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Abstract Background Prior studies have shown that presence of increased circulating plasma cell (PCs) identified using a slide-based immunofluorescence method is an adverse prognostic marker for overall survival in multiple myeloma (MM), and increases the risk of progression in patients with MGUS and smoldering MM. However, utility in clinical settings has been limited by the cumbersome nature of the test and lack of widespread availability. We studied the prognostic value of circulating PCs using sensitive multiparametric flow cytometry that enable us to quantitatively assess circulating PCs in patients with MM. Methods We evaluated all newly diagnosed MM patients seen at the Mayo Clinic, Rochester from 2009 to 2011 who had their peripheral blood samples evaluated by flow cytometry prior to therapy. Patients with plasma cell leukemia were excluded. Each blood sample had its peripheral blood mononuclear cells isolated by ficoll gradient and stained with antibodies to CD45, CD19, CD38, CD138 and cytoplasmic Kappa and Lambda Ig light chains. A six-color multi-parameter flow cytometer (Becton Dickinson FacsCantos II) was used to examine each sample with a target of detecting 150,000 events (cells) that was then analyzed using the Facs Diva Software. PCs were selectively analyzed through combinatorial gating using light scatter properties and CD38, CD138, CD19, and CD45. Normal PC's were then separated from clonal PCs based on the differential expression of CD45, CD19 and polytypic Ig light chains. The clonal PCs detected were reported out as the number of clonal events/150,000 collected total events. For those samples where less than 150,000 events were gated or examined, the number of final clonal events was adjusted to 150,000 events. Survival analysis was performed by the Kaplan-Meier method and differences assessed using the log rank test. Results There were 158 consecutive patients with newly diagnosed MM who had their peripheral blood evaluated via flow cytometry as part of their routine clinical evaluation. The median age of this group was 66 years (39-95) and 59% were male. At the time of this analysis, 25 patients had died and the 2-year OS rate for the cohort was 83%. The 2-year OS for the 89 (55%) patients with any circulating PCs was 76% compared with 91% for those with none (P=0.02). The median number of circulating clonal PCs was 33 (range, 0-46,413)/ 150,000 gated events. Using a ROC analysis the best cutoff predicting 1 and 2-year mortality were 435 and 376 events, respectively. Based on this, we defined >=400 events as a cutoff for defining patients with high-risk disease. The median time-to-next-treatment (TTNT) for patients with circulating clonal PCs >=400 (n=37, 23%) was 14 months compared with 26 months for those with <400 events (n=121, 77%) (p<0.001; Fig 1a). The median OS for those with >=400 clonal PC events was 32 months compared with not reached for those with <400 events (p<0.001; Fig 1b). Patients with >= 400 circulating PCs had higher ISS stage, creatinine, LDH, PC labeling index and bone marrow PC% compared with the rest. In a univariate analysis examining the presence of circulating PC >=400, LDH, labeling index, marrow PC% and FISH risk status, only circulating PCs were prognostic for overall survival (P = 0.0011). Among the 89 patients with any circulating PCs, 26 (30%) had CD45+ clonal PCs. The TTNT in patients with a clonal CD45+ population was inferior to those with no CD45+ clonal PCs in circulation (median 11 vs. 19 months, P = 0.034) as was the OS (P = 0.039). Conclusion Quantitative estimation of circulating clonal PCs in patients with newly diagnosed MM is a powerful predictor of early relapse from therapy and mortality. A cutoff of >=400 clonal events/150,000 gated mononuclear events predicts for a median TTNT of 14 months and OS of 32 months. This parameter is more powerful than the current high-risk parameters such as FISH risk status as well as traditional high-risk markers such as ISS stage and LDH levels, and is able to identify a group of patients with particularly poor outcome. Disclosures: Kumar: Celgene: Consultancy, Research Funding; Millennium: Consultancy, Research Funding; Onyx: Consultancy, Research Funding.

Abstract Abstract 3047 Background: There is concern about the increased incidence of extramedullary plasmacytomas among patients with multiple myeloma (MM) in recent years (Varettoni et al Annals of Oncology 21: 325–330, 2010). There is controversy about whether novel agents increase the risk of extramedullary disease (EMD). EMD may be associated with decreased overall survival in MM. The purpose of this study was to determine the incidence of true, treatment-emergent EMD in MM among a cohort of patients who have been previously exposed to novel agent (thalidomide, lenalidomide, or bortezomib) therapy, and to evaluate the activity of pomalidomide in patients with EMD. Methods: We examined 174 consecutive patients with relapsed refractory multiple myeloma that were enrolled on a phase II clinical trial of pomalidomide plus low-dose dexamethasone. The study cohort was chosen since all patients had previously been exposed to novel agents, and were followed systematically. We adopted a strict definition of EMD which required that in order to be considered extramedullary, plasmacytomas must not have risen from any bone. Thus, masses arising from the bone with a soft tissue component were not considered extramedullary. Results: Of 174 patients studied, 16 patients (9.2%) had EMD prior to enrollment. In 3 of the 16 patients, EMD was present at time of diagnosis and was therefore not considered as treatment-emergent disease for this analysis. In 13 of 174 patients (7.5%) EMD developed during the course of MM, after starting therapy. All 13 patients by inclusion criteria were exposed to novel agents prior to the onset of EMD, including 100% to immunomodulatory agents (thalidomide or lenalidomide); and 78% (10 patients) were exposed to bortezomib prior to developing EMD. The median number of lines of prior therapy in these patients was 6, range 1–12). EMD occurred a median of 48 months following diagnosis (range, 16–183 months); the rate of EMD in the first 3 years following diagnosis of MM was 3%. Since all patients had prior exposure to immunomodulatory agents in this cohort, we were able to calculate the median length of time from initiation of immunomodulatory agents to onset of EMD as 24 months (range 7–119 months). The EMD sites involved included the temporal area soft tissue (3), muscle (3 [1 pt with 10 different areas of involvement, 1 pt with 5 muscles involved]), chest wall not attached to bone (3), abdominal/pelvic masses (3), kidney (2), scrotum (2), sinus (1), paraspinal (1), hilar/pleural based (1), paraesophageal (1), subcutaneous tissue (1), pancreas (1), spleen (1), mediastinum (1), pleural fluid (1), liver (1). Per protocol, all patients received pomalidomide (2-4 mg per day) and low dose dexamethasone (40 mg once a week). Of the 13 patients, there were 2 CR (with complete disappearance of EMD), 2 PR, 2 stable disease, 3 with progressive disease, and 4 patients who did not have their EMD re-evaluated. Thirty percent (n=4) of patients had a 50% or greater reduction in size of the EMD including one patient who received concomitant radiation. Overall survival from measured from trial entry was significantly shorter for patients who presented with EMD compared to those who did not have EMD, median 16 months versus not reached, p=0.002 (log-rank). Conclusion: We found that 7.5% of patients with relapsed refractory myeloma in the era of novel agents develop EMD during the course of their myeloma, including 3% within 3 years of diagnosis. The underlying reasons for the possible increased incidence of EMD may include better radiographic detection (the role of PET/CT scans and MRI), improved overall survival of patients in recent years, and the possibility that novel agents may increase the risk for strictly defined, true EMD among patients who did not have EMD at time of initial MM diagnosis. These need further study. Disclosures: Dispenzieri: Celgene: Honoraria, Research Funding; Binding Site: Honoraria. Gertz:Celgene: Honoraria; Millennium: Honoraria, Membership on an entity's Board of Directors or advisory committees. Kumar:Celgene: Consultancy, Research Funding; Millennium: Research Funding; Merck: Consultancy, Research Funding; Novartis: Research Funding; Genzyme: Consultancy, Research Funding; Cephalon: Research Funding.

