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Abstract Abstract 1803 Poster Board I-829 Background Plasma cell proliferative disorders are monitored by a variety of methods. Serum protein electrophoresis (SPEP) and/or urine PEP M-spike quantitation are commonly assessed in patients with monoclonal gammopathy of undetermined significance (MGUS), smoldering multiple myeloma (SMM), and multiple myeloma (MM) to determine disease progression, response, or relapse. Serum immunoglobin (Ig) concentrations can be quantitated when the M-spike is large or if the migration is obscured within the SPEP beta fraction. Serum FLC quantitation provides a rapid indicator of response, will detect the rare occurrence of FLC escape, and will allow disease monitoring in the absence of a measurable serum or urine M-spike. The International Myeloma Working Group (IMWG) has recommended that the serum and urine M-spike should be used to monitor disease, and that FLC quantitation should be used only if there is no measurable disease by electrophoresis and if the monoclonal FLC concentration is greater than 10 mg/dL in the context of an abnormal FLC K/L ratio. We have studied serial samples in clinically stable patients in order to assess the total variability (analytic and biologic) of these assays and to confirm the IMWG recent recommendations. Methods Serial data from stable MGUS patients (n=35) were identified by the availability of all 3 serum test results (M-spike, Ig, FLC) in at least 4 serial samples that were obtained 9 months to 5 years apart and whose serum M-spikes varied by less than 25%. For MM (n=60) and SMM (n=48) the samples were within 9-15 months and serum M-spikes varied by less than 0.5 g/dL. Among the 60 MM, 48 SMM, and 35 MGUS patients, there were 23, 41, and 18 patients with measurable disease by serum M-spike (i.e. M-spike >1 g/dL); 19, 10, and 10 patients with an evaluable FLC (i.e. monoclonal FLC > 10 mg/dL and an abnormal FLC ratio); and 5, 5, and 1 patient with an evaluable urine (i.e. M-spike > 200mg/24 hr). The FLC data was analyzed as the involved FLC concentration (iFLC), the difference between the involved and uninvolved FLC concentration (dFLC), and the FLC K/L ratio (rFLC). The coefficients of variability (CV) were determined for each methodology in each patient sample set, and the average CVs were determined. Igs were quantitated by immunonephelometry using a Siemens BNII and Siemens reagent sets; kappa and lambda FLC were quantitated using a Siemens BNII and Freelite reagent sets from The Binding Site; M-spikes were quantitated using Helena SPIFE SPE and reagent sets. Results The CVs for the Ig quantitation, SPEP M-spike, FLC quantitation, and urine M-spike in each of the patient groups are listed in the table: Our laboratory's interassay analytic CV for replicate samples are 4-5% for Ig quantitation, 6-8% for SPEP M-spikes, 6-7% for FLC quantitation, and 5-7% for urine M-spikes. The analytic CVs of the methods are similar, but the total (analytic + biologic) CVs are very different. The samples have been selected by restricting the variability of serum M-spike values; when we apply the same criteria to the IgG quantitation, the IgG total CV comes closer to the serum M-spike CVs. The remaining differences, however, may be due to biologic variability contributed by polyclonal Ig. The total CV for iFLC is similar to the urine M-spike CV and suggests a previously unrecognized large biologic CV for serum FLC. The iFLC and dFLC CVs were comparable but were smaller than the rFLC CV. Conclusion The variability of the serum and urine M-spike, Ig, and FLC measurements confirm the IMWG recommendations for patient monitoring. If a patient has a measurable M-spike >1 g/dL, then the serum M-spike should be followed. If there is no measurable disease, then the iFLC can be monitored, provided that the rFLC is abnormal and the iFLC concentration is >10 mg/dL. Although the number of patients with evaluable urine M-spikes in this study is small, larger studies may confirm the utility of serum FLC compared to urine M-spike for monitoring patients with monoclonal gammopathies. Disclosures No relevant conflicts of interest to declare.

