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Abstract Introduction: Immunoglobulin light chain (AL) amyloidosis is associated with significant morbidity and mortality. Several models were developed to allow survival prediction, but head-to-head model comparison is lacking. Patients and Methods: Five prognostic models were compared: Mayo 2004; Mayo 2012; 2013 European modification of Mayo 2004 (where Mayo 2004 stage 3 is subdivided into 3 subgroups based on NT-proBNP at 8500 ng/L and systolic blood pressure at 100 mmHg); 2015 European modification of Mayo 2004 (where Mayo 2004 stage 3 is subdivided into 2 subgroups based on NT-proBNP at 8500 ng/L); and organ model (a model based on number of involved organs). All patients with available baseline data for the 5 models were included in this study (n=1005). Improvements in predictive accuracy of the various models were determined by calculating a net improvement in survival prediction for each pair of prognostic models. Net improvement was considered as the proportion where model A outperforms model B minus the proportion where model B outperforms model A. Results: For all models, there was increasing risk for death with increasing stage. The organ model was the least powerful system with a hazard ratio of 2.8 for ≥4 organs compared to 1 involved organ. The organ model was consistently outperformed by the other 4 systems. In the cohort as a whole, the biomarker models (Mayo 2004; Mayo 2012; European 2013; European 2015) were comparable in ability to predict survival (Figure). However, a slightly superior performance of the European 2013 modification of the Mayo 2004 system was seen over the Mayo 2004 system in the group as a whole (net improvement 4.1%, P=0.023) and when restricted to non-ASCT population (net improvement 6.3% P=0.014). The European 2015 modification performed slightly better than the Mayo 2004 system in the ASCT population (net improvement 3.4%, P=0.025). 1-year mortality was better predicted by the European models (net improvement 11-14%, P<0.05), while the Mayo 2012 had better survival prediction to all other biomarker models in 3-year landmark comparison (net improvement 7-9%, P<0.05). Conclusion: Using biomarker based staging is a clear improvement over the organ staging system. The different biomarker staging systems' abilities to predict for survival were relatively comparable, solidifying the importance of soluble cardiac biomarkers and free light chain measurement as prognosticators in AL amyloidosis. Mayo 2004-based models better predict for early death while Mayo 2012 model has a better prediction for long-term survival. Figure. Figure. Disclosures Gertz: Ionis: Honoraria; celgene: Consultancy; spectrum: Consultancy, Honoraria; janssen: Consultancy; Amgen: Consultancy; Abbvie: Consultancy; Medscape: Consultancy; annexon: Consultancy; Teva: Consultancy; Research to Practice: Consultancy; Apellis: Consultancy; Alnylam: Honoraria; Prothena: Honoraria; Physicians Education Resource: Consultancy. Lacy:Celgene: Research Funding. Dingli:Millennium Takeda: Research Funding; Millennium Takeda: Research Funding; Alexion Pharmaceuticals, Inc.: Other: Participates in the International PNH Registry (for Mayo Clinic, Rochester) for Alexion Pharmaceuticals, Inc.; Alexion Pharmaceuticals, Inc.: Other: Participates in the International PNH Registry (for Mayo Clinic, Rochester) for Alexion Pharmaceuticals, Inc.. Kapoor:Celgene: Research Funding; Takeda: Research Funding. Russell:Vyriad: Equity Ownership. Kumar:Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; KITE: Membership on an entity's Board of Directors or advisory committees, Research Funding; AbbVie: Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding. Dispenzieri:Celgene, Takeda, Prothena, Jannsen, Pfizer, Alnylam, GSK: Research Funding.

