Normalization of free light chain kappa/lambda ratio is a robust prognostic indicator of favorable outcome in patients with multiple myeloma

The implication of serum HLA-G in angiogenesis of multiple myeloma

BACKGROUND

Despite the advances of therapies, multiple myeloma (MM) remains an incurable hematological cancer that most patients experience relapse. Tumor angiogenesis is strongly correlated with cancer relapse. Human leukocyte antigen G (HLA-G) has been known as a molecule to suppress angiogenesis. We aimed to investigate whether soluble HLA-G (sHLA-G) was involved in the relapse of MM.

METHODS

We first investigated the dynamics of serum sHLA-G, vascular endothelial growth factor (VEGF) and interleukin 6 (IL-6) in 57 successfully treated MM patients undergoing remission and relapse. The interactions among these angiogenesis-related targets (sHLA-G, VEGF and IL-6) were examined in vitro. Their expression at different oxygen concentrations was investigated using a xenograft animal model by intra-bone marrow and skin grafts with myeloma cells.

RESULTS

We found that HLA-G protein degradation augmented angiogenesis. Soluble HLA-G directly inhibited vasculature formation in vitro. Mechanistically, HLA-G expression was regulated by hypoxia-inducible factor-1α (HIF-1α) in MM cells under hypoxia. We thus developed two mouse models of myeloma xenografts in intra-bone marrow (BM) and underneath the skin, and found a strong correlation between HLA-G and HIF-1α expressions in hypoxic BM, but not in oxygenated tissues. Yet when stimulated with IL-6, both HLA-G and HIF-1α could be targeted to ubiquitin-mediated degradation via PARKIN.

CONCLUSION

These results highlight the importance of sHLA-G in angiogenesis at different phases of multiple myeloma. The experimental evidence that sHLA-G as an angiogenesis suppressor in MM may be useful for future development of novel therapies to prevent relapse.

The role of serum-free light chain ratios in the prediction of poor prognosis in multiple myeloma patients: a systematic review and meta-analysis

BACKGROUND

The association between the serum free light chain (sFLC) ratio and the prognosis of multiple myeloma (MM) patients is controversial.

AIM

The purpose of this study is to explore the relationship between the sFLC ratio and the prognosis of MM patients through meta-analysis.

METHODS

Online public databases were searched to find relevant studies. The retrieval time is limited from the establishment of the database to July 2021. The overall survival (OS) and progression-free survival (PFS) rates were compared. The results were described using hazard ratio (HR) and a 95% confidence interval (CI). Qualitative studies were also included.

RESULTS

A total of 9 studies involving 2864 participants were included. A pooled analysis based on four studies including newly-diagnosed MM patients, demonstrated that an abnormal sFLC ratio was associated with poor outcomes of OS (HR = 1.82, 95% CI: 1.15-2.90) and PFS (HR = 1.87, 95% CI: 1.20-2.90). Three qualitative studies showed that an abnormal sFLC ratio was related with poor outcomes of OS (studies all included newly diagnosed MM patients) and PFS (two studies included newly-diagnosed MM patients and one study included non-newly-diagnosed MM patients). Two studies stated that the sFLC ratio is not associated with OS (both studies included non-newly-diagnosed MM patients) and one study reported that the sFLC ratio is not associated with PFS (study included non-newly-diagnosed MM patients).

CONCLUSION

sFLC ratio could be used to predict adverse outcomes in newly-diagnosed MM patients, but is not suitable for non-newly-diagnosed MM patients.

Prognostic Impact of Serum Free Light Chain Ratio Normalization in Patients with Multiple Myeloma Treated within the GMMG-MM5 Trial

Simple Summary

For multiple myeloma (MM) patients with measurable disease, there is no recommendation to monitor serum free light chains during therapy. However, this could provide important information in terms of prognosis. We investigated the prognostic impact of serum free light chain ratio (FLCr) normalization in 590 patients with secretory MM during first-line treatment within the German-Speaking Myeloma Multicenter Group MM5 trial. We are able to show that there is an increasing percentage of patients who achieve FLCr normalization during therapy. Importantly, we demonstrate that FLCr normalization at any time before the start of maintenance is significantly associated with prolonged progression-free and overall survival in multivariable time-dependent Cox regression analyses. This suggests that FLCr normalization during therapy is an important and simple way to assess prognostic factor in MM and supports the serial measurement of serum free light chains during therapy, even in patients with secretory MM.

