Vesole, David H.

Abstract Background: Lenalidomide has shown efficacy in patients with relapsed myeloma in phase II and III clinical trials, and is currently being investigated as initial therapy for the disease. We report results of a phase III trial comparing lenalidomide plus high-dose dexamethasone (Dex) versus lenalidomide plus low-dose Dex as first line therapy in newly diagnosed multiple myeloma (MM). Methods: Pts with newly diagnosed, untreated, symptomatic MM were eligible. Pts in both arms received lenalidomide 25 mg/day PO on days 1–21 every 28 days. In addition, patients in the high-dose Dex arm (Arm A) received Dex 40 mg on days 1–4, 9–12, and 17–20 PO every 28 days, while pts in the low-dose Dex arm (Arm B) received Dex 40 mg on days 1, 8, 15, and 22 PO every 28 days. 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 until progression. Response was defined as a decrease in serum and urine monoclonal (M) protein by 50% or higher. If the serum M protein was unmeasurable, a 90% or higher decrease in urine M protein was required. Responses need to be confirmed at least 4 weeks apart. Patients with disease progression or not responding to lenalidomide within 4 months switched to thalidomide with the same dose of dexamethasone they were receiving (Arms C and D, respectively). An independent Data Monitoring Committee approved release of these results. Results: 445 pts were enrolled: 223 randomized to Arm A and 222 to Arm B. Median age was 65 yrs. Serious adverse event data based on expedited reporting (AdEERS) is available on all pts (see table). Common adverse events of Grade 3 or higher were thromboembolism (18.4% in arm A vs 5.4% in Arm B), infection/pneumonia (18.8% vs 9.0%) and hyperglycemia (5.8% vs 1.8%). Incidence of any grade 4 or higher toxicity was 22.0% in Arm A vs 12.6% in Arm B. Response data is being analyzed. Conclusions: Lenalidomide plus two different schedules of Dex was investigated in this phase III trial. Preliminary results suggest that toxicity rates are higher in the high-dose Dex arm. The differences in the response rates between the two arms will dictate future trials and clinical practice. Major Toxicties (AdEERS) Toxicity Arm A (n=223) Arm B (n=222) Cardiac ischemia (Grade >=3) 2.7% 0.5% Hyperglycemia (Grade >=3) 5.8% 1.8% Infection/Pneumonitis (Grade >=3) 18.8% 9.0% Neuropathy (Grade >=3) 0.9% 0.9% Thromboembolism (Grade >=3) 18.4% 5.4% Any non-Hem toxicity (Grade >=3) 53.4% 36.0% Any toxicity (Grade >=4) 22.0% 12.6% Death (Grade 5) 4.5% 1.4%

Abstract Background: HLA associations for the risk of developing MM have been described in various non-Caucasian ethnic groups but have not revealed consistent results. Racial and genetic differences in cytokine polymorphisms linked to extended haplotypes; association of autoimmune disorders with HLA types; the proximity of the HLA Class I and II genes to TNF and other Class III genes responsible for complement and cytokines suggest that HLA polymorphisms may be associated with the risk of developing MM. Aim: We compared HLA-A,-B and -DRB1 2-digit allele and haplotype frequencies in patients with MM to the normal population in order to define HLA specificities associated with the risk of developing MM. Methods: A cohort of 1803 US Caucasian patients with MM were identified based on availability of HLA-A, B, DRB1 DNA-based typing or serologic typing converted to 2-digit alleles. These patients had either received a matched sibling allogeneic transplant for MM reported to the CIBMTR (N=174) or had HLA typing performed for an unrelated donor search conducted through the US National Marrow Donor Program (NMDP) (N=1629). HLA-A, B and DRB1 allele frequencies among patients were compared to A-B-DRB1 frequencies in HLA typed healthy US Caucasian controls (N= 433838) from the NMDP database. The most frequent alleles among patients and controls as well as HLA haplotype frequencies