Abstract Abstract 2797 Poster Board II-773 Background: Primary systemic amyloidosis (AL) is characterized by deposition of light chain derived amyloid fibrils in multiple organs leading to varying degree of dysfunction. Cardiac involvement is a common feature of AL, and when significant is highly predictive of poor outcome. The currently used prognostic classification is based on cardiac biomarkers troponin-T (cTnT) and N-terminal pro B-type Natriuretic peptide (NT-ProBNP) and is effective at predicting outcome in patients with AL. However, this is driven primarily by the degree of cardiac involvement and does not take into account the degree of plasma cell burden and its impact on the disease course. It is possible that some of the heterogeneity in outcome can be explained by the plasma cell characteristics rather than the degree of the end organ damage. Methods: We examined the baseline clinical and laboratory data from 2119 patients with AL who were seen at our institution with in 90 days of their diagnosis. The data were collected from a prospectively maintained data base, and additional testing was done for free light chain levels (FLC) on stored sera from patients seen before the routine introduction of FLC testing. Cox proportional hazards analysis was performed to estimate the prognostic values of different variables. Results: We first examined the impact of plasma cell clone related characteristics namely, difference between involved and uninvolved FLC (FLC-Diff), bone marrow plasma cell (BMPC) %, plasma cell labeling index (PCLI), beta 2 microglobulin (B2M), and presence of circulating plasma cells, on overall survival (OS) from diagnosis. All variables were dichotomized into high and low based on their median value (FLC-diff: 20 mg/dL, BMPC: 10%, PCLI as a continuous variable, B2M: 3 mg/dL and circulating cells: absent or present). While all were found to be prognostic for OS in univariate analysis; in a multivariate analysis incorporating a stepwise selection only B2M and FLC-diff were significant. We then used these two variables along with the cTnT and NT-ProBNP that are used in the current model to develop a staging system. The median values for all four variables were used for developing the scores. Patients were assigned a score of 1 for presence of each characteristic (FLC difference > 20 mg/dL, troponin-T > 0.02, NT-ProBNP > 1000, and B2M > 3) or 0 if the value was at or below the cutoff. The scores were added to obtain a composite prognostic score that grouped the 370 patients (who had all the variables available for analysis) into 5 groups with very different OS (4.4, 9.3, 24.4, 43, and not reached for stages 4, 3, 2, 1, and 0 respectively; Figure A). However, since the NT-ProBNP did not have independent impact on survival in a multivariable model incorporating all the four variables, we also examined a system that only included FLC-diff, cTnT and B2M. This system again allowed grouping of patients (n=450 with all three variables available) into four distinct groups with divergent outcome with OS of 4.6, 10.5, 36.8, and not reached for stages 3, 2, 1, and 0 respectively; (Figure B). Conclusion: Incorporation of plasma cell related measurements into the existing staging system using cardiac biomarkers allows better risk stratification of patients with AL amyloidosis. The system using FLC, B2M and troponin has the advantage of easily available laboratory values and can be widely adopted. Addition of NT-ProBNP into the system allows better refinement of the intermediate risk groups. This system will allow upfront risk stratification and development of risk-adapted therapies for patients with AL. Disclosures: Gertz: Genzyme: Research Funding.

Abstract Abstract 3014 Background: Proteasome inhibitors have proven particularly effective in treatment of multiple myeloma, the second most frequent hematologic malignancy in the western world. Bortezomib, the first in class proteasome inhibitor in clinical use, was first approved in 2003 via fast FDA track, given the remarkable activity shown during phase II clinical trials. Nevertheless, more than 50% of multiple myeloma patients did not respond to single agent bortezomib when administered as second line agent. Moreover, bortezomib is only available for intravenous administration, representing a cumbersome therapy for patients, and its use is limited by significant toxicities (especially peripheral neuropathy). MLN9708 (Millennium Pharmaceuticals, Inc.), an investigational orally available, small molecule, is a potent, specific and reversible inhibitor of the 20S proteasome. It is currently under clinical investigation for the treatment of hematologic and non-hematologic malignancies. Upon exposure to aqueous solutions or plasma, MLN9708 rapidly hydrolyzes to MLN2238, the biologically active form, and MLN2238 was used for all of the preclinical studies reported here. In vitro biochemistry studies have shown that MLN2238 has a faster dissociation rate from the proteasome compared to bortezomib, and in vivo studies of MLN2238 have shown antitumor activity in a broader range of tumor xenografts when compared to bortezomib. Given these encouraging preclinical results, we set to investigate the anti-myeloma activity of MLN2238 in vitro. Results: MLN2238 proved to have anti-proliferative and pro-apoptotic activity against a broad range of MM cell lines with EC50 at 24 hours ranging between 10 and 50 nM, even in relatively resistant MM cell lines (OPM2, DOX6, RPMI, etc.). In MM.1S cells, induction of apoptosis was time and dose dependent and related to activation of both caspase 8 and 9. When compared to