SummaryIbrutinib‐related data in Waldenström macroglobulinaemia (WM) remain sparse, particularly outside of trials. We report on 80 patients [previously treated, n = 67 (84%), treatment‐naïve, n = 13 (16%)] with WM, evaluated consecutively at Mayo Clinic, who received ibrutinib off‐study after its approval in 2015 for WM. Overall response rate (ORR) was 91%; major‐response rate (MRR) was 78%. The median time to first response and best response was 2·9 [95% confidence interval (CI): 2–4] and 5·7 (95% CI: 4–12) months, respectively. The median follow‐up was 19 (95% CI: 14–21) months; 18‐month progression‐free survival (PFS) was 82%. The median time on therapy was 12·5 (95% CI: 9·3–16·7) months, and the median duration‐of‐response was 32 (range: 23–32) months. Twenty‐five patients (31%) had discontinued therapy at last follow‐up (68% due to treatment‐related toxicities) and 18% of patients required dose reduction. Fatigue (12%) and atrial‐fibrillation (11%) were common non‐haematological toxicities. IgM rebound occurred in 36% of patients who abruptly discontinued ibrutinib. Following ibrutinib discontinuation, 84% of patients received subsequent treatment, achieving an ORR of 57% and MRR of 50%. The median PFS from commencement of subsequent salvage therapy was 18 months. Ibrutinib therapy, outside of clinical trials, is effective in WM, but is associated with toxicities and challenges, including IgM rebound and a high drug discontinuation rate for reasons other than disease progression.

Summary Improvement in survival in Light chain (AL) amyloidosis has been seen over recent decades, enabling more patients to achieve long‐term survival. Patients with AL amyloidosis who survived ≥10 years from time of diagnosis ( n = 186) were the subject of this study. Ten‐year survivors represented 22% of the total population. These patients were characterized by favourable patient, organ and plasma cell features. Of note, trisomies were less common among 10‐year survivors compared to those who did not survive to 10 years. All‐time best haematological response was complete response in 67%, very good partial response in 30%, partial response in 2% and no response in 1%, with 11% having received a consolidative strategy for inadequate response to first line therapy. The overall organ response rate to first‐line therapy was 76%, which increased to 86% when considering subsequent line(s) of therapy. Forty‐seven percent of the 10‐year survivors did not require a second‐line therapy. The median treatment‐free survival (TFS) among the 10‐year survivors was 10·5 years (interquartile range 7·4‐12·2). On multivariate analysis independent predictors for TFS were the achievement of complete haematological response and lack of cardiac involvement. Long‐term survivors are increasingly seen in AL amyloidosis and present distinct patient, organ and clonal disease features.

BackgroundThere exist insufficient data characterizing patients with multiple myeloma (MM) who experienced prolonged survival. A population‐based analysis of long‐term survivors was conducted to investigate the roles of sociodemographic factors and upfront stem cell transplantation (SCT).MethodsThe National Cancer Data Base is a US cancer database of approximately 34 million patients from >1500 cancer centers. Patients with MM were identified using the International Classification of Diseases for Oncology (ICD‐O) code 9732 from January 2004 to December 2006 and were divided into 4 groups based on overall survival (OS). Sociodemographic characteristics, treatment facility, and use of SCT were recorded. The univariate and multivariate analyses were performed using multiple logistic regression and Pearson chi‐square tests.ResultsA total of 26,986 patients with MM were identified. The median OS was 2.74 years. The majority of patients were male (54%), white (77%), insured (93%) and otherwise healthy (78%), lived in a metropolitan area (82%), were of high income (66%) and educational (58%) levels, and received treatment at nonacademic facilities (63%). Upfront SCT was used in 10% of patients. One in 6 patients (16%) were long‐term survivors (group 4). When comparing group 4 (OS of ≥8.22 years) with the other groups (OS of <8.22 years), young age, female sex, high income and educational levels, residence in a rural area, insured status, no comorbidity, receipt of upfront SCT, and treatment at high‐volume facilities were associated with long‐term survival.ConclusionsKey differences in sociodemographic characteristics, patient volume at treatment facilities, and upfront SCT were associated with long‐term survival. Improvements in health care access and health literacy, upfront SCT, and treatment at high‐volume facilities might prolong patient survival.