generated using the EM (expectation-maximization) algorithm were compared using Chi-Square analysis with Bonferroni correction for the number of comparisons. Results: Patients with MM had a median age of 49 (range 3–78) years and M/F ratio of 1.86 (1172/631). The controls had a median age of 44 (range 18–60) years and M/F ratio of 0.735 (183785/250053). Comparison of HLA-A, -B and –DRB1 single-locus allele frequencies between the myeloma patients and controls (those in the top 10 in either group) revealed similarity except for HLA-B*07 and B*44. B*44 was observed less frequently among the patients (a protective effect) frequency (f): 0.126 vs 0.145 (p= 0.005, Odds Ratio (OR): 0.848). On the contrary, HLA-B*07 was more common (a predisposing effect) among patients (OR: 1.135, p=0.047). Among the top 20 two locus (HLA-A-B and HLA-B-DRB1) haplotype frequencies in either group, B*44-DRB1*13 and B*07-DRB1*13 were significant: OR: 0.506 and 1.714 (p=0.003 and 0.007) respectively. A-B-DRB1 haplotype comparisons showed significance for: A*02-B*44-DRB1*04 (OR: 0.686, p=0.021), A*02-B*44-DRB1*13 (OR: 0.445, p=0.065) and A*02-B*07-DRB1*04 (OR: 1.968, p=0.029) confirming the single and B-DRB1 combination comparison results. Significantly different HLA-A, -B and -DRB1 single-locus allele or haplotype frequencies between patients and controls are shown in table 1. Conclusion: This is the largest epidemiologic study of HLA allele frequencies and the first study on HLA haplotype frequencies in MM. We observed a protective effect on the risk of developing MM with B*44 and a predisposing effect with B*07. Similar predisposing and protective haplotype associations were observed with A*02-B*07-DRB1*04 and A*02-B*44-DRB1*04 respectively. A revised analysis using a gender-matched control group is in progress. Further study including major histocompatibility region SNP mapping and candidate gene testing will help elucidate the genetic basis underlying this observation. Table 1. Allele/Haplotype Frequency Controls Frequency MM Odds Ratio (OR) P value (corrected) OR = odds of observing the allele/haplotype in patients compared to controls A*02-B*44-DRB1*13 0.00620 0.00277 0.445 0.065 B*44-DRB1*13 0.01359 0.00686 0.507 0.003 A*02-B*44-DRB1*04 0.02605 0.01813 0.686 0.021 B*44 0.14552 0.12618 0.848 0.005 B*07 0.13313 0.14836 1.134 0.047 B*07-DRB1*13 0.00814 0.01397 1.714 0.007 A*02-B*07-DRB1*04 0.00367 0.00721 1.968 0.029

Background: Autologous hematopoietic cell transplantation (AHCT) is an effective treatment to achieve deep and durable remission in multiple myeloma (MM). Typically, AHCT is offered to patients <70 years of age, although the median age of diagnosis of MM is 70 years. We compared the outcomes of upfront AHCT across age groups for newly diagnosed MM in the era of novel therapies using the Center for International Blood and Marrow Transplant Research (CIBMTR) database. Methods: We analyzed the outcomes of 15,999 MM patients aged 20 years and older from the USA who received a single AHCT with melphalan conditioning within 12 months of diagnosis between 2013 and 2017 and reported to the CIBMTR. Multivariate analysis was performed for non-relapse mortality (NRM), relapse/progression (REL), progression-free survival (PFS) and overall survival (OS) using Cox proportional hazards model with age at transplant in decades as the main effect. Hazard ratio (HR) with 95% confidence intervals (CI) are reported. Because of the large sample size, a p-value of <0.01 was considered significant a priori. Results: Table 1 shows patient, disease and treatment characteristics by age group at diagnosis. All age groups had similar distribution of gender, race, ethnicity, Karnofsky performance score (KPS), comorbidity index (HCT-CI), stage III by Durie-Salmon/International Staging System. There was a higher proportion of high-risk cytogenetics in patients ≥70 years (30%), compared