Abstract

We investigated the prognostic impact of time-dependent serum free light chain ratio (FLCr) normalization in 590 patients with secretory multiple myeloma (MM) during first-line treatment within the German-Speaking Myeloma Multicenter Group MM5 trial. Serum free light chains (sFLC) were assessed by the Freelite test at baseline, after induction, mobilization, autologous blood stem cell transplantation, consolidation and every three months during maintenance or follow up within two years after the start of maintenance. The proportion of patients with a normal or normalized FLCr increased from 3.6% at baseline to 23.2% after induction and 64.7% after consolidation. The achievement of FLCr normalization at any one time before the start of maintenance was associated with significantly prolonged progression-free survival (PFS) (p < 0.01, hazard ratio (HR) = 0.61, 95% confidence interval (95% CI) = 0.47–0.79) and overall survival (OS) (p = 0.02, HR = 0.67, 95% CI = 0.48–0.93) in multivariable time-dependent Cox regression analyses. Furthermore, reaching immune reconstitution, defined as the normalization of uninvolved immunoglobulins, before maintenance was associated with superior PFS (p = 0.04, HR = 0.77, 95% CI = 0.60–0.99) and OS (p = 0.01, HR = 0.59, 95% CI = 0.41–0.86). We conclude that FLCr normalization during therapy is an important favorable prognostic factor in MM. Therefore, we recommend serial measurements of sFLC during therapy until achieving FLCr normalization, even in patients with secretory MM.

Quantification of measurable residual disease in patients with multiple myeloma based on the IMWG response criteria

Stringent complete response (sCR) is defined as a deeper response than complete response (CR) in multiple myeloma. Whether achieving sCR correlates with better survival remains controversial. We evaluated the outcomes in patients with intact immunoglobulin multiple myeloma (IIMM) and light chain multiple myeloma (LCMM) who achieved a very good partial response (VGPR) or better. Multicolour flow cytometry was used to assess the depth of response. LCMM patients with sCR had significantly lower measurable residual disease (MRD) levels than those with CR (median MRD: 7.9 × 10^-4 vs. 5.6 × 10^-5, P < 0.01). Nonetheless, no significant difference was observed in MRD levels across the responses in groups of patients with IIMM (VGPR vs. CR: 3.5 × 10^-4 vs. 7.0 × 10^-5, P = 0.07; CR vs. sCR: 7.0 × 10^-5 vs. 5.4 × 10^-5, P = 0.81. In accordance with MRD levels, the median overall survival of patients with sCR was significantly longer (sCR, CR, VGPR; not reached, 41 months, and 58 months, respectively; VGPR vs. CR, P = 0.83; CR vs. sCR, P = 0.04) in LCMM, but not in IIMM (sCR, CR, VGPR; not reached, 41 months, and not reached, respectively; VGPR vs. CR, P = 0.59; CR vs. sCR; P = 0.10). Our results show that sCR represents a deeper response that correlates with longer survival in patients with LCMM, but not IIMM.

Utility of serum free light chain ratio in response definition in patients with multiple myeloma

Patients with an abnormal sFLC ratio because of LC suppression have outcomes similar to those with a normal ratio. sFLC ratio has prognostic value in patients achieving CR who have an absence of clonal BMPCs assessed by MFC.

Pulsatilla saponin A Induces Apoptosis and Differentiation of Myeloma Cells

OBJECTIVES

To investigate the performance of Pulsatilla saponin A (PsA) in Multiple Myeloma (MM) cells.

METHODS

Proliferation, cell cycle analysis, apoptosis and TUNEL assays were conducted to detect the growth and apoptosis in MM cells. Western blotting was used to identify the change in the protein.

RESULTS

In cell assays, PsA significantly inhibited the growth and apoptosis in MM cells. Cyclin B1, caspase-3, cleaved-caspase-3, PARP, cleaved-PARP, p-ERK increased, while Bcl-2 decreased after PSA treatment. The CD49e positive rate of U266 cells was increased after 96h PsA treatment. At the same time, immunoglobulin and the Free Light Chain (FLC) ratio in the culture supernatant obviously increased. Also, the differentiation induced by PsA was confirmed in the primary myeloma cells.

CONCLUSION

Our findings reveal that PsA may exert its antitumor effect by causing G2 arrest and apoptosis in myeloma cells. And low-dose PsA can induce the differentiation of myeloma cell lines and primary myeloma cells, probably through the MEK/ERK signaling pathway in vitro.

Early Normalization of Free Light Chains Predicts Better Outcomes in Patients with Multiple Myeloma

Background: The half-life of free light chain is short and can be used as an early marker for tumor response in patients with multiple myeloma [MM]. This prospective study is aimed at evaluating whether early light chain response can predict response to treatment in patients with MM.

