. The risk of progression to active multiple myeloma (MM) is not uniform, and several markers are useful for identifying patients at high risk of progression. The definition of the disease has recently been revisited and asymptomatic MMs at 80% to 90% of progression risk at 2 years are now considered to be active MM candidates for treatment. In the future, more precise biomarkers are necessary for accurate risk stratification to plan an optimized follow-up according to the risk of progression, as well as to expand the group of patients that can obtain a benefit if they receive early treatment. A phase 3, randomized trial in high-risk patients with SMM comparing early treatment versus observation has shown a significant benefit in terms of time to progression and overall survival for early intervention and confirmatory clinical trials will definitively contribute to establish the early treatment as standard of care in 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.

A mathematical model of cell equilibrium and joint cell formation in multiple myeloma

In Multiple Myeloma Bone Disease healthy bone remodelling is affected by tumour cells by means of paracrine cytokinetic signalling in such a way that osteoclast formation is enhanced and the growth of osteoblast cells inhibited. The participating cytokines are described in the literature. Osteoclast-induced myeloma cell growth is also reported. Based on existing mathematical models for healthy bone remodelling a three-way equilibrium model is presented for osteoclasts, osteoblasts and myeloma cell populations to describe the progress of the illness in a scenario in which there is a secular increase in the cytokinetic interactive effectiveness of paracrine processes. The equilibrium state for the system is obtained. The paracrine interactive effectiveness is explored by parameter variation and the stable region in the parameter space is identified. Then recently-discovered joint myeloma-osteoclast cells are added to the model to describe the populations inside lytic lesions. It transpires that their presence expands the available parameter space for stable equilibrium, thus permitting a detrimental, larger population of osteoclasts and myeloma cells. A possible relapse mechanism for the illness is explored by letting joint cells dissociate. The mathematics then permits the evaluation of the evolution of the cell populations as a function of time during relapse.

MGUS and Smoldering Multiple Myeloma: Diagnosis and Epidemiology

Monoclonal gammopathy of undetermined significance (MHUS) is characterized by the presence of a serum M-protein less than 3 g/dL, less than 10 % clonal plasma cells in the bone marrow, and the absence of myeloma-defining event. Smoldering multiple myeloma (SMM) is an asymptomatic disorder characterized by the presence of ≥3 g/dL serum M-protein and/or 10-60 % bone marrow plasma cell infiltration with no myeloma-defining event. The risk of progression to multiple myeloma (MM) requiring therapy varies greatly for individual patients, but it is uniform and 1 % per year for MGUS, while higher (10 % per year) and not uniform for SMM patients. The definition of MM was recently revisited patients previously labeled as SMM with a very high risk of progression (80-90 % at 2 years) were included in the updated definition of MM requiring therapy. The standard of care is observation for MGUS patients and although this also applies for SMM, a recent randomized trial targeting high-risk SMM showed that early intervention was associated with better progression-free and overall survival. Biomarkers have become an integrated part of diagnostic criteria for MM requiring therapy, as well as clinical risk stratification of patients with SMM. This paper reviews and discusses clinical implications for MGUS and SMM patients.

The road to treating smoldering multiple myeloma

The management of smoldering multiple myeloma (SMM) has been a challenge to clinicians, ever since the condition was first characterized in 1980. While the risk of progression to symptomatic myeloma is greater for SMM (10% per year) compared to MGUS (1% per year), several SMM patients remain asymptomatic for years without evidence of disease progression. Early clinical trials focusing on early treatment of SMM have been equivocal with no clear benefit. However, the last decade has seen a greater understanding of the pathogenesis of plasma cell disorders, including SMM, and development of better therapeutics. A recent randomized trial has provided evidence of clinical benefit with early treatment of high-risk SMM. In this review, we summarize issues related to the early treatment of SMM including risk stratification and possible outcomes with therapy initiation. In the context of reviewing recent clinical trial data supporting early treatment, we define challenges faced by clinicians and provide future directions to the road to treating SMM.

Smoldering multiple myeloma

Smoldering multiple myeloma (SMM) is an asymptomatic clonal plasma cell disorder. SMM is distinguished from monoclonal gammopathy of undetermined significance by a much higher risk of progression to multiple myeloma (MM). There have been major advances in the diagnosis, prognosis, and management of SMM in the last few years. These include a revised disease definition, identification of several new prognostic factors, a classification based on underlying cytogenetic changes, and new treatment options. Importantly, a subset of patients previously considered SMM is now reclassified as MM on the basis of biomarkers identifying patients with an ≥80% risk of progression within 2 years. SMM has assumed greater significance on the basis of recent trials showing that early therapy can be potentially beneficial to patients. As a result, there is a need to accurately diagnose and risk-stratify patients with SMM, including routine incorporation of modern imaging and laboratory techniques. In this review, we outline current concepts in diagnosis and risk stratification of SMM, and provide specific recommendations on the management of SMM.

Smoldering multiple myeloma: when to observe and when to treat?

Smoldering multiple myeloma (SMM) is an asymptomatic disorder characterized by the presence of at least 3 g/dL of serum M-protein and/or 10% to 60% bone marrow plasma cell infiltration with no myeloma-defining event. The risk of progression to active multiple myeloma (MM) is not uniform and several markers are useful for identifying patients at high risk of progression. The definition of the disease has recently been revisited and patients with asymptomatic MM at 80% to 90% of progression risk at 2 years are now considered to have MM. Although the current standard of care is not to treat, a randomized trial in patients with high-risk SMM that compared early treatment versus observation demonstrated that early intervention resulted in substantial benefits in terms of time to progression and overall survival (OS). These findings highlight the need to follow a correct diagnosis by an accurate risk stratification to plan an optimized follow-up according to the risk of disease progression.