to age group 40-49 years (24%) and 20-39 years (20%) in this population. Older patients were more likely to be White compared to younger patients: 85% ≥70 compared to 64% 20-39 years. While 82% of the overall population received melphalan 200 mg/m2, 58% of the ≥70% received Mel 140 mg/m2. There were more ASCT performed in the ≥70-year age group in 2017 (28%) compared to 2013 (15%). Univariate outcomes by age groups shown in Table 2 revealed that 100-day NRM was higher in ≥70 years at 1% compared to younger patients (p <0.01) and 2-year OS was lower in ≥70 years at 86 (85-88)% compared to 60-69 years, 89 (88-89)% (p<0.01). When adjusted for other variables (Table 3), compared to reference age group of 60-69 years, patients ≥70 had similar NRM (HR 1.3, 95% CI 1, 1.7, p 0.06), REL (HR 1.03, 95% CI 0.9, 1.1, p 0.6), PFS (HR 1.06, 95% CI 1, 1.2, p 0.2), and OS (HR 1.2, 95% CI 1, 1.4, p 0.02). The leading cause of death across all age groups was primary disease. Among the ≥70 years cohort, melphalan dose was a surrogate for worse outcomes including NRM at 100 days (Mel 140, 1 (1-2)% vs Mel 200 0 (0-1)%, p 0.003, PFS at 2 years Mel 140 64 (60-67)% vs Mel 200 69 (66-73)%, p 0.003, and OS at 2 years (Mel 140 85 (82-87)% vs Mel 200 89 (86-91)%, p 0.01) (Figure). Conclusions: This is the largest study of AHCT in older adults with MM. More MM patients ≥70 years are being transplanted in the US over time. While our data may highlight referral and access biases regarding which older patients may be referred for ASCT, our results confirm that patients ≥70 years can undergo transplant safely and achieve similar benefits as 60-69 years' old patients. Our results also suggest that melphalan 200 mg/m2 may be given safely in the ≥70 years population. While melphalan conditioning dose 140 mg/m2 in the ≥70 group is associated with worse outcomes, this is likely a surrogate for higher frailty and comorbidities in this cohort of patients. Our analysis confirms that AHCT has similar benefits in terms of disease control (REL and PFS) in both young and older MM patients. This benefit is seen even in a contemporaneous era where proteasome inhibitors and/or immunomodulator drugs are used in upfront treatment. Thus, AHCT remains a safe consolidation therapy across all age groups of MM patients. Disclosures Hari: Celgene: Consultancy, Honoraria, Research Funding; Takeda: Consultancy, Honoraria, Research Funding; BMS: Consultancy, Research Funding; Janssen: Consultancy, Honoraria; Kite: Consultancy, Honoraria; Amgen: Research Funding; Spectrum: Consultancy, Research Funding; Sanofi: Honoraria, Research Funding; Cell Vault: Equity Ownership; AbbVie: Consultancy, Honoraria. Kumar:Janssen: Consultancy, Research Funding; Takeda: Research Funding; Celgene: Consultancy, Research Funding. Shah:Poseida: Research Funding; Bristol-Myers Squibb: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Nkarta: Consultancy, Membership on an entity's Board of Directors or advisory committees; Kite: Consultancy, Membership on an entity's Board of Directors or advisory committees; Celgene, Janssen, Bluebird Bio, Sutro Biopharma: Research Funding; University of California, San Francisco: Employment; Genentech, Seattle Genetics, Oncopeptides, Karoypharm, Surface Oncology, Precision biosciences GSK, Nektar, Amgen, Indapta Therapeutics, Sanofi: Membership on an entity's Board of Directors or advisory committees; Indapta Therapeutics: Equity Ownership; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Teneobio: Consultancy, Membership on an entity's Board of Directors or advisory committees. Qazilbash:Genzyme: Other: Speaker; Bioclinical: Consultancy; Amgen: Consultancy, Other: Advisory Board; Autolus: Consultancy. D'Souza:EDO-Mundapharma, Merck, Prothena, Sanofi, TeneoBio: Research Funding; Prothena: Consultancy; Pfizer, Imbrium, Akcea: Membership on an entity's Board of Directors or advisory committees.