Materials and Methods: Thirty six patients with a diagnosis of MM and with an abnormal to normal light chain ratio of > 10 were included in this study.

Results: The median age at presentation was 56 years. Fourteen patients had lambda light chain disease, whereas 22 patients had kappa light chain disease. Twenty-four patients [66.6%] had reduction of abnormal to normal light chain ratio to < 10 after 2 cycles, of whom 15 [62.5%] achieved a CR or VGPR after 6 cycles. Among 12 patients who did not have reduction of abnormal to normal light chain ratio to < 10, only 1 patient achieved CR while 11 patients [91.6%] achieved a PR or less[Fishers exact p=0.004]. Median follow-up was 13 months. Median progression-free survival for the entire cohort was 15 months. One-year Progression-Free Survival was 77% vs 57.1%, [p= 0.008], respectively for patients with early normalization and those who did not show early normalization.

Conclusion: Early light chain response after 2 cycles of chemotherapy is a good predictor for treatment response in patients with MM treated with bortezomib based chemotherapy. Treatment intensification based on early light chain response merits further evaluation in a prospective trial

End points and statistical considerations in immuno-oncology trials: impact on multiple myeloma

Unlike conventional cancer treatment, immuno-oncology therapies are commonly associated with delayed clinical benefit and durable responses, as seen with immuno-oncology therapies for multiple myeloma (MM). Therefore, a longer-term approach to immuno-oncology data assessment is required. Appropriate study designs, end points and statistical methods are essential for evaluating immuno-oncology therapies to assess treatment outcomes, and may better accommodate immuno-oncology clinical trial data. In addition to conventional end points including median progression-free survival (PFS) and overall survival (OS), end points such as hazard ratios for PFS and OS over time, PFS and OS landmark analyses beyond the median, and immune-response end points might provide better indications of the efficacy of immuno-oncology therapies. Long-term data with these agents will allow better prediction of outcomes in MM.

Abnormal heavy/light chain ratio after treatment is associated with shorter survival in patients with IgA myeloma

Immunoglobulin (Ig) heavy/light chain (HLC) assays enable the separate quantification of the different light chain types of each Ig class. We retrospectively analyzed the correlation of heavy/light chain ratio (HLCR) with clinical status and its impact on outcome in 120 patients with multiple myeloma (MM). Abnormal HLCR was seen more frequently in patients with poorer myeloma response, and it appeared to be more sensitive for detecting clonality in IgA myeloma compared to IgG myeloma after treatment. Among the 85 patients who achieved ≥VGPR, the patients remained HLCR abnormal were showed significantly shorter overall survival (OS) compared to those achieving a normal HLCR (not reached vs 55.5 months, P = 0.032). This correlation was seen in IgA myeloma patients (not reached vs 30.1 months, P = 0.014), but not in IgG myeloma patients when patients were analyzed separately. Univariate and multivariate analysis of factors that may affect survival identified abnormal HLCR at the best response as the only independent risk factor (hazard ratio, 4.7; 95% confidence interval, 1.4 – 15.26; P = 0.012) for shorter OS in this subset of patients. This study highlighted the HLC assay as a prognostic predictor in patients with IgA myeloma.

Prognostic Value of Serum Free Light Chains Measurements in Multiple Myeloma Patients

Background

The outcome for patients with Multiple Myeloma (MM) is highly variable, therefore, the existence of robust and easy to determine prognostic markers is extremely important for an efficient management of these patients. Presently, there is a debate about the role of the serum free light chains (sFLC) in the prognosis of MM patients both at diagnosis and after treatment. The aim of this study is to evaluate in a cohort of newly diagnosed MM patients from the Southern area of Spain, the prognostic value of sFLC both at baseline and after treatment.

Materials and Methods

180 patients with a median age of 69 years were followed-up for a median time of 35 (18–61) months. The sFLC ratio (sFLCR) was calculated using the monoclonal sFLC as numerator. Patients were divided in two groups according to a sFLCR cut-off based on ROC analysis. The primary endpoints were the Overall Survival (OS) and the Progression-free Survival (PFS). Additionally, thirty-six MM patients treated with novel agents (Bortezomib/Dexamethasone) that achieved Complete Response (CR) or stringent CR (sCR) before autologous stem cell transplantation were studied to assess the impact of sCR in Disease Free Survival (DFS) and OS.

Results

During follow-up there were 72 disease-related deaths. The 5-years OS for the whole group was 51%. However, separate analysis of patients with sFLCR above (group “high”) or below (groups “low”) the cut-off value of 47 shows an OS of 23% and 73%, respectively (HR = 5.03, 95%CI 2.99–8.50, p<0.001). In addition, analysis by ISS stage, showed that the presence of high sFLCR was always significantly associated with a worse OS. Multivariate analysis identified sFLCR (HR = 4.42, 95%CI 2.57–7.60, p<0.001) and beta-2-microglobulin (B2M) (HR = 3.04, 95%IC 1.75–5.31, p<0.001) as independent risk factors for adverse outcome. A new risk stratification model based on sFLCR≥47 and B2M>3.5 mg/L provided a statistically more significant result for this cohort when compared with the conventional ISS system. The HR for the new model were 2.84 (95% CI, 1.39–5.79, p = 0.004) for patients in stage 2 and 15.39 (95% CI, 6.35–37.33, p<0.001) for those in stage 3. Finally, in the group of patients reaching CR (19/36) or sCR (17/36) after induction, the median DFS for CR patients was 29 months, and NR for sCR patients (HR = 3.73; 95% CI 1.15–12.13, p = 0.03). Importantly, achieving sCR also translated into a significantly longer OS (5y-OS: sCR-89% versus CR-49%; p = 0.003; OS: sCR-NR versus CR-52 months).

Conclusions

Our findings confirm the observations that the sFLCR has a major role in the survival of MM patients. A cut-off of sFLCR≥47 was shown to have an independent prognostic value at diagnosis, and a proposed “New Staging System” allows an accurate and simple method to risk stratify MM patients. Furthermore, because achievement of sCR was shown to represent a response state deeper than conventional CR resulting in greater OS and DFS, our study supports the continuity of sFLC ratio as part of the response criteria for MM patients.

Serum Free Light Chain Assay and κ/λ Ratio: Performance in Patients With Monoclonal Gammopathy-High False Negative Rate for κ/λ Ratio

Background

Serum free light chain assay (SFLCA) and κ/λ ratio, and protein electrophoretic methods are used in the diagnosis and monitoring of monoclonal gammopathies.

Methods

Results for serum free light chains, serum and urine protein electrophoreses and immunofixation electrophoreses in 468 patients with a diagnosis of monoclonal gammopathy were compared. The results of the two methods were graded as concordant, non-concordant or discordant with the established diagnoses to assess the relative performance of the methods. Results of κ/λ ratio in samples with monoclonal protein detectable by electrophoretic methods were also analyzed.

Results

Protein electrophoreses results were concordant with the established diagnoses significantly more often than κ/λ ratio. The false negative rate for κ/λ ratio was higher than that for electrophoretic methods. κ/λ ratio was falsely negative in about 27% of the 1,860 samples with detectable monoclonal immunoglobulin. The false negative rate was higher in lesions with lambda chains (32%) than those with kappa chains (24%). The false negative rate for κ/λ ratio was over 55% in samples with monoclonal gammopathy of undetermined significance. Even at first encounter, the false negative rates for κ/λ ratios for monoclonal gammopathy of undetermined significance, smoldering myeloma and multiple myeloma were 66.98%, 23.08%, and 30.15%, respectively, with false negative rate for lambda chain lesions being higher.

Conclusions

Electrophoretic studies of serum and urine are superior to SFLCA and κ/λ ratio. Abnormal κ/λ ratio, per se, is not diagnostic of monoclonal gammopathy. A normal κ/λ ratio does not exclude monoclonal gammopathy. False negative rates for lesions with lambda chain are higher than those for lesions with kappa chains. Electrophoretic studies of urine are underutilized. Clinical usefulness and medical necessity of SFLCA and κ/λ ratio is of questionable value in routine clinical testing.

[The roles of serum free light chain ratio in the diagnosis and prognosis of newly diagnosed multiple myeloma]

OBJECTIVE

The roles of serum free light chain ratio (sFLCR) in the diagnosis and prognosis of newly diagnosed multiple myeloma (NDMM) patients were analyzed.

METHODS

The clinical data was retrospectively analyzed for 82 newly diagnosed multiple myeloma (NDMM) patients in the first affiliated hospital of Soochow University from September 28, 2012 to July 18, 2105. The serum free light chain levels were measured and κ/λ ratios were calculated, so we could analyze the roles of sFLCR in the diagnosis and prognosis of newly diagnosed multiple myeloma (NDMM) patients.

RESULTS

It was 85.5% (70/82) positive of M protein by serum protein electrophoresis (SFE) and 93.9%(77/82) by serum immunofixation electrophoresis (IFE). Both sFLC and sFLCR abnormalities were 96.3% (79/82). The estimated 40-months overall survival was 87% for the high free light chain ratio group (sFLCR ≥100 or≤0.01) and 61% for the low free light chain ratio group (0.01

CONCLUSION

sFLC assay is much more sensitive than the common methods used, such as SPE and IFE for the diagnosis of MM. The patients with significantly abnormal sFLCR have more tumor burden, higher aggressive progression, and adverse prognosis. Compared with the patients who have normal renal function, the patients with renal insufficiency acquire the same effect after receiving reasonable treatment actively.

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Key Words

• 血清游离轻链比率
• 多发性骨髓瘤
• 诊断
• 预后
• free light chain ratio
• muliple myeloma
• diagnosis
• prognosis

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MESH Headings

• Bone Marrow Cells
• Humans
• Immunoglobulin Light Chains/blood
• In Situ Hybridization, Fluorescence
• Multiple Myeloma/blood
• Multiple Myeloma/diagnosis
• Myeloma Proteins/chemistry
• Prognosis
• Renal Insufficiency/complications
• Retrospective Studies

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Grants Collapse

Affiliation(s)

P F Wang First Affiliated Hospital of Soochow University, Jiangsu Institute of Hematology, Key Laboratory of thrombosis and hemostasis of Ministry of health , Hematology Collaborative Innovation Center , Suzhou 215006, China
Y Xu
S Yan
Y Yao
H F Zheng
L Ma
S Jin
Y Xu
F R Gong
J Z Zhou
H R Chang
C C Fu

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Potential pitfalls of serum free light chain analysis to assess treatment response for multiple myeloma

Response to treatment in patients with a plasma cell disorder is typically measured by evaluating the bone marrow and myeloma markers, including monoclonal protein spike and immunofixation (IFE) in blood and urine, and serum free light chains (sFLCs). Stringent complete response criteria for Multiple Myeloma (MM) patients require a normal FLC ratio and absence of clonal cells in bone marrow by immunohistochemistry or immunofluorescence. We performed a retrospective chart review to further evaluate these criteria. A total of 142 patient charts were analysed. Of these, 17 patients were found to have an abnormal sFLC ratio, but no other evidence of disease, including normal flow cytometry and normal fluorescence in situ hybridization (FISH) analysis on highly selected plasma cells. In all patients, the abnormal sFLC ratio was caused by abnormalities in the serum kappa light chains. These results suggest that current definitions may need to be revised to take aberrancies related to abnormal immune recovery into account.

Audit of Use and Overuse of Serum Protein Immunofixation Electrophoresis and Serum Free Light Chain Assay in Tertiary Health Care: A Case for Algorithmic Testing to Optimize Laboratory Utilization

OBJECTIVES

Overuse of laboratory tests is a persistent issue. We examined the use and overuse of serum immunofixation electrophoresis and serum free light chain assays to develop an algorithm for optimizing utilization.

METHODS

A retrospective review of all tests, for investigation of monoclonal gammopathies, for all patients who had any of these tests done from April 24, 2014, through July 25, 2014, was carried out. The test orders were categorized as warranted or not warranted according to criteria presented in the article.

RESULTS

A total of 237 patients were tested, and their historical records included 1,503 episodes of testing for one or more of serum protein electrophoresis, serum immunofixation electrophoresis, and serum free light chain assays. Only 46% of the serum immunofixation and 42% serum free light chain assays were warranted. Proper utilization, at our institution alone, would have obviated $64,182.95/year in health care costs, reduced laboratory cost of reagent alone by $26,436.04/year, and put $21,904.92/year of part B reimbursement at risk.

CONCLUSIONS

Fewer than half of the serum immunofixation and serum free light chain assays added value. The proposed algorithm for testing should improve utilization. Risk to part B billing may be a disincentive to reducing test utilization.

Prognostic impact of serial measurements of serum-free light chain assay throughout the course of newly diagnosed multiple myeloma treated with bortezomib-based regimens

We retrospectively investigated the role of serial serum-free light chain (sFLC) evaluations in 150 multiple myeloma (MM) patients treated with first-line bortezomib-based regimens. Baseline sFLC ratio (sFLCR) identified three groups of patients - normal, lightly abnormal (<100), and highly abnormal (≥100) - with different progression-free survival (PFS: 3-year estimate 72% versus 61% versus 44%, respectively, p = 0.03). Moreover, the achievement of a normal sFLCR correlated with extended PFS (49 versus 17 months, p < 0.0001) and overall survival (75 versus 43 months, p < 0.0001) as compared with abnormal sFLCR, a gain maintained in a multivariate analysis for PFS. At relapse, a high sFLCR was associated with earlier start of salvage therapy compared with sFLCR <100 (3-month probability: 89% versus 64%, p = 0.0426). In 20% of patients, sFLC escape preceded the conventional relapse by a median of 3.8 months. Our results highlight the role of sFLC assay in the prognosis and follow-up of MM.

The role of interleukin-1 beta in the pathophysiology of Schnitzler's syndrome

Introduction

Schnitzler’s syndrome (SchS) is a disabling autoinflammatory disorder, characterized by a chronic urticarial rash, an M-protein, arthralgia, and other signs of systemic inflammation. Anti-interleukin-1 (IL-1) beta antibodies are highly effective, but the pathophysiology is still largely unknown. Here we studied the effect of in-vivo IL-1 inhibition on serum markers of inflammation and cellular immune responses.

Methods

Eight patients with SchS received monthly subcutaneous (s.c.) injections with 150 mg canakinumab for six months. Blood was drawn for measurement of serum markers of inflammation (12 times per patient) and for functional and phenotypic analysis of both freshly isolated and toll-like receptor (TLR)-ligand-stimulated peripheral blood mononuclear cells (PBMCs) (five times per patient). All data were compared to results of healthy controls.

Results

IL-6 levels in serum and in lysates of freshly isolated PBMCs and serum myeloid-related protein (MRP8)/14 and S100A12 levels correlated with disease activity. In vitro, LPS stimulation resulted in higher IL-6 and IL-1 beta production in PBMCs from symptomatic SchS patients compared to healthy controls, whereas patient cells were relatively hyporesponsive to poly:IC and Pam3Cys. The mRNA microarray of PBMCs showed distinct transcriptomes for controls, symptomatic patients and anti-IL-1-treated patients. Numbers of T- and B-cell subsets as well as M-protein concentrations were not affected by IL-1 inhibition. Free light chain levels were elevated in 4 out of 8 patients.

Conclusions

In conclusion, patient PBMCs are hyperresponsive to LPS, and clinical efficacy of IL-1 beta inhibition in patients with SchS is associated with in-vivo and ex-vivo suppression of inflammation. Interestingly, patient PBMCs showed divergent responses to TLR2/6, TLR3 and TLR4 ligands. Our data underscore that IL-1 beta plays a pivotal role in SchS.

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-015-0696-0) contains supplementary material, which is available to authorized users.

High incidence of intact or fragmented immunoglobulin in urine of patients with multiple myeloma

In this prospective study we determined the incidence of intact/fragmented immunoglobulin and Bence Jones protein in urine immunofixation using Sebia reagents and HydrasysTM 2 apparatus and compared the results to concentrations of serum free light chains (FLC) assessed using Siemens BNTM II nephelometer and the immunoassay Freelite (Binding Site) in 289 patients with multiple myeloma at diagnosis. It was found that in one third of IgG, IgA and IgD myeloma patients, intact/fragmented immunoglobulin can be detected in urine and is connected with impaired renal function and reduced survival. Urine immunofixation detects monoclonal protein (FLC and intact/fragmented immunoglobulin) in 66-79% of IgG and IgA myeloma patients while serum FLC immunoassay detect it in 82-94% of IgG and IgA myeloma patients. However, the latter method is inadequate for detection of intact/fragmented immunoglobulin in urine. Serum FLC immunoassay and urine immunofixation are complementary methods in diagnosing and monitoring monoclonal protein in patients with myeloma.

Utility of serum free light chain measurements in multiple myeloma patients not achieving complete response to therapy

Normalization of the serum free light chain ratio (FLCr) with the absence of bone marrow monoclonal plasma cells following achievement of a complete response (CR) to therapy denotes a stringent CR in multiple myeloma (MM), and is associated with improved overall survival (OS). However, its value in patients achieving <CR is not clear. We hypothesized that patients achieving a normalization of FLCr with initial therapy of MM will have an improved outcome, even in the absence of a CR. We retrospectively evaluated 449 patients with newly-diagnosed MM with measurable disease at baseline, who did not achieve a CR with initial therapy. One hundred fifty three patients (34%) had a normal FLCr while 296 (66%) had an abnormal ratio. Patients with a normal FLCr had a longer progression-free survival (PFS) (29 vs. 16 months, P <.001) and OS (91 vs. 58 months, P <.001). Normalization of FLCr retained its prognostic value in a multivariable model. Our results suggest an important role for sFLC measurement in disease monitoring even in patients who achieve only a partial response to therapy. Obtaining a normal FLCr confers a favorable prognosis independent from other factors, supporting the inclusion of sFLC in all levels of response criteria.

Multicentered patient-based evidence of the role of free light chain ratio normalization in multiple myeloma disease relapse

INTRODUCTION

The normalization of free light chain ratio (FLCr) has been introduced as a marker of stringent complete remission (CR) of multiple myeloma (MM). There is currently a lack of literature assessing the role of FLCr on MM disease progression and remission status.

PATIENTS AND METHODS

A multicentered retrospective review of 125 patients with MM in CR and various FLCr values was completed. Parameters of interest included patient demographics, FLCr values, complete remission (CR)/relapse status, and time to progression (TTP). The FLCr values were recorded to provide time-dependent findings on the role of FLCr on progression-free survival and overall survival (OS).

RESULTS

The mean follow-up time of 125 patients from five hospitals in the Czech Republic was 31 months. A total of 47.2% of patients relapsed (54 of 125) during the follow-up period. The median TTP of patients with normal FLCr (n = 66) was 54.4 and 40.2 months for patients with abnormal FLCr (n = 59) (P = 0.217). None of the patients reached median overall survival regardless of FLCr values (P = 0.821). In the subgroup of newly diagnosed patients after upfront autologous stem cell transplantation (ASCT), there were 55.6% of patients (35 of 63) with normal FLCr and 44.4% (28 of 64) with abnormal FLCr. A total of 34.9% of patients (22 of 63) relapsed in this subgroup. Within the abnormal FLCr patients, a median TTP was 56.3 months, but no median TTP was reached among the normal FLCr patients (P = 0.746). Median OS in patients with normal (nFLCr) and abnormal FLCr (aFLCr) was not reached (P = 0.787).

CONCLUSION

We did not observe any benefit from FLCr normalization in CR in myeloma patients in terms of progression-free survival or overall survival.

Bayesian joint selection of genes and pathways: applications in multiple myeloma genomics

It is well-established that the development of a disease, especially cancer, is a complex process that results from the joint effects of multiple genes involved in various molecular signaling pathways. In this article, we propose methods to discover genes and molecular pathways significantly associated with clinical outcomes in cancer samples. We exploit the natural hierarchal structure of genes related to a given pathway as a group of interacting genes to conduct selection of both pathways and genes. We posit the problem in a hierarchical structured variable selection (HSVS) framework to analyze the corresponding gene expression data. HSVS methods conduct simultaneous variable selection at the pathway (group level) and the gene (within-group) level. To adapt to the overlapping group structure present in the pathway–gene hierarchy of the data, we developed an overlap-HSVS method that introduces latent partial effect variables that partition the marginal effect of the covariates and corresponding weights for a proportional shrinkage of the partial effects. Combining gene expression data with prior pathway information from the KEGG databases, we identified several gene–pathway combinations that are significantly associated with clinical outcomes of multiple myeloma. Biological discoveries support this relationship for the pathways and the corresponding genes we identified.

Serum free light chain response after 2 courses of induction chemotherapy predicts prognosis in myeloma patients

BACKGROUND

The aim of this study was to investigate the prognostic effect of serum free light chain (sFLC) response after 2 cycles of first-line chemotherapy (CT) in multiple myeloma (MM) patients.

MATERIALS AND METHODS

The data of 78 newly diagnosed MM patients who had sFLC levels at diagnosis and after 2 cycles of first-line CT were included in the study. The prognostic effect of sFLCs were evaluated with normalization of sFLC κ/λ ratio after 2 cycles of CT and involved/uninvolved (i/u) sFLCs.

RESULTS

At the end of follow-up the probability of overall survival (OS) was 95.7% versus 68.5% in patients with and without normalized sFLC κ/λ ratio, respectively (P = .072). The probability of OS with i/u sFLC assessment was 97.4% versus 55.8% with regard to i/u sFLC ≤ 10 and > 10, respectively (P = .001). In univariate and multivariate analysis including sFLC ratio, age, sex, and International Staging System, i/u sFLC ratio > 10 after 2 cycles of CT was identified as an independent risk factor for OS (P = .015; hazard ratio [HR], 13.2; 95% confidence interval [CI], 1.668-104.65 vs. P = .011; HR, 15.17; 95% CI, 1.85-123.89).

CONCLUSION

Early response assessment in terms of sFLC after 2 courses of induction CT seems to have a prognostic effect in MM patients. The methodology and timing of the evaluation based on sFLCs needs to be validated in prospective studies.

Targeting paraprotein biosynthesis for non-invasive characterization of myeloma biology

Purpose

Multiple myeloma is a hematologic malignancy originating from clonal plasma cells. Despite effective therapies, outcomes are highly variable suggesting marked disease heterogeneity. The role of functional imaging for therapeutic management of myeloma, such as positron emission tomography with 2-deoxy-2-[¹⁸F]fluoro-D-glucose (¹⁸F-FDG-PET), remains to be determined. Although some studies already suggested a prognostic value of ¹⁸F-FDG-PET, more specific tracers addressing hallmarks of myeloma biology, e.g. paraprotein biosynthesis, are needed. This study evaluated the amino acid tracers L-methyl-[¹¹C]-methionine (¹¹C-MET) and [¹⁸F]-fluoroethyl-L-tyrosine (¹⁸F-Fet) for their potential to image myeloma and to characterize tumor heterogeneity.

Experimental Design

To study the utility of ¹¹C-MET, ¹⁸F-Fet and ¹⁸F-FDG for myeloma imaging, time activity curves were compared in various human myeloma cell lines (INA-6, MM1.S, OPM-2) and correlated to cell-biological characteristics, such as marker gene expression and immunoglobulin levels. Likewise, patient-derived CD138⁺ plasma cells were characterized regarding uptake and biomedical features.

Results

Using myeloma cell lines and patient-derived CD138⁺ plasma cells, we found that the relative uptake of ¹¹C-MET exceeds that of ¹⁸F-FDG 1.5- to 5-fold and that of ¹⁸F-Fet 7- to 20-fold. Importantly, ¹¹C-MET uptake significantly differed between cell types associated with worse prognosis (e.g. t(4;14) in OPM-2 cells) and indolent ones and correlated with intracellular immunoglobulin light chain and cell surface CD138 and CXCR4 levels. Direct comparison of radiotracer uptake in primary samples further validated the superiority of ¹¹C-MET.

Conclusion

These data suggest that ¹¹C-MET might be a versatile biomarker for myeloma superior to routine functional imaging with ¹⁸F-FDG regarding diagnosis, risk stratification, prognosis and discrimination of tumor subtypes.

Biologic frontiers in multiple myeloma: from biomarker identification to clinical practice

Since the mid-1990s, the multiple myeloma treatment landscape has evolved considerably, which has led to improved patient outcomes and prolonged survival. In addition to discovering new, targeted agents or treatment regimens, the identification and validation of biomarkers has the potential to further improve patient outcomes. The International Staging System relies on a number of biochemical parameters to stratify patients into risk categories. Other biologically relevant markers that are indicative of inherited genetic variation (e.g., single-nucleotide polymorphisms) or tumor-acquired genetic events (e.g., chromosomal translocations or mutations) have been studied for their prognostic potential. In patients with high-risk cytogenetics, plasma cells (PC) undergo genetic shifts over time, which may partially explain why high-risk patients relapse and are so difficult to treat. Although novel agents have improved treatment outcomes, identification of markers that will enable clinicians to determine which treatment is most appropriate for high-risk patients following initial diagnosis represents an exciting frontier in the clinical management of multiple myeloma. Biomarkers based on quantitating PCs or factors that are secreted from them (e.g., serum free light chain) may also help to risk-stratify patients with asymptomatic multiple myeloma. Eventually, identification of novel biomarkers may lead to the creation of personalized treatment regimens that are optimized to target clonal PCs that express a specific oncogenomic profile. Although the future is exciting, validation will be necessary before these biologic and molecular beacons can inform decision-making processes in a routine clinical setting.

Serum free light chains in clinical laboratory diagnostics

Monoclonal free light chains (FLCs) are important disease biomarkers in patients with plasma cell-proliferative disorders. The increasing evidence for clonal diversity and evolution in multiple myeloma highlights the importance of laboratory algorithms that measure both intact immunoglobulins and monoclonal FLCs, at diagnosis and when monitoring response to treatment. A particular focus in the field has been on the utility of serum FLC (sFLC) assays to replace urine electrophoresis for monoclonal FLC measurement. Due to the limited sensitivity and practical constraints of urine analysis, a serum-based algorithm of SPE and sFLC has been adopted by many laboratories as a first line screen in patients with suspected monoclonal gammopathies. This review will discuss the data supporting the use of this simple serum-based algorithm at initial diagnosis, including its utility for the rapid identification of monoclonal FLC in the setting of unexplained acute kidney injury, and provide a comprehensive review of the diagnostic sensitivity of sFLC in patients with multiple myeloma, AL amyloidosis and light chain deposition disease.

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.