Serum Free Light Chain Research Articles

632 PREVALENCE OF VARIANT GENOTYPE IN PATIENTS WITH SUSPECTED CARDIAC ATTR AMYLOIDOSIS

Abstract Background Emerging therapeutic options and availability of non-invasive diagnostic tools are increasing recognition of cardiac ATTR (transthyretin) amyloidosis worldwide. However, the relative prevalence of hereditary ATTR amyloidosis may be underestimated, particularly in aged males in whom the disease may be assumed to be wild- type and TTR genetic test not performed. TTR gene variants associated with a predominant cardiac phenotype are known to result in worse prognosis. Identification of a pathogenic variant may not only guide treatment strategy but also allow for genetic counselling and cascade testing in at risk relatives. Purpose To identify the prevalence and type of genetic mutations in patients referred to our Centre for suspected cardiac ATTR amyloidosis. Methods We evaluated consecutive patients referred to our Centre from January 2017 to December 2021 for suspected cardiac ATTR amyloidosis based on signs of heart involvement on echocardiogram or magnetic resonance, a Perugini score 2 or 3 bone scintigraphy or a tissue biopsy proving TTR amyloid deposition, no family history, no signs of neurological or other organ involvement. All patients underwent clinical evaluation and laboratory analysis including serum and urine immunofixation, serum free light chains, and TTR genetic testing. As AAPOA-I amyloidosis is reported in Northern Italy we also routinely perform APOA1 genetic test in patients with suspected cardiac amyloidosis. Diagnosis was ultimately established on a tissue biopsy in patients in which a monoclonal component (CM) was identified. Results 481 patients were included, mean age at presentation was 76 years (min-max 50-93), 40 (8%) were women. In all patients with CM (29%), tissue biopsy confirmed TTR amyloid deposition by immunoelectron microscopy or proteomics. 439 patients (91%) did not carry TTR or APOA1 variants, while 42 (9%) had a heterozygous pathogenic mutation. 41 patients have a pathogenic TTR mutation the most frequent being Ile68Leu (n=28; 67%), followed by Tyr78Phe, Val122Ile and Val94Leu (n=3/2/2 respectively). One novel mutation, namely Pro43Thr, was identified. In one patient APOA1 Leu75Pro variant was identified and diagnosis of AApoA-I amyloidosis confirmed by typing on endomyocardial biopsy. No significant differences were found between ATTRwt and ATTRv patients apart from gender distribution. Although age did not differ among the two groups, the prevalence of a variant genotype raises when considering only patients younger than 70 years (14%). 20% of women carry a pathogenic variant, irrespective of age. Interestingly, among women with ATTRwt (n=32), almost one third (31%) was diagnosed with hip dysplasia in childhood, requiring multiple orthopaedic surgeries and prothesis implantation. Conclusions In our cohort, one out of ten patients referred for suspected cardiac ATTR amyloidosis was ultimately diagnosed with ATTRv. Our results emphasize the importance of performing genetic testing irrespective of age at presentation. Diagnosis of ATTRv is relevant for monitoring disease progression, for defining treatment strategy and for offering genetic counselling and presymptomatic test in at risk relatives. Finally, the high prevalence of hip dysplasia among women with ATTRwt deserves further investigation to define whether it may represent a novel, gender-related red flag for this disease.

903 NOVEL MALIGNANT MUTATION IN HYPERTROPHIC CARDIOMYOPATHY

Abstract Background Hypertrophic cardiomyopathy (HCM) is a common inherited disease almost invariably caused by mutations in sarcomeric genes. The HCM phenotype is clinically heterogeneous with myocyte hypertrophy, disarray, and myocardial fibrosis as histological hallmarks. This condition is recognized as an important cause of sudden cardiac death (SCD) in the youth and of heart failure (HF) in the elderly. Current guidelines mandate genetic analysis as a class I indication in HCM. Indeed, the advent of the next generation sequencing in the medical practice has led to decipher the molecular etiology of HCM and to assess the disease risk in family members with relevant insights into the clinical course. Clinical case A 62-year-old man followed-up at another Hospital with a non-obstructive HCM diagnosis, was referred to our Hospital for therapy optimization and clinical follow-up. Past medical history included third degree atrioventricular block at age 40 treated with dual chamber pacemaker (PM) and, at age of 60, atrial flutter with high ventricular response complicated with cardiogenic shock and stroke. Due to worsening systolic function and ventricular sustained tachycardia he was upgraded to implantable cardioverter defibrillator which delivered appropriate shocks. Echocardiography performed during current hospitalization showed a moderate concentric hypertrophy (intraventricular septum 17 mm, cardiac mass index 258 g/m2), dilated ventricle with reduced ejection fraction (33%) and akinesis of the mid inferior and infero-septal walls of the left ventricle and of the apex, with a stratified thrombotic apposition. Magnetic resonance was contraindicated because of non-compatible PM. Due to alteration in serum proteins and free light chain, to rule out systemic disease, extensive imaging diagnosis was performed including bone scintigraphy and abdominal ultrasonography which resulted negative. While waiting for bone marrow aspiration and biopsy the patient rapidly deteriorated with worsening renal failure, ensuing proteinuria until exitus. After an appropriate pre-test counseling the family consented to genetic test in the proband. Clinical exome sequencing revealed the presence of a missense mutation in MYH7 gene. This new mutation is characterized by the substitution of cysteine residue by a serine in 905 codon of MYH7 gene. Cys905Ser results in a semi-conservative amino acid substitution which may impact disulfide bond formation in the MYH7 protein. To date no study has described this mutation as a cause of HCM. A mutation affecting this same codon, Cys905Phe was reported in only one patient with HCM. From a biological point of view, this variant lies in the head region of the protein where the majority of the missense variants are grouped and statistically associated to HCM phenotype. Several studies reported that the occurrence of atrial fibrillation (AF) tends to be more prevalent in patients carrying the MYH7 mutation. Furthermore, AF is associated with substantial risk for HF-related mortality, stroke, and severe functional disability. Awareness regarding the spectrum of MYH7 mutations probably related to SCD or HF combined with a thorough patient characterization for molecular and clinical features, may help to improve the genotype and phenotype correlation. This important challenge could elucidate better the mechanism of HCM enabling cardiologists to a better clinical decision-making and patients’ care.

591 SEQUENCE OF DIAGNOSTIC TESTING IN CARDIAC AMYLOIDOSIS: EARLY MONOCLONAL PROTEIN STUDY IS ASSOCIATED WITH BETTER OUTCOMES IN AL AMYLOIDOSIS

Abstract Background Isolated cardiac amyloidosis (CA) is a complex diagnostic scenario, highlighting the need for physician awareness in differential diagnosis. Among the different types of amyloidosis, nearly all cases of CA are caused by light chain (AL) and transthyretin amyloidosis (ATTR). Patients with suspect CA without monoclonal components (MC) in both serum and urine and normal free light chain (FLC) ratio can have a non-biopsy diagnosis of ATTR amyloidosis with bone scintigraphy (1). However, in all suspected CA with a MC (approximately 20% of patients with ATTR amyloidosis), amyloid typing is mandatory. Thus, the diagnostic pathway of CA diverges based on MC-studies. We aim to assess if different sequence of diagnostic tests can affect outcomes in patients with cardiac AL amyloidosis. Methods Pavia Amyloidosis prospectively maintained database was searched for patients with isolated cardiac AL amyloidosis referred to our Centre from January 2016 to December 2020. Patients with a known monoclonal gammopathy (MG) and with multiple organ involvement were excluded. We searched for the date of symptom onset and first suspect of CA (i.e. recognition of clinical, imaging or laboratory signs of CA). In addition, we recorded the date of the different diagnostic tests performed: i.e. echocardiogram; serum and urine immunofixation and FLC measurement (MC-study); bone scintigraphy and cardiac magnetic resonance (defined as advanced cardiac imaging). We calculated the interval between those time-points and the final diagnosis: (a) from symptom onset to diagnosis, (b) from first suspect to final diagnosis, (c) from first suspect to MC-study and (d) to advanced cardiac imaging tests. We then searched for possible intervals of time amongst those, that were able to predict death at 3 months, by means of a ROC analysis. Results A total of 94 patients were included in the analysis (25% of all patients with cardiac AL amyloidosis diagnosed in the study period). Six (6%) patients died <1 month from diagnosis, and 27 (29%) died <3 months. Median overall survival (OS) of the whole cohort was 8 months, and the median follow-up of living patients was 39 months (range 16-73). The median time from symptom onset to diagnosis was 9 months (range 1-44) and the median time from the first suspect to diagnosis was 2 months (range 0-9). An interval from the first suspect to MC-study ≥6 weeks was the only predictor of death at 3 months. None of the other tested periods were associated with a significant ability to predict survival. A delay in MC-study ≥6 weeks identified patients with more advanced cardiac stage (50% vs. 25% were stage IIIb, P=0.02) and was associated with a significantly worse outcome (median survival 13 months vs. 4 months, P=0.012). In the whole cohort, a total of 76 (81%) patients underwent at least one advanced imaging examination. Amongst those, 37 (49%) performed the imaging tests before MC-study with a higher percentage of patients who had a delay in MC-studies evaluation (69% vs. 27%; P<0.001). Conclusion In patients who present with isolated cardiac AL amyloidosis with previously unknown MG, a relatively short delay in identifying the amyloid MC results in a considerable reduction of survival. A delay in MC-study was associated with more advanced cardiac stage. MC studies should be the first step in the work-up of patients with suspected CA to guide biopsy vs. non-biopsy diagnostic approach.