Abstract Introduction: In the ASPIRE and ENDEAVOR trials, multiple myeloma (MM) patients treated with carfilzomib (K) had significantly improved progression‐free survival and overall survival compared with standard of care. The incidence of all-grade adverse cardiovascular events (ACVE) was 26.6% and 24.5% in the K treated groups in ASPIRE and ENDEAVOR respectively. The atherosclerotic cardiovascular disease (ASCVD) score is a risk stratification tool used by cardiologists to classify patients with a score ≥7.5% as high risk for the incidence of ASCVD events. To date, there are no clinically relevant models that predict the likelihood of ACVE in MM patients treated with K nor are we aware of any protective factors against ACVE. Our study aims to identify factors which can predict and mitigate the incidence of ACVE. Methods: A retrospective chart review of 372 MM patients who were treated with K between 2011 and 2018 at our institution was performed.Data were summarized using descriptive statistics; Chi-square tests of association and Kruskal-Wallis tests were employed to test for differences across groups, where appropriate. Logistic regression was performed to examine the risk factors associated with ACVE. Results: Of the 372 patients, 243 (65%) were Durie-Salmon Stage (DSS) III, 70 (19%) were International Staging System (ISS) III; 186 (50%) were men. There were a total of 102 (27%) ACVE and 33 (9%) ≥grade 3 events. The most common ACVE were congestive heart failure (29%), asymptomatic elevations in pulmonary arterial systolic pressure (PASP) (27%), and hypertension (HTN) (16%). Sixty-eight (66%) Caucasians, 14 (14%) African Americans and 17 (17%) Hispanics developed ACVE. Aspirin (ASA) (64%), beta blockers (BB) (51%), calcium channel blockers (CCB) (43%) and statins (37%) were the most common cardiac medications patients were taking at the time of K initiation. Regardless of cardiac history, patients who were taking a CCB had higher odds of experiencing an ACVE compared to patients who were not taking a CCB (CCB + Cardiac history: OR=1.9; CI=1.0-3.7; CCB, no Cardiac history: OR=6.3; CI= 2.1-18.4) (Table 1). Patients with an ASCVD score ≥7.5% did not have an increased incidence of ACVE but did have an increased incidence of ≥grade 3 vs. grade 1-2 ACVE (100% vs. 78%, p=0.092). Prior cardiac history, including history of HTN, was common (59%) but not associated with incidence or severity of ACVE. Those with type 2 diabetes had a higher rate of ≥grade 3 vs. grade 1-2 ACVE (33% vs. 10%, p=0.004). Patients on certain CV medications while receiving K-based treatment had a higher incidence of ACVE compared to those not on these medications, including BB (51% vs. 34%, p=0.002), CCB (43% vs. 26%, p=0.002), aldosterone antagonists (AA) (8% vs. 3%, p=0.024) and statins (37% vs. 25%, p=0.022). Patients on ASA were more likely to experience ≥grade 3 compared to grade 1-2 ACVE (78% vs. 53%, p=0.016). ACE inhibitors or angiotensin receptor blockers (ACE/ARB) were not associated with increased incidence or severity of ACVE. The use of K in relapsed, as opposed to induction setting, was associated with a higher incidence of ACVE (31% vs. 20%, p=0.035). Maximum dose and number of K doses were not associated with ACVE. There was no relationship between PASP elevation and age >75, use of BB, CCB, AA, ACE/ARB, number of K treatments or maximum dose of K. Factors that were associated with increased odds of ACVE in multivariate analysis included patients who received K in the relapsed setting (OR= 1.7; CI=0.94-3.0) and use of an AA (OR= 4.5; CI=1.4-14.1) (Table 1). Conclusion: In line with prior studies, 28% of MM patients treated with K at our institution developed an ACVE, with 9% grade 3 or above. Use of CCB and AA were particularly associated with increased risk of ACVE, while use of ACE/ARB were not. ASCVD score ≥7.5% was associated with an increased incidence of ≥grade 3 ACVE in K-treated patients and should perhaps be evaluated as a predictive tool in prospective studies. Disclosures Siegel: Celgene: Consultancy, Honoraria, Research Funding, Speakers Bureau; Janssen: Consultancy, Honoraria, Speakers Bureau; Takeda: Consultancy, Honoraria, Speakers Bureau; Novartis: Honoraria, Speakers Bureau; Amgen: Consultancy, Honoraria, Speakers Bureau; BMS: Consultancy, Honoraria, Speakers Bureau; Karyopharm: Consultancy, Honoraria; Merck: Consultancy, Honoraria, Speakers Bureau. Biran:Merck: Research Funding; Amgen: Consultancy, Speakers Bureau; Takeda: Consultancy, Speakers Bureau; Celgene: Consultancy, Honoraria, Speakers Bureau; BMS: Research Funding.

Abstract Abstract 824 There is no standard therapy for MM relapsing after autologous hematopoietic cell transplantation (AHCT). A second AHCT can result in additional progression-free survival (PFS). Nonmyeloablative/reduced intensity conditioning (NST/RIC) allogeneic transplantation (AlloHCT) has the advantages of a tumor-free graft and the potential of a graft-versus-myeloma (GVM) effect. Few studies have compared second AHCT vs. NST/RIC AlloHCT. We compared the outcome of second AHCT or NST/RIC AlloHCTafter relapse from prior AHCT in patients with MM reported to the CIBMTR from 1995–2008. Recipients of planned tandem transplants, AlloHCT for graft failure or second malignancies and myeloablative alloHCT were excluded. 137 patients underwent second AHCT and 152 underwent NST/RIC AlloHCT (32 HLA-identical sibling and 120 unrelated donor). The table below illustrates clinical characteristics and patient outcomes. AlloHCT recipients were significantly younger (median 53 years [yrs] of age vs. 56 yrs in the AHCT cohort (p < 0.001). The groups were similar in Karnofsky performance score (KPS) and gender. Conditioning regimens differed between groups. In the AHCT cohort, 85% were melphalan based. In the NST/RIC alloHCT cohort, 38% received melphalan + other drugs and 24% received total body irradiation +/− other drugs but no melphalan (p <0.001). Time from 1st to 2nd transplant was significantly shorter for the AlloHCT cohort (30 vs. 23 months, p = 0.014). Acute graft-versus-host disease (GVH) was 35% at 60 days while chronic GVHD was 44% at 36 months.Patient CharacteristicsAutologousAllogeneicP-valueNumber of patients137152Age at 2nd transplant, median (range), years56 (28–65)53 (32–65)0.001*Gender Male84 (61)90 (59)0.720Karnofsky Score pre-transplant ≥90%68 (50)76 (50)0.884Time from 1st to 2nd transplant, months, median (range)30 (6–122)23 (6–78)0.014* 6–24 months44 (32)78 (51)0.001* >24 months93 (68)74 (49)OutcomesTreatment-related Mortality (TRM)12 months2 (1–5)13 (8–19)<0.001*60 months4 (2–8)15 (10–21)<0.001*Relapse/Progression12 months51 (43–58)72 (64–79)<0.001*36 months82 (76–88)80 (73–86)0.655Progression-free survival12 months47 (40–54)15 (10–21)<0.001*36 months13 (9–19)6 (3–10)0.038*Overall Survival (OS)12 months83 (77–89)51 (42–58)<0.001*36 months46 (37–54)20 (14–27)<0.001*60 months29 (21–38)9 (5–15)<0.001**Significant difference The most common cause of death in both cohorts was progression of MM. On multivariate analysis risk of death was higher for alloHCT (HR 2.38, p < 0.001), KPS < 90 (HR 1.96, p < 0.001), and year of transplant (2004 or earlier, HR 1.77, p = < 0.001). AlloHCT was associated with significantly higher risk of TRM (HR 7.14, p < 0.001). Durie-Salmon Stage III was associated with a higher risk of relapse (HR 2.70, 95% CI: 1.93–3.80, P<0.001) and treatment failure in the alloHCT group (HR 3.05, 95% CI: 2.20–4.22, p < 0.001). We conclude that patients with MM who underwent NST/RIC alloHCT after AHCT failure experienced higher TRM and lower probability of survival compared with those who received second AHCT. Because genetic risk data were not available for these patients, we cannot exclude the possibility that the alloHCT population was a higher risk population. Despite this limitation, our data demonstrate that the value of alloHCT after relapse from prior AHCT is limited. Disclosures: No relevant conflicts of interest to declare.

Abstract Abstract 2877 FLC assay measures circulating unbound k and l light chains and is of diagnostic and prognostic value in plasma cell disorders. Normalization of FLC ratio is considered a higher level of complete response (CR) in MM but this has not been well validated prospectively. HLC is a novel antibody based assay that targets the unique junctional epitopes between the heavy chain and light chain constant regions of intact immunoglobulin (Ig) molecules. It separately measures in pairs the light chain types of each immunoglobulin class generating ratios of monoclonal Ig/background polyclonal Ig concentrations (i.e IgGκ/IgGλ, IgAκ/IgAλ and IgMκ/IgMλ); potentially simplifying assessment of monoclonal protein response. To assess the prognostic impact of these assays and to correlate them with electrophoretic/immunofixation (SPE/IFE) assessment, we analyzed 497 stored serum samples from patients enrolled in the Blood and Marrow Transplant Clinical Trials Network (BMT CTN) 0102 clinical trial, sponsored by the NHLBI and NCI, of tandem autologous (autoHCT) vs. tandem autoHCT- allogeneic (alloHCT). Samples were collected prior to the first autoHCT and analyzed for FLC (Freelite™) and HLC (Hevylite™) at The Binding Site, UK. Corresponding disease status determination was centrally performed by an expert data review committee using uniform response criteria and correlated with FLC and HLC results. HLC remission was defined as normalization of composite heavy and light chain ratios across all 3 measured heavy/light chain pairs or the normalization of clonal isotype with normal ratios of uninvolved pairs. The demographics of 497 patients with HLC/FLC samples at baseline were concordant with the main study and showed similar patient proportions from the 2 study arms. Of the 211 pts with baseline SPE response better than or equal to a very good partial response (>VGPR), 188 also had an HLC remission (Sensitivity=89%). Comparison of the HLC remission with the >VGPR disease state also identified a specificity of 52%, positive predictive value (PPV) of 58% and a negative predictive value (NPV) of 87%. Similarly, all 56 patients in complete remission (CR) by SPE/IFE were in HLC remission. Compared with conventional CR assessment, sensitivity of HLC remission was 100%, specificity 39%, PPV and NPV values of 17% and 100% respectively. FLC remission correlated with >VGPR disease state had a sensitivity of 47%, specificity of 81% and a PPV and NPV of 64% and 67% respectively. Multivariate models for post transplant progression free survival (PFS) indicated that baseline disease response (>VGPR vs. partial remission (PR) or<PR) was associated with longer PFS. Adjusted models including baseline response, myeloma stage and study arm were used to compare the predictive utility of HLC and FLC assays. There was a lower risk of treatment failure (HR 0.74, p=0.02) and superior PFS for patients who achieved an HLC remission. When stratified by baseline disease response states, there was no additional prognostic impact for HLC remissions on PFS. Normalization of FLC ratio among patients with >VGPR disease state did not impact PFS (HR 0.96, p=0.83). Abnormal HLC after induction therapy has a high negative predictive value (100%) for identifying patients not achieving CR by uniform response criteria and is also associated with shorter PFS after transplant. FLC ratio normalization had no impact suggesting that stringent CR criteria may need further validation. Disclosures: Krishnan: Celgene: Speakers Bureau; Millenium: Speakers Bureau. Alvi:the binding site: Employment. Harding:The Binding Site Group Ltd: Employment. Maloney:Cellgene: Consultancy.

Abstract Multiple Myeloma (MM) is the most common indication for autologous hematopoietic stem cell transplantation (auto HCT). However, little information is available regarding the outcome of patients (pts) with the rarer immunoglobulin subtypes IgD and IgM, which represent 2% and 0.5%, respectively, of all MM cases. In addition, IgD MM has been reported previously to have a poorer prognosis, at least after conventional therapy. The CIBMTR conducted a retrospective analysis of MM pts transplanted between 1995–2005 to describe the characteristics and results of auto HCT in IgD (n=36) and IgM (n=11) among 3578 MM patients with auto HCT during this period. Median follow-up of survivors was 41 (range 2–130) months for pts with IgD and 58 (range 5–101) months for those with IgM MM. Among pts with IgD subtype, median age was 52 years (yrs), 67% were male, 36% had a creatinine >2 mg/L, 61% had Durie-Salmon stage III disease at diagnosis and 33% had Kappa Serum Light chain; the corresponding values for IgM pts were 58 yrs, 36%, 73% and 55% respectively. Prior to auto HCT, 75% of IgD pts were chemosensitive and 25% had received >2 lines of chemotherapy, while all IgM pts were chemosensitive and none had received more than 2 lines of prior therapy. Median time from diagnosis to auto HCT was 9 months in both subtypes. The most common conditioning regimen was singleagent melphalan, and all but 1 pt with IgD disease were grafted with blood stem cells. The small sample size precluded multivariate analysis for potential prognostic factors for outcome. Below table summarizes the post-auto HCT results in these pts contrasted with a reference pool of IgG and IgA MM receiving auto HCT in the same time period. Outcomes, probability (95% CI) IgD IgM IgG/IgA (n=36) (n=11) (n=1475) 100-day mortality, % 0 9 ( 0 – 32) 7 (5 – 8) Non MM deaths, % @ 1 yr 0 9 (0 – 32) 5 (4 – 7) @ 3 yrs 3 (0 – 13) 21 (2 – 51) 16 (14 – 18) Relapse/ Progression, % @ 1 yr 21 (9 – 37) 20 (2 – 49) 18 (16 – 20) @ 3 yrs 59 (41 – 76) 32 (8 – 64) 36 (34 – 39) Progression-free survival, % @ 1 yr 79 (63 – 91) 71 (41 – 93) 77 (74 – 79) @ 3 yrs 38 (21 – 56) 47 (17 – 78) 47 (44 – 50) Overall survival, % @ 1 yr 87 (74 – 97) 91 (68 – 100) 79 (77 – 85) @ 3 yrs 69 (51 – 84) 68 (36 – 93) 53 (50 – 57) No striking differences are apparent in the post auto HCT outcomes of patients with IgD and IgM MM. These results are also consistent with published outcomes of pts with IgD/ IgM MM (Wechaleker et al Ann Hematol. 2005 Feb; 84(2):115–7; Maisner et al Bone Marrow Transplant. 2008 Jan; 41(1):51–4).

Abstract Abstract 504 Background: There is limited data on the outcomes of AHCT for MM as a salvage approach following relapse after an initial (upfront) AHCT. We analyzed the outcomes of second salvage AHCT for relapsed MM. Methods: From the CIBMTR database we identified 187 patients (63% male) who had second AHCT (AHCT2) as salvage for MM relapsing after a prior AHCT (AHCT1). Planned tandem AHCT and AHCT2 within 6 months after AHCT1 were excluded. Cumulative incidence of relapse, non-relapse mortality (NRM) and the probabilities of progression-free (PFS) and overall survival (OS) were analyzed and multivariate analysis performed using proportional hazards models. Results: Median age at transplant was 57 (range 28–72) and 59 years (range 28–74) respectively at AHCT1 and AHCT2 respectively. Median follow up after AHCT2 was 47 months (range: 3–97). The proportion of IgG, IgA and free light chain subtypes was 48, 20 and 18% respectively. Durie Salmon stage at diagnosis was stage I (6%), II (21%), III (59%) respectively. Seven and 13% had serum creatinine > 1.5 mg/dl at AHCT1 and AHCT2 respectively. Conditioning regimen was single agent melphalan was in 78% and 84% for AHCT1 and AHCT2 respectively. At the time of AHCT2, majority (60%) were chemotherapy resistant compared with 80% patients with sensitive disease prior to AHCT1. Median time from AHCT1 to relapse was 18 months, with 32% relapsing within the first year, 29% in the second year, 19% in the third year and 19% beyond the third year after AHCT1. There was heterogeneity in the time to AHCT2 after relapse although 67% had AHCT2 within a year after relapse (median 7 months). Median between AHCT1 and AHCT2 was 32 months with the majority (69%) beyond 24 months. After AHCT2, day 28 engraftment rates of neutrophils and platelets were 96% (95% CI: 93–98) and 88% (95% CI: 83–92). Complete remission (CR) rates after AHCT1 were 43% whereas it was only 25% following AHCT2. After AHCT2, cumulative incidence of relapse at 1, 3 and 5 years was 51, 82, and 91% respectively. After AHCT2, one year NRM was 2%. PFS was 47%, 13% and 5% and OS was 83%, 46% and 29% at 1, 3 and 5 years respectively. In multivariate analysis, those relapsing within 36 months of AHCT1 had a higher risk of relapse (HR 1.58, p = 0.036) and higher risk of treatment failure and inferior PFS (HR1.52, p= 0.04). Mortality was higher for those relapsing early after AHCT1 (<36 months, HR 1.91, p = 0.02). OS was superior and mortality lower for AHCT2 performed after 2004-08 (HR 0.61, p=0.02). Conclusion: AHCT2 can be safely performed in relapsed MM with the best outcomes observed in later relapses (>36 months from AHCT1). OS has improved since 2004, but NRM, relapse and PFS after AHCT2 were not impacted by year of AHCT2. Thus the improved OS likely reflects greater availability of novel agents for post AHCT progression. Disclosures: No relevant conflicts of interest to declare.

Abstract Abstract 532 Primary Plasma cell leukemia (PCL) is a rare plasma cell disorder characterized by an aggressive clinical course. The efficacy of autologous and allogeneic HCT in PCL is uncertain due to the small number of patients that have been reported in the literature. To determine the potential for long-term disease control using HCT in PCL, we performed a retrospective review of 160 patients with primary PCL who received autologous (n=107), allogeneic (n=52) or syngeneic (n=1) HCT and were reported to the CIBMTR between 1995 and 2006. Kaplan–Meier analysis was used for overall survival (OS) and progression free survival (PFS). Cumulative incidence estimates of non-relapse mortality (NRM), relapse, acute and chronic GVHD were calculated. Median age at the time of autologous HCT was 57 years (range, 32-74 years) and allogeneic HCT was 48 years (range, 24-62 years). Median time from initial treatment to autologous HCT was 7 months and allogeneic HCT was 6 months. At the time of transplant, in the autologous HCT group, 19% patients were in complete remission, 56% in partial remission and 1% had relapsed/progressive disease; in the allogeneic HCT group, 17% were in complete remission, 46% in partial remission and 10% had relapsed/progressive disease. In the allogeneic HCT group, 83% of the patients received myeloablative conditioning regimens and 17% received nonmyeloablative/reduced-intensity conditioning. The rate of acute GVHD was 35% (95% confidence interval [CI], 22%-49%) and the rate of chronic GVHD at 3 years was 27% (95% CI, 13%-40%). After a median follow-up of 38 months, 20 of the 52 patients (38%) are alive in the allogeneic HCT group and 68 of the 107 pts (64%) are alive in the autologous HCT group (Figure 1). Progressive disease accounted for 38% of the deaths in the allogeneic HCT group and 86% of the deaths in the autologous HCT group. The outcomes are summarized in table 1. The remarkable overall survival of patients after autologous HCT in this analysis is noteworthy and indicates that autologous HCT is a safe and acceptable treatment option for patients with primary PCL. Although relapse rates are lower, allogeneic HCT carries a much higher risk of NRM and should be considered primarily in the context of a clinical trial. Disclosures: Lonial: Celgene: Consultancy; Millennium: Consultancy, Research Funding; BMS: Consultancy; Novartis: Consultancy; Gloucester: Research Funding.

Abstract Background: Conventional AlloTx for MM is associated with TRM exceeding 20%. Non-myeloablative AlloTx (NST) utilizes the known graft-vs-myeloma (GVM) effect in an attempt to eradicate minimal residual disease. Preliminary studies of NST in MM demonstrated significant CR and low 100 day post-NST TRM (Badros et al Blood97:2574, 2001). However, even though response rates were high, the vast majority of pts with significant MM disease at the time of transplant, relapsed within the first year. To provide maximal tumor cytoreduction to allow for a subsequent GVM effect, the ECOG designed a Phase II trial of AHSCT for maximal tumor cytoreduction followed by a matched sibling NST to allow for a GVM effect. Methods: The study was designed as a two-stage process based upon early transplant mortality in the first 100 days. Eligibility included pts treated as part of induction therapy or salvage therapy. Chemotherapy responsive disease was not required. Only matched sibling donors were allowed. Pts must have had adequate PS and physiologic organ function. After stem cell mobilization, pts received melphalan 200 mg/m2 with AHSCT. Pts underwent NST 100–182 d post-AHSCT following fludarabine 30 mg/m2 daily × 5 and cyclophosphamide 1 g/m2 for 2 days. GVHD prophylaxis included cyclosporine and corticosteroids. For pts with acute GVHD, Zenapax 1 mg/kg for 5 doses q 3 d was recommended. GM-CSF was incorporated post-AHSCT and NST. The primary endpoints were day 100 TRM, early graft failure, extent of acute GVHD, toxicities, DFS and OS. The study was suspended for 6 mo after the first 19 pts to evaluate early TRM-no early TRM was observed and the study was re-opened. Results: From 5/3/01 to 1/14/05, 32 pts from 10 institutions were enrolled on the study. 23 patients, median age 51 (range 32–64) completed both transplants (28% drop-out rate): 7 (30%) CR (2 in CCR), 11 (48%) PR and 2 (9%) NR and 3 (13%) NE as the best overall response. Of the 32 pts who completed AHSCT, there were 12 grade 4 toxicities pre-NST; 11/23 pts had grade 4 toxicities post-NST. Acute grade III/IV GVHD was observed in 4 (17%); chronic GVHD was observed in 9 pts (39%): 5 limited; 4 extensive resulting in 3 CR (33%), 1 CCR, and 3 PR (33%). 1 pt (4%) had graft-failure. Two pts (8.7%; 95% CI 1.6%, 24.9%) had TRM prior to day + 100 post-NST. With a median follow up of 3.5 years from registration, the median PFS was 4.4 years and the 2-year survival rate was 78% (95% CI: 61% ∼ 95%) for the 23 pts who completed both transplants. Conclusions: AHSCT followed by NST is feasible in a Cooperative Group setting with a low early TRM. The PFS and OS were superior to historical reports for single and tandem AHSCT. AHSCT-NST tandem transplants resulted in a 78% overall response, including 30% CR (2/7 CCR) - similar to other reports for AHSCT-NST. 3/9 pts with chronic GVHD achieved CR demonstrating the GVM effect. However, a plateau in PFS or OS was not observed indicating that the GVM effect is not sufficient to produce long- term disease control and is unlikely curative using this treatment schema. Future studies should include novel therapies to induce better responses pre-transplant and consideration for post-NST maintenance to further eradicate MRD while allowing for GVM.