Abstract The high-risk abnormality del(17p) can be detected by fluorescence in situ hybridization on malignant plasma cells (PCs) and has an adverse prognostic impact in patients with multiple myeloma (MM). Patients with del(17p) have reduced overall survival (OS). Patients who acquire del(17p) later during the disease course are not well described. The disease characteristics at diagnosis predicting for acquired del(17p) and its overall impact on patient survival is not known. We compared 76 patients with MM who were negative for del(17p) at diagnosis and acquired it later with 152 control MM patients who did not acquire del(17p) at a comparable time point. Patients acquired del(17p) at a median of 35.6 months (range, 4.6-116.1 months) from diagnosis of MM after a median of 2 lines of therapy (range, 1-10 lines of therapy). When compared with controls, patients with acquired del(17p) had shorter median progression-free survival (PFS) (30.1 vs 23.0 months; P = .032) and OS (106.1 vs 68.2 months; P &lt; .001) from diagnosis. After the detection of del(17p), the median PFS was 5.4 months and the median OS was 18.1 months. High lactate dehydrogenase level (odds ratio [OR], 3.69; 95% confidence interval [CI], 1.11-12.24) and presence of t(4;14) (OR, 2.66; 95% CI, 1.09-6.48) or any high-risk translocation (OR, 2.23; 95% CI, 1.00-4.95) at diagnosis predicted acquisition of del(17p). High PC proliferative rate predicted shorter OS from detection of del(17p) (hazard ratio, 2.28; 95% CI, 1.31-3.96; P = .004). Our study shows that acquisition of del(17p) is an important molecular event associated with reduction in OS in MM. Certain baseline factors may predict acquisition of del(17p). This needs validation in prospective data sets.

Background:Previous literature has established “long‐term survivors” as patients who survive greater than 10 years from diagnosis of active multiple myeloma (MM). With the rapid discovery and evolving use of novel therapeutic agents, a greater proportion of patients are reaching this milestone. Although these patients share in their extended survival, they also constitute a heterogeneous group in terms of treatments and outcomes.Aims:The aim of this study is to examine a large cohort of long‐term survivors with protracted follow‐up as an attempt to identify a subset of patients within ten‐year survivors who have longstanding disease remission, and examine the predictors of their especially exceptional prognosis.Methods:All patients with active MM evaluated at Mayo Clinic, Rochester between January 1, 1999 and July 1, 2008 were included in the study. Patients with MGUS, smoldering MM, and solitary plasmacytoma were excluded. The overall survival (OS) was calculated from time of symptomatic disease requiring treatment. Patients with greater than 10 year survival from diagnosis were then divided into three cohorts based upon treatment and remission status: Cohort 1 included patients off therapy ≥ 5 years and in sustained remission, Cohort 2 included patients on maintenance therapy ≥ 5 years and in sustained remission, and Cohort 3 included patients who had relapsed within the past 5 years. Differences between the groups were compared using Wilcoxon, Chi‐square, and Fisher's exact test as applicable. “Early” stem cell transplant was defined as patients who received a stem cell transplant within one year of diagnosis.Results:During the time frame of the study, 2,125 patients were identified who fulfilled the diagnostic criteria for active MM. Three‐hundred ninety nine (19%) had survived at least 10 years from diagnosis. Among these patients, based on the available data regarding remission and ongoing treatment status, 332 patients were categorized into three cohorts, seen in Table 1. Sixty patients (18% of long‐term survivors) comprised Cohort 1, 48 patients (14% of long‐term survivors) comprised Cohort 2, and 224 patients (68% of long‐term survivors) comprised Cohort 3. Sex difference was statistically significant between the groups, with more females constituting Cohorts 1 and 2 (p = 0.03). Within Cohort 1, 77% of patients underwent an autologous stem cell transplant (ASCT). The median progression free survival following ASCT in this cohort was not reached (95% CI 15–NR, p < 0.001). In addition, patients in Cohort 1 and Cohort 2 were more likely to undergo an early ASCT as compared to patients in Cohort 3 (p = 0.002). There were no significant differences in high or intermediate risk FISH/cytogenetics at diagnosis, ISS at diagnosis, or induction therapies used at diagnosis among the three groups.Summary/Conclusion:Our study identified a small subset (3% of all patients diagnosed with active MM) of long‐term survivors who are off of therapy and remain in sustained longstanding remission. Female sex, progression free survival following ASCT, and receiving an early ASCT were factors that portended a positive prognosis amongst long term survivors.image