Fonseca, Rafaël

Abstract Background: Immunomodulatory agents and proteasome inhibitors have significantly improved outcomes in the management of patients with multiple myeloma (MM). As a consequence, the role of upfront autologous stem cell transplant (ASCT) has become more controversial. The ECOG-ACRIN Cancer Research Group trial E4A03 demonstrated the superiority of lenalidomide (LEN) and low-dose dexamethasone (DEX; Ld) over LEN and high dose DEX (LD) in newly diagnosed MM (Rajkumar SV, Lancet Oncol, 2010). This led to the universal acceptance of Ld as a standard induction regimen. More recently, the FIRST study demonstrated the superiority of Ld as continuous therapy vs Ld given x 18 cycles and melphalan-thalidomide-prednisone x 12 cycles proving continuous Ld should be considered standard of care (Benboubker L, NEJM, 2014). Upon completion of four cycles of therapy, patients enrolled in E4A03 had the option of proceeding to ASCT or continuing on their assigned Ld or LD. A prior post-hoc retrospective landmark analysis (Siegel DS, Abstract, Blood 2010) comparing outcomes of early ASCT vs. no early ASCT showed that in patients <65, 65-70, and >70, the survival with early ASCT at 3 years appeared higher, supporting the role of early consolidative ASCT in newly diagnosed patients. This analysis is the long-term follow-up of the aforementioned study. Methods: A post hoc, retrospective landmark analysis was performed evaluating overall survival (OS) by early ASCT vs. no early ASCT overall and within age subgroups. The Kaplan-Meier method was used to estimate survival distributions and Cox regression for hazard ratio (HR) estimates. The landmark analysis included only patients surviving the first four cycles of therapy. Results: 21% of patients opted for early ASCT (n=90). At baseline (four cycles prior), early ASCT patients were younger (median 57.5y vs 66y), more fit (ECOG PS 0 45% vs 56%) and with less aggressive disease (ISS Stage 3 12% vs 28%). Median treatment duration was 7.6m for no early ASCT patients. The 1, 2, 3, 4, and 5-year survival probability estimates were higher for early ASCT vs. no early ASCT at 99%, 93%, 91%, 85%, and 80% vs. 94%, 84%, 75%, 65%, and 57%. The median OS in the early ASCT vs. no early ASCT was not reached vs. 5.8 years, respectively (Table 1). The survival hazard ratio (HR) for early ASCT was 0.55 [95%CI (0.38-0.80)]. In a further subgroup analysis of patients </= 65, 5-yr survival probability of those who had early ASCT vs. no early ASCT was 79% [95%CI (67-87)] vs. 62% [95%CI (54-69)], respectively. In patients </= 65, median OS in the early ASCT vs. no early ASCT was not reached vs. 7.4 years and the survival HR was 0.74 [95%CI (0.48-1.15)]. For patients >65, 5-yr survival probability of those who had early ASCT vs. no early ASCT was 83% [95%CI (56-94)] vs. 52% [95%CI (45-59)], respectively. In patients >65, median OS in the early ASCT vs. no early ASCT was not reached versus 5.2 years and the survival HR was 0.38 [95%CI (0.17-0.87)]. In all age groups, overall response rate was similar prior to the decision of proceeding with ASCT vs. no early ASCT. In a multivariable model adjusting for baseline prognostic factors, early ASCT retained marginal significance. Conclusions: The landmark analysis demonstrated that patients opting for ASCT after induction Ld/LD had a higher 1, 2, 3, 4, and 5- year survival probability and improvement in median OS regardless of DEX dose density. Results were stronger within the older age cohort and upheld in adjusted models. Limitations include lack of randomization and data on salvage therapy. At a time when lenalidomide and dexamethasone as induction is gaining worldwide acceptance in all age groups, early ASCT is safe and efficacious and should remain a standard of care for newly diagnosed MM even in the era of novel therapies. Table 1. Survival Probabilities (Time from Registration) for all Patients Included in the Landmark Analysis Median 1 year 2-year 3-year 4-year 5-year N Events Median (Yrs)(95% CI) Events Survival Probability(95% CI) Events Survival Probability(95% CI) Events Survival Probability(95% CI) Events Survival Probability(95% CI) Events Survival Probability(95% CI) No Early ASCT All 341 195 5.78(5.11 - 6.59) 22 0.94 (0.90 - 0.96) 53 0.84 (0.80-0.88) 84 0.75 (0.70-0.79) 