Abstract Monoclonal gammopathies, including multiple myeloma (MM), represent a group of plasma cell (PC) disorders that comprise of mostly incurable hematopoietic malignancies with an increasing incidence in the US. Previous epidemiological studies demonstrated a 2-3 fold higher incidence of monoclonal gammopathy of undetermined significance (MGUS) and a similarly higher incidence of MM along with a ~4-year younger age of onset among African Americans (AA) compared to European Americans (EAs) (Fonseca, Leukemia, 2017). This suggests a possible ancestral-associated genetic predisposition of AAs to the development of monoclonal gammopathies (Landgren, Blood, 2006). When access to care is equal, AAs have a better overall survival compared to EAs suggesting that AAs may have a genetic predisposition that renders them better responders to treatment or have more favorable cytogenetic subtypes of MM (Waxman, Blood, 2010). Previous efforts to understand this disparity have relied on self-reported race rather than genetic ancestry. We hypothesize that quantifying genetic ancestry is necessary to fully understand the genetic mechanisms of racial disparities of monoclonal gammopathies. We describe our study of 881 patients with monoclonal gammopathies who had undergone uniform testing to identify MM-specific cytogenetic abnormalities. DNA from the bone marrow samples was genotyped on the Precision Medicine Research Array. Biogeographical ancestry was assessed using the Geographic Population Structure Origins tool, which provides the ancestral breakdown of 36 admixture components for each individual representing different geographic regions and outputs admixture proportions corresponding to those ancestries (Elhaik, Nat Commun, 2014). We evaluated whether an increase in the percentage of African Ancestry altered the odds of any primary cytogenetic abnormality. We demonstrated that a 10% increase in the percentage of African ancestry was associated with a 6% increase in the odds of detecting either an t(11;14), t(14;16) or t(14;20) (odds ratio = 1.06, 95% CI: 1.02 - 1.11; p-value = 0.05). Although we observed an increase in the odds of each of the individual translocations with 10% increase in African ancestry, l t(11;14) (OR=1.03) t(14;16) (OR=1.11) and t(14;20) (OR=1.10), these three abnormalities were combined to achieve greater statistical power. The differences in cytogenetic abnormalities were most striking among individuals with ≥80.0% African (n=120) compared to individuals with <0.1% African ancestry (n=235). Using these cutoff values comparing the ≥80.0% and <0.1% African ancestry cohorts, there was a higher prevalence of t(11;14), t(14;16) and t(14;20) (51% vs. 33%, respectively, p-value=0.008) and a lower prevalence of trisomies (with or without IgH translocations) (48.3% vs. 61.3%, respectively, p-value=0.066). In addition, the ≥80% African ancestry cohort also displayed a slightly lower prevalence of monosomy 13/13q deletion compared to the cohort with <0.1% African ancestry (34.2% vs. 38.7%, respectively, p-value=0.021). Further, we observed a significantly higher prevalence in the proportion of females with monoclonal gammopathies among the ≥80% African ancestry cohort compared to the cohort with <0.1% African ancestry (56.7% vs. 42.1%, respectively, p-value=0.028). We complement our past studies that relied on self-reported race and characterized patients' demographic and uniformly collected cytogenetic data in relation to genetically defined African ancestry. We demonstrate the prevalence of having one of three specific subtypes (i.e., t(11;14), t(14;16), or t(14;20)) was significantly higher in those with highest (≥80%) compared to lowest (<0.1%) African ancestry demonstrating African ancestry is associated with a subtype distribution of MM that differs from non-African individuals. These differences were only revealed after analysis of individuals with the highest and lowest percentage of African ancestry. Since 38.3% of the individuals with ≥80% African ancestry have the favorable t(11;14) translocation (in comparison to 26.8% of <0.1% African individuals), this finding may explain improved survival with equal access to care. Understanding the genetic mechanisms of this disparity is a fundamental step to understanding differences in incidence and outcomes of patients with monoclonal gammopathies. Disclosures Elhaik: DNA Diagnostics Center: Consultancy. Baird:DNA Diagnostics Center: Employment. Cerhan:Jannsen: Other: Scientific Advisory Board; Nanostring: Research Funding; Celgene: Research Funding. Stewart:Amgen Inc., BMS, Celgene, Takeda, Roche, Seattle Genetics, Janssen, Ono: Consultancy; Amgen Inc., Celgene, Roche, Seattle Genetics: Research Funding. Dispenzieri:Celgene, Takeda, Prothena, Jannsen, Pfizer, Alnylam, GSK: Research Funding. Kumar:Novartis: Research Funding; KITE: Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding; Takeda: Membership on an entity's Board of Directors or advisory committees; AbbVie: 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; Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding; KITE: Membership on an entity's Board of Directors or advisory committees, Research Funding; Merck: 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; Oncopeptides: Membership on an entity's Board of Directors or advisory committees; AbbVie: Membership on an entity's Board of Directors or advisory committees, Research Funding; Roche: Research Funding.

