Monoclonal gammopathy of undetermined significance (MGUS) and smoldering multiple myeloma (SMM): novel biological insights and development of early treatment strategies

Monoclonal gammopathy of undetermined significance-making it understandable to patients

Oncology nurses working in ambulatory care often encounter patients with nonmalignant hematologic disorders because the specialties of hematology and oncology are closely entwined. A variety of nonmalignant hematologic disorders can evolve into blood malignancies; therefore, close surveillance of nonmalignant hematologic disorders in an oncology/hematology clinic is important for early detection of malignancy. Monoclonal gammopathy of undetermined significance (MGUS) is one nonmalignant, hematologic disorder that is usually aproblematic; however, it can evolve into a blood malignancy such as multiple myeloma or be associated with other chronic conditions. This article provides an overview of MGUS with a focus on implications for the oncology nurse and patient education.

Altered cortical microarchitecture in patients with monoclonal gammopathy of undetermined significance

Patients with monoclonal gammopathy of undetermined significance (MGUS) are at increased fracture risk, and we have previously shown that MGUS patients have altered trabecular bone microarchitecture compared with controls. However, there are no data on whether the porosity of cortical bone, which may play a greater role in bone strength and the occurrence of fractures, is increased in MGUS. Thus, we studied cortical porosity and bone strength (apparent modulus) using high-resolution peripheral quantitative computed tomography imaging of the distal radius in 50 MGUS patients and 100 age-, gender-, and body mass index-matched controls. Compared with controls, MGUS patients had both significantly higher cortical porosity (+16.8%; P < .05) and lower apparent modulus (-8.9%; P < .05). Despite their larger radial bone size, MGUS patients have significantly increased cortical bone porosity and reduced bone strength relative to controls. This increased cortical porosity may explain the increased fracture risk seen in MGUS patients.

MicroRNA theragnostics for the clinical management of multiple myeloma

Theragnostics represent cutting-edge, multi-disciplinary strategies that combine diagnostics with therapeutics in order to generate personalized therapies that improve patient outcome. In oncology, the approach is aimed at more accurate diagnosis of cancer, optimization of patient selection to identify those most likely to benefit from a specific therapy and to generate effective therapeutics that enhance patient survival. MicroRNAs (miRNAs) are master regulators of the human genome that orchestrate myriad cellular pathways to control growth during physiologic and pathologic conditions. Compelling evidence shows that miRNA deregulation promotes events linked to tumor initiation, metastasis and drug resistance as seen in multiple myeloma (MM), an invariably fatal hematologic malignancy. miRNAs are readily detected in body fluids, for example, serum, plasma, urine, as well as circulating tumor cells to demonstrate their potential as readily accessible, non-invasive diagnostic and prognostic biomarkers and potential therapeutics. Specific miRNAs are aberrantly expressed early in myelomagenesis and may more readily detect high-risk disease than current methods. Although only recently discovered miRNAs have rapidly advanced from preclinical studies to evaluation in human clinical trials. The development of miRNA theragnostics should provide widely applicable tools for the targeted delivery of personalized medicines to improve the outcome of patients with MM.

Modeling progression risk for smoldering multiple myeloma: results from a prospective clinical study

The risk of progression to multiple myeloma (MM) from the precursor condition smoldering MM (SMM) varies considerably among individual patients. Reliable markers for progression to MM are vital to advance the understanding of myeloma precursor disease and for the development of intervention trials designed to delay/prevent MM. The Mayo Clinic and Spanish PETHEMA have proposed models to stratify patient risk based on clinical parameters. The aim of our study was to define the degree of concordance between these two models by comparing the distribution of patients with SMM classified as low, medium and high risk for progression. A total of 77 patients with SMM were enrolled in our prospective natural history study. Per study protocol, each patient was assigned risk scores based on both the Mayo and the Spanish models. The Mayo Clinic model identified 38, 35 and four patients as low, medium and high risk, respectively. The Spanish PETHEMA model classified 17, 22 and 38 patients as low, medium and high risk, respectively. There was significant discordance in overall patient risk classification (28.6% concordance) and in classifying patients as low versus high (p < 0.0001), low versus non-low (p = 0.0007) and high versus non-high (p < 0.0001) risk. There is a need for prospectively validated models to characterize individual patient risk of transformation to MM.

Immunomodulation as a therapeutic strategy in the treatment of multiple myeloma

Growth and survival of multiple myeloma (MM) cells depend on intrinsic, cell-autonomous parameters, such as the genetic lesions harboured by the MM cells, as well as extracellular, cell-non-autonomous factors, including the interaction between MM cells and bone-marrow stromal cells and the suppression of the host's anticancer immune responses. Thalidomide and the immunomodulatory agents lenalidomide and pomalidomide have pleiotropic effects on MM cells and their microenvironment, including promotion of direct mechanisms of MM-cell apoptosis, as well as indirect mechanisms mediated by perturbation of cell adhesion, modulation of cytokine production, and inhibition of tumor-associated angiogenesis. The immunomodulatory properties of these agents are mediated by effects on T-cell proliferation and function, stimulation of natural killer cells, and inhibition of regulatory T cells. Thalidomide and lenalidomide have established roles in the treatment of patients with newly diagnosed MM and those with relapsed/refractory disease. Pomalidomide is currently being evaluated in clinical trials, and preliminary clinical data suggest that it is active in patients with MM that is refractory to lenalidomide and bortezomib treatment. This article provides an overview of the current and potential future roles of immunomodulation in the management of MM, and how improved anticancer immune responses may improve treatment outcomes.

"Idiopathic Bence-Jones proteinuria": a new characterization of an old entity

Idiopathic Bence-Jones proteinuria (BJP) is a rare plasma cell dyscrasia, of which the clinical and biological characteristics are yet unclear. Historical data suggested that they are at higher risk of progression to multiple myeloma or other related neoplasms, while recent findings are contradictory. To address these open questions, we evaluated a series of both BJP and monoclonal gammopathy of undetermined significance (MGUS) with production of an intact immunoglobulin plus Bence-Jones proteinuria (MGUS+BJP) with long-term follow-up, regarding their clinical characteristics and progression to multiple myeloma, amyloidosis or other related B cell lymphoproliferative disorders. Two hundred and twenty-nine persons fulfilling the 2004 criteria of MGUS were included in the final analyses: 31 had BJP and 198 had MGUS+BJP. At the time of diagnosis, significantly more persons in the BJP group had renal impairment, anaemia and polyneuropathy. A more detailed analysis revealed discrepancies between the serum and urine light chain type in nine cases, reflecting clonal heterogeneity. The number of disease progressions was higher in MGUS+BJP (n = 30) when compared to BJP (n = 1), with a rate of 1.6 and 0.4 progressions per 100 person-years, respectively. In conclusion, BJP has distinct clinical characteristics and a lower risk of progression when compared to MGUS+BJP. Our data suggest that MGUS+BJP being closer to malignant transformation may be due to the higher portion of genetically heterogeneous, pre-malignant plasma cell subclones.

Randomized clinical trial of zoledronic acid in multiple myeloma patients undergoing high-dose chemotherapy and stem-cell transplantation

BACKGROUND

A growing body of evidence is demonstrating that the nitrogen-containing bisphosphonate zoledronic acid (zol) improves clinical outcomes in various cancer settings, including multiple myeloma. Those findings provided the rationale for conducting an open-label randomized controlled phase iii trial to evaluate the effect of zol on overall survival (os) and progression-free survival (pfs) in patients with previously untreated high-risk multiple myeloma.

METHODS

The trial randomly assigned 308 adult patients less than 65 years of age with previously untreated symptomatic multiple myeloma (1:1) to receive zol 4 mg intravenously once every 28 days for 24 months (n = 151) or no zol (n = 157). Before autologous stem-cell transplantation (asct), all patients received a high-dose noncytotoxic induction regimen of dexamethasone, all-trans-retinoic acid, and interferon alpha 2b.

RESULTS

After a median follow-up of 69.8 months (range: 36.5-96 months), the 10-year pfs (66% vs. 52%, p < 0.001) and os (67% vs. 48%, p < 0.001) rates were significantly higher in treated patients than in control patients. Overall response (77% zol vs. 75% control), complete response (52% vs. 46%), and very good partial response (25% vs. 29%) rates were similar between the groups. Treatment was generally well tolerated, with no reports of renal impairment or osteonecrosis of the jaw.

CONCLUSIONS

In symptomatic previously untreated multiple myeloma patients, zol combined with high-dose therapy followed by asct improved os and pfs without appreciable toxicity. These findings provide additional evidence of the meaningful anticancer activity of zol in this patient population.

