Laboratory testing plays an essential role in the diagnosis and management of patients with multiple myeloma. A variety of chemistry and molecular assays are routinely used to monitor patient ...progress, response to treatment and relapse. Here, we have reviewed current literature and core guidelines on the details of laboratory testing in myeloma-related investigations. This includes the use and value of protein electrophoresis, serum free light chain and cytogenetic testing. Furthermore, we discuss other traditional chemistry assays essential to myeloma investigation, and potential interferences that may arise due to the disease nature of myeloma, that is, the presence of a monoclonal immunoglobulin. Finally, we discuss the importance of communication in protein electrophoresis results, where laboratorians are required to relate clinically relevant myeloma-relevant information to the ordering physician on the background of a complex pattern of serum or urine proteins. Laboratory testing in myeloma-related investigation relies on several traditional chemistry assays. However, we anticipate new tests and technologies to become available in the future with improved analytical sensitivity, as well as improved clinical sensitivity in identifying patients who are at high risk of progression to multiple myeloma.
There is limited knowledge regarding the prevalence of geriatric impairments and frailty among patients with multiple myeloma (MM) in a real-world setting. This study evaluated the distribution of ...frailty profiles among 116 patients with newly diagnosed or relapsed MM, using four common frailty scales. The proportion of patients classified as frail varied significantly, ranging from 15.5% to 56.9%, due to differences in how frailty was operationalized between each frailty measure. Functional, cognitive, and mobility impairments were common overall and irrespective of performance status. Analyses between frailty and treatment selection (dose reduction and doublet vs. triplet therapy) demonstrated significant differences in non-steroid MM drug dose reductions between frail vs. non-frail patients, as scored by the International Myeloma Working Group (IMWG) Frailty Index and Simplified Frailty Score (
< .05). A standardized approach to frailty assessment that is practical in application, and beneficial in guiding treatment selection and minimizing treatment related toxicity is necessary to provide optimal tailored care.
A baseline involved to uninvolved free light chain ratio (FLCr) ≥100 with involved FLC ≥ 10 mg/dL is a multiple myeloma (MM)-defining event (MDE). However, multimeric light chain aggregates may ...contribute to increased FLC levels and impair renal light chain clearance. Therefore, we conducted a retrospective study to assess the association between urine monoclonal protein (uMCP) excretion and the risk of progression. We included 822 asymptomatic MM patients with an elevated MDE as the only MDE (n = 120 with FLCr ≥100, n = 702 with FLC < 100). Patients with a FLC ≥ 100 were grouped based on 24-h uMCP excretion (≥200 mg/24 h n = 35, <200 mg/24 h n = 85). The 2-year risk of progression to symptomatic MM or light chain (AL) amyloidosis was significantly higher in patients with uMCP excretion ≥200 versus <200 mg/24 h (36.2% versus 13.5%, respectively; HR 2.79, 95%CI 1.57–4.96, p < 0.001). However, the progression risk was similar in patients with a baseline FLCr <100 versus FLC ≥ 100 with uMCP <200 mg/24 h (log rank p = 0.127). We showed that increased uMCP excretion in the setting of a FLCr ≥100 is an unfavorable prognostic marker. This underscores the importance of conducting a diagnostic 24-h urine assessment and may help refine the subset of patients warranting therapy if the FLCr is the only MDE.
Background: Iron deficiency (ID), a common cause of anemia, is often overlooked among patients with hematologic malignancies given alternative etiologies. Daratumumab is an anti-CD38 monoclonal ...antibody used in the management of multiple myeloma (MM). Approximately 45% of patients on daratumumab are anemic. In a study of 22 patients with relapsed refractory AL amyloidosis treated with daratumumab, 40% developed iron deficiency requiring IV iron replacement. It is unclear whether iron deficiency in this setting is specific to AL amyloidosis, or whether it is universally seen with daratumumab treatment. In this study we evaluated iron deficiency parameters, including bone marrow iron stores, in MM patients treated with daratumumab. Methods: We conducted a retrospective study to evaluate the prevalence of ID among newly diagnosed MM patients who were treated uniformly in a phase II study with the combination of daratumumab, ixazomib, lenalidomide and dexamethasone conducted at our center. Laboratory values of ferritin, hemoglobin and MCV were extracted from the medical records at trial enrollment and at 1-year from treatment initiation. ID was defined as ferritin <30 mcg/L. Bone marrow iron stores were assessed at pre-trial and 1-year from therapy initiation by Prussian blue stain of bone marrow clot sections, with grade 0 (absent iron) or grade 1 (trace to low iron) considered as depleted iron storage. Results: Among 54 included patients, 2 (3.7%) had ferritin <30 mcg/L at trial-enrollment, while 27 (50%) developed ID within 1 year and 33 (61%) became iron deficient during their treatment course. All patients (100%) had lower ferritin at 1 year compared to pre-trial value. The median reduction of ferritin at 1-year was 109 (IQR: 41-239 mcg/L), a decrease by 75% (IQR:56- 86%) from baseline value. Fifteen patients (28%) received IV or oral iron replacement, and 4 were already on iron-repletion before the 1-year landmark assessment. The median ferritin improved from 16 to 84 mcg/L (p<.0001) following iron replacement. Forty patients (74%) had improved hemoglobin at 1-year compared to baseline correlated to disease response to therapy. The median increment in hemoglobin was 1.1 (IQR: -0.3 - 2.7 g/dL). Hemoglobin at 1-year was higher in patients having ferritin ≥ 30 mcg/L compared to the ID group: 13.5 (IQR: 12.3-14.1 g/dL) vs 12.8 (IQR: 12.3-13.4 g/dL), p=.05. BM samples from pre-trial (n=37) and 1-year on-trial (n=36) were available for iron staining. Depleted iron storage was more frequent at1-year compared to baseline (63.9% vs 40.5%, p<.05). The median ferritin was lower in patients with iron depleted versus non-iron depleted BM: 58 (IQR: 31-120 mcg/L) vs 243 (IQR: 125-486 mcg/L) at baseline, p=.0002; 27 (IQR: 16-41 mcg/L) vs 59 (IQR: 19-245 mcg/L) at 1-year landmark, p=.07. Comparisons of laboratory markers at initiation and after 1-year on daratumumab trial are listed in Table 1. Conclusions: Our study demonstrated a high prevalence of ID among patients receiving daratumumab-based treatment for newly diagnosed MM. While some decrease in ferritin over treatment course may be caused by myeloma disease control and improved systemic inflammation, this study should increase awareness for ID among MM patients treated with daratumumab. Future studies are needed to better understand the possible role of daratumumab in the pathogenesis of ID in MM and other plasma cell disorders.
Introduction: A baseline involved to uninvolved free light chain ratio (FLCr) ≥100 with involved free light chain (iFLC) ≥10 mg/dL is considered a multiple myeloma (MM)-defining event (MDE). However, ...prior reports have demonstrated that the presence of multimeric light chain aggregates can contribute to falsely increased FLC levels due to impaired renal light chain clearance. Therefore, we aimed to compare the disease progression risk in patients with high versus low urine monoclonal protein (uMCP) excretion in the setting of an elevated serum FLCr.
Methods: We retrospectively evaluated untreated smoldering MM (SMM) and asymptomatic MM patients diagnosed between January 1, 2000 and January 10, 2020. Included patients had a baseline bone marrow plasma cell (BMPC) burden of 10-59% without concomitant end organ damage (hypercalcemia, anemia, renal failure, or lytic lesions on x-ray or cross-sectional imaging; “CRAB” MDE). Patients with a baseline FLCr ≥100 and iFLC >10 mg/dL were included if they had a 24-hour urine collection and electrophoresis. Survival analyses were performed using the Kaplan-Meier method. Progression was defined as treatment for systemic AL amyloidosis or symptomatic MM (typical “CRAB” MDE). SMM patients treated due to evolving biomarkers or “SLiM” MDE (lytic lesions on MRI, BMPC ≥60%, or FLCr ≥100) were censored. Cox proportional hazards models were used for uni- and multivariable analyses. A two-sided p-value <0.05 was considered statistically significant.
Results: We included 822 patients without MDE besides elevated FLCr (n=120 with FLCr ≥100, n=702 with FLC <100). Patients with a FLC ≥100 were grouped based on 24-hour uMCP excretion (≥200 mg/24h n=35, <200 mg/24h n=85). Among included patients with a baseline FLCr ≥100, the median iFLC was 79.9 (IQR 42.9-131.5) mg/dL and median FLCr was 207.1 (IQR 137.7-400.3). Patients with a FLCr ≥100 and high (≥200 mg/24h) versus low (<200 mg/24h) uMCP excretion had a median iFLC of 101 versus 66.5 mg/dL (p=0.001), median estimated glomerular filtration rate (eGFR) 74.4 versus 74.6 mL/min/1.73m 2 (p=0.505), and median BMPC burden of 30% versus 21% (p=0.088), as shown in Table 1.
The 2-year risk of progression to symptomatic MM or AL amyloidosis was significantly higher in patients with uMCP excretion ≥200 versus <200 mg/24h (36.2% versus 13.5%, respectively; HR 2.79, 95% CI 1.57-4.96, p<0.001, see Figure 1). However, the progression risk was similar in patients with a baseline FLCr <100 versus those with a FLCr≥100 and uMCP <200 mg/24h (log rank p=0.127). After adjusting for baseline eGFR, BMPC burden, iFLC, and light chain isotype, the progression risk was still 2.7 times higher in patients with high versus low uMCP excretion (HR 2.66, 95% CI 1.39-5.10, p=0.003). In patients with a baseline FLCr ≥100 that had cross-sectional imaging at diagnosis or prior to progression confirming the absence of osteolytic lesions, the risk of progression remained significantly higher in patients with a high versus low uMCP excretion (n=14 versus n=53, respectively; HR 4.20, 95% CI 1.86-9.49, p<0.001).
In patients with FLCr ≥100, there were a total of 52 patients with end organ damage at progression (26 50% patients with anemia, 8 15% with renal failure, 21 40% with lytic lesions, 6 12% with systemic AL amyloidosis). Among patients who progressed, 5 (25%) of 20 patients with high uMCP excretion and 3 (9.4%) of 32 patients with low uMCP excretion presented with renal failure as the MDE. In patients with baseline high versus low uMCP excretion that experienced renal failure at progression, the median serum creatinine of 2.7 (range 1.9-4.1) versus 2.5 (range 1.9-3.2) mg/dL (p=0.653), median uMCP 4964 (range 738-5910) versus 512 (range 196-734) mg/24h (p=0.052), and median iFLC 388 (range 317-1640) versus 437 (range 199-1030) mg/dL (p=1.00).
Conclusions: Increased uMCP excretion in the setting of a FLCr ≥100 is an unfavourable prognostic marker and is associated with an increased risk of progression. The progression risk in patients with a FLCr ≥100 and low uMCP excretion (<200 mg/24h) is similar to patients with a baseline FLCr <100. Our findings underscore the importance of conducting a 24-hour urine assessment at diagnosis and may help refine the subset of patients with FLCr ≥100 in whom pre-emptive therapy is warranted.
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Kapoor: AbbVie: Research Funding; Takeda: Research Funding; Sanofi: Research Funding; Karyopharm: Research Funding; Glaxo SmithKline: Research Funding; Regeneron Pharmaceuticals: Research Funding; Ichnos Sciences: Research Funding; Amgen: Research Funding; Karyopharm: Consultancy; Cellectar: Consultancy; BeiGene: Consultancy; Pharmacyclics: Consultancy; Sanofi: Consultancy. Gertz: Akcea Therapeutics, Ambry Genetics, Amgen Inc, Celgene Corporation, Janssen Biotech Inc, Karyopharm Therapeutics, Pfizer Inc (to Institution), Sanofi Genzyme: Honoraria; Aurora Biopharma: Other: Stock option; Akcea Therapeutics, Alnylam Pharmaceuticals Inc, Prothena: Consultancy; AbbVie Inc, Celgene Corporation: Other: Data Safetly & Monitoring; Ionis Pharmaceuticals: Other: Advisory Board. Dingli: Novartis: Research Funding; GSK: Consultancy; Alexion: Consultancy; Sanofi: Consultancy; Janssen: Consultancy; Apellis: Consultancy. Kumar: Antengene: Consultancy, Honoraria; Bluebird Bio: Consultancy; Roche-Genentech: Consultancy, Research Funding; Novartis: Research Funding; Astra-Zeneca: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; BMS: Consultancy, Research Funding; Carsgen: Research Funding; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Merck: Research Funding; Oncopeptides: Consultancy; KITE: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Beigene: Consultancy; Tenebio: Research Funding; Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Amgen: Consultancy, Research Funding; Abbvie: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Adaptive: Membership on an entity's Board of Directors or advisory committees, Research Funding; Sanofi: Research Funding.
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Background: Proteinuria evaluation is essential for diagnosing and monitoring of renal involvement in light chain (AL) amyloidosis. A 24 hour protein collection (24h UP) is the ...gold standard for proteinuria assessment however it is cumbersome and can be inaccurate. A spot urine albumin to creatinine ratio (uACR) has been proposed as a convenient method to estimate 24hUP. We aimed to validate the correlation between uACR and 24hUP in a large cohort of patients. Methods: We retrospectively studied systemic AL amyloidosis patients evaluated between 2010 and 2019 at Mayo Clinic, with a uACR and 24hUP collected less than 7 days apart. Linear regression analysis was used to construct a prediction model for 24hUP with uACR as the primary predictor. Possible confounders (age, gender, body mass index, morning versus afternoon spot urine collection, estimated glomerular filtration rate) for the primary relationship between uACR and 24h UP were evaluated in the model. We used receiver operating characteristic (ROC) analysis to identify the best uACR cutoff to predict significant proteinuria (defined as a 24hUP > 500mg). Results: We included 665 patients, with a median age of 66 years (IQR 59-72). The spot urine was collected in the morning (before 1200 hours) in 382 (57%) patients, and in the afternoon in 283 (43%) patients. The median 24hUP was 321 (IQR 129-2512.5) mg, median uACR was 107 (IQR 13.5-1845) mg/g, and median serum creatinine was 1.2 (IQR 1-1.8) mg/dL. The uACR correlated well with 24h UP (Pearson’s r= 0.83, 95% CI 0.80-0.85). Linear regression showed that E (24h UP
i
) = 362 + 1.05(uACR
i
), and this model was statistically and clinically significant (p < 0.001 and R
2
of 0.68, respectively). Age, gender, body mass index, eGFR, and time of day of spot urine collection did not confound the primary relationship between uACR and 24hUP, and no collinearity was observed. A uACR cutoff of > 280 mg/g was the best predictor of a 24hUP > 500 mg (area under the ROC curve 0.98, sensitivity 92%, specificity 97%). For simplicity, we assessed the predictive value of uACR > 300 mg/g for 24h UP > 500 mg. Among patients with 24huACR > 300 mg/g 264 (96%) had a 24hUP > 500 mg, and 31 (7%) of patients with uACR < 300 mg/g had a 24h UP > 500 mg (p < 0.001). Conclusions: In systemic AL amyloid patients, we showed that uACR on a random urine sample correlated well with 24h UP, and can be used to estimate proteinuria with a linear regression model. Based on these findings, and the convenience of uACR testing for patients, we propose that uACR should be used to monitor renal response to AL amyloidosis therapy.
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