AbstractThe median survival in primary systemic (AL) amyloidosis is less than 18 months. No published series of patients with AL amyloidosis have reported survival of more than 10 years. The records of all Mayo Clinic patients with a diagnosis of AL amyloidosis between January 1, 1966 and March 1, 1987 were reviewed. Patients with secondary amyloidosis, familial amyloidosis, senile systemic amyloidosis, and localized amyloidosis were excluded. During the 21 years of the study, 841 patients with AL amyloidosis were seen. Of these, 29 were excluded because the diagnosis was made at autopsy, and 2 others were excluded because no follow-up data were available. Actuarial survival for the 810 patients was 51% at 1 year, 16% at 5 years, and 4.7% at 10 years. Thirty patients survived for 10 years or more after the histologic diagnosis of AL amyloidosis; all received alkylating-agent therapy. In 14 patients, the monoclonal protein disappeared from the serum or urine. Of 10 patients with nephrotic syndrome, 4 had an objective response. Congestive heart failure, older age, creatinine value of 2 mg/dL or more, bone marrow plasma cell value of 20% or more, platelet count of 500 × 109/L or less, and the presence of peripheral neuropathy were underrepresented in the 10-year survivors and are unfavorable prognostic features. Five percent of patients with AL amyloidosis survived for 10 years or more.

Abstract Background: Monoclonal gammopathy of undetermined significance (MGUS) affects 3% of persons age 50 yrs or greater. Reliable predictors of progression of MGUS to myeloma or related malignancy are needed. We hypothesized that the presence of monoclonal unbound (free) kappa or lambda immunoglobulin light chains in MGUS, as detected by an abnormal serum kappa/lambda free light chain (FLC) ratio would indicate clonal evolution in the neoplastic plasma cell and increase risk of progression to malignancy. Methods: Patients (pts) from Southeastern Minnesota with MGUS seen at the Mayo Clinic from Jan 1, 1960 through Dec 31, 1994 who had baseline serum samples collected and stored at the time MGUS was first recognized were studied. Free kappa and lambda chains were measured using the serum FLC assay (FREELITETM, The Binding Site Ltd). Results: Of 1384 pts with MGUS during the defined time period, baseline serum samples obtained within 30 days of diagnosis of MGUS were available in 1148 pts. At a median follow-up of 15 yrs, malignant progression has occurred in 87 (7.6%) pts: myeloma (53 pts), IgM lymphoma (17), primary amyloidosis (6), macroglobulinemia (6), chronic lymphocytic leukemia (3) and plasmacytoma (2). An abnormal kappa/lamda FLC ratio (kappa/lambda ratio <0.26 or >1.65) indicating presence of monoclonal FLC was detected in 379 (33%) pts. In a Cox proportional hazards model, the risk of progression in pts with an abnormal kappa/lamda FLC ratio was significantly higher (hazard ratio 3.5, 95% CI 2.3–5.5; p<0.001) compared to pts with a normal ratio. After adjusting for the size of the serum monoclonal (M) protein by multivariate analysis, the hazard ratio was only slightly reduced to 2.8, p<0.001. The risk of progression to myeloma or related malignancy at 10 years was 17% with an abnormal kappa/lambda FLC ratio versus 5% with a normal ratio; corresponding rates at 20 years were 35%, and 13%, respectively. MGUS pts with both an abnormal serum FLC ratio and high serum M protein had a risk of progression at 20 years of 46% (high-risk), versus 26% with one of two risk factors (intermediate-risk) and 7% with no risk factors (low-risk) (Table). The true life-time (28 year) risk of myeloma or related malignancy in the low-risk group was only 5.3% when other competing causes of death were taken into account. Conclusions: Presence of monoclonal FLC in the serum as detected by an abnormal kappa/lamda FLC ratio is a major independent risk factor for progression of MGUS to myeloma or a related malignancy. The new risk-stratification identifies a low-risk subset with a remarkably small life-time risk of progression, a finding of significant importance for the management of MGUS. Risk-stratification of MGUS using the size of the serum M spike and free light chain ratio Risk Group No. of patients Hazard ratio Absolute risk of progression at 20 years Low-risk (Serum M protein <1.5 gm/dL and normal FLC ratio [0.26–1.65]) 606 1 7% Intermediate-risk (Either risk factor present) 373 3.5 26% High-risk (Serum M protein >/=1.5 gm/dL and abnormal FLC ratio [<0.26 or >1.65]) 169 6.8 46%

Abstract Malignant plasma cells characteristically home to the bone marrow (BM). However, the mechanisms by which cells are recruited into and mobilized from the bone marrow into the peripheral blood (PB) are not well understood. In this study, we explore the molecular mechanisms involved in homing and migration of plasma cells in response to CXCR4 and investigated the role of the PI3K pathway in migration of MM cells in response to SDF-1. CXCR4 surface expression was determined by FACS analysis (PE CXCR4, Pharmingen) using samples from bone marrow and peripheral blood of patients diagnosed with multiple myeloma (MM), monoclonal gammopathy of undetermined significance (MGUS) and primary systemic amyloidosis (AL). All results were expressed as percent expression in gated CD38+ and CD45+ cells. Boyden chamber in vitro migration assays were performed using Kas6/1MM cells. In addition, live confocal microscopy was used to visualize changes in the subcellular location of YFP-fluorescent CXCR4 before and after SDF-1 stimulation. Cells were pretreated with 10mM LY294002 or 200nM rapamycin to assess the effect of inhibition of PI3K or mTOR on CXCR4 subcellular localization. Immunoblotting was performed to confirm inhibition of the PI3K pathway. Comparisons between groups was performed using Mann-Whitney testing. The median CXCR4 expression is described in table 1. There was a significant difference between expression of BM CXCR4 in MM and MGUS (p=0.02). SDF-1 induced dose dependent migration of Kas 6/1 cells indicating a functional CXCR4 receptor. MM cells transfected with YFP-CXCR4 demonstrated surface localization on the cells. 3-Dimensional and continuous live imaging after SDF-1 stimulation for 30 minutes demonstrated alterations in the CXCR4-YFP leading to its capping, internalization subcellularly, and production of pseudopodia in response to SDF-1. This process was abrogated with pretreatment with LY294002 and rapamycin. These data demonstrate for the first time that the surface expression of CXCR4 is markedly elevated in the peripheral blood as compared to the bone marrow. Once in the bone marrow, and with the presence of excess SDF-1, the receptor becomes internalized and downregulated. In contrast to MM, CXCR4 expression on plasma cells in the bone marrow of normal and MGUS patients was higher. In addition, we demonstrate that the process of CXCR4 subcellular localization is abrogated by the administration of PI3K inhibitors LY294002 and rapamycin. These data suggest that CXCR4 expression is required for MM cells to circulate, and that downregulation occurs in the BM leading to immobilization of the cells. Future clinical trials using CXCR4 inhibitors, or inhibitors of PI3K and mTOR to prevent the homing and migration of MM cells into the bone marrow may be explored. This was supported in part by CAP50 CA97274. CXCR4 expression N=45 Median CXCR4% expression of total plasma cells Range MM BM (n=23) 27 4.3–90.1 MM PB (n=5) 91 60–95.5 MGUS BM (n=6) 65 41–78.6 AL BM (n=7) 46 17.5–71.6 Normal BM (n=4) 59 6.3–69.5 Kas6/1 cell line 100 -

Abstract Chronic Idiopathic Bence Jones Proteinuria (first reported in 1982) is an asymptomatic plasma cell proliferative disorder that is associated with a risk of progression to symptomatic multiple myeloma (MM) or primary amyloidosis (AL). We defined it as the presence of a monoclonal light chain in the urine, absence of an intact immunoglobulin M protein (IgH expression) in the serum, fewer than 10% bone marrow plasma cells (if done), and no evidence of MM, AL or other related plasma cell proliferative disorders. Following approval by the Mayo Clinic Institutional Review Board, we searched a computerized database and reviewed the records of all patients who were seen at Mayo Clinic within 30 days of the recognition of a monoclonal light chain (Bence Jones protein) in the urine between 1960 and 1996. Patients found to have end-organ damage at diagnosis as the result of the plasma cell proliferative disorder (including MM or AL), received chemotherapy, or had a nephrotic syndrome were excluded. Follow-up included review of each subject’s medical record at Mayo Clinic as well as review of death certificates for patients who died. Patients were sent letters of inquiry if they had not visited Mayo Clinic in the preceding year. The risk of progression to MM and AL was compared to those expected on the basis of Surveillance, Epidemiology and End Results (SEER) rates for MM in Iowa and the prevalence of AL in Olmsted County, Minnesota. Two-hundred twenty-three patients fulfilled the criteria for Idiopathic Bence Jones Proteinuria during the 37-year period (1960 – 1996). The median age at diagnosis was 69 yrs (range, 36–90 yrs) and only 1% were < 40 years of age. Sixty-seven percent were male. The urine M protein ranged from unmeasurable to 4.7 g/24h. The median was 0.09 g/24h and only 8% were > 1 g/24h. Kappa light chain accounted for 57% while lambda was present in 43%. Eighty-one percent of patients died during follow-up. Twenty-six percent had a monoclonal light chain in the serum on immunofixation. Concentrations of uninvolved (normal, polyclonal or background) immunoglobulins were reduced in 45%. During 1408 person years of follow-up, 11 patients developed symptomatic MM (relative risk 28.5; 95% CI, 14.3 – 51.1) and an additional 9 patients developed AL (relative risk 61.8; 95% CI, 28.3 – 117.4). The cumulative probability of progression to active MM or AL was 7% at 5 yrs, 13.5% at 10 yrs., and 18% at 15 yrs. The factors evaluated with respect to predicting progression to MM or AL included sex, hemoglobin value, serum albumin, amount of urine M protein/24h, type of urine light chain (kappa or lambda), reduction of uninvolved (background) immunoglobulins, and elevation of serum calcium or creatinine. The amount of the urine M protein/24h was the only significantly predictive parameter for progression. As a continuous variable, a higher urine M protein was associated with an increased risk of progression (hazard ratio = 2.1 for a 1g increase, p=0.003). The amount of the urine M protein was also significant as a dichotomous variable. Patients who had a urine M protein ≥ 1g/24h had an increased risk of progression (hazard ratio = 3.6, p=0.007). We conclude that patients with Idiopathic Bence Jones Proteinuria are at risk for the development of MM or AL and need to be followed indefinitely.

The median survival in primary systemic (AL) amyloidosis is less than 18 months. No published series of patients with AL amyloidosis have reported survival of more than 10 years. The records of all Mayo Clinic patients with a diagnosis of AL amyloidosis between January 1, 1966 and March 1, 1987 were reviewed. Patients with secondary amyloidosis, familial amyloidosis, senile systemic amyloidosis, and localized amyloidosis were excluded. During the 21 years of the study, 841 patients with AL amyloidosis were seen. Of these, 29 were excluded because the diagnosis was made at autopsy, and 2 others were excluded because no follow-up data were available. Actuarial survival for the 810 patients was 51% at 1 year, 16% at 5 years, and 4.7% at 10 years. Thirty patients survived for 10 years or more after the histologic diagnosis of AL amyloidosis; all received alkylating-agent therapy. In 14 patients, the monoclonal protein disappeared from the serum or urine. Of 10 patients with nephrotic syndrome, 4 had an objective response. Congestive heart failure, older age, creatinine value of 2 mg/dL or more, bone marrow plasma cell value of 20% or more, platelet count of 500 × 109/L or less, and the presence of peripheral neuropathy were underrepresented in the 10-year survivors and are unfavorable prognostic features. Five percent of patients with AL amyloidosis survived for 10 years or more.

Abstract Abstract 1861 Idiopathic Bence Jones Proteinuria (Smoldering Monoclonal Light-Chain Proteinuria), first reported in 1982, is an asymptomatic plasma cell proliferative disorder associated with an elevated risk of progression to symptomatic MM or amyloidosis (AL). We defined it as the presence of a monoclonal light chain in the urine ≥200 mg/24h, absence of an intact immunoglobulin M protein (IGH expression) in the serum and no evidence of MM, AL or other related plasma cell proliferative disorders. Following approval by our Institutional Review Board, we searched a computerized database and reviewed the records of all patients seen at Mayo Clinic within 30 days of the recognition of a monoclonal light chain (Bence Jones protein) in the urine from January 1, 1960 through June 30, 2004. Patients with end-organ damage at diagnosis resulting from the plasma cell proliferative disorder (including MM or AL), or who had received chemotherapy or had a nephrotic syndrome were excluded. Follow-up included review of each patient's medical record at Mayo Clinic, as well as review of death certificates for patients who died. Patients were sent letters of inquiry if they had not visited Mayo Clinic in the preceding year. The risks of progression to MM and AL were compared to those expected on the basis of Surveillance, Epidemiology and End Results (SEER) rates for MM in Iowa and the incidence of AL in Olmsted County, Minnesota. One-hundred and one patients fulfilled the criteria for diagnosis during the 44-year period (1960–2004). The median age at diagnosis was 67 years (range 18–90 years), and only 2% were < 40 years old. Seventy-three percent were male. The urine M protein ranged from 200 mg/24h to 4.7 g/24h (median value, 500 mg/24h); 29% had > 1 g/24h. Kappa light chain accounted for 50% while the remaining 50% were lambda. Fifty-seven (56%) had a monoclonal light chain in the serum on immunofixation. Concentrations of uninvolved (normal, polyclonal or background) immunoglobulins were reduced in 62%. Eighty-eight percent of patients died during follow-up. During 900 person years of follow-up, 29 patients developed symptomatic MM (relative risk, 140.3; 95% CI, 93.9–201.5) and an additional 9 patients developed AL (relative risk, 104.4; 95% CI, 47.8–198.4). Four patients had both multiple myeloma and AL amyloidosis. The cumulative probability of progression to active MM or AL was 19% at 5 years, 31% at 10 years and 42% at 15 years. The factors associated with progression to MM or AL included size of urine M protein, percentage of bone marrow plasma cells, serum free light chain ratio < 1/100 or > 100, serum creatinine and reduction of all 3 uninvolved immunoglobulins. We conclude that patients with Idiopathic Bence Jones Proteinuria (Smoldering Monoclonal Light-Chain Proteinuria) are at risk for the development of MM or AL and must be followed indefinitely. Disclosures: No relevant conflicts of interest to declare.