Immunoparesis and monoclonal gammopathy of undetermined significance are disassociated in advanced age

Immunoparesis and a skewed serum free light chain (FLC) ratio are indicators of immune dysfunction predictive of progression from monoclonal gammopathy of undetermined significance (MGUS) to multiple myeloma (MM). Previous studies have reported increased prevalence of MGUS by age, but no study has examined the relationship between immunoparesis and abnormal FLC ratios in the elderly. We screened 453 older adults (median age, 80 years; range, 65-96) to characterize the patterns of immunoparesis and abnormal FLC ratio in relation to MGUS. We defined MGUS in 4.4% of the subjects; the prevalence was 12.5% among individuals of >90 years. In MGUS (vs. non-MGUS) cases, immunoparesis and abnormal FLC ratios were detected in 70.0% (vs. 49.0%; P = 0.07) and 50.0% (vs. 12.9%; P = 0.0001), respectively. Based on small numbers, MGUS patients with abnormal FLC ratio were borderline (P = 0.07) more likely to have immunoparesis. Overall, the prevalence of immunoparesis varied in a nonlinear fashion, with lowest frequencies in the youngest and oldest groups. Our observed disassociation between MGUS prevalence and impaired immunoglobulin production suggests that separate mechanisms are involved in the development of MGUS and immunoparesis in advanced age. These findings emphasize the need for molecularly defined methods to characterize myeloma precursor states and better predict progression to MM.

[Cutaneous manifestations revealing cryofibrinogenaemia associated with monoclonal gammopathy]

BACKGROUND

Cryofibrinogenaemia is an under-recognized cutaneous thrombotic vasculopathy that may be revealed by purpura or chronic necrotic ulcerations. We report two original cases characterized by their severity, their association with a monoclonal gammopathy and their excellent response to treatment.

PATIENTS

A 38-year-old woman was admitted for large necrotic leg ulcers appearing 1 year earlier and already investigated. Non-specific signs were seen on a previous skin biopsy and the diagnosis of a factitious disorder was considered at that time. Further investigations revealed circulating cryofibrinogen associated with IgG kappa monoclonal gammopathy without cryoglobulinaemia. Plasmapheresis followed by bortezomid-dexamethasone to treat the monoclonal gammopathy resulted in rapid and complete healing of the ulcers, militating in favour of its involvement in cryofibrinogen formation. The second patient, a 91-year-old woman, was referred to our department for acute necrotic purpura of the legs. Skin biopsy revealed leukocytoclastic vasculitis. Glomerular nephropathy with acute renal failure and multiple arterial thromboses were associated with the skin condition. The cryofibrinogen assay was positive without cryoglobulinaemia and other causes of vasculitis were ruled out. The main component was monoclonal IgG lambda. Prednisone-cyclophosphamide treatment led to complete healing of the skin lesions and to recovery from the systemic consequences of cryofibrinogen without sequelae.

CONCLUSION

Routine screening for cryofibrinogen in plasma should be performed to explore cutaneous symptoms of unexplained thrombotic vasculopathy, even in the presence of a non-specific skin biopsy. Specific treatment of cryofibrinogenaemia associated monoclonal gammopathy appears to be highly effective against manifestations of cryofibrinogenaemia.

Monoclonal gammopathy of undetermined significance and smoldering multiple myeloma: biological insights and early treatment strategies

After decades of virtually no progress, multiple myeloma survival has improved significantly in the past 10 years. Indeed, multiple myeloma has perhaps seen more remarkable progress in treatment and patient outcomes than any other cancer during the last decade. Recent data show that multiple myeloma is consistently preceded by a precursor state (monoclonal gammopathy of undetermined significance [MGUS]/smoldering multiple myeloma [SMM]). This observation provides a framework for prospective studies focusing on transformation from precursor disease to multiple myeloma and for the development of treatment strategies targeting "early myeloma." This review discusses current biological insights in MGUS/SMM, provides an update on clinical management, and discusses how the integration of novel biological markers, molecular imaging, and clinical monitoring of MGUS/SMM could facilitate the development of early treatment strategies for high-risk SMM (early myeloma) patients in the future.

Differential diagnosis of monoclonal gammopathy of undetermined significance

Monoclonal gammopathy of undetermined significance (MGUS) is an asymptomatic plasma cell disorder occurring in 4.2% of adults > 50 years of age, which can progress into symptomatic diseases either through proliferation of the plasma cell clone, giving rise to multiple myeloma and other lymphoplasmacellular neoplasms, or through organ damage caused by the monoclonal protein, as seen in light-chain amyloidosis and related conditions. Differential diagnosis of asymptomatic and symptomatic monoclonal gammopathies is the determinant for starting therapy. The criteria for determining end-organ damage should include markers of organ injury caused by the monoclonal protein. Patient assessment and optimal follow-up are now performed using risk stratification models that should also take into account the risk of developing AL amyloidosis. Patients with low-risk MGUS (approximately 40% of all MGUS patients) need limited assessment and very infrequent follow-up. The ongoing development of novel molecular biomarkers and advanced imaging techniques will improve the identification of high-risk patients who may benefit from early therapeutic intervention through innovative clinical trials.

PDK1 inhibition is a novel therapeutic target in multiple myeloma

BACKGROUND

Cancer cells utilise the glycolytic pathway even when adequate oxygen is present, a phenomenon known as the Warburg effect. We examined whether this system is operative in multiple myeloma (MM) cells and whether glycolysis inhibition is a potential therapeutic modality.

METHODS

The MM cells were purified from 59 patients using CD138-immunomagnetic beads. The expression levels of genes associated with glycolysis, c-MYC, GLUT1, LDHA, HIF1A and pyruvate dehydrogenase kinase-1 (PDK1) were determined by real-time PCR. Glucose consumption and lactate production by MM cell lines were analysed. Oxamate, an LDH inhibitor, and dichloroacetate (DCA), a PDK1 inhibitor, were employed. Inhibition of PDK1 expression was achieved using a siRNA.

RESULTS

High LDHA expression was found to be an indicator of poor prognosis. It was also positively correlated with the expression of PDK1, c-MYC and GLUT1. Greater glucose consumption and lactate production in MM cells was associated with higher LDHA expression. All the glycolysis inhibitors (oxamate, DCA and PDK1 siRNA) induced apoptosis in MM cells. DCA combined with bortezomib showed additive cytotoxic effects.

CONCLUSION

The present data suggest that the Warburg effect is operative in MM cells. As PDK1 is not overexpressed in normal tissues, PDK1 inhibition could serve as a novel therapeutic approach.

Novel anticancer agents for multiple myeloma: a review of the evidence for their therapeutic and economic value

Recent advances in oncology treatment have improved patient outcomes at the expense of increasing healthcare costs. The indication multiple myeloma is especially characterized by a recent and continuing flood of expensive novel agents. A review encompassing all elements necessary to perform an economic evaluation of novel agents for multiple myeloma was conducted for thalidomide, bortezomib and lenalidomide. Improvements in efficacy have led to a switch from conventional therapy to novel agents as standard therapy. Incremental cost-effectiveness ratios for novel agents alone or in combination with conventional agents were generally regarded to be within acceptable ranges. Conflicting results were reported for the incremental cost-effectiveness of bortezomib versus lenalidomide, as unresolved questions remain regarding their comparative effectiveness. Future economic evaluations will require an assessment of the cost-effectiveness of these agents in terms of sequence within the treatment paradigm and in combination with one another.

Bone marrow microenvironment in multiple myeloma progression

Substantial advances have been made in understanding the biology of multiple myeloma (MM) through the study of the bone marrow (BM) microenvironment. Indeed, the BM niche appears to play an important role in differentiation, migration, proliferation, survival, and drug resistance of the malignant plasma cells. The BM niche is composed of a cellular compartment (stromal cells, osteoblasts, osteoclasts, endothelial cells, and immune cells) and a noncellular compartment including the extracellular matrix (ECM) and the liquid milieu (cytokines, growth factors, and chemokines). In this paper we discuss how the interaction between the malignant plasma cell and the BM microenvironment allowed myeloma progression through cell homing and the new concept of premetastatic niche.

High levels of peripheral blood circulating plasma cells as a specific risk factor for progression of smoldering multiple myeloma

Smoldering multiple myeloma (SMM) carries a 50% risk of progression to multiple myeloma (MM) or related malignancy within the first 5 years following diagnosis. The goal of this study was to determine if high levels of circulating plasma cells (PCs) are predictive of SMM transformation within the first 2–3 years from diagnosis. Ninety-one patients diagnosed with SMM at Mayo Clinic from January 1994 through January 2007 who had testing for circulating PCs using an immunofluorescent assay and adequate follow up to ascertain disease progression, were studied. High level of circulating PCs was defined as absolute peripheral blood PCs >5000 ×10⁶/L and/or > 5% cytoplasmic immunoglobulin (Ig) positive PCs per 100 peripheral blood mononuclear cells. Patients with high circulating PCs (14 of 91 patients, 15%) were significantly more likely to progress to active disease within 2 years compared with patients without high circulating PCs, 71% versus 25%, respectively, P=0.001. Corresponding rates for progression within 3 years were 86% versus 35%, respectively, P<0.001. Overall survival (OS) after both SMM diagnosis and MM diagnosis was also significantly different. High levels of circulating PCs identify SMM patients with an elevated risk of progression within the first 2 to 3 years following diagnosis.

Prognostic factors associated with progression of smoldering multiple myeloma to symptomatic form

BACKGROUND

Smoldering multiple myeloma (SMM) presents a high risk of progression to symptomatic MM (sy-MM). Herein, we analyzed some predictors of development of sy-MM. In 144 patients with SMM, we also compared the risk of progression predicted by bone marrow plasma cell (BMPC) involvement on the bone marrow biopsy (BMB) versus bone marrow aspirates (BMA).

METHODS

From January 1980 to July 2010, 397 patients with SMM observed in 12 centers of the Multiple Myeloma GIMEMA (Gruppo Italiano Malattie EMatologiche dell'Adulto) Latium Working Group have been analyzed. At progression to sy-MM, the severity of clinical presentation was graded according to the need of intensive supportive care.

RESULTS

After a median follow-up of 135 months, the cumulative incidence of progression rates to sy-MM were 45%, 55%, and 75% at 10, 15, and 20 years, respectively. Hemoglobin ≤12.5 g/dL, monoclonal component ≥2.5 g/dL, and BMPC ≥60% were the only parameters negatively affecting the cumulative incidence of progression. In particular, 10 of 397 (2.5%) patients with BMPC ≥60% had a 5.6-fold increased risk of fast progression (within 2 years), which occurred with severe clinical manifestations in 62% of cases. BMB was more sensitive for the detection of BMPC involvement, even though BMA was a more reliable indicator of a rapid progression to sy-MM.

CONCLUSIONS

The highest risk of rapid evolution to sy-MM and the severity of clinical manifestation at the progression suggest that SMM patients with a BMPC ≥60% should be treated soon after diagnosis. Moreover, BMPC is a more reliable index for progression to sy-MM if assessed by BMA.

Monoclonal gammopathy of undetermined significance, smoldering multiple myeloma, and curcumin: a randomized, double-blind placebo-controlled cross-over 4g study and an open-label 8g extension study

Monoclonal gammopathy of undetermined significance (MGUS) and smoldering multiple myeloma (SMM) represent useful models for studying multiple myeloma precursor disease, and for developing early intervention strategies. Administering a 4g dose of curcumin, we performed a randomised, double-blind placebo-controlled cross-over study, followed by an open-label extension study using an 8g dose to assess the effect of curcumin on FLC response and bone turnover in patients with MGUS and SMM. 36 patients (19 MGUS and 17 SMM) were randomised into two groups: one received 4g curcumin and the other 4g placebo, crossing over at 3 months. At completion of the 4g arm, all patients were given the option of entering an open-label, 8g dose extension study. Blood and urine samples were collected at specified intervals for specific marker analyses. Group values are expressed as mean ± 1 SD. Data from different time intervals within groups were compared using Student's paired t-test. 25 patients completed the 4g cross-over study and 18 the 8g extension study. Curcumin therapy decreased the free light-chain ratio (rFLC), reduced the difference between clonal and nonclonal light-chain (dFLC) and involved free light-chain (iFLC). uDPYD, a marker of bone resorption, decreased in the curcumin arm and increased on the placebo arm. Serum creatinine levels tended to diminish on curcumin therapy. These findings suggest that curcumin might have the potential to slow the disease process in patients with MGUS and SMM.

Monoclonal B-cell lymphocytosis: right track or red herring?

Monoclonal B-cell lymphocytosis (MBL), a newly recognized entity found in approximately 3% of normal persons, precedes chronic lymphocytic leukemia. However, MBLs progress into overt malignancy only in a very minor portion of cases, thus raising the clinical concern of whether and how we can discriminate at diagnosis which rare cases will evolve into a fully fledged tumor. Understanding the molecular/biologic features underlying the risk of progression may significantly modify our strategies for correctly managing B-cell premalignant states. MBL cells bear the same chromosomal abnormalities of chronic lymphocytic leukemia. Genome-wide sequencing and animal models indicate that genetic abnormalities disrupting the control of cell growth and survival cooperate with microenvironment-triggered events, mainly represented by antigen-mediated B-cell receptor and coreceptor stimulation, to trigger and fuel clonal expansion. The initial functional activation of survival/proliferation pathways may later become subsidized by autonomous genetic abnormalities (eg, a single mutation) affecting the same or parallel critical signaling pathway(s).