MM.1S treated for 24 hours with EC50 dose of bortezomib, treatment with EC50 dose of MLN2238 resulted in the same extent of caspases cleavage occurring at an earlier time point (8-12 hours), possibly suggesting more rapid onset and/or irreversibility of apoptosis in cells treated with MLN2238. Treatment with MLN2238 was associated with early, but persistent induction of endoplasmic reticulum (ER) stress with BiP being induced 2–4 hours after treatment with EC50 dose and gradually increasing over time. While bortezomib has been associated with early induction and late decrease in proteins involved in ER stress, MLN2238 appears to induce a persistent rise in these factors, suggesting either more sustained proteasome blockade with stabilization of proteasome substrates or de-novo induction of unfolded protein response (UPR) genes. MLN2238 also proved effective in reducing phosphorylation of ERK1-2 with no overall alteration in the total ERK level, thus accounting for the observed reduction in proliferation upon treatment. Preliminary data indicate potential for additive and synergistic combination with widely used drugs, including doxorubicin and dexamethasone. Conclusion: While further clinical data are needed to establish the effectiveness of MLN2238 in the treatment of multiple myeloma, these preliminary nonclinical data, together with the favorable biochemical and pharmacokinetic properties, including oral bioavailability, make the investigational agent MLN9708 an appealing candidate for treatment of multiple myeloma. Further in vitro data could help establish whether a difference in the apoptotic mechanisms exist between MLN2238 and other proteasome inhibitors, primarily bortezomib, and could also help inform combination treatment approaches aimed at increasing effectiveness, overcoming bortezomib resistance and decreasing toxicity. Disclosures: Kumar: Celgene: Consultancy, Research Funding; Millennium: Research Funding; Merck: Consultancy, Research Funding; Novartis: Research Funding; Genzyme: Consultancy, Research Funding; Cephalon: Research Funding.

Abstract Abstract 1892 Background: Primary or light chain amyloidosis (AL) is a clonal plasma cell disorder characterized by a relatively low plasma cell burden and multi-organ deposition of immunoglobulin light chain derived amyloid fibrils. The survival of patients with amyloidosis is quite variable with median survival of 12–18 months in different series, and largely dependent on the number and severity of organs involved. In addition to new drugs, the combination of melphalan and dexamethasone is an effective regimen for AL and risk adapted approaches to SCT has decreased treatment related mortality. It is not clear if the recent progress in risk stratification and treatment approaches have translated into improved survival for these patients. Methods: We studied two separate cohorts of patients; the first cohort consisting of 2118 patients with AL seen at Mayo Clinic over a 40-year period between November 1967 and August 2006 was used to examine the trends in overall survival from diagnosis during this time period. The second cohort of 443 patients seen between September 2006 and August 2009 were examined only for the changes in early mortality and for validation of a model for predicting early mortality developed using the first cohort of patients. Results: The estimated median follow up for the entire group was 7.8 years (95% CI; 7.1, 8.5). The patients were divided into 4 cohorts based on date of diagnosis; 1966–1976 (n=121), 1977–1986 (n=343), 1987–1996 (n=636) and 1997–2006 (n=1017). The median OS from diagnosis for the four cohorts were 0.9, 1.2, 1.2 and 1.5 years respectively, P < 0.001 (Figure 1). More importantly there was steady improvement in the long-term survival among these patients with 4-year survival estimates of 16%, 21%, 24% and 33% respectively. Next, we specifically looked at the survival trends within the last cohort (1996-2006), dividing the patients into three time periods; 1996–1999 (n=263), 2000–2003 (n=291) and 2003–2006 (n=463). While the OS from diagnosis was relatively unchanged between the first and second time periods (28 vs. 30% 4 year survival), there was significant improvement in the last three year period (42% survival at 4 years); P =0.02. Given the high early mortality in this disease, we specifically examined the one-year mortality among the entire patient cohort and found no clear improvement in terms of one-year mortality. Using logistic regression analysis, we identified cTnT > 0.01, NT-ProBNP > 4200 and Uric Acid > 8.0 mg/dL to be the best predictors of death within one year of diagnosis. The probability of death within one year for those with none, 1, 2, and 3 risk factors was 19, 38, 61, and 78% respectively, P < 0.01 (Figure 2). This model was further validated among patients seen during the most recent three years, September 2006 and August 2009. Conclusion: Survival in AL amyloidosis has improved over time, particularly in the recent years and likely reflects the recent improvements in therapy. However, early mortality remains a problem and baseline factors can be used to identify patients at risk for early mortality, who then can be targeted for risk adapted therapy approaches in clinical trials. Disclosures: Kumar: Celgene: Consultancy, Research Funding; Millennium: Research Funding; Merck: Consultancy, Research Funding; Novartis: Research Funding; Genzyme: Consultancy, Research Funding; Cephalon: Research Funding. Off Label Use: Lenalidomide for treatment of newly diagnosed myeloma. Dispenzieri:Celgene: Honoraria, Research Funding; Binding Site: Honoraria.

Abstract Abstract 1964 Background: Thalidomide (thal), lenalidomide (len) and pomalidomide (pom) have been shown to have considerable efficacy in patients with newly diagnosed as well as relapsed multiple myeloma (MM). They are often used as initial therapy in patients proceeding to stem cell transplant (SCT), and based on the initial response, are usually considered for salvage therapy during their disease course. However, the retreatment efficacy of these compounds is unknown. We conducted this study to ascertain the degree of response that can be obtained by retreatment with immunomodulatory compounds. Patients and Method: 410 patients with newly diagnosed MM who received either thalidomide-dexamethasone or lenalidomide-dexamethasone were studied. Of these, 183 patients received thalidomide, lenalidomide or pomalidomide (with or without dexamethasone) as one of the salvage regimens following relapse, and form the study group. We included all patients who received the repeat immunomodulatory therapy as salvage treatment at any time during the MM disease course. Results: The median (range) age of the MM patient group was 60 (29-80) years; 117 (64%) were male. Thalidomide and lenalidomide were used as initial therapy in 106 (58%) and 77 (42%) patients, respectively. Patients received a median of 2 treatments (range, 1–6) prior to salvage therapy; bortezomib was used as one of the salvage treatment (prior to the repeat immunomodulatory therapy) in 41 (22%) patients. An autologous stem cell transplant was performed in 118 (64%) patients after the initial immunomodulatory therapy. Almost one half (89; 49%) of the patients went off the first line therapy to undergo a SCT; whereas drug toxicity (26; 14%) and disease progression (21; 11%) were other causes requiring a treatment change. The compound used for salvage therapy was thalidomide, lenalidomide or pomalidomide in 40 (22%), 129 (70%) and 14 (8%) patients, respectively. The responses to salvage therapy based on the initial therapy and the salvage regimen are as shown in Table 1. Overall, 67 (37%) patients achieved a partial response or better and 73 (40%) patients achieved less than a partial response (stable and progressive disease) to repeat immunomodulatory therapy, while the remaining 43 (23%) had non evaluable disease response. Conclusions: Retreatment with an immunomodulatory therapy, especially a different compound, was associated with excellent response rates. Lowest response rates were seen in patients retreated with thalidomide after having received lenalidomide as their initial therapy after the diagnosis of MM. This information is valuable in deciding on the choice of repeat therapy with immunomodulatory compounds in patients with relapsed disease. Disclosures: Dispenzieri: Celgene: Honoraria, Research Funding; Binding Site: Honoraria. Kumar:Celgene: Consultancy, Research Funding; Millennium: Research Funding; Merck: Consultancy, Research Funding; Novartis: Research Funding; Genzyme: Consultancy, Research Funding; Cephalon: Research Funding.

Abstract Abstract 2878 Poster Board II-854 Background: Significant advances have been made in the treatment of myeloma with the introduction of thalidomide, its analogue, lenalidomide, and the proteasome inhibitor bortezomib. While these new drugs have improved the outcome of patients with myeloma, the disease still remains incurable. Effectiveness of upcoming new therapies will need to be assessed in the context of anticipated outcome with the currently available therapies. However, given the rapid pace of development over the past decade, outcome of patients who have relapsed on the new therapies remain unclear. Methods: In order to further study this group of patients, we undertook a study of patients who have relapsed on or are refractory to one of the IMiDs (thalidomide or lenalidomide) as well as bortezomib. A total of 300 cases from 8 sites in the US, 5 sites in Europe and one site in Asia were identified for this study. Enrolled patients had relapsed and refractory multiple myeloma, per the EBMT or IMWG response criteria, after at least 2 prior treatments. Patients were refractory to bortezomib, defined as having no response on a prior bortezomib-containing regimen or experiencing disease progression within 60 days of a bortezomib-containing regimen. Patients also should have relapsed, refractory, intolerant, and/or ineligible in the opinion of the investigator, to other therapies, including an IMiD (thalidomide or lenalidomide). Clinical and laboratory data pertaining to the time of diagnosis and from the time of individual relapses were obtained from the clinical records. The date patients satisfied the above entry criteria was defined as time zero. Results: The current analysis includes the first 119 patients with complete data available. The median age at initial diagnosis was 59 years (range, 31-86 yr); 71% were males. The ISS stage distribution at diagnosis was 33%, 39% and 28% for stages 1, 2, and 3 respectively. 19 patients (37%) had high risk disease by FISH [t(4;14), t(14;16), del17p] or by cytogenetics [del 13, hypodiploidy]. The median time from diagnosis to time zero was 3.8 yrs (range 0.2-18.7 yr) and the median reported lines of therapy before time zero was 2. 74% patients had at least 1 autologous stem cell transplant prior to becoming eligible for the study. Following time zero, 77 (65%) pts had a treatment recorded, including an autologous SCT in 21 (18%), with the treatment regimen starting at a median of 1 month after time zero. A variety of treatment regimens were utilized beyond time zero (median=1; range 0-7). Thirty-two (27%) patients had a response any time following time zero, and only 8 had a subsequent response. Response to the first treatment, or supportive care for patients not treated, recorded following time zero included minor response or stable disease (n=14; 12%), PR (n=17, 14%), and VGPR or better (n=6, 5%). Patients treated with SCT had a higher rate of PR or better compared to patients receiving other treatments (85%; 17/20 vs. 26%; 15/57). In a multivariate analysis, the only significant predictor of a PR or better after time zero was younger age (<60 yrs). The median overall survival (OS) and event free survival (EFS) were 6 mos (95% CI, 4-7 mos) and 1 month (95% CI,1-2 mos) respectively. In a multivariate analysis normal creatinine predicted for a better overall survival and having an IgG M protein type predicted for better EFS. A complete analysis from all 300 patients will be presented at the meeting. Conclusions: This study confirms the poor outcome of patients once they become relapsed and refractory to agents that have become the mainstay of myeloma therapy. The findings highlight the incurable nature of the disease and urgent need to develop newer effective therapeutic agents for this group of patients, who currently do not have effective treatment options. Disclosures: Kumar: CELGENE: Research Funding; MILLENNIUM: Research Funding; BAYER: Research Funding; GENZYME: Research Funding; NOVARTIS: Research Funding. Jagannath:Merck: Membership on an entity's Board of Directors or advisory committees; Millennium: Membership on an entity's Board of Directors or advisory committees. Laubach:Novartis: . Palumbo:Ortho Biotech, Janssen-Cilag: Honoraria; Celgene: Honoraria, Speakers Bureau. Richardson:Millennium Pharmaceuticals, Inc.: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Johnson and Johnson: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Novartis: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Keryx: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; BMS: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. San Miguel:Millennium: Membership on an entity's Board of Directors or advisory committees; Janssen-Cilag: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees. Siegel:Celgene: Speakers Bureau; Millennium: Speakers Bureau. Sonneveld:Janssen-Cilag: Honoraria. Durie:Celgene: Membership on an entity's Board of Directors or advisory committees; Millennium: Membership on an entity's Board of Directors or advisory committees.

Abstract Abstract 2803 Poster Board II-779 Background. The rate of asymptomatic amyloidosis (asym-amyloidosis) detected in patients with newly diagnosed multiple myeloma (MM) or smoldering multiple myeloma (SMM) is unknown. This topic is significant because unrecognized AL may be associated with increased mortality may change the patient's management. The objective of the present investigation was to evaluate the number and clinical significance of asym-amyloidosis in MM and SM patients at the time of the diagnostic bone marrow (BM) biopsy for MM. Materials and Methods. The study population was selected from the Mayo Clinic Dysproteinemia database and consisted of consecutive patients with an established diagnosis of MM or SMM without recognition of symptomatic AL. Bone marrow biopsies at diagnosis of MM or SMM were retrospectively stained with Congo Red and reviewed by a single pathologist. A patient was considered to have asym-amyloid if Congo Red staining with apple green birefringence was found. Results. Biopsies from 144 (M 84, F 59) patients were evaluated: 77 had a diagnosis of MM and 67 of SMM. The median age was 59 (range 26-84) years. No differences were found regarding hemoglobin, platelets, prothrombin time, serum and urine proteins, serum albumin, alkaline phosphate, creatinine and β2-microglobulin among MM and SMM patients. At a median follow-up 76 months (range 0-216), 32% patients were alive, 65% dead and 2.7% lost to follow-up. Immunoglobulin isotypes were as follows: 96/144 (67%) had IgG 23/144 (16%) IgA, 12/144 (8%) had light chain only, 1/77 (1%) had IgD, none had IgM and 12/144 (8%) had biclonal or indeterminate; 84/144 (58%) were κ restricted. The presence of amyloid was found in only 2 cases (1%, 95% CI – 0.6 to 3.2), 1 in MM and 1 in SMM group. Neither of these patients had or developed signs or symptoms suggestive of organ involvement by amyloid. Among the 142 other patients without amyloid deposition in their index bone marrow, 1 (0.7%, 95% CI -0.6 to 2.0) developed symptomatic AL after 119 months of follow-up. Characteristics of these three patients are shown in table 1. Conclusions. We found only 2 cases (1%) of amyloidosis in the 144 cases of MM or SMM. Our estimates are lower than the rates which have been reported by others, perhaps because of our high level of suspicion for amyloid at our Amyloidosis Center. These data do not support the need for searching for asym-amyloidosis in patients with newly diagnosed MM or SMM as long as they have no clinical features of AL. Disclosures: Off Label Use: Hydroxyurea use in myelofibrosis. Gertz:celgene: Honoraria; millenium: Honoraria, Membership on an entity's Board of Directors or advisory committees. Witzig:Novartis: Research Funding. Kumar:celgene: Honoraria; millenium: Honoraria, Membership on an entity's Board of Directors or advisory committees.

Abstract Background: A phase III trial comparing thalidomide plus dexamethasone (Thal/Dex) versus dexamethasone alone (Dex) as first line therapy in newly diagnosed multiple myeloma (MM). The results of an interim analysis on 109 of 207 enrolled patients (pts) were reported earlier (Rajkumar et al, Proc ASCO 2004). This report provides results from 198 of 202 eligible pts entered on this study. Methods: Pts with newly diagnosed, untreated, symptomatic MM were eligible. Pts in the Thal/Dex arm (Arm A) received Thal 200 mg/day PO with Dex 40 mg on days 1–4, 9–12, and 17–20 PO. Pts in the Dex arm (Arm B) received Dex alone, at the same dose as Arm A. Therapy was repeated monthly. The primary endpoint was best response at 4 months on intent to treat basis. At 4 months pts could go off study for stem cell transplant or elect to continue therapy. Response was defined as a decrease in serum and urine monoclonal (M) protein by 50% or higher. If serum M protein was unmeasurable, a 90% or higher decrease in urine M protein was required. Responses had to be verified on 2 consecutive determinations separated by at least 2 weeks. Results: 207 pts were enrolled as planned: 103 randomized to Thal/Dex and 104 to Dex alone. Median age was 65 yrs. 6 pts were ineligble for failing to meet eligibility criteria for study entry and are excluded from response analysis. Response to therapy could be assessed at this time on 198 of 202 eligible pts. Response rate with Thal/Dex was significantly higher than with Dex: 58% versus 42%, respectively, (p=0.0164; one-sided Fisher’s exact test). The corrected response rate allowing for use of serum M protein levels in pts in whom a measurable urine M protein was unavailable at follow-up was 69% with Thal/Dex versus 51% with Dex. Median time to response was rapid, and similar in both arms (1.1 months). 3% of pts in the Thal/Dex arm and 5% in the Dex arm met criteria for disease progression within the first 4 months. Toxicity data are available on 204 pts. Grade 3 or greater non-hematologic toxicities occurred within the first 4 months/cycles in 68% of pts on the Thal/Dex arm and 43% in the Dex arm. Grade 3 or higher cardiac ischemia occurred in 3 (2 prior to 4 months, 1 approx. 1 wk after 4 months) pts in Arm A and 2 pts (both prior to 4 months) in Arm B. As a planned analysis, incidence rates of grade 3 or higher deep vein thrombosis (DVT), rash, bradycardia, and neuropathy and any grade 4–5 toxicity in the first 4 months were compared (see Table). The p-value (one-sided Fisher’s exact test) for increased toxicity (of the specified types) is <0.0001. In this period, 18 pts died, 7 in arm A and 11 in Arm B. Conclusions: Thal/Dex demonstrates superior response rates in newly diagnosed MM compared to Dex, comparable to historical results with VAD. The use of Thal/Dex must be weighed in each pt given the higher toxicities compared to Dex alone. Both regimens have low progression rates as pre-transplant induction therapy, and negate the need for intravenous VAD. Major Grade 3–4 toxicities Toxicity Arm A (n=102) Arm B (n=102) DVT (Grade>=3) 18% 3% Rash (Grade>=3) 4% 0% Sinus Bradycardia (Grade>=3) 1% 0% Neuropathy (Grade>=3) 7% 4% Toxicity of Any Type (Grade>=4) 34% 17% Total 46% 20%

Abstract Background: FLC is a valuable diagnostic tool to monitor response in patients with AL and oligosecretory MM. It is also prognostic in patients with MGUS. Its value in patients with non-oligosecretory myeloma has not been defined. Because of the short half-life of free-light chains, an early drop in free-light chain might be predictive for long term outcome post PBSCT. Methods: Between 8/1/03 and 12/10/04, 45 patients with multiple myeloma and abnormal FLC ratios (less than 02.6 or greater 1.65), who were undergoing PBSCT consented to have waste serum from routine post-transplant daily blood draws collected and frozen for future FLC analysis. The immunoglobulin FLC assay (Binding Site, U.K.) was run on samples collected from day +1 until patients were dismissed from our transplant center. Hematologic response was coded according to standard IBMTR criteria at approximately 3 months status post transplant (BJH 1998). Two types of immunoglobulin FLC response were coded: 50% reduction (FLC50) and 90% reduction (FLC90) of the difference of the involved and uninvolved FLC (Leukemia 2006). Two time periods of FLC response were analyzed: early (day 7); and delayed (day 19, range 13 to 24). Endpoints analyzed were overall response (>=PR), complete response rate (CR), progression free survival (PFS), and overall survival (OS). Results: The median age of the myeloma group was 59 years, and 53% were male. Thirty-three patients were monoclonal kappa, and 12 lambda. Forty-two percent were transplanted in response/plateau, 22% were primary refractory, and 36% relapsed disease. The overall hematologic response rate was 93% with a CR rate of 33%. Twenty-five patients have relapsed at a median of 14.2 months. Twelve patients have died, and median overall survival for the group has not been reached at a median follow-up of 24.6 months. Forty-nine and 58 percent of patients had early and delayed FLC90, respectively. Early FLC90, but not delayed FLC90, predicted for complete response (p<0.001). Neither early nor delayed FLC90 predicted for either PFS or OS. In addition, 89% and 96% of patients had an early and delayed FLC50, respectively. FLC50 at either time point did not predict for overall response, CR, PFS, or OS. Conclusion: Immunoglobulin free light chain responses are seen within the first weeks post high dose chemotherapy with peripheral blood stem cell transplant. A 90% reduction in FLC seen within the first seven days predicts for complete response. However, this does not yet translate into prolonged PFS or OS, but with longer follow-up separation of the survival curves may be seen.