119 0.65 (0.59-0.69) 144 0.57 (0.51 - 0.62) Early ASCT All 90 34 NR 1 0.99 (0.92 - 1.00) 6 0.93 (0.86 - 0.97) 8 0.91 (0.83 - 0.95) 13 0.85 (0.76 - 0.91) 18 0.80 (0.69 - 0.87) NR = not reached Disclosures Biran: Celgene: Speakers Bureau. Siegel:Celgene Corporation: Consultancy, Speakers Bureau; Amgen: Speakers Bureau; Takeda: Speakers Bureau; Novartis: Speakers Bureau; Merck: Speakers Bureau. Fonseca:Millennium: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties, Research Funding; Sanofi: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties, Research Funding; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties, Research Funding; Applied Biosciences: Membership on an entity's Board of Directors or advisory committees; Onyx/Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties, Research Funding; Binding Site: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties, Research Funding; Bayer: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties, Research Funding; BMS: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties, Research Funding; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties, Research Funding. Vesole:Idera Pharmaceuticals: Research Funding; Celgene Corporation: Speakers Bureau. Williams:Celgene: Consultancy, Research Funding. Abonour:Celgene: Research Funding, Speakers Bureau.

Abstract Background: In Phase II trials, carfilzomib (Cfz) was associated with dyspnea (34%), hypertension (14%), renal insufficiency (24%), and peripheral edema (24%) with cardiac events reported in 7% of patients (pts). In order to better understand these toxicities, we prospectively instituted detailed cardiac evaluation in 62 Cfz treated multiple myeloma (MM) pts. Methods: Pts received Cfz between 8/11-5/14. Parameters recorded included Cfz dose, concurrent chemotherapy, hydration, blood pressure, day 1 and 2 creatinine, troponin and NT-proBNP, baseline and cycle 4 echocardiograms with EF, strain and compliance. Notable cardiac events were examined for attribution. Results: Median age was 65 years, with 60% male. 20 pts had no prior therapies, 42 were relapsed; mean 4 prior therapies (range 1-10). 20 received induction chemotherapy (Cfz, dex, thalidomide, cyclophosphamide). At relapse, Cfz was given alone in 21 pts, with added cyclophosphamide in 10, and with an IMiD in 10. Cfz dose was 20mg/m2 days 1,2 and ranged from 27-45mg/m2in subsequent treatment days. Dex was given at 20-40mg weekly in 77% pts. Hydration (250-500ml) was delivered in 89% of patients pre and 63% post treatment. Baseline hypertension (>140mmHg) was present in 20% of pts and rose ≥10mmHg in 26% on day 2, but dropped ≥10mmHg in 36%. On day 8, more pts (32%) had hypertension pre-treatment. Baseline creatinine was elevated in 25% pts. 7 of 55 (13%) pts had a creatinine rise (≥0.3 mg/dL) on day 2, 5 of whom had elevation at baseline. Thus, with normal baseline creatinine and pre-treatment hydration 2/45 (4%) pts had a creatinine rise. Troponin levels on day 1 were normal in all 16 tested patients. 2/25 pts had an elevated troponin on day 2, one with associated MI on day 4. In these 2 pts, symptomatic pre-existing ischemic heart disease and severe cardiac amyloid were confounding factors. Mean baseline NT-proBNP (n=22) was elevated at 565 pg/mL (range <50-3666; normal <77) with normal baseline values in only 41%. On day 2 (n=25), the mean was significantly higher at 1580 pg/mL. Between day 1 and 2, 72% of pts had a rise ≥50 pg/mL; mean change 1387 (range 0 to +6187). On day 2, 52% had a NT-proBNP ≥500 pg/mL, while 36% were ≥1000 pg/mL. 30 pts had baseline and post-C4 treatment echocardiograms, all with normal pre-treatment EFs. Three pts (10%) developed impaired systolic function (EF<50%), however, 2 had plausible concurrent alternative etiologies (VTE/PE, hospitalized multilobar pneumonia) while one patient (during C2) had an asymptomatic unexplained decline in EF (56 to 42%) detected pre-op while hospitalized for hip fracture. Thus, 1/30 (3%) had an EF change in absence of concurrent acute illness. A fourth patient had normal echo at C4 but was hospitalized at C10 with severe sepsis and a diminished EF was documented. All 4 pts with low EF were pre-treated (≥2 therapies plus SCT). Changes in cardiac strain often precede an EF fall. Only 14/25 pts had normal baseline cardiac strain (≥ -18%). Post treatment strain measurement significantly improved in 4 pts and worsened in 4 pts, the latter accompanied by EF decline within the normal range in 2 pts (68/60%, 65/58%). 28 pts had E/e’ ratio (LVEDP) reviewed as a marker of ventricular compliance. 46% had abnormal ratios (≥ 15), prior to Cfz treatment. 20% of patients experienced worsening parameters post treatment, however, an equal number of pts demonstrated improvement. There was no consistent correlation with change in EF. Conclusions: MM pts frequently have baseline elevated cardiac peptides (59%) and abnormal cardiac strain (15% of newly diagnosed and 36% at relapse). A frequent, and sometimes dramatic, rise in the NT-proBNP occurs immediately following Cfz based chemotherapy. Acute structural cardiac events were however uncommon (3%) in the absence of confounding illness. Overall 5/62 (8%) patients had serious cardiac events during treatment with Cfz (4 EF decline, 1 MI). These toxicities were considered probably attributable to Cfz in 3/62 (5%) patients. Prospective controlled studies with longer term follow up and bortezomib treated controls are necessary to accurately document the cardiovascular impact of Cfz and the role of proteasome inhibition. Disclosures Off Label Use: bortezomib was used in combination therapy to treat relapsed low grade lymphomas and Waldenstrom's macroglobulinemia. Fonseca:Medtronic, Otsuka, Celgene, Genzyme, BMS, Lilly, Onyx, Binding Site, Millennium, AMGEN: Consultancy, patent for the prognostication of MM based on genetic categorization of the disease. He also has sponsored research from Cylene and Onyx Other, Research Funding. Bergsagel:Novartis: Research Funding; Constellation Pharmaceutical: Research Funding; OncoEthix: Research Funding; MundiPharma: Research Funding. Reeder:Millennium, Celgene, Novartis: Research Funding. Mikhael:Onyx: Research Funding; Celgene: Research Funding; Sanofi: Research Funding; Novartis: Research Funding. Stewart:Celgene Novartis Array BioPharma BMS, research funding Millenium: Consultancy, Research Funding.

Abstract It is well established that 17p13(del) and p53 mutations represent poor prognosis in MM patients. We have previously shown that p53 is a haploinsufficient tumor suppressor in myeloma and p53 expression level is correlated with functional status of the pathway. In addition, p53 expression levels do not always correlate with p53 genotype. The absence of p53 expression in myeloma cells severely abolishes the integrity of its downstream signaling response, thus, driving disease aggressiveness and drug resistance. There is a pressing need for a more effective treatment strategy for high-risk patients harbouring p53 abnormalities. PRIMA-1 is a first-in-class drug that was identified to specifically kill cancer cells harboring mutant p53. It has shown substantial efficacy in various solid tumors with mutant as well as non-mutant p53. However, the discovery of the anti-myeloma activity of PRIMA-1 is still at its infancy. By utilizing human myeloma cell lines (HMCLs) of different p53 status as our study model, we aim to identify the efficacy of PRIMA-1 in MM and to dissect the mechanisms behind PRIMA-1-induced toxicity. Despite its known ability to reactivate mutant-p53 function, we did not observe any restoration of mutant p53 transcriptional activities. The expression levels of the p53-direct-targets, p21, MDM2 and PUMA, were unchanged upon treatment in the p53-mutant-HMCLs. In fact, PRIMA-1 was found to be able to decrease the cell viability of all the HMCLs, irrespective of their p53 status (Mutant, WT, Null), strongly indicating a p53-independent response. Importantly, PRIMA-1 showed the highest cytotoxicity in a p53-deficient background (IC50 of 16uM in -/-, 55uM in WT/WT and 70uM in mutant HMCLs). This finding was validated when p53 silencing in a WT HMCL significantly enhanced its sensitivity to PRIMA-1. GEP analysis on the two most sensitive cell lines (JJN3 and KMS11) demonstrated significant enrichment of genes related to unfolded (p=1.90E-06 in JJN3 and 6.12E-08 in KMS11) and misfolded protein (p=2.99E-06 in JJN3 and 8.21E-08 in KMS11) responses. Subsequent validation by Western blot and qPCR confirmed the activation of ER stress pathway in response to PRIMA-1, evidenced by the up-regulation of ER stress markers such as GRP78, GADD34 and CHOP. Further investigations then revealed that the PERK/CHOP axis was most important as CHOP knockdown saw an attenuation of MM cells sensitivity to PRIMA-1-induced apoptosis. Recently, it was reported that cells with increased ER stress are more sensitive to bortezomib. Indeed, we showed that PRIMA-1 synergizes with bortezomib, and was able to rescue bortezomib resistance when both compounds were co-incubated in a bortezomib-resistant-HMCL. In conclusion, we identified a novel pathway by which PRIMA-1 exerts its toxicity in MM through induction of ER stress. This may be a novel therapeutic strategy to induce ER stress to sensitize cells to proteasome inhibitor. Owing to the versatility of the drug in targeting myeloma cells with or without p53 abnormalities; PRIMA-1 can potentially be used alone or in combination with other drugs such as bortezomib in a broad range of MM including those with high-risk disease. Disclosures No relevant conflicts of interest to declare.

Abstract Although multiple myeloma is clinically defined as the accumulation of clonal, malignant plasma cells in the bone marrow, the disease shows significant heterogeneity with regard to morphology, progression and therapeutic response. Our hypothesis is that this heterogeneity likely is due, in part, to germline genetic polymorphisms that contribute significantly to an individual’s disease course and response. In particular, individuals deficient in the repair of DNA damage are not only at high risk for developing cancer, but also could show DNA repair dependent responses associated with DNA damaging therapeutic agents. In this study we examined the association of functional genetic polymorphisms in the DNA repair genes, XRCC1 (SNP positions 280, 399) and ERCC2 (SNP positions 312, 751), with toxicities and clinical outcomes in the ECOG, 3 arm chemotherapeutic trial, E9486 [A-VBMCP, B-VBMCP+Cylophosphamide, C- VBMCP+interferon]. DNA from 359 patients was genotyped and examined for association with response, toxicities, blood counts, bone pathology, and survival parameters. Notably, in the interferon arm of the trial significant associations were observed in progression free survival and polymorphisms of XRCC399 (AA median survival 51 months versus AG/GG median survival of 33 months; p=,008), ERCC751 (AA/AC median survival 33 months versus CC median survival of 48 months; p=.05), and ERCC312 (AA median survival 49 months versus AG/GG median survival of 34 months; p=.02). Hazard ratios ranged form 1.7 to 2.05 for survival differences associated with DNA repair genes in this arm. Interestingly, T cell counts are known to be impacted by interferon; and DNA repair polymorphisms in this arm were also associated with CD8+ T cell counts. While this represents a single arm of one clinical trial, it is intriguing to consider the impact of genetic polymorphisms on DNA repair in light of chemotherapeutic agents that may affect cells of the immune system. Previous studies from the ECOG Myeloma Committee of the E9486 trial show highly significant associations of survival and immune status in myeloma patients. Our results suggest genetic polymorphisms in DNA repair genes may influence clinical outcome in certain therapeutic regimens. Genetic polymorphisms in these DNA repair genes are currently being completed in 800 patients of the SW9321 SWOG/ECOG intergroup trial and additional association studies will be included in the presentation.

Abstract Background:A goal of “post-genomic” cancer care is development of specific, affordable, reliable and rapid next-generation sequencing-based assays determining prognosis, therapeutic selection and minimal disease monitoring, replacing older technologies in the diagnostic and monitoring workup. In this regard, we designed and deployed a custom gene panel for identification of mutations, copy-number changes and clonal frequency in multiple myeloma (MM) samples. Methods: The MM Mutation Panel Version 2.0 (M3P 2.0)1 includes 1271 amplicons from 77 genes that are either mutated in MM (genes with a published mutation incidence ≥3%), represent critical pathophysiological pathways, are targetable with small molecule-based therapies and/or are associated with drug resistance (eg. XBP-1, CRBN, IