Zeldenrust, Steven R.

Abstract 5079 Introduction: IgD monoclonal proteins are rare. They are not seen as a MGUS and are present in 1% to 2% of patients with myeloma. In light chain amyloidosis (AL), IgD monoclonal proteins are rare. When an IgD protein is found, amyloidosis is often omitted from the differential diagnosis. An IgD protein in amyloidosis has been reported in single cases but never as a patient series. We report IgD AL in 53. Patients & Methods: Clinical and demographic data for patients were retrieved from the patient records. Factors of interest were compared between patients who did and did not have an IgD protein. Results: Among 3,955 patients with AL amyloidosis seen, 53 patients (1.3%) had a serum IgD monoclonal protein. (Table 1) A serum monoclonal protein peak was visible on SPE in only 14, and only 5 had an M spike greater than 1 g/dL. On immunofixation of the serum, the IgD light chain was k in 11, λ in 35, and uncertain in 6; 1 patient had a biclonal D λ and G k protein. A urine monoclonal protein was detected in 43 of 51 patients; urinary immunofixation detected a λ light chain in 33 and a k light chain in 10. Biopsy of tissues showed amyloid deposits in the bone marrow in 47% and in the fat aspirate in 73%. Six patients (age 47–63 years) underwent autologous SCT. Four had renal & two had cardiac AL. All 6 had hematologic PR, 4 CR, and 4 had organ response. One patient had relapse of disease and is now on dialysis, and another had relapse and is alive with salvage chemotherapy. One patient had disease relapse and died of progressive GI amyloidosis at 22 months. The other 5 are alive at a median of 68 months (range, 7.5–83.5 months). We compared the 53 patients with IgD amyloidosis with 144 patients with non-IgD amyloidosis. (Table 2) Findings that were significantly different between groups included a lower frequency of renal amyloidosis (P=.005) and a lower prevalence of cardiac amyloidosis (P=.047). There was a higher serum albumin level (P=.04) related to the lower level of proteinuria. No difference in survival was seen between the groups. (Figure). Variables that might affect survival—liver size, performance status, septal thickness, serum creatinine level, and β2-microglobulin level—were not different between groups. Conclusions: IgD AL patients have a lower frequency of renal involvement and possibly also of cardiac involvement. The overall survival of these patients does not appear to be different from that of patients who have AL associated with another monoclonal protein. IgD monoclonal proteins are so closely linked to the diagnosis of multiple myeloma in the mind of a clinician that the possibility of amyloidosis may be overlooked. Disclosures: No relevant conflicts of interest to declare.

Abstract Abstract 2868 Introduction: Improvement in renal parameters is fundamental for the assessment of organ response to treatment in immunoglobulin light chain amyloidosis (AL). Renal response, defined as a >50% reduction in proteinuria with <25% decrease in renal function, is associated with superior overall survival (OS); however, a systematic study of the interplay of proteinuria, creatinine, and free light chain has not been performed. The intent of this study is to better understand the components of the renal response criteria. Methods: Patients who underwent autologous stem cell transplantation from 1995 to 2010 were eligible for this retrospective analysis if they had > 1 year of follow-up and a baseline 24 hour urine protein > 1 g/d. Those who were dialysis dependent or died before 1 year were excluded as not evaluable for renal response. Results: Of the 435 patients screened, 152 met criteria. On univariate analysis, >50% proteinuria reduction (p < 0.001), serum free light chain (sFLC) reduction by >50% (p = 0.002), <25% increase in serum creatinine (Scr) (p = 0.0003), and a 50% proteinuria reduction within 15 months of treatment (p = 0.04) were associated with better OS. Multivariate analysis using a proportional hazard model showed that sFLC reduction by >50% (0.006), <25% increase in serum creatinine (Scr) (p = 0.0005) and >50% proteinuria reduction (p = 0.0006) were independently associated with OS. In addition, OS was significantly better among patients achieving >85% reduction in proteinuria than those with < 85% but >50%, p = 0.03 (Figure 1). Patients with >75% reduction in sFLC were more likely to achieve >50% proteinuria reduction (p = 0.009). Most importantly, among those with > 25% increase in Scr, only those patients who had <85% proteinuria reduction had a worse OS (Figure 2a, p = 0.006). There was no difference in OS among those with >85% proteinuria reduction and a rise in Scr of > 25% (Figure 2b, p = 0.77). Conclusion: Renal response is an excellent prognostic marker in patients with AL. This is the first study to show the depth of renal response correlates with OS. Patients who had the highest levels of proteinuria reduction (> 85%) had a significantly better OS than those with >50% but <85%. We also found that the negative impact of >25% decrease in renal function was only pertinent in those who did not have >85% reduction in proteinuria. These findings should help better refine the definition of renal response criteria in AL patients. Disclosures: Leung: Binding Site: Honoraria.

Abstract Abstract 3101 The POEMS (polyneuropathy, organomegaly, endocrinopathy, M-protein, skin changes) syndrome is a rare paraneoplastic disorder secondary to a clonal plasma cell process. The most experience with successful outcomes in POEMS with disseminated disease has been with high dose chemotherapy followed by autologous stem cell transplantation (ASCT). However, the risk of relapse of POEMS following an ASCT or the outcome of the patients who relapse is not known. We therefore performed a retrospective review of POEMS patients who underwent ASCT at our center and subsequently relapsed or progressed. Over the past 12 years, 58 patients with POEMS underwent autologous stem cell transplantation at the Mayo Clinic, Rochester between Mar 18, 1999 and Jun 22, 2011. With a median follow up of 40 months (1–147 months), 12 patients have relapsed. The median time to relapse was 41 months. The 1, 2, and 5 year PFS rates were 98%, 94%, and 75%, respectively (Figure 1), and the 1, 2, and 5 year OS rates were 98%, 98%, and 94%. Of the 12 patients with documented relapse, 7 had baseline PET/CT scans all of which had FDG avid lesions. By 1 year, the FDG avidity had not resolved in 4 of these patients who then went on to either develop additional lesions or increasing SUV of existing lesions. Of the 12 patients with documented relapse, 8 had baseline VEGF measurements, and all but 1 had normalization by 1 year. The first sign of relapse was a clinical deterioration in 2, a rising M-protein in 3, and a rising plasma VEGF level in 5 patients. All of these patients had new or worsening of existing lesions on PET/CT scan (n= 9) or x-ray imaging (n= 3). The symptoms of clinical relapse included pain at the site of the lytic lesion and generalized pain with swelling. Of the patients who relapsed, 5 were treated with radiation therapy, 4 received lenalidomide or thalidomide, 2 had alkylator based therapy and 1 had bortezomib based therapy. One patient was treated with surgical resection of his hepatic plasmacytoma and 2 patients have been observed without needing definitive treatment as of yet. One patient also received anti-VEGF treatment with bevacizumab unsuccessfully after failing cyclophosphamide therapy. In this large cohort of POEMS patients treated with high dose chemotherapy and autologous stem cell transplantation in a single center, a relapse rate of 21% was noted. Not every patient who relapsed has been deemed to need further treatment, and most patients could be salvaged with chemotherapy or radiation. Only one patient died from relapsed POEMS following stem cell transplantation. Disclosures: No relevant conflicts of interest to declare.

Abstract Abstract 2945 Background: We have previously reported on a Phase II trial using IL-1Ra and dexamethasone, in patients with SMM/IMM, showing that IL-1Ra targets the myeloma proliferative component which parallels a decrease in the C-reactive protein, a surrogate for IL-6 production. (Mayo Clinic Proceedings 84 :114 (Feb. 2009)). In early stage myeloma, IL-6 is a central myeloma growth factor and we have shown that abnormal production of IL-1 β in the myeloma microenvironment stimulates the generation of paracrine IL-6. These patients are the individuals most likely to benefit from anti-cytokine therapy in an attempt to delay/prevent the development of active myeloma. We now present updated results of this study including survival data. Methods: Patients that had ≥ 10% bone marrow plasma cells and/or an IgG or IgA M-spike ≥ 3 g/dL and did not require immediate chemotherapy were eligible. All patients received 100 mg of Anakinra (IL-1Ra) SQ qd for 6 months. Patients with evidence of reduction in M-protein levels continued receiving IL-1Ra alone. Patients with stable disease at 6 months or those with a rising M-protein before 6 months received low dose dexamethasone (20 mg qweek) in addition; the dose was adjusted based on response/toxicity. Results: Data were available on 47 patients based on intent to treat, and pts were classified as smoldering (72%) vs. indolent (28%). All SMM patients were in Group 1 or 2 and thirty-eight patients (81%) had greater than 20% bone marrow plasma cells. All 47 patients received IL-1Ra initially and 25/47 subsequently received IL-1Ra/Dex. Seven patients had a decrease in the plasma cell labeling index (PCLI) on IL-1Ra alone which paralleled a decrease in the high sensitivity C-reactive protein (CRP) in all cases. Three patients achieved a minor response to IL-1Ra alone and 9 patients achieved a PR/MR after addition of dexamethasone. For the group of 47 patients, the median progression-free survival was 45 months and the median overall survival has not been reached. When patients were grouped into whether they exhibited a reduction in the C-reactive protein from baseline after 6 months of therapy, the median PFS for patients without (21 patients) or with (26 patients) a greater than one-third reduction in baseline CRP was 1 year vs more than 8 years (p<.01). Similarly, the median OS for patients without or with a reduction in baseline CRP was 7.9 years vs. median not reached (p=.02; see Figure). Toxicity included injection site reactions during the first month of therapy in 86% of patients. Grade 3–4 adverse events consisted mainly of asymptomatic neutropenia (17% of patients) and infection (18% of patients). Patients that progressed to active MM have been treated with standard therapies including lenalidomide, bortezomib, transplant, and novel therapies. In contrast, seven of the 26 patients with a CRP decrease continue with stable disease and minimal toxicity on IL-1Ra alone or in combination with standard agents. Conclusion: The above results suggest that agents such as IL-1Ra that specifically inhibit paracrine IL-6 production are effective at targeting the proliferative myeloma component and warrant further investigation in combination with standard myeloma therapies. Combination therapy that effectively targets both the proliferative and the IL-1 producing myeloma components may be useful in patients with active myeloma that have an elevated growth rate at diagnosis. Disclosures: Lust: Mayo Clinic: Patents & Royalties. Off Label Use: IL-1Ra use in smoldering myeloma. Donovan:Mayo Clinic: Patents & Royalties.

Abstract Abstract 2950 Background: The median age of patients diagnosed with MM is approximately 70 years, and it is a relatively uncommon disease in the younger population. Both conventional chemotherapy and stem cell transplantation (SCT) have favorably impacted the overall survival (OS) of young MM patients. The median survival of patients < 40 years of age, diagnosed prior to 1993 was reportedly 54 months at our institution. However, the impact of novel agents in this patient population is not well known. We studied the outcome of young patients presenting to our institution over the last decade. Methods: Records of 1538 patients presenting between 01/99 to12/08 were reviewed. The demographics, features and therapeutic interventions in patients up to 45 years of age at diagnosis were analyzed using descriptive statistics. The survival outcome of this group was compared with the remainder of the cohort using the Kaplan-Meier method. Results: One-hundred (6.5%) out of 1538 newly diagnosed MM patients were ≤ 45 years of age at diagnosis. The median follow-up of this group of young patients was 86 months. The disease and patient characteristics are outlined in table 1. A median of 5 regimens (range 1–14) was administered, and 85% patients had received high-dose therapy. 15 patients underwent allogeneic SCT after at least one prior autologous SCT. Novel agents were used both in the front-line and relapsed setting (lenalidomide 60%, thalidomide 56%, pomalidomide 9% and bortezomib 49%), and 45% of initial regimens were novel agent based. The 5 and 7-year OS from diagnosis was 69% and 59%, respectively and the median OS was 93 months. In contrast, the median OS of patients >45 years diagnosed during this period was 53 months (P=0.001, figure 1). Conclusion: A marked improvement in OS of young patients with MM diagnosed in the novel agent era is noted in comparison to the historical control of similar age group. In addition, the age associated survival benefit in the younger patient population prevails in the era of novel therapies. Disclosures: Gertz: Celgene: Honoraria. Lacy:Celgene: Research Funding. Dispenzieri:Binding site: Honoraria; Celgene: Research Funding. Kyle:Millennium: Consultancy; Binding Site: Honoraria. Kumar:Millennium Pharmaceuticals, Inc.: Research Funding; Celgene: Consultancy, Research Funding; Genzyme: Research Funding; Novartis: Research Funding; Merck: Consultancy, Honoraria.

Abstract Background Pomalidomide (POM) is the newest Immunomodulatory agent (IMiDs) that has shown clinical efficacy in relapsed multiple myeloma (MM) refractory to lenalidomide (LEN) and thalidomide (THAL). Studies of MM cell microenvironment suggest that tumor subclones compete for dominance during changes in drug therapy. It was previously observed that a minor clonal population increased in prominence of MM cells after 1 year of treatment with LEN. We examined whether the patients having THAL or LEN as the most recent prior-line therapy affects response to POM. Methods We studied 208 patients enrolled in a phase II trial of POM / dexamethasone between November 2007 and March 2012 at Mayo Clinic, Rochester. We reviewed the immediate prior-line therapy before enrollment in our trial. Comparison of treatment duration of POM and response rates were conducted between patients who had either THAL or LEN as latest prior-line therapy, and patients who were treated with non-IMiDs immediate before enrollment in POM trial. Treatment duration of POM was estimated using Kaplan Meier method and the survival curves were compared using log-rank test. We used univariate Cox proportional hazard models to estimate the prognostic impact of different variables. Results The median age of patients was 63 (range from 32 to 88). 68 % were males. 80 patients (38.5%) had THAL or LEN immediate prior to POM. Median prior-line therapies were 3. Patients who received THAL or LEN immediately prior to POM had a lower response rate than those who had non-IMiDs as latest therapy (29% vs 44%, p 0.04) and shorter median duration of POM treatment (5.7 months vs 7.3 months, p 0.02). In 190 (91%) patients who were previously treated with LEN and THAL at any time, median time between the end of LEN or THAL treatment and the initiation of POM was higher for POM responders than non-responders (10 months vs 3 months, p 0.0008). Patients responded to POM had a shorter duration of prior LEN or THAL treatment compared to non-responders (9 months vs 15 months, p 0.001). Conclusion THAL or LEN as an immediate prior-line therapy to POM is associated with a lower response rate and shorter effective treatment duration. Longer interval between prior immunomodulatory compounds and POM, and shorter exposure to previous immunomodulatory compounds are associated with better POM treatment response. Disclosures: Gertz: Celgene: Honoraria. Kumar:Merck: Consultancy, Honoraria; Celgene: Consultancy, Research Funding; Millennium: The Takeda Oncology Company: Research Funding; Novartis: Research Funding; Genzyme: Research Funding. Lacy:Celgene Corporation: Research Funding.

Abstract Background Immunoglobulin light chain-associated amyloidosis (AL) is caused by deposition of immunoglobulin light chain molecules with unique, clonotypic variable (V) regions. Detection and identification of the V region, however, has been challenging due heterogeneity inherent in V regions. We developed a new method for detecting IGKV and IGLV region fragments in AL deposits using protein mass spectrometry and novel bioinformatics approach. We report distinct IGKV and IGLV usage in localized versus systemic AL. Methods Shotgun protein mass spectrometry on amyloid plaques was performed as previously described (Blood. 2009; 114: 4957-9). Peptide tandem mass spectra (MS/MS) were searched against a composite sequence database containing SwissProt's human complete proteome augmented with 1764 IG V region sequences obtained from ImMunoGeneTics database and a Mayo Clinic internal database. Reversed sequences were appended to the database for estimating identification false discovery rates (FDRs). Peptide identifications were processed with Scaffold software. Confident protein identifications (probability > 0.9) with at least one unique peptide identifications and five MS/MS matches were considered. Detected variable gene family (if any) with most number of peptide and spectral matches is considered to be present in the deposit. The method was first validated in 8 cases of AL amyloidosis with known IGKV and IGLV region sequences and then applied on 1238 systemic and 393 localized AL cases. Differences between groups were measured by generating hypergeometric p-values. Results In all 8 AL cases with known IGKV and IGLV region usage, gene family identified in the AL deposit via proteomics matched the gene family inferred from bone marrow plasma cells by Sanger sequencing of IGLC genes. Armed with this method, we analyzed the amyloid proteomics data from 1238 patients with systemic AL amyloidosis and 393 patients with localized AL amyloidosis. The anatomical site distribution in systemic cohort was 296 GI tract, 364 heart, 225 kidney, 81 liver and 272 fat aspirate; Localized cohort has 78 bladder, 158 lung and 157 skin cases. Figure 1 shows the normalized frequency of the variable gene families detected between the systemic and localized AL amyloidosis. For AL-kappa, KV1 was more prevalent in systemic cases when compared to localized cases (p=7.2E-12) suggesting KV1 clones as a hallmark for systemic AL-kappa amyloidosis. KV3 was more frequently seen in localized AL-kappa cases when compared to systemic AL-kappa cases (p =2.8E-11). For AL-lambda, LV1 and LV2 gene families were more prevalent in localized cases when compared to systemic cases (p= 0.039 and 2.7E-05). LV6 was more prevalent in systemic AL-lambda cases (p=1.4E-07). We also detected a higher incidence of mixed AL/AH type in localized AL (18%) when compared to systemic AL (5%; Odds Ratio=4.2673, p<0.0001). We next turned to the organ specific IGKV and IGLV gene family usage patterns in patients with localized amyloidosis. For 147 localized AL-kappa cases, KV3 was most dominant in lung (64%) and KV1 was dominant in skin (38%). For 246 localized AL-lambda cases, LV2 was most prevalent in lung (34%) and LV3 was most prevalent in skin (36%). For bladder, both LV1 and LV2 had comparable prevalence (42% and 32%). For 361 systemic AL-kappa cases, KV1 consistently ranked at the top of gene families used in GI tract (55%), heart (71%), kidney (59%), liver (75%) and fat aspirate (50%). For 877 systemic AL-lambda cases, LV2 was predominant in GI tract (30%), LV3 in heart (35%) and LV6 in kidney (33%). The prevalence of LV1, LV2 and LV3 in liver is comparable (36%, 22% and 31%). LV6 and LV3 had comparable prevalence (22% and 24%) in AL-lambda fat aspirates. Conclusion The novel proteomics method detects IGLC V family usage in large cohorts of AL patients. It identifies unique profiles in systemic and localized cases, and in different organ sites. This information will be helpful in determining systemic versus localized nature of AL amyloidosis at diagnosis and to assess risk of specific end organ involvement. We found also a strong association between IGKV and IGLV gene usage and organ involvement. Disclosures: No relevant conflicts of interest to declare.

Abstract Abstract 2942 Background: Pomalidomide (pom) is a distinct immunomodulatory (IMid) drug with high response rates in relapsed MM, including patients previously treated with thalidomide, bortezomib and lenalidomide. However, its duration of response and long term outcome is unknown. We evaluated the long term outcomes of the first Mayo Clinic cohort of pts treated with Pom. Methods: Pts with relapsed/refractory myeloma with 1–3 prior therapies were enrolled. Pom 2 mg/d was given orally continuously on 28 day cycle with weekly dexamethasone 40 mg. All pts received DVT prophylaxis with aspirin, heparin or warfarin. Results: 60 pts with relapsed MM were enrolled from Nov 2007-Aug 2008. Median age was 65.5; 36 were male. Median time from diagnosis was 45.6 mo (9.–-192.5). Nineteen (32%) were high-risk according to mSMART (msmart.org), and 78% were ISS Stage 2/3. Prior therapies included transplant (65%), bortezomib (33%), thalidomide (47%), lenalidomide (35%) [previous IMiD 60%] and radiation (38%). Toxicities at least possibly attributed to Pom included G3/4 anemia (5/0%), leukopenia (17/3%) and thrombocytopenia (3/0%). G3/4/5 non-hematological toxicities occurred in 30 (50%) and included fatigue (18/0/0%), pneumonia (8/2/2%), hyperglycemia (5/0/0%) and constipation (5/0/0%). Only one pt had grade 3 neuropathy. Treatment adjustment for occurred in 30 pts (50%) for pom (mostly for neutropenia) and 35 pts (58%) for dex. A median of 11.5 cycles were administered. With median follow up of 30.1 months (mo), overall response was seen in 39 (65%) [4 sCR, 5 CR, 16 VGPR, 14 PR]. Median time to first reponse (≥PR) was 1.7 mo (0.8–14.8). Median duration of response (in responders of ≥PR) was 21.3 mo. Median PFS was 13 mo and the 2 year OS rate was 76%. Standard risk pts had median PFS of 18.4 mo and 2 year OS rate was 85%; high risk pts had median PFS of 9.2 mo and 2 year OS rate was 57%. (Figure 1) Conclusions: Pom/dex is highly effective and well tolerated in relapsed MM, with a response rate of 65% even in pts with multiple prior therapies, including other IMiDs, bortezomib and transplant. The response is also durable, with median duration in excess of 21 months. Pom/dex provides long term benefit with median PFS 13 months and 2 year OS rate of 76%. Disclosures: Kumar: Merck: Consultancy, Membership on an entity's Board of Directors or advisory committees. Stewart:Celgene Corporation: Consultancy, Research Funding; Millenium: Consultancy, Research Funding; Novartis: Consultancy, Research Funding; BMS: Consultancy, Research Funding; Onyx: Consultancy, Research Funding. Fonseca:Consulting :Genzyme, Medtronic, BMS, Amgen, Otsuka, Celgene, Intellikine, Lilly Research Support: Cylene, Onyz, Celgene: Consultancy, Research Funding. Lacy:Celgene: Research Funding.

Abstract Amyloidosis is a group of hereditary and acquired disorders of diverse pathogenesis united by end organ damage due to tissue deposition of misfolded proteins. The diagnosis is typically based on demonstrating Congo red positive amyloid deposits in tissue biopsies of clinically involved sites. Because treatment options for amyloidosis patients are highly varied and intricately tied to the identity of the protein that constitutes the amyloid deposits, adequate diagnostic evaluation now requires identification of the amyloidogenic protein. Traditionally, immunohistochemistry with antibodies to amyloid-associated proteins was the clinical technique of choice for subtyping amyloid deposits in tissue sections. This technique suffers from poor analytical sensitivity and specificity and is a suboptimal technique on which to base treatment decisions for amyloidosis patients. We developed a highly accurate and reproducible liquid chromatography electrospray tandem mass spectrometery (LC-MS/MS)-based shotgun proteomics assay for subtyping amyloid deposits (Blood. 2009; 114: 4957-9) from microdissected paraffin embedded tissue samples. Implementation of this assay in a CAP/CLIA clinical laboratory has subsequently transformed the standard of amyloidosis care at Mayo Clinic. Since 2008, we utilized the assay in routine practice to identify 20 different amyloid types in tissue samples from diverse anatomic sites from 4139 patients (Table 1). Although AL and ATTR were most common, the cases include a large variety of unusual, and in many cases clinically unsuspected amyloid types. In addition, the amyloid protein subtypes had different frequencies in different anatomic sites (A partial list of tissue sites and their amyloid types analyzed in this study includes: bone marrow: AL 82%, ATTR 15%, AA 2%, other 1%; kidney: AL 51%, ALect2 18%, AA 17%, AH 5%, AFib 4%, other 5%; liver: AL 64%, ALect2 23%, AApoA1 6%, AA 3%, ATTR 2%, other 2%; heart: ATTR 60%, AL 37%, AANF1%, other 2%; GI tract: AL 78%, ATTR 13%, AA 6% AApoA4 1%, other 2%; eye [primarily adnexae] AL 63%; eye [primarily cornea] TGFB induced protein ig-h3 34%, other 3%). One caveat is that these distributions of amyloid types may not accurately reflect population prevalence. More likely, the findings reflected a composite prevalence that included challenging amyloidosis cases.Table 1Frequency of amyloid subtypes observed in the Mayo Amyloid Cohort (n=4139). Asterisk denotes non-canonical subtypesAmyloid SubtypeNumber (%) of casesAL2553 (61.68)ATTR1015 (24.52)AA151 (3.65)ALect2148 (3.58)AIns48 (1.09)Keratin*36 (0.87)AApoA130 (0.72)AH27 (0.65)AFib26 (0.63)TGFB1-IP*22 (0.53)AApoA420 (0.48)AANF14 (0.34)Ab2M12 (0.29)AGel12 (0.29)ASem112 (0.29)APro7 (0.17)ALys3 (0.07)ACal2 (0.05)Enfuvirtide*2 (0.05)AIAPP2 (0.05) The prevalence of diverse and unexpected amyloid types in many tissues suggest that shotgun proteomic-based analysis may be the only way to accurately assign amyloid subtype in tissue samples. The technique avoids the analytical problems of immunohistochemistry and the bias introduced by assigning probable amyloid type based on clinical presentation and disease distribution. It provides the clinician with an amyloid subtype that allows for confident individualized patient management. Accurate amyloid subtyping by LC-MS/MS is not only possible, but has proven to be a robust routine clinical tool for the evaluation of numerous amyloidosis patients in our practice. Disclosures: No relevant conflicts of interest to declare.

Abstract Background: Multiple myeloma (MM) is a heterogeneous disease with very divergent outcomes that are dictated in a large part by specific cytogenetic abnormalities, as well as other prognostic factors such as the proliferative rate of marrow plasma cells. Prognostic systems incorporating these factors have shown clinical utility in identifying high-risk patients, and are increasingly being utilized for treatment decision-making. However, the prognostic relevance of these factors may change with the application of novel therapies. The objective of this study was to determine the impact of risk-stratification (incorporating plasma cell metaphase cytogenetics, interphase fluorescent in-situ hybridization (FISH) and the slide-based plasma cell labeling index (PCLI)) in a cohort of patients with newly diagnosed MM treated initially with lenalidomide + dexamethasone (Rev-Dex). Methods: From March 2004 to November 2007, 100 consecutive patients treated with Rev (25mg/day) on days 1 through 21 of a 4-week cycle in combination with dexamethasone as initial therapy for newly diagnosed myeloma, were identified. High-risk MM was defined as presence of any one or more of the following: hypodiploidy, monoallelic loss of chromosome 13 or its long arm (by metaphase cytogenetics only), deletion of p53 (locus 17p13) or PCLI ≥ 3% or immunoglobulin heavy chain (IgH) translocations, t(4;14) (p16.3;q32) or t(14;16)(q32;q23) on FISH. PFS and OS survival estimates were created using the Kaplan Meier method, and compared by log-rank tests. Results: The median estimated follow-up of the entire cohort (N=100) was 36 months. The median PFS was 31 months; the median OS has not been reached. The 2- and 3-year OS estimates were 93% and 83%, respectively. 16% patients were deemed high-risk by at least one of the 3 tests (cytogenetics, FISH or PCLI). Response rates (PR or better) were 81% versus 89% in the high-risk and standard risk groups, respectively, P=NS; corresponding values for CR plus VGPR rates were 38% and 45% respectively. The median PFS was 18.5 months in high-risk patients compared to 37 months in the standard-risk patients (n=84), P<0.001(Figure). Corresponding values for TTP were 18.5 months and 36.5 months, respectively, P=<0.001. OS was not statistically significant between the two groups; 92% 2-year OS was noted in both the groups. Overall, 95 patients had at least one of the 3 tests to determine risk, while 55 patients could be adequately stratified based on the availability of all the 3 tests, or at least one test result that led to their inclusion in the high-risk category. The significant difference in PFS persisted even when the analysis was restricted to the 55 patients classified using this stringent criterion; 18.5 months vs. 36.5 months in the high-risk and standard- risk groups respectively; P<0.001. In a separate analysis, patients who underwent SCT before the disease progression were censored on the date of SCT to negate its effect, and PFS was still inferior in the high-risk group (p=0.002). Conclusion: The TTP and PFS of high-risk MM patients are inferior to that of the standard-risk patients treated with Rev-Dex, indicating that the current genetic and proliferation-based risk-stratification model remains prognostic with novel therapy. However, the TTP, PFS, and OS obtained in high-risk patients treated with Rev-Dex in this study is comparable to overall results in all myeloma patients reported in recent phase III trials. In addition, no significant impact of high-risk features on OS is apparent so far. Longer follow-up is needed to determine the impact of risk stratification on the OS of patients treated with Rev-Dex. Figure Figure