Tixagevimab Plus Cilgavimab Does Not Affect the Interpretation of Electrophoretic and Free Light Chain Assays.

There is concern that the anti-severe acute respiratory syndrome coronavirus 2 therapeutic monoclonal antibodies, used as preexposure prophylaxis in patients with multiple myeloma, may appear as a detectable monoclonal protein by electrophoretic methods, resulting in misinterpretation or inability to measure therapeutic responses in some patients. In this pilot study, we characterize the effect of tixagevimab plus cilgavimab (Evusheld; T + C) on interpretation of serum protein electrophoresis (SPE), immunofixation electrophoresis (IFE), and serum free light chain (sFLC) assays. We performed spiking experiments with T + C at serum maximum concentration following a 300-mg dose (1× Cmax) and at 10 times the concentration of Cmax (10× Cmax) with pooled serum samples. SPE and IFE technical procedures were performed on the SPIFE 3000, and sFLC and immunoglobulin G1 (IgG1) subtype quantitation was performed on the Optilite. T + C-associated interference was not visible as an M-spike in normogammaglobulinemic pooled samples. Hypogammaglobulemic pooled samples at 10× Cmax demonstrated an M-spike in SPE and immunoglobulin Gκ pattern in IFE. No increases were noted in the results of sFLC or IgG1 levels. This study indicates that T + C at pharmacologic Cmax is unlikely to interfere with SPE, IFE, sFLC, or IgG1 analyses when spiked into patient serum samples, but further evaluation of recently injected patients may be warranted.

Can urine studies be replaced by serum free light chains measurements to assign responses in multiple myeloma patients?

Serum and urine protein electrophoresis and immunofixation are the preferred techniques for monitoring monoclonal proteins and evaluating treatment response in multiple myeloma (MM) patients with measurable disease. However, urine studies are subjected to limitations that may lead to inaccuracies or prevent guidelines compliance. We retrospectively studied if the substitution of urine studies by measuring serum free light chains (sFLCs) results in a comparable disease monitoring, both in intact immunoglobulin (II) and light chain (LC) MM patients. In our cohort, equal or higher percentages of disease were identified by sFLCs at baseline and maximum response as compared to urine studies. Achieving very good partial response or better (≥VGPR) according to the response criteria proposed by the French group (evaluating sFLCs instead of urine) and the IMWG response criteria were associated to a 62% and 63% reduced risk of progression, respectively. A similar prognostic value for reaching ≥VGPR was also observed among LCMM patients when the French group and the IMWG response criteria were applied. Overall, these results support the replacement of urine studies by the sFLCs assay in IIMM. In LCMM, sFLCs could be used for monitoring and urine studies could be performed only to confirm complete remissions and progressions.

Free Light Chains, High Mobility Group Box 1, and Mortality in Hemodialysis Patients.

Background: Uremic toxins are associated with immune dysfunction and inflammation. The inadequate removal by hemodialysis (HD) of serum free light chains (FLCs) determines their accumulation. This study evaluated FLCs in HD patients, analyzing their relations with other biomarkers, such as serum high mobility group box 1 (HMGB1). Methods: FLC and HMGB1 were evaluated in a cohort of 119 HD patients. κFLC and λFLC were summated to give a combined (c) FLC concentration. Patients were followed prospectively until the end of the observation period of four years, or until the endpoint: the patient’s death. Results: cFLC values in HD patients were 244.4 (197.9−273.5) mg/L. We detected a significant reduction in CD8+ cells and a decreased CD4+/CD8+ ratio. HMGB1 levels were 94.5 (55−302) pg/mL. After multivariate analysis, cFLCs correlated with β2-microglobulin and the CD4+/CD8+ ratio. Subjects with cFLC values above 263 mg/L and with sHMGB1 values < 80 pg/mL experienced a significantly faster evolution to the endpoint (mean follow-up time to progression of 27.5 and 28.5 months, respectively; p < 0.001). After an adjusted multivariate Cox analysis, cFLCs were associated with 11% increased risk of death, whereas low sHMGB1 increased this risk by 5%. Conclusions: cFLCs and HMGB1 reflect the inflammation and immune dysfunction in HD patients representing two strong and independent risk markers of mortality.

A Novel Serum Free Light Chain Metric Provides Greater Diagnostic Specificity and Robustness to Variation in Renal Function

The serum free light chains (sFLC) assay provides a minimally invasive method for probing plasma cell clonality and has clinical value in diagnosing, monitoring, and prognosticating patients with monoclonal gammopathies (MGs). sFLC interpretation involves the calculation of the kappa to lambda sFLC concentration ratio (sFLC-ratio). An abnormal sFLC-ratio can provide evidence of a clonal plasma cell process. However, the sFLC-ratio is prone to false positives in patients with impaired renal function (IRF). To address this problem, prior studies have proposed renal specific reference intervals for use in patients with IRF, defined as an estimated glomerular filtration rate (eGFR) less than 60 mL/min/1.73m2. This solution has several important limitations. First, a contemporaneous eGFR result is required to identify which reference interval should be reported. Second, the cutoff of 60 mL/min/1.73m2 is arbitrary and not data-driven. Third, performing multiple reference interval studies poses a major cost barrier. Finally, most laboratory information systems (LIS) do not support the use of multiple reference intervals for a single discrete result. The overall goal of this study was to provide a practical solution to improve the diagnostic utility of the sFLC assay for patients with IRF. The LIS and electronic health records of Barnes Jewish Hospital (BJH, St. Louis, MO) were queried to retrieve all sFLC results, sFLC-order associated diagnosis codes, serum immunofixation electrophoresis (IFIX), serum protein electrophoresis (SPEP), and Creatinine (Cr) results between 01/01/2019 and 01/01/2022. sFLC and Cr results were matched based on closest collection time. For patients with multiple paired sFLC/Cr results the earliest set was retained leaving 5,542 pairs of unique patient results. eGFR was calculated using the 2021 CKD-EPI formula. A non-MG cohort of 413 patients was defined based on a negative IFIX and the absence of an order-associated diagnosis code of an MG. In addition, an MG cohort was defined comprising 1,296 patients with a paraprotein on IFIX or SPEP and an order-associated ICD10 code of an MG. It was observed that 46.1% of patients subjected to sFLC testing had IRF. Among non-MG patients, those with IRF had a significantly greater median[IQR] sFLC ratio compared to those without IRF, 1.7[1.36-2.16] versus 1.29[1.03-1.56] g/dL (p<0.001 by Wilcoxon rank sum test). In addition, the MG false positive rate of the sFLC-ratio was significantly greater among those with IRF, 52.9% versus 19.6% (p<0.001 by Chi-square test). Next, using principal component analysis, a new metric was defined that represents distance from the principal axis of variation in kappa and lambda concentrations among non-MG patients (Figure 1). A diagnostic interval was defined for this metric (-0.64 to 0.59) using the 2.5-97.5% range of the distribution observed among non-MG patents. Visual inspection suggested the new interval separated the data from the MG and non-MG cohorts better than the manufacturer's sFLC-ratio based interval (Figure 2). The novel metric had significantly improved specificity overall (94.7% vs 63.5%, p<0.001) as well as among patients with IRF (91.7% vs 46.4%, p<0.001). Consistent with prior studies, this work provides evidence that IRF is common among patients tested using the sFLC assay and is associated with poor diagnostic specificity of the sFLC-ratio. We describe a novel metric and demonstrate its use for improving the diagnostic specificity of the sFLC assay. An attractive feature of our approach is that it can be implemented with a single diagnostic interval because the metric presented is robust to variation in renal function. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

How to Treat Isolated Leptomeningeal Relapse of Multiple Myeloma 11 Years after Autologous Stem Cell Transplantation (ASCT)

Post transplant relapse of Multiple Myeloma (MM) in the central nervous system (CNS) is rare and it is almost always associated with systematic relapse and in most instances, shortly after initial treatment. We did not encounter reports of relapse isolated to the CNS ten years post-transplant. In October 2009, a 49-year-old male presented with an IgG lambda MM, ISS II. He was treated with Bortezomib/Dexamethasone, autologous PBSCT, followed by two years maintenance with Lenalidomide, attaining stringent CR, confirmed by PET/CT. He discontinued follow up and returned after 11y/8m progression free survival, in June 2021 with paraplegia due to cauda equina syndrome. NMR consistent with leptomeningeal infiltration, single focal intramedullary lesion at L1 level without bone affectation. No MM defining criteria (CRAB). Normal levels of serum Immunoglobulins (IGs), serum and urine immunofixation, and serum free light chains. Flow cytometry negative in bone marrow. Spinal tap was unsuccessful and through an Ommaya reservoir, that was placed after NMR showed evidence of cranial leptomeningeal involvement, CSF showed infiltration by countless malignant plasma cells. Patient received immediate conformational radiotherapy and biweekly IT methotrexate and hydrocortisone. A month later his course was complicated by left leg proximal deep vein thrombosis and pulmonary embolism which was treated with Apixaban. Given the rarity of this type of relapse, we questioned the appropriateness of the treatment and searched the literature with respect to the accessibility of the CNS by the different novel drugs used to treat MM in order to determine the most effective strategy. In addition to corticosteroids, there is clinical evidence that thalidomide crosses the blood-brain barrier (BBB), in murine models pomalidomide also has good penetration into the CNS. Both have a penetration of 30 to 40% into the CSF. Among proteasome inhibitors, only marizomib has been observed to cross the BBB in a murine model, while bortezomib does not. With respect to anti CD38 monoclonal antibodies, mass spectrometry at 12, 15, and 19 days after daratumumab infusion showed antibody levels in CSF 71 times less than in serum on the three sample days. It is not known if weekly doses of daratumumab could attain therapeutic levels in CSF. We found only 14 cases of isolated CNS relapse in patients with MM treated with ASCT with a median interval between transplant and relapse of 3 months (0.5-96m), with only one reported relapse 7.5 years after autologous transplant and the median overall survival was only 3 months. Two cases died in less than a month and only one case survived for a year after the CNS relapse.To date, our patient has received 12 cycles of Pomalidomide/dexamethasone with progressive improvement, now he is able to carry on his life unassisted and there is no evidence of MM relapse anywhere. The rarity of this case scenario highlights the lack of knowledge regarding the best approach to CNS MM relapse. There is no evidence of the effectiveness of methotrexate and Ara C, in MM, and no novel drug can be instilled into the CSF. We conclude that the systemic use of pomalidomide and dexamethasone should be the best approach of MM isolated CNS relapse. Further investigations will clarify if other novel drugs are active in this context.

Use of Clinical Decision Support to Improve the Laboratory Evaluation of Monoclonal Gammopathies

Introduction: Since its introduction in 2001, the serum free light chain (sFLC) assay has played an increasingly prominent role in the initial clinical evaluation of patients with suspected monoclonal gammopathies (MGs). This is primarily due to its superior sensitivity for detecting monoclonal proteins especially in light chain disease. In 2009, the International Myeloma Working Group (IMWG) recommended ordering the combination of an SPEP, sFLC and sIFE for initial screening for all MGs. However, there is still significant heterogeneity in sFLC ordering practices. A recent survey of over 700 clinical laboratories found that sFLC were included in the most common screening order sets for the initial evaluation of MGs in only 19.7% of centers. Methods: We performed a retrospective analysis of SPEP and sFLC ordering practices at our institution over a 6-year period (2014-2019). We then designed and implemented a clinical decision support (CDS) alert to improve compliance with IMWG's recommendations. The alert fires when a provider orders an SPEP without a concurrent sFLC order or result in the last 30 days and suggests the ordering of sFLC. We analyzed the impact on ordering practices and diagnostic outcomes over the course of a 10-month period. Results: Our retrospective analysis of over 90,000 SPEP results, associated sFLC orders, and ICD-10 codes revealed that many providers deviated from society guidelines for the use of sFLC in the initial laboratory evaluation of MGs. Prior to the alert 62.8% of all SPEP evaluations included sFLC testing, while post-implementation nearly 90% of evaluations included sFLC (Figure 1). When restricting our analysis to patients with no prior sFLC results, we found that the alert contributed to the clinical care of as many as 2,791 patients. Twenty nine percent (810/2,791) of these patients had an abnormal kappa/lambda ratio (rFLC). In 462 of these patients the rFLC was the only laboratory evidence of a monoclonal protein (Table 1). Moreover, within this population there were numerous instances of new diagnoses of multiple myeloma and other MGs. Conclusions: In the initial laboratory evaluation of MGs, a CDS alert was an effective tool to increase clinical practice compliance with society guidelines. More importantly, the alert prompted sFLC orders that contributed to the diagnosis of numerous MGs that may have been missed or warrant further investigation and follow up. This study will hopefully serve as a useful guide for other institutions addressing the gap between clinical practice and evidence-based guidelines. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Monoclonal Gammopathy of Undetermined Significance and Risk of Chronic Kidney Disease: Results of the Population-Based Iceland Screens, Treats, or Prevents Multiple Myeloma (iStopMM) Study

Background: Monoclonal gammopathy of undetermined significance (MGUS) and chronic kidney disease (CKD) are common conditions. When monoclonal gammopathy causes CKD it is referred to as monoclonal gammopathy of renal significance (MGRS) and a kidney biopsy is required to confirm the diagnosis. Because of this, some have speculated that MGRS may be severely underdiagnosed and have recommended considering a kidney biopsy in all individuals with MGUS who have microscopic hematuria, proteinuria, or declining estimated glomerular filtration rate (eGFR) of <60 mL/min/1.73m2. If MGRS were more common than previously thought, the prevalence of CKD in persons with MGUS would be expected to be higher than persons without MGUS. We aimed to compare the prevalence of CKD in individuals with and without MGUS in a large, prospective, screened, population-based cohort. Furthermore, we aimed to assess possible association between M protein concentration and kidney function. Methods: A total of 75,422 participants in the Iceland Screens, Treats or Prevents Multiple Myeloma (iStopMM) study were screened for MGUS with serum protein electrophoresis (SPEP), serum free light chains (FLC), and immunofixation (IFE). All previous clinical laboratory samples were obtained, including serum creatinine (SCr), urine albumin/creatinine ratio (ACR) and urinalysis. CKD was defined as SCr-based eGFR of <60 mL/min/1.73m2, or proteinuria or hematuria, present for >90 days. Participants diagnosed with lymphoproliferative disorders or without data on kidney function were excluded. Power analysis demonstrated that this sample size yielded 90% power to detect a 1.5% absolute difference in the prevalence of CKD in persons with and without MGUS. Prevalence of CKD was evaluated using multivariable logistic regression adjusted for age, sex and MGUS status. The association between eGFR and M protein concentration was assessed with linear regression for continuous eGFR and ordinal logistic regression for CKD categories. All models included age and M protein concentration as four knot restricted cubic splines. Sensitivity analyses were performed where CKD was defined solely by persistently lowered eGFR and as a combination of persistently lowered eGFR, proteinuria, and hematuria. Results: A total of 69,120 participants had SCr measurements and 34,294 had urine studies available. MGUS was present in 4,547 (6.6%) participants, of which 2,242 (49.3%) were non-IgM; 703 (15.5%) were IgM; 1,295 (28.5%) were light chain (LC-MGUS); and 307 (6.7%) were biclonal MGUS. A total of 6,680 (9.7%) participants had CKD defined either as eGFR <60 mL/min/1.73 m2 (N=5,915) or persistent proteinuria or hematuria (N=693), or were receiving treatment for end-stage kidney disease (N=74). Participants with MGUS were significantly older (median [IQR] age 69 [60-76] vs 60 [52-69] years) and more predominantly male (55% vs 41%) compared with participants without MGUS. After adjusting for age and sex, no significant association was found between heavy chain MGUS and CKD (odds ratio [OR] 1.00, 95% confidence interval [CI] 0.95-1.17). This also remained true for subgroups of non-IgM MGUS, IgM MGUS, and biclonal MGUS (Table). Participants with LC-MGUS were less likely to have CKD than participants without MGUS (OR 0.39, 95% CI 0.31-0.49, p <0.001). Sensitivity analyses of CKD definition yielded similar results. M protein concentration had a small negative correlation with eGFR (r= -0.08, p<0.001) but when stratified by age and sex category no significant correlation remained. No significant association was found between M protein concentration and worse eGFR category on ordinal logistic regression model adjusted for nonlinear age and sex (OR 1.01, 95% CI, 0.28-3.66). No significant correlation was found between M protein concentration and severity of proteinuria assessed with urine ACR. Conclusion: In this nationwide prospective population-based screening study of nearly 70,000 individuals, we found no association between MGUS and CKD, regardless of whether CKD was defined based on eGFR, urinary findings, or both. Furthermore, we found no association between M protein concentration and eGFR or severity of albuminuria. We conclude that in the absence of multiple myeloma, the results of SPEP, IFE, and serum FLC measurements are of little value in the evaluation of CKD. Furthermore, our results are not consistent with substantial underdiagnosis of MGRS. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Artificial Intelligence-Enhanced Models to Predict Light Chain Amyloidosis from Patients with Monoclonal Gammopathy of Undetermined Significance and Smoldering Multiple Myeloma

Background: Early diagnosis of AL amyloidosis remains a diagnostic challenge, mainly due to the low prevalence of the disease and heterogeneity of presentation. Artificial intelligence (AI) is a tool which can assist in improving disease recognition. Objective: To establish an AI-based model to accurately discriminate patients with AL amyloidosis from patients with monoclonal gammopathy of undetermined significance (MGUS) and smoldering multiple myeloma (SMM), who are at risk of developing AL amyloidosis. Material & Methods: We screened all consecutive patients from the dysproteinemia database at Mayo Clinic Rochester with the diagnoses of MGUS, SMM and AL amyloidosis who were diagnosed between January 1, 2000, and December 31, 2018 and evaluated within 90 days of their diagnosis. Patients who had more than one diagnosis were excluded. The choice of variables to be included in the models were those in whom data was available in >50% of the patients (with one exception being serum free light chain assay which was available in 44% of patients but deemed important for modeling). The variables included in the modeling were the following: Age, gender, height, weight, systolic blood pressure, diastolic blood pressure, heart rate, hemoglobin, MCV, white blood count, absolute lymphocyte count, platelet count, creatinine, albumin, calcium, SGOT, alkaline phosphatase, total bilirubin, serum free kappa and serum free lambda. In a subset model, we incorporated the AI-enhanced electrocardiogram (AI-ECG) score for cardiac amyloidosis (available in routine clinical practice at Mayo Clinic). This variable is AI-based captures from standard 12-lead ECG to predict the probability of cardiac amyloidosis.1 We randomly divided the final study cohort in a 1:1 ratio to training and validation set. Random forest algorithm was used for modeling to predict the probability of AL amyloidosis diagnosis versus non-AL amyloidosis diagnosis (i.e., MGUS/SMM). Results: 20, 579 patients were screened, of which 4,087 patients (19.9%) were included in this study (MGUS n=2716, AL amyloidosis n=1217, SMM n=154). The first model (ALERT 20) included the above-mentioned 20 variables, of which 7 were clinical and 13 were common blood count and blood chemistry testing. The validation set yielded an AUC-ROC of 0.946 for accurate classification of AL amyloidosis against MGUS/SMM. The second model (ALERT 20-ECG model) included all variables used in the ALERT 20 mode plus the AI-ECG score. In this model, 3090 patients were included, after excluding patients with missing ECG (MGUS n=1896, AL amyloidosis n=1075, SMM n=119). By adding the AI-ECG score, the AUC-ROC in the validation set for accurate disease classification increased modestly to 0.958. Analysis of the relative contribution of each variable to model performance identified serum free light chains, serum albumin and AI-ECG as the most influential variables. As disease prevalence decreases the positive predictive value (PPV) and increases the negative predictive value (NPV) of a model, we tested the models’ performance in various prevalence scenarios, including the estimated prevalence of AL amyloidosis among MGUS/SMM patients (estimated at 1/100-1/1000 person years). Although the PPVs of ALERT 20 and ALERT 20-ECG were low (<1-27.6%), the NPV was over 99% (Figure). Summary & Conclusion: Two AI-based algorithms to aid clinicians in recognizing patients with AL amyloidosis and distinguishing them from patients with MGUS/SMM are presented. These models, when tested in populations at risk of AL amyloidosis (where the prevalence of AL amyloidosis is sufficiently elevated), have a plausible PPV to be used as screening tool for this uncommon, yet life-threatening, disease. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Sars-Cov-2 Vaccinations Do Not Lead to Progression of Monoclonal Gammopathy of Undetermined Significance: Results from the Population-Based Istopmm Screening Study

Background: In patients with monoclonal gammopathy of undetermined significance (MGUS), the pre-malignant cells are antibody producing plasma cells. Stimulating humoral immunity mediated by plasma cells is an important factor in vaccine efficacy. Therefore, concerns have been raised about whether vaccine administration in patients with MGUS could trigger progression of the underlying pre-malignant clone, leading to an increase in the monoclonal-(M)-protein or even progression to full-blown malignancy. Immune stimulation has been found to be a risk factor for monoclonal gammopathies. However, immune stimulation inherent to vaccines and the subsequent antibody formation by plasma cells has, to our knowledge, not been studied in a systematic manner in MGUS. The current SARS-CoV-2 pandemic provide a unique opportunity to evaluate if SARS-CoV-2 vaccination has an impact on the risk of progression from MGUS to MM, or not. To study this we performed a prospective nationwide study based on the Iceland Screens, Treats, or Prevents Multiple Myeloma (iStopMM) study. Methods: The iStopMM study screened a total of 75,422 individuals for M protein and free light chains (FLC) between September 2016 and December 2020. The study diagnosed 3,358 individuals with MGUS and then randomized them to one of three arms. Individuals in arms 2 and 3 (N=2,037) are followed longitudinally with repeated serum protein electrophoresis (SPEP) and FLC and comprise the study population. All SARS-CoV-2 vaccinations in Iceland are centrally registered, which gives complete nationwide information on vaccination coverage, type of vaccine used, and frequency of administration. By cross-linking the vaccine data to the iStopMM database, MGUS patients who had received at least one SARS-CoV-2 vaccination and had follow-up serum samples after vaccination were identified. As M protein levels change with age, linear mixed modelling was used to estimate changes in M protein concentration as a function of age before vaccination and after vaccination. The slope of the evolution of M protein level over age was modelled as a continuous linear effect and compared before and after each vaccination to determine the effects of SAR-CoV-2 vaccination on changes in M protein levels. Results: A total of 1,814 SARS-CoV-2 vaccinated MGUS individuals were included in the study. The participants had 6,094 serum samples available with a median of 3 (range 1-21) per person (Table 1). All had at least one M protein measurement after receiving at least a single dose of vaccine. Median age at first vaccination was 71 (range 42-98) years and 53.9% were males. Median follow-up was 2.3 (range 0.5-5.5) years, and 98.9% of individuals had received at least two doses of SARS-CoV-2 vaccine. The most common vaccine (first dose) was BNT162b2 (Pfizer) 54.4%, followed by ChAdOx1 (Astra Zeneca) 38.0%, mrna-1273 (Moderna) 5.7% and AD26.COV2.S (Janssen) 1.9%. Comparing M protein levels pre- and post-vaccination showed a 1.9% increase in M protein concentration in males and 0.3% in females. However, there was no difference in the rate of M protein increase following vaccination compared to that observed before vaccination. This was true for both men and women (Figure A). After adjusting for age, sex, and calendar year, no difference in M protein concentration was observed when comparing the increase before and after vaccination (Exponentiated beta coefficient (Exp(β)): 0.99; 95% confidence interval [CI], 0.96-1.03). The same was true when analyzed for each sex separately (Exp(β): 1.00; 95% CI, 0.96-1.04 for males and Exp(β) 0.98; 95% CI, 0.93-1.04 for females). No difference was observed between the different types of vaccines used. Similarly, neither second doses of vaccine (Exp(β): 1.00; 95% CI, 0.96-1.04) nor boosters (Exp(β): 1.03; 95% CI, 0.94-1.12) had an impact on the M protein concentration. Conclusion: In this large, prospective, population-based, screening study including 1,814 individuals with MGUS who were observed before and after covid vaccinations, we found no evidence for MGUS progression after SARS-CoV-2 vaccination. The same was true when analyzed separately by sex, age, type of vaccine, and the number of doses given. Our findings indicate that SARS-CoV-2 vaccination is safe in individuals with MGUS and does not lead to progression irrespective of the number of vaccine doses administered and type of vaccine used. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Abnormal Free Light Chains in Individuals with African Ancestry Screened for Monoclonal Gammopathy: Definition of New Reference Range Accounting for Renal Function and Race

Introduction Serum free light chain (sFLC) are important for diagnosis and prognosis of plasma cell dyscrasias and are known to be affected by kidney function and inflammatory conditions. However, African Americans (AA) have been reported to have significantly higher Kappa (κ) and Lambda (λ) sFLC levels than European Americans (EA) in a biobanked population, even after adjusting for kidney function (El-Khoury et al., Lancet Haem 2022). Data on race-adjusted reference ranges for sFLC and sFLC ratio (sFLCr) remain limited. We hypothesize that an adjustment in sFLC reference ranges for individuals of African and European ancestry is needed. Methods We analyzed serum samples from 738 healthy Black South African (SA) and 3402 US individuals (AA+EA) as part of an international study screening for individuals at high risk of multiple myeloma (MM) and precursor conditions. Self-identification as Black or having family history of hematologic cancer or MM precursor were key eligible criteria. sFLC levels were measured using the Optilite® Freelite assay (The Biding Site). All participants were screened for Monoclonal Gammopathy of Undetermined Significance (MGUS; M protein concentration ≥ 0.2 g/L) by matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry. Serum Cystatin C (Optilite®) was used to calculate estimated Glomerular Filtration Rate (eGFR) with CKD-EPI Cystatin C Equation (2012) formula for 752 individuals (568 SA, 184 AA). Clinical data was collected using validated questionnaires at study enrollment. Group medians were compared with Wilcoxon tests. Abnormal sFLCr was defined as any value outside the normal reference range with the involved sFLC above the manufacturer's normal reference range. We used 95% central interval (CI) values to compute new sFLCr reference values for each group. Results After excluding individuals with Heavy Chain-MGUS, our study population consisted of 654 SA, 326 AA, and 2,551 EA. Median age was 52 (IQR 46-59), 56 (IQR 50-65, and 58 (IQR 50-64) for the three groups, respectively. There was a female predominance in the AA (74%) and EA (73%) groups compared to SA (52%). Chronic kidney disease (CKD) was self-reported in 0.2%, 1% and 1% of the three groups, respectively. Calculated median eGFR was 118 ml/min (IQR 106-134) for SA and 112 (IQR 98-123) for AA. HIV positivity was higher (23%) in SA than the other groups (<1%) and 99% were under treatment (Tenofovir 92%, which is known to be nephrotoxic). The median free κ was higher in SA (32 mg/l, IQR 24.8-46) than AA (18.1 mg/l, IQR 14.4-23, +80%, p<0.01) and EA (13.7 mg/l, IQR 10.8 - 17.1, +133%, p<0.01). Similarly, median free λ was higher in SA (24.6 mg/l, IQR 18.8-33.4) than AA (15 mg/l, IQR 11.7-19.3, +64%, p<0.01) and EA (11.9, mg/l IQR 9.1-15.5, +106%, p<0.01). 92% of SA, 43% of AA, and 16% of EA had κ values above the normal range. Similarly, 43% of SA, 10% of AA, and 3% of EA had λ values outside the normal range. Median sFLCr was higher in SA (1.34, IQR 1.13-1.65) than AA (1.25, IQR 1.03-1.48, p<0.01), and EA (1.18, IQR 0.99-1.39, p<0.01) (Fig 1). Using the standard manufacturer ranges, 25% of SA, 11% of AA and 3% of EA had abnormal sFLCr and involved FLC. Decreasing eGFR, increasing age, HIV positivity, and the cohort (SA, AA, or EA) were all significant predictors of changes in sFLCr in univariate analysis. In multivariate logistic regression, increasing age, HIV positivity, and decreasing eGFR were independent predictors of abnormal sFLCr (Table 1) for SA or AA compared to EA. In SA with normal renal function (eGFR >60 ml/min), excluding those with free κ and λ outside the 95% CI, we identified a new reference (95% CI) for FLCr of 0.80-2.38. Conclusions This is the first report of sFLC measurements in an African population screened for MG and compared to AA and EA. We observe a significantly higher sFLC for Black (SA and AA) than White individuals (EA), independent of renal function. This difference could be due to genetic background and socioeconomic and environmental factors (e.g., HIV epidemiology). In contrast with previous reports (Zemlin, et al, J Clin Pathol 2015), HIV was associated with higher FLCr, maybe with a possible role of nephrotoxic HIV drugs. Here, standard reference ranges do not apply to SA participants. While further validation is needed, we propose to use a different sFLC range for African ancestry populations with normal renal function. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Patients with IgM Monoclonal Gammopathy of Undetermined Significance (MGUS) or IgA with an M Band < 1.0 g/DL Have the Same Low Risk of Progression to Lymphoplasmacytic Neoplasm (LPN) As Those with IgG MGUS and an M-Band < 1.5 g/DL

Background Patients with MGUS can progress to LPN. Non-IgG subtype and the size of the M-band are known to correlate with the risk of progression. Consensus guidelines recommend that patients be monitored on an annual basis, but that IgG MGUS with an M-band < 1.5 g/dL, and a normal serum free light chain ratio is at low risk and can be managed with less intensive monitoring. There are limited data on the risk of progression to LPN in non-IgG MGUS with small M-bands. Methods Kaiser Permanente Northern California (KPNC) is a large integrated health care system serving more than 4 million members representative of Northern California residents. We identified a cohort of 3,303 KPNC health plan members who had at least one serum protein electrophoresis (SPEP) performed between January 1997 and December 2006 and extracted follow up data through December 2016. We excluded those with an M-Band > 3 g/dL, absence of a confirmatory immunofixation, or LPN before through 3 months after initial SPEP. The primary end point was progression to LPN, defined as multiple myeloma (MM), non-Hodgkin's lymphoma, or amyloidosis, and identified via an integrated tumor registry and, in the case of amyloidosis, by clinic diagnosis. Findings The median age of this cohort was 73 (IQR 63-80), 54.5% were male, and the ethnicity of this group was White 66.9%, Black 17.2%, Asian 6.7%, Hispanic 7.7%, and others 1.6%. Sixty six percent had an IgG gammopathy and 73% of gammopathies were < 1.0 g/dL. Overall, there were 2.1 (2.0-2.3) progressions per 100 patient years. The number of progressions per 100 patient years for an M-band < 1.0 g/dL, 1.0-1.5 g/dL, and 1.5-3.0 g/dL were 1.4 (1.2-1.6), 3.5(2.9-4.1), and 6.6 (5.5-7.7) respectively. As can be seen in the Figure, the cumulative risk of progression to LPN was clinically similar for patients with an IgG ≥ 1.5 g/dL and IgA ≥ 1.0 g/dL and considerably increased compared to those with an IgG gammopathy < 1.5 gm/dL, IgA gammopathy < 1.0 g/dL, or an IgM of any size. Discussion It has been estimated that there are several million individuals in the United States with MGUS. Following a patient with MGUS indefinitely is a financial burden and creates a substantial psychologic burden for the patient. Others have found that the effect of an MGUS diagnosis on quality of life is greater than a new diagnosis of symptomatic MM. Therefore, identifying additional categories of MGUS that could be assigned to a low-risk category could potentially diminish the burden and stress of ongoing monitoring. Limitations of our study are that, owing to the period from which our cohort was accrued, and the nature by which they were identified, free light chain levels were not obtained, bone marrow biopsies were done infrequently, and modern advanced imaging was not performed. In the modern era, many of our cohort would likely be identified with more advanced neoplasia such as smoldering or frank MM accounting for the higher rates of progression compared with other published reports. We found that during much of the period covered by our study, the clinical diagnosis of Waldenstrom's Macroglobulinemia was used in a non-discriminatory manner. We therefore limited our definition of progression only to those subjects developing frank malignancy that qualified for inclusion in our tumor registry rather than the less rigorously defined entity of "Waldenstrom's Macroglobulinemia.". This likely accounts for the lower risk of progression to LPN among our cohort with IgM gammopathy than has been described elsewhere. Conclusion Patients with either IgM MGUS of any size or IgA MGUS with an M-band < 1.0 g/dL have an equivalent clinical risk of progression as patients with an IgG MGUS < 1.0 g/dL and should potentially be assigned to a low-risk category to decrease the burden and stress of ongoing monitoring. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Outcomes in Patients with Renal Monoclonal Immunoglobulin Deposition Disease

BACKGROUND: Monoclonal immunoglobulin deposition disease (MIDD) is characterized by the production of abnormal monoclonal immunoglobulins that deposit in the kidney and other organs. MIDD causes proteinuria, renal damage and eventually renal failure. Currently, there are few studies on the outcomes of patients (pts) with renal MIDD (R-MIDD). METHODS: We performed a single-center retrospective analysis on patients that were seen at the University of California San Francisco Hematology clinic for MIDD from 2010 to 2020. All pts must have had biopsy-proven R-MIDD. Demographic and disease-related characteristics at diagnosis were collected as well therapies administered. Diagnosis of multiple myeloma was per IMWG criteria (Rajkumar et al. Lancet Oncology 2014). Hematologic response and renal response were assessed per previously published criteria (Palladini et al. J Clin Oncol 2012; Palladini et al. Blood 2014). Overall survival (OS), time-to-next treatment (TTNT), time-to-renal progression (TTRP), time-to-dialysis (TTD) were estimated using the Kaplan-Meier method. TTRP was defined as time from the start of treatment to renal progression censored by last follow-up or date of renal transplant. TTD was defined as time from start of treatment to dialysis or last follow-up. Pts already on dialysis at diagnosis were excluded from TTRP and TTD. RESULTS: Thirty-four pts with R-MIDD were identified, 31 light chain deposition disease, 2 heavy chain deposition disease and 1 light and heavy chain deposition disease. Median age at diagnosis was 63 (IQR 58-70) with 13 (38.2%) females. Median creatinine and estimated GFR at diagnosis were 2.80 mg/dL (IQR 3.17-5.57) and 25 ml/min/1.73m2 (IQR 13-40) respectively. Median involved free light chain (FLC) was 819 mg/L (IQR 130-2870), and difference in FLC 433 mg/L (IQR 85-1022). All pts had abnormal serum free light chains and 25 (73.5%) pts had kappa R-MIDD. Median bone marrow plasma cells percentage was 19% (IQR 10-38%). The most common cytogenetic abnormality was del 13 in 6/25 pts (24.0%). A concurrent diagnosis of myeloma was presented in 10 (32.3%) pts. Pts underwent a median of 2 lines of treatment (IQR 1-2). Median follow-up was 5.95 years (range 0.27 - 22.3 years). Pts were treated at induction with the following therapies: Group 1) immunomodulatory drug (IMiD) +/- bortezomib (Bor) (8/34, 23.5%); Group 2) Bor without IMiD (24/34, 70.6%) or Group 3) other (2/34, 5.9%). Autologous stem cell transplant (ASCT) was performed in 82.4% of pts. The 3- and 6-month hematologic response of ≥VGPR was 30.4% (7/23) and 55.6% (15/27) respectively. At the 6-month, Group 1, 2 and 3 had a ≥VGPR of 14.3%, 26.3% and 100% respectively though Group 3 only had 2 pts. Of the 29 pts assessed for best renal response, 9 pts (31.0%) had a renal response. Best renal response for group 1, 2, and 3 occurred in 0%, 38.1% and 100% of pts, respectively. Median TTNT was 2.9 years. Of 34 pts, only 5 died and median overall survival was not reached (Fig.1A). Improved median OS was associated with diagnosis after 2010 v ≤2010 (p=0.1) (Fig. 1B), >60 years old at diagnosis v ≤60 (p=0.1) (Fig. 1C) and treatment with ASCT (p=0.058) (Fig. 1D), though none met statistical significance. Renal progression occurred in 63.3% pts with median TTRP of 1.8 years. Dialysis dependence occurred in 33.3% pts with median TTD not reached (Fig. 2A). TTD did not differ significantly for pts diagnosed >2010 v ≤2010 (p=0.9) (Fig. 2B), ASCT (p=0.7) (Fig. 2D) though was better for pts who were diagnosed >age 60 vs ≤60 (p=0.027) (Fig. 2C). Five pts had a renal allograft, 3 of whom received the allograft after chemotherapy initiation, with 1 graft failure. In a landmark analysis at 6 months, OS and TTRP was better in pts with ≥VGPR compared to <VGPR, though both did not meet statistical significance (p=0.3 and p=0.2, respectively) (data not shown). No significant difference between ≥VGPR compared <VGPR was observed in TTD (p=0.5) (data not shown). CONCLUSION: In this limited retrospective study, we showed that R-MIDD pts were diagnosed late in the disease when pts already developed severe CKD. R-MIDD pts frequently had a concomitant diagnosis of multiple myeloma. Despite treatment with novel agents and ASCT, only a third of pts had a renal response and a third of pts required eventual dialysis. This study highlights the need for early diagnosis of R-MIDD and better treatments for this disease. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Identifying Multiple Myeloma Patients Using Automated Data Capture from Electronic Medical Records

Background: Multiple myeloma (MM) is an incurable plasma cell (PC) malignancy typified by the presence of monoclonal proteins on serum protein electrophoresis (SPEP) and immunofixation or elevation of either kappa or lambda serum free light chains (sFLC) and end organ damage. Electronic Medical Records (EMR) offer a potential source of real world data that is more generalizable than clinical trial data and more granular than registry data. However, MM cohort derivation is challenging: diagnostic codes have poor specificity, and manually created registries are time consuming and frequently focus only on patients diagnosed on site, excluding second opinions or patients transferring care. Attempts to combine diagnostic codes with procedure codes for lab tests, biopsies or radiology studies have reported sensitivities of 73-90% and positive predictive values (PPV) of 60-93%. These approaches relied on test completion, not test results, which may misclassify patients as having MM. As part of an ongoing quality improvement project at the University of California Davis (UCD) designed to identify all patients with MM treated at our institution, we hypothesized that integrating test results, rather than their utilization, with diagnostic codes would create a more specific algorithm while maintaining sensitivity and high PPV. Methods: Patient diagnostic codes, lab, and bone marrow (BM) biopsy reports were loaded from EMR into the Temporal Data Association Platform (TDAP), a patient level data matrix that integrates multi-modal clinical data and organizes it by time allowing for temporal association of clinical events and the ability to assess patient trends over time. Bone marrow (BM) biopsy reports are evaluated by a machine learning algorithm trained to identify the presence and quantity (CD138 percentage) of clonal PCs. Patients identified in the screen set are then passed through both the evaluative and fast track. The UCD algorithm then runs on TDAP and consists of two components (Figure 1): an evaluative track, and a fast-track. Like prior algorithms, the Fast-Track identifies MM specific diagnostic codes, but only evaluates visits at the UCD Cancer Center. The evaluative track classifies patients into categories based the International Myeloma Working Group diagnostic criteria (Figure 2): 1) treatment ineligible smoldering MM (SMM), 2) treatment eligible SMM, 3) symptomatic MM. Patients not meeting criteria for these categories are excluded. Patients enter the UCD MM cohort if identified as treatment eligible SMM or symptomatic MM or via the fast-track. The UCD algorithm was built using a training set of 141 unique patients identified at the UCD Cancer Registry and sampled at random from the EMR. These charts were manually reviewed and labeled as MM, including treatment eligible SMM, (n=112) or not (n=29). To assess the performance of this and a previously described algorithm (Brandenburg 2019) once predictions were made by each algorithm, we assessed accuracy (the proportion of accurate predictions), PPV, and sensitivity. Results: The UCD algorithm identified 111 of the MM cases and excluded MM in 9 of the negative cases with 20 false positives and only 1 false negative. This resulted in a PPV of 85% and sensitivity of 99% with an accuracy of 85%. The evaluative track alone identified 69 (sensitivity 62%) of MM cases and correctly excluded 19 negative cases, for an overall accuracy of 62%. The Brandenburg algorithm identified MM in 67 cases and excluded MM in 28 of the negative cases. It had only 1 false positive case but had 45 false negatives. This resulted in PPV of 99%, but a sensitivity of only 60% for an overall accuracy of 67%. Conclusions: We describe a novel approach to the identification of MM patients incorporating lab and pathology results with diagnostic codes to create a sensitive algorithm while maintaining high accuracy and PPV. Evaluating test results was inadequate, and incorporating diagnostic codes allowed for higher sensitivity. Further refinement to increase specificity while maintaining sensitivity is ongoing. Performance on a validation cohort will be presented at the meeting. By incorporating test results in a temporal framework, TDAP, we can associate temporally related events such as rise in M-spike and new end organ damage. Future directions are expansion of the algorithm to other institutions and automated assessment of MM disease status. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Hypercalcemia: A Risk Factor for Early Disease Progression and Poor Survival in Cytogenetically Standard-Risk Multiple Myeloma

Introduction The advent of novel therapies over the last decade, including proteasome inhibitors, immunomodulators, and monoclonal antibodies, has drastically improved the outcomes in patients with Multiple Myeloma (MM). It is common in both clinical practice and design of clinical trials to risk stratify patients to determine poor-prognosis based on known high-risk cytogenetics and baseline health status. Despite efforts to unify and refine the definition of high-risk disease, significant heterogeneity exists within risk strata and the majority of MM patients do not harbor high-risk cytogenetics. Many patients with ostensibly standard-risk disease progress rapidly, exhibiting a clinical presentation that aligns more closely with high-risk disease biology. We retrospectively evaluated outcomes within an institutional database to determine whether variation in prognosis among patients with standard risk MM may be predicted by clinical and biochemical features that are measurable at the point of care. Methods This retrospective cohort study included patients diagnosed with MM at the Cleveland Clinic in Cleveland, OH between 1/1/2008 - 12/31/2015 who had relapsed or died prior to initiation of the study. Patients with conventional high-risk cytogenetic features including: del(17p), t(4;14), t(14,20) or t(14;16) by fluorescence in situ hybridization (FISH) were excluded. Multiple variables at diagnosis were included in the analysis: race, gender, age, serum calcium (Ca), B-2-microglobulin, albumin, kidney function, hemoglobin, involved: uninvolved serum free light chain ratio, lactate dehydrogenase (LDH), serum monoclonal (M) protein, International Staging System (ISS) stage, Eastern Cooperative Oncology Group (ECOG) score, and the presence of extramedullary disease. Hypercalcemia (HCa) was defined using 3 groups - Group 1: Ca <10.0, Group 2: 10.1 - 12.5, and Group 3: > 12.5 mg/dL. Time to event analysis was conducted using the Kaplan Meier method. The impact of clinical and biochemical features at presentation on PFS and OS was quantified using a Cox Proportional Hazard on a univariate and multivariate basis in order to determine risk factors for early relapse among this cohort of patients with standard-risk cytogenetics. Results A total of 264 NDMM patients were screened for high-risk cytogenetics and the 18 patients excluded. An additional 99 patients were excluded from our analysis due unavailable FISH data at diagnosis. Twenty-one patients did not have serum calcium levels available at the time of diagnosis and were excluded, resulting in a study population of 126. Among these patients, the median age was 61.5 years old, 77.6% (n=97) of patients were Caucasian, and 47.6% (n=60) were male. The median time to follow up was 5.2 (2.9-7.0) years. A total of 13.6% had extramedullary disease (n=17) and 25.4% had a frontline autologous stem cell transplant (ASCT) (n=32). Stratification was conducted utilizing ISS stage: 34.4% Stage 1 (n=42), 31.1% (n-38) Stage II, and 34.4% (n=42) and ECOG score: 34.4% (n=42) Score 1, 38% (n=38) Score 2, and 42% (n=34.4) Score 3. The three hypercalcemia groups were similar with regard to demographics, ECOG, and laboratory data; however, ISS stage (23%, 47%, and 73%, p=0.002) and serum creatinine (median 0.96, 1.4, and 2.3 mg/dL, p=0.001) were positively correlated with calcium level at time of diagnosis. There was a statistically significant difference in 2-year PFS among the HCa groups (54.4%, 36.1%, and 9.1%, p = 0.002 and p <0.001, respectively) (Figure 1). There was also a statistically significant difference in OS among the HCa groups (Median OS years/5-year OS: 6.1/65.3%, 4.5/46.9%, 2.4/9.1%, p=0.032 and p <0.001, respectively) as well (Figure 2). Differences in PFS and OS remained significant after adjusting for age, race, ISS stage, extramedullary disease, ECOG. and frontline ASCT. Conclusion Our results showed that serum calcium level predicted disease progression and survival in a large cohort of patients without high-risk cytogenetic features. Variation in outcomes among MM patients who do not harbor high risk cytogenetics has not been fully explained. These results may help to inform clinical decision making, refine current risk stratification models, and identify a subpopulation with the strata of standard risk for correlative studies to evaluate disease genomics and biology. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Venetoclax-Targeted Therapy in t(11;14) AL Amyloidosis Patients after Frontline Daratumumab and Cybord: A Retrospective Analysis from the French Amyloidosis Network

Background: Systemic AL amyloidosis is caused by the deposition of misfolded monoclonal immunoglobulin serum free light chains (sFLC) in various organs. Treatment of AL amyloidosis relies mainly on chemotherapy aimed at suppressing the underlying secreting plasma cell clone. Organ responses and survival are greatly influenced by the degree of hematological response evaluated by the decrease in sFLC. Over the last 2 years, anti CD38 monoclonal antibodies (mAb), such as daratumumab (DARA), have emerged as breakthrough targeted therapies for patients (pts) with AL amyloidosis and DARA received approval in combination with CyBorD in frontline pts. Unfortunately, some pts will still not achieve complete response (CR) or ultimately relapse. BCL-2 inhibition represents a promising therapeutic approach in plasma cells dyscrasia and venetoclax (VEN) is an oral BCL-2-selective BH3 mimetic. VEN has shown activity in multiple myeloma (MM) cell lines with t(11;14), partly because of greater BCL-2 co-dependence of such clones. VEN is safe in MM pts with encouraging clinical efficacy. VEN should provide a novel targeted therapy in AL amyloidosis as 50-60% of the pts have a t(11;14). Various retrospective cohorts are now reported with VEN alone or in combination with bortezomib (BOR) and/or DARA, with rapid and deep hematological and organ responses. Objective: To report efficacy of VEN based regimen in AL amyloidosis pts as consolidation or relapsed therapy in frontline AL pts treated with DARA-CyBorD or equivalent. Material & Methods: In this retrospective study, we reviewed charts of 9 pts with AL amyloidosis, from the French Amyloidosis Network, who received VEN as part of their regimen as consolidation (n=3) or for biological progressive disease (n=6) after DARA-CyBorD frontline therapy. Individual data were prospectively and retrospectively collected in the French Amyloidosis database. Pts should have received at least 1 cycle of VEN-containing regimen to be analyzed. Responses were reviewed using current criteria for CR (serum and urine negative immunofixation and normal involved FLC) and for very good partial response (VGPR;differential FLC<40 mg/l). Results: Regarding baseline characteristics (Table 1), pts had a median age of 67 years (IQR:61-71) and all except one had more than 10% bone marrow plasma cells (but no overt MM). Six pts had ≥2 organs involved with heart in 67 % and kidney in 56 %; 6 had MAYO stage 3/4 and median NT-proBNP/troponin levels were 3333 ng/l (IQR:185-9685) and 44 pg/ml (IQR:18-96), respectively. Six pts had FLC only AL amyloidosis. Median dFLC for the whole cohort was 255 mg/l (IQR:140-1060), and 6 pts had baseline dFLC>180 mg/l. All pts had t(11;14) with an additional 11q gain in 3, and 1q gain in 1. Median time from diagnosis to VEN therapy was 6.0 months (IQR: 2.5-7.5). Regarding frontline therapy, 7 pts received DARA-CyborD (median 3 cycles), 1 DARA-CyBorD plus CAEL and 1 pt received DARA-RVD. All pts were DARA exposed, 8 pts had a suboptimal response to DARA and 2 were DARA "refractory". Five pts never reached VGPR or better with DARA-based regimen. VEN (400 mg/day) was given alone in 1 pt or in association with dexamethasone/DEXA (n=1), BOR (n=2), or DARA+BOR (n=5); Median time on therapy was 7.0 months (IQR:3.0-9.5). At data cut-off (06/2022), 6 pts had discontinued therapy because of CR (n=5) and/or GI tract toxicity (n=4). The hematologic response rate was 89%; 78% of pts achieved CR, and 11% partial response (PR) (Figure 1). Among CR pts, all pts achieved dFLC<10 mg/l, and 2 had an iFLC<10 mg/l. Responses were fast and median time to CR was 1 month (IQR:1-3). Regarding VEN monotherapy +/_ DEXA, 50% of pts reached CR; with the addition of BOR, or DARA+BOR, CR was 100, and 80%, respectively. In consolidation pts, all pts achieved CR in 1 month (1-3) with the addition of VEN to DARA-CyBorD. In progressive/relapsed pts, 4/6 (67%) achieved CR and 1 was in stable disease. One pt reached PR and progressed to end-stage renal disease. Finally, both DARA R/R pts reached CR with VEN alone or in association with BOR. Summary & Conclusion: Venetoclax is a promising targeted therapy in AL amyloidosis. Venetoclax can be used in combination with daratumumab and/or bortezomib as consolidation or relapsed therapy after frontline DARA-CyBorD, even in refractory patients, with expected good safety profile. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

T Cells Expressing a Fully-Human Anti-BCMA Chimeric Antigen Receptor with a Heavy-Chain-Only Antigen-Recognition Domain Exhibit Rapid and Durable Activity Against Multiple Myeloma

Chimeric antigen receptor (CAR)-expressing T cells targeting B-cell maturation antigen (BCMA) are effective multiple myeloma therapy, but improvement in durability of responses is needed. We incorporated a fully-human heavy-chain-only anti-BCMA binding domain (FHVH33) into a CAR. Since it is only a heavy chain domain with no linker or artificial junctions, FHVH33 should be less immunogenic than a scFv. The CAR containing FHVH33 is called FHVH33-CD8BBZ. FHVH33-CD8BBZ contains CD8α hinge and transmembrane domains, a 4-1BB domain, and a CD3ζ domain; it was encoded by a γ-retroviral vector (Lam et al. Nature Communications 2020). T cells expressing FHVH33-CD8BBZ (FHVH-T) were produced from unsorted blood mononuclear cells in 7 days. Twenty-five patients received 300 mg/m2 of cyclophosphamide and 30 mg/m2 of fludarabine on days -5 to -3 followed by infusion of FHVH-T on day 0. Five dose levels were assessed, and 6x106 CAR+ T cells/kg was selected for an expansion cohort based on efficacy and manufacturing factors (Table). Patients had received a median of 6 lines of therapy (range 3 to 10) prior to enrollment. Twenty-three of 25 patients (92%) obtained partial response (PR) or better. Eighteen patients (72%) attained best responses of stringent complete response (sCR) or very good partial response (VGPR). Median progression-free survival (PFS) of all treated patients is 65 weeks to date; eleven patients have ongoing responses. One striking feature of the anti-myeloma activity of FHVH-T was the rapidity of myeloma elimination. Some myeloma markers including serum free light chains, urine monoclonal light chains, and bone marrow plasma cells decrease rapidly after any type of effective therapy while intact immunoglobulin monoclonal proteins decrease slowly due to long serum half-lives, which are 20-25 days for most types of IgG. Following rapidly changing myeloma markers such as free light chains shows the actual tempo of myeloma elimination without the confounding factor of long serum half-lives of intact immunoglobulins. Among the 12 patients with rapidly changing main myeloma markers, most anti-myeloma activity occurred within the first month after FHVH-T infusion since myeloma markers underwent a 99-100% reduction in all 12 patients by 1 month after FHVH-T infusion. In 10/12 patients with rapidly changing main myeloma markers, a 99-100% decrease had occurred by 14 days after FHVH-T infusion. We assessed FHVH-33 T early after infusion during the time of most anti-myeloma activity. Blood CAR+ cell levels were assessed by quantitative PCR (qPCR). The median peak blood CAR+ cell number was 121 (range 3 to 3414) cells/μL. Peak CAR+ cell levels occurred a median of 12 (range 7 to 15) days after FHVH-T infusion. One month after infusion, the median blood CAR+ cell number was 11 (range 0 to 305) cells/μL. Median blood CAR+ cell levels one month after infusion were 20 cells/μL in patients with a PFS of 12 months or more versus 4 cells/μL in patients with PFS less than 12 months (P=0.0273). The CD4/CD8 ratio of CAR+ T cells decreased from the time of infusion until the time of peak blood CAR+ cells (P=0.0004). From the time of infusion until the time of peak blood CAR+ cells, there was an increase the percentage of T cells with an effector memory phenotype (C-C-chemokine receptor-7 (CCR7)-negative and CD45RA-negative), (P<0.001). Expression of CCR7 on infusion CD4+ FHVH-T correlated with peak CAR+ cell level (P=0.0018). Frequency of infusion CD4+ FHVH-T with a central memory phenotype (CCR7+, CD45RA-negative) correlated with peak and 1-month post-infusion CAR+ cell levels. Peak interferon (IFN)γ and interleukin (IL)-6 levels were associated with Grade 3 or 4 CRS (P=0.0034). Peak serum levels of IFNγ, IL2, IL6, IL8, IL10, and IL15 were higher (P<0.003 for all) in patients with neurologic toxicity. Single-cell RNA sequencing revealed extensive changes in FHVH-T gene expression between infusion and the time of peak blood CAR+ cell levels. Surprisingly, humoral immune responses against the fully-human CAR expressed by FHVH-T were detected in 4/12 evaluated patients after one FHVH-T infusion. In one patient who received 2 FHVH-T treatments, a humoral anti-CAR response was associated with lack of efficacy and absence of blood FHVH-T. FHVH-T therapy led to durable responses with most anti-myeloma activity occurring within 14 days after FHVH-T infusion. Blood levels of FHVH-T correlated with CD4+CCR7+ infusion cells. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Evidence Supporting Light Chain Cast Nephropathy As a Myeloma Defining Event

BACKGROUND In 2014, the International Myeloma Working Group (IMWG) revised the Renal involvement of the CRAB (hyperCalcemia, Renal, Anemia, Bone lesions) criteria for the diagnosis of multiple myeloma (MM) as an acute decline in kidney function represented by either a serum creatinine (Scr) > 2 mg/dl or an estimated glomerular filtration rate of < 40 ml/min/1.73 m2 secondary to light chain cast nephropathy (LCCN) biopsy proven or suspected. Since LCCN occurs only in patients with high serum free light chain (FLC) levels, a high tumor burden is presumed but how often it occurs with other myeloma defining events (MDE) is unknown. METHODS Patients were selected from 2 cohorts. The first cohort came from a multicenter study on LCCN who were all diagnosed with MM between 2000 and 2018. Only newly diagnosed patients were included in this study. A second cohort was identified from the Mayo Clinic Kidney Biopsy database from 2003 to 2013. Inclusion criteria of this cohort were: the LCCN must be the dominate pathology on the kidney biopsy and it is secondary to a plasma cell proliferative disorder. Laboratory and radiologic data were collected to assess for CRAB criteria. Bone lesions were assessed by standard skeletal X-ray, MRI or CT/PET. Most had skeletal X-ray. The new SLiM CRAB criteria which have the addition 3 biomarkers: (S) >60% bone marrow plasma cells, (Li) an involved to uninvolved free light chain (FLC) ratio > 100 and (M) >1 bone lesion on MRI were also assessed. RESULTS From the multicenter study, 28 patients were excluded for having relapsed MM and 27 were from Mayo who were included in the second cohort leaving 123 patients. In the Mayo cohort, 52 patients were identified who met criteria. Both cohorts were comparable in age, sex, bone marrow plasma cells and hemoglobin at diagnosis (Table 1). Interestingly, 3.3% of the multicenter cohort and 3.9% of the Mayo cohort did not meet the R criterion due to a presenting creatinine of ≤ 2.0 mg/dl. In the multicenter cohort 2/99 (2.0%) and 4/52 (7.7%) of the Mayo cohort had < 10% bone marrow plasma cells. The presenting involved FLC was higher in the multicenter group (p = 0.001). In the multicenter cohort, 99.1% met at least one of the SLiM criteria and 84.7% met one the C,A,B criteria. In the Mayo cohort, fewer patients met at least one of the SLiM criteria (86.5%, p < 0.001) but more patients met one or more of the C,A,B criteria (98.1%, p = 0.01). All but 1 patient from the multicenter cohort met one or more of the SliM C,A,B criteria. The most common SLiM criteria met in the multicenter cohort was Li while it was M in the Mayo cohort. The most common C,A,B criteria in the multicenter cohort was A while it was B in the Mayo cohort. DISCUSSION This study provides the first evidence that nearly all patients who present with biopsy proven LCCN have at least one other MDE. Bone marrow burden was met in 98.0% of the multicenter cohort where all patients were diagnosed with MM, 92.3% of the Mayo cohort where the diagnosis of MM was not a prerequisite. More importantly, 84.7% and 98.1% of patients from the 2 cohorts respectively had another MDE besides LCCN confirming that LCCN is associated with high tumor burden. All but 1 patient would have been diagnosed with MM based on the SLiM CRAB criteria. In comparison to patients with other kidney lesions associated with monoclonal immunoglobulin, generally only 20-30% met the CRAB criteria for MM. This is why it is more appropriate to classify those patients as having monoclonal gammopathy of renal significance while patients with LCCN should be diagnosed with MM. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal