Dispenzieri, Angela

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.

Abstract Abstract 956 Background: Autologous SCT has been an integral part of myeloma therapy since randomized trials demonstrated improved survival for SCT compared to conventional therapy. However, the conventional treatment of MM has changed with the introduction of novel therapies such as IMiDs and there is an increasing trend towards delaying SCT. While trials in the pre-novel agent area have shown equivalent outcomes with early or delayed SCT, it is not clear if this holds true with novel agent induction. Patients and methods: We reviewed the outcome of patients seen at Mayo Clinic between 2001 and 2008, who received initial therapy with thalidomide-dexamethasone (TD) or lenalidomide-dexamethasone (LD) (n=410). All patients in whom a stem cell harvest was attempted (started on growth factor irrespective of collection success; n=292, 71%) were included as a method to identify transplant eligible patients. Patients undergoing SCT within 12 months of diagnosis and in whom the SCT was performed within 2 months of stem cell harvest were considered in the early SCT group vs. delayed SCT for the remaining patients irrespective of whether an SCT was actually done (immediate vs. collect and store approach). Variables were compared between the groups using a chi-square or t-test as appropriate. Survival curves were generated using Kaplan Meier method and compared using log rank test. Results: Among the 292 transplant eligible patients, 125 (43%) received TD and 167 (57%) received LD as initial therapy. An early SCT approach was undertaken in 174 patients 60%, with the remaining 118 in the delayed group, 46 of whom have been transplanted to date. The median estimated follow up for the entire group was 54 months from diagnosis, 52 and 61 months respectively for the early and delayed groups. The median estimated time to SCT was 5.3 months among the early group compared to 39 months in the delayed group COMMENTS/* MERGEFORMAT . 83 (66%) patients receiving TD had an early SCT compared to 91 (55%) patients in the LD group; p =0.04. At baseline, the groups were comparable for age and gender. The median overall survival from diagnosis was 86 months for the early SCT compared to NR for the late SCT; P=0.3. The median OS was similar between the Early and Delayed group in the TD group (86 vs. 64 months respectively) as well as in the LD group (NR for either group; 82% vs. 86% at 4 years respectively). Conclusion: In this group of newly diagnosed patients treated with thalidomide or lenalidomide as initial therapy, an approach of continued initial therapy and delayed transplant at the time of first relapse appears comparable to upfront transplant. This is consistent with the findings of randomized trials in the setting of alkylator based initial therapies. The timing of transplant in the era of novel agents remains the top question on the mind of physicians and patients, and this is the first study to examine this very important question. The rationale governing the decision to go forward with an early SCT or delayed transplant is difficult to ascertain for any particular patient in this retrospective study. These findings should be confirmed in prospective randomized trials. Disclosures: Kumar: celgene: Research Funding; millenium: Research Funding. Gertz:celgene: Honoraria; millenium: Honoraria, Membership on an entity's Board of Directors or advisory committees.

Abstract Abstract 747 Background: Light chain amyloidosis is a monoclonal plasma cell proliferative disorder characterized by multiorgan deposition of monoclonal light chain derived amyloid fibrils. The diffuse organ infiltration by the amyloid fibrils leads to various AL related clinical features. Therapy of AL has been primarily aimed at elimination or control of the monoclonal plasma cells, thus decreasing the light chain available for amyloid formation. Assessment of response to therapy has been grouped into hematological response demonstrating elimination or reduction of the monoclonal population and organ response demonstrating actual improvement in its structure or function. Given the potentially long delay in observing organ improvement, hematological response has been the surrogate short term marker for long term outcome given the relatively rapid decline seen in the monoclonal protein with effective therapy, as well as studies showing improved long term outcome with a hematological response, especially complete response. However, conventional hematological response criteria give priority to the intact monoclonal protein rather than the light chain, which is the amyloidogenic protein. We hypothesized that a light chain response will correlate better with outcome than changes in the intact monoclonal protein levels. Methods: We identified 348 patients who had undergone stem cell transplant (SCT) for AL from among a large group of patients undergoing different treatments for AL, and in whom serial tests results were available. We identified the lowest value attained following SCT for various hematological response parameters (intact serum M-protein [MP], the difference between involved and uninvolved serum free light chain [FLC-diff], and urine M-protein [UP]) before an alternate therapy was instituted. We first estimated the best cutoff for the degree of change in each parameter that predicted 5-year survival from SCT. Cox proportional hazards model was used for multivariable analysis of factors influencing overall survival (OS). Results: We first examined the relative contribution of the MP and the FLC-diff on the overall survival following transplant. The best cutoff for reduction in FLC-diff to predict OS at 5 years from SCT was 88% if all patients were considered and 90% if only those with a baseline FLC diff > 7.5 mg/dL were considered. The best cutoff for MP reduction was 40% for 5 year survival for all patients and 67% for those with a baseline MP > 1.0 gm/dL. We then looked at the impact of FLC reduction and MP reduction in a multivariable analysis using OS as endpoint. For all patients, FLC reduction, but not MP reduction significantly impacted outcome, and results were similar when considering patients with MP>1.0 gm/dl and FLC-diff > 7.5 mg/dl at baseline. Among those with a baseline FLC-diff >7.5 mg/dL (n=125), the overall survival was 35 mos from SCT for those with less than 90% decrease in FLC-diff (45 pts) compared to not reached for those with at least 90% decrease (80 pts); P < 0.001 (Figure). Conclusions: The current study supports the notion that reductions in the free light chain parameters represent a more useful measure of hematological response that translates into better overall survival and possible better chance at organ improvement. A reduction in the FLC difference of 90% appears to correlate best with prolonged survival. Disclosures: Kumar: CELGENE: Research Funding; MILLENNIUM: Research Funding; BAYER: Research Funding; GENZYME: Research Funding; NOVARTIS: Research Funding. Gertz:celgene: Honoraria; millenium: Honoraria, Membership on an entity's Board of Directors or advisory committees. Lacy:celgene: Research Funding.

Abstract Abstract 1802 Poster Board I-828 Background Heterogeneity in multiple myeloma (MM) leads to disparate outcomes with a wide variation in overall survival (OS). Based upon the evidence predominantly gathered from newly diagnosed patients treated with standard chemotherapy and/or transplantation, the current Mayo (mSMART) prognostic model uses a combination of metaphase cytogenetics, fluorescence in-situ hybridization (FISH) and plasma cell labeling index (PCLI) for risk-stratification at diagnosis of MM. The objective of our study was to evaluate the significance of this stratification model in the era of novel therapies, and to assess the independent prognostic value of each of the components in the model. Methods Data were abstracted from a cohort of 1556 consecutive patients with MM who presented to our institution between January 1999 and March 2009 within ninety days of diagnosis of MM A total of three hundred and eighty six patients had been evaluated with conventional cytogenetics near diagnosis in addition to interphase FISH. Out of this cohort, three hundred and sixty six patients had availability of all the three tests, including the slide-based PCLI. High-risk MM was defined as presence of any one or more of the following: cytogenetics: hypodiploidy, monosomy of chromosome 13 or deletion 13q ; FISH: deletion of p53 (locus 17p13) or immunoglobulin heavy chain (IgH) translocations, t(4;14) (p16.3;q32) or t(14;16)(q32;q23); PCLI ≥3%. Survival estimates were created using the Kaplan-Meier method and compared by log-rank tests. The impact of each of the three tests was assessed by a multivariate (MV) analysis using Cox proportional hazards model. Results The median OS of the cohort of 366 patients was 65 months from presentation. One hundred and twelve (31%) patients were deemed high risk by any one or more of the three tests: Metaphase cytogenetics, FISH or PCLI (current mSMART definition of high-risk MM). The median OS of high risk patients was 52 months versus 71 months for standard-risk (P=0.007). We then studied the prognostic value of the three tests separately. Patients classified as high risk by FISH had a median OS of 35 months versus 65 months for the standard risk, HR= 2.3, P<0.001. Similarly, cytogenetics alone was also able to classify patients into high and standard risk with a comparable HR of 2.1 (P=0.008, median survival 37 vs. 64 months). In contrast, PCLI did not have a significant prognostic value (HR =1.41, P=0.32). This was confirmed on multivariate analysis in a model that included all 3 tests. FISH (HR=2.36, P=0.001) and cytogenetics (HR=1.99; P=0.017) emerged as independent determinants of prognosis in the multivariable analysis, while PCLI (HR=1.03, P=0.93) did not provide additional prognostic value. We then examined whether the prognostic value of FISH contributed additionally in patients classified into high and standard risk by conventional cytogenetics, and vice versa. Those classified as high risk by cytogenetics (n=44, 11 %), were further categorized into 2 groups by additional prognostic information obtained by FISH (median survival 18 vs. 52 months; P=0.005). Similarly, those classified as standard risk by cytogenetics (n=342, 89 %), were further categorized into 2 groups (median survival 52 vs. 71 months; P=0.017) by additional FISH-based stratification. Similarly, high-risk patients defined by FISH (n=65, 17 %) were further classified into 2 groups with significant difference in median OS (18 vs. 52 months, P=0.004), based on the presence or absence of high-risk features on cytogenetics. In contrast, no additional prognostic information was gained by cytogenetics in patients who were stratified as standard risk by FISH alone (n=321, 83%). Conclusion Our study validates high risk features defined by FISH and conventional cytogenetics in the mSMART risk stratification model among patients treated after the introduction of novel therapies. Either test identifies a high risk cohort with a hazard ratio of approximately 2 (median survival ∼37 versus ∼65 months). In patients known to have high risk disease by one of the two tests, knowledge of the other appears to add additional prognostic value. Disclosures Fonseca: Amgen, BMS, Celgene, Otsuka, Genzyme and Medtronic: Consultancy. Gertz:celgene, millennium: Honoraria. Dispenzieri:celgene: Research Funding. Kumar:celgene, genzyme, millennium, novartis, bayer: Research Funding; genzyme: Membership on an entity's Board of Directors or advisory committees.

Abstract Abstract 946 Background: The emerging therapies directed at the plasma cell clone have dramatically increased overall survival (OS) for both myeloma and amyloidosis patient populations. As more treatment trials are done in patients (pts) with AL, benchmarks for outcomes among previously treated AL pts are required, especially for those pts who are not candidates for high-dose chemotherapy with peripheral blood stem cell transplantation (ASCT). Inadequate information is available about the number of non-transplant pts who go on to receive second line treatment for AL amyloidosis. Methods: To ascertain the outcomes of pts who did not receive ASCT as primary therapy but who required a second line of therapy, we reviewed the experience of pts seen at Mayo Rochester between 1990 and 2010 according to an IRB approved retrospective review protocol. 1828 pts had their first Mayo visit for AL during this time period. Pts were excluded from this study for the following reasons: 571 had upfront transplant; 907 pts had received only one line of treatment for their amyloid; 91 had longstanding other associated malignancy [Waldenstrom's macroglobulinemia (8), lymphoma (15), CLL (6), multiple myeloma (62)]; and 93 had inadequate follow-up information. One-hundred and sixty-six pts received 2 or more lines of therapy for their AL amyloid and are the subject of these analyses. Statistical analyses were done using JMP statistical software (SAS, Carey, NC). Results: Of the 166 pts, the median age was 64 years (range 34, 84). 49% were male. Baseline organ involvement was as follows: cardiac 84/166 (50%); renal 118/166 (71); liver 23/166 (13.8%); peripheral nerves 19/166 (11.4%); and gastrointestinal 14/166(8.4%). Thirty-one percent (52/16) had both cardiac and renal involvement. Only 73 pts had cardiac biomarkers (NT pro BNP and Troponin T) done at baseline. Of these pts, 26% were stage 1, 49.3% were stage 2, and 24.6% were stage 3 according to original Mayo cardiac biomarker staging system. By inclusion criteria definition, all 166 pts received 1st and 2nd line therapies; 53 (32%) pts received 3rd line of treatment; 20 (12%) received 4th line of treatment; and 10 (6%) received 5th line of treatment. For first line therapy, the most common drugs given either singly or in combination were corticosteroid (147/166; 88.5 %), alkylator (99/166; 59.6%), IMID (34/166; 20.4 %), and bortezomib (19/166; 11.4%). The median time from diagnosis to 2nd line therapy was 10.3 months. Second line regimens received included: corticosteroid, 108/166 (65.1%); alkylator, 76/166 (45.8 %); IMID, 46/166 (27.7%); and bortezomib, 46/166 (27.8%). The median time from diagnosis to 3rd line therapy was 19.8 months. For the 53 pts who received 3rd line treatment, regimens included: corticosteroid, 41/53 (77.3%); IMIDs, 17/53 (32.1%); alkylator, 17/53 (32.1%); bortezomib, 12/53 (22.6%). The median time from diagnosis to 4th line therapy was 31.8 months. For the 20 pts receiving 4th line treatment, regimens included: corticosteroids, 15/20(75%); alkylator, 12/20 (60%), bortezomib, 7/20 (35%); and IMIDs, 4/20(20%). Eighty-three pts have died. The 1 year mortality of our study population was only 8%. The median follow-up of surviving pts was 47.6 months. Figure 1 demonstrates Kaplan-Meier estimates of overall survival (OS) from initiation of each successive therapy. The median OS from initiation of 1st, 2nd, and 3rd lines of treatment were 65, 49.5 and 36.7 months respectively. The median OS after the 4th line of treatment was not reached. The 4 year OS rates from initiation of 1st, 2nd, 3rd and 4th lines of therapy were 58%, 50.8 %, 50 % and 53.4% respectively. Conclusion: Outcomes among relapsed or refractory AL pts are better than what one might expect. Multiple publications have demonstrated that the 1 year mortality of newly diagnosed AL is in the vicinity of 40%. Thereafter, the rate at which pts die dramatically decreases. Our study provides explicit data characterizing the fate of pts unfortunate enough to require additional therapy but fortunate enough to survive past the exceedingly high risk period of death that occurs within 6–12 months of diagnosis. These data provide useful information for benchmarking future trials for treatments of AL amyloidosis. Disclosures: No relevant conflicts of interest to declare.

Abstract Abstract 591 Background: Survival of patients with MM has improved over the past two decades, in part due to the use of AHCT. Increasingly, second primary malignancies (SPMs) are observed in MM survivors. Determining the baseline incidence and risk factors associated with SPMs after AHCT is important to assess risk and to evaluate the risk-benefit ratio of newer therapies. Methods: We analyzed the incidence of SPMs in 3784 MM patients receiving (“upfront”) AHCT for MM within 18 months of diagnosis between 1990 and 2010 and reported to the CIBMTR. Cumulative incidence rates of SPMs were estimated taking into account the competing risk of death. For each transplant recipient, the number of person-years at risk was calculated from the date of transplantation until date of last contact, death, or diagnosis of SPM, whichever occurred first. Incidence rates for all invasive cancers in the general population were obtained from the SEER database. Age-, sex-, and race- specific incidence rates for overall SPMs and particular anatomical sites were applied to the appropriate person-years at risk to compute the expected numbers of cancers. Observed–to –expected (O/E) ratios were calculated, and Poisson distribution 99% confidence intervals (CIs) were generated. Poisson regression model was used to analyze risk factors for overall SPMs and AML/MDS. Results: Pre-transplant therapy included novel agents in 56% including thalidomide (35%), lenalidomide (9%), bortezomib (16%) or their combinations (11%). Majority (80%) received high dose melphalan conditioning. Post-transplant maintenance therapy included thalidomide (16%), lenalidomide (8%), bortezomib (9%) and interferon (6%). Median follow-up of survivors was 52 months (range 3 to 192 months).With 12707 person years of follow up, 153 new malignancies were reported with a crude rate of 1.2 SPM per 100 person years of follow up. Observed/Expected [O/E] ratio for all SPMs was 0.99 (99% CI, 0.80–1.22). Cumulative incidence of SPM overall was 2.48% (95% CI, 1.96–3.05) at 3 years and 6.0% (95% CI, 4.96–7.10) at 7 years [Figure 1]. Individual SPMs observed significantly more frequently than expected are summarized in Table 1. The cumulative incidence of MDS/AML was 0.5% (95% CI, 0.28–0.78) at 3 years and 1.3 (95% CI, 0.85– 1.9%) at 7 years. Majority had MM progression prior to diagnosis of SPM (65 of 102 patients overall and 15 of 23 patients for MDS/AML). In multivariate analysis, significant risk factors for development of SPMs included: obesity [Hazard ratio = HR 1.89(95%CI, 1.21–2.93), p=0.0047 for BMI>30 vs. BMI<25], older age: [HR10.53 (95%CI, 1.46–75.82), p=0.0195] for 60–69 year olds and HR14.4 (95%CI, 1.89–109.75), p=0.01 for 70+ year olds compared to the 18–39 year old group. Specific conditioning regimens did not correlate with the risk of SPM. The low number of MDS/AML (33 events out of 3784 cases) limited the power of multivariate analysis. Increasing age was significantly associated with development of MDS (HR10.77, (95%CI,92.09–55.51), p=0.004 for 70+ year old vs. 40–49 year olds). Conclusion: In this large cohort of AHCT recipients for MM, the incidence of MDS/AML, melanoma and other skin cancers was significantly higher compared to age and sex matched general population. However the overall risk of SPM was similar to that expected for age and sex matched population. It was also similar to the placebo arms of recent reports by McCarthy Pl et al and Attal M et al (N Engl J Med. 10; 366(19):1770–91). Lenalidomide (8%) or thalidomide maintenance (16%) used in a small subset of patients with comparatively short follow up, was not associated with risk of SPM in the analysis of the overall cohort. Disclosures: Gale: Celgene: Employment. Brandenburg:Celgene: Employment, Equity Ownership. Lonial:Millennium, Celgene, Novartis, BMS, Onyx, Merck all Consultancy. Krishnan:Celgene and Millennium: Consultancy, Speakers Bureau. Dispenzieri:Celgene and Millennium: Research Funding. Hari:Celgene: Consultancy, Honoraria.

Abstract Abstract 596 Background Large population-based studies have demonstrated a significant improvement in survival (OS) for patients (pts) with multiple myeloma (MM) over time since the mid-1990s. The improvement has mostly affected younger patients suggesting a beneficial impact of AHCT. The availability of novel drugs within the last decade and their impact on the utilization and outcomes of AHCT recipients is unknown. Methods We retrospectively reviewed the characteristics and outcomes of 20,278 patients undergoing AHCT within 12 months of diagnosis in USA and Canada and reported to CIBMTR in the periods of 1995–1999 (n=2226), 2000–2004 (n=6408) and 2005–2010 (n=11644) including a subgroup of 4373 individuals with detailed patient, disease and treatment information. We subsequently compared survival and analyzed patient, disease and treatment characteristics across the three periods with the time period serving as a surrogate for pre- and post-transplant exposure to novel agents. Results Across the 3 time periods, there was a marked increase in the number of upfront transplants across all age groups (Figure 1a). Patients receiving upfront HSCT in the more recent period were older, less likely to have stage 3 MM at diagnosis and more likely to have received thalidomide (<1 % vs. 22% vs. 52%), lenalidomide (0% vs. <1% vs. 21%) or bortezomib (0% vs. 2% vs. 35%) and have chemosensitive disease at the time of AHCT. The proportion of African-American patients remained low and stable across the three periods (14 vs. 13 vs. 15%). Over the 3 periods, there was a decrease in chemotherapy based stem cell mobilization and increase of single agent G-CSF based mobilization (24% vs. 24% vs. 41%). The use of single agent Melphalan conditioning increased from 54% in 1995–1999 to nearly 100% in the latest period concomitant with near disappearance of total body irradiation-based and multi-drug conditioning regimens. Compared with 1995–99 cohort, survival was superior in the 2000–04 and 2005–09 cohorts at 24 (72% vs. 79% vs. 84%, P<0.001), 48 (54% vs. 60% vs. 64%, P<0.001) and 60 months (47% vs. 52% vs. 55%, P<0.001) (Figure 1b). In multivariate analysis, we found that transplant in the 2000–04 period (HR=0.77, 95% C.I. 0.67–0.89) or in the 2005–10 period (HR=0.68, 95% C.I. 0.59–0.79) along with Karnofsky performance score of 80–100 (HR=0.59, 95% CI 0.51–0.70) and chemosensitivity (HR= 0.76, 95% C.I. 0.66–0.87) were associated with lower risk of death. Factors associated with higher risk of death were age 50–65 (HR=1.29 95% 1.13–1.47), age 65–80 (HR=1.45, 1.23–1.72), Durie-Salmon or ISS stage III at diagnosis (HR 1.56, 95% C.I. 1.39–1.76) and more than one prior line of therapy (HR=1.15, 95% C.I. 1.03–1.28). In comparison to patients transplanted in 1995–99, post relapse survival was superior for patients transplanted in 2000–04 and 2005–10 at 24 months (58% vs. 65% vs. 72%, P=0.005 and <0.001 respectively) and 48 months (33% vs. 39% vs. 40%, P=0.023 and 0.033 respectively). The use of maintenance therapy has changed with 27% in 1995–99 receiving planned interferon vs. 23% in 2005–09 receiving planned thalidomide, lenalidomide or bortezomib maintenance. Conclusions Utilization of upfront AHCT is increasing in the USA, particularly in older patients. Improvement in survival for MM patients seen in population studies results not only from greater utilization of AHCT but also from the improvement in outcomes after AHCT and a significant recent improvement in post-relapse survival. Pre- and post-transplant exposure to novel agents likely contributes to survival. AHCT and novel agents are complementary and should be combined for the optimal management of newly diagnosed MM. Disclosures: No relevant conflicts of interest to declare.

Abstract Abstract 1988 Background With the utilization of novel agent-based combination therapies and autologous stem-cell transplantation (ASCT) in multiple myeloma (MM), the rigorous response category of stringent complete remission (sCR) in the international uniform response criteria is increasingly becoming attainable. In addition to the standard criteria for complete remission (CR), sCR requires normalization of the free light chain ratio and disappearance of clonal cells as determined by the marrow immunofluorescence or immunohistochemistry. We have previously validated the new response category of sCR created in by the International Myeloma Working Group and demonstrated that sCR represents a deeper level of response, translating into a superior OS. Herein we report the survival outcomes of patients attaining sCR or standard CR, from a 2-year landmark after ASCT in a cohort of patients with extended follow-up. Additionally, we report the outcome of patients who remained in sCR for at least 6 months (sustained-sCR) after ASCT. Patients and Methods Maximal response rates of four hundred and forty-five consecutive patients who underwent ASCT within 12 months of diagnosis of MM were determined. The population achieving varying degrees of complete remission (n=237) is the focus of this study. We performed a landmark analysis 2 years after ASCT to ensure that all the patients attaining at least CR had sufficient time to reach the response levels being studied. Patients were categorized as having sustained sCR (sus-sCR) if the duration of sCR was at least 6 months. Overall survival (OS) was estimated by the Kaplan Meier method and the survival curves were compared by log-rank test. Results The median follow-up of the entire cohort was seventy-seven months (95% CI: 73–82 months). The sCR rate after ASCT was 24% (n=109). Median time to progression (TTP) of patients attaining sCR was 50 months from ASCT, and median overall survival (OS) is not reached, in contrast to those attaining standard CR (n=37, TTP=20 months, OS=81 months) or near CR/nCR (n=91; TTP= 19 months, OS=60 months, p<0.0001 for both TTP and OS). OS of patients surviving at least 2 years from ASCT (Figure 1a) continued to remain superior for those attaining sCR (n=105, median: not reached) versus 70 months for the CR group (n=32; p=0.004). Among patients achieving sCR (n=109), OS of patients with sus-sCR (n= 75) at 6 months from ASCT is not reached (5-year OS=91%, 7-year OS=86%) versus median OS of 66 months (5-year OS=49%, 7-year OS=37%; p<0.0001) for those who had non-sustained-sCR (n=34) after ASCT (Figure 1b). Conclusion In our landmark analysis of patients with MM who survived at least 2 years from ASCT, those attaining sCR have a markedly superior outcome compared to those attaining standard CR. However, among patients attaining sCR, those with sustained sCR of 6 months or greater had the best outcome. Myeloma trials reporting response rates should identify patients achieving sCR and CR separately owing to markedly disparate outcomes of the two categories. Disclosures: No relevant conflicts of interest to declare.

Abstract Abstract 1788 Poster Board I-814 Background Clinically available prognostic factors for progression of MGUS to myeloma include the size of the M-spike, heavy chain isotype, and free light chain (FLC) K/L ratio. The combined use of these variables provides approximately a 10-fold difference in risk for progression. The highest risk group, however, still has only a 27% twenty year risk of progression. Therefore, additional predictors of progression are needed. Suppression of uninvolved immunoglobulins has been an inconsistent predictor of progression. The novel Hevylite” assay measures concentrations of each isotype-specific immunoglobulin heavy light chain (HLC) pair (i.e., IgG kappa, IgG lambda, IgA kappa, IgA lambda) and enables us for the first time to determine if suppression of isotype-specific Ig of the opposite HLC is occurring and if it is predictive of progression of MGUS to myeloma. We studied the prognostic value of isotype specific HLC suppression of uninvolved immunoglobins as a predictor of progression in MGUS. Methods: Total immunoglobulins were quantitated by immunonephelometry, and suppression was defined as concentrations less than the lower limit of the reference range. HLC concentrations were quantitated with Hevylite reagents (The Binding Site, Ltd). The antibodies used in this investigational nephelometric assay span epitopes in the junctional areas between the HLC constant regions. Based on reference ranges for GK (407-1130 mg/dL), GL (188-583 mg/dL), AK (55-292 mg/dL), and AL (39-249 mg/dL) that we derived from 276 normal samples, we compared the proportion of patients who had isotype specific suppression of the opposite HLC pair among 30 patients with MGUS who progressed to myeloma versus 36 patients who had not progressed over a similar follow-up period. To confirm the relationship of isotype specific HLC pair suppression compared to suppression of uninvolved immunoglobulins of other heavy chain classes, we tested a second cohort of stored samples from 50 IgG and 14 IgA MGUS patients prior to the development of MM. Results In the initial samples from 36 IgG MGUS patients who had stable disease, 6% had suppression of uninvolved intact immunoglobulins of IgA and/or IgM, while 22% had isotype specific suppression of the opposite HLC pair (i.e., IgG lambda suppressed in IgG kappa MGUS, and vice versa). In contrast, in baseline samples from 30 IgG MGUS patients who eventually progressed to myeloma or related malignancy, 7% had suppression of IgA and/or IgM, while 40% had isotype specific suppression of the opposite IgG HLC pair. Thus, HLC pair suppression was more frequent than suppression of Igs from other heavy chain classes, and MGUS patients who eventually progressed had a 2-fold higher rate of isotype specific HLC pair suppression than stable MGUS patients. These findings were confirmed independently on a second cohort of patients who progressed to myeloma 5-10 years after blood collection. In samples from 50 IgG MGUS patients, 42% had suppression of Igs of other heavy chain classes, while 80% had suppression of the isotype specific HLC by the Hevylite assay. In the last samples prior to progression, the suppression of heavy chain classes increased to 60%, while isotype specific HLC suppression rose to 90%. Interestingly, the 14 IgA patients had equivalent suppression of gamma or mu heavy chain classes as compared to the HLC pairs, with 50% of the patients having suppression in the initial sample and 79% in the last sample prior to MM. Conclusion Our data suggest that suppression of the opposite IgG HLC pair is a predictor of patients destined for progression. Isotype specific HLC pair suppression of this nature is more frequent in these patients (more sensitive) than suppression of other heavy chain classes. We were not able to demonstrate a similar effect in IgA MGUS. Larger studies are underway to determine if HLC pair suppression is independent of M-spike quantitation, heavy chain isotype, and FLC ratio. Biologically, our findings suggest that clonal IgG plasma cells are able to suppress other IgG producing non-clonal plasma cells far more effectively than IgA or IgM secreting cells, and this occurs more frequently with cells that will eventually undergo malignant transformation. Disclosures Bradwell: The Binding Site Group Ltd: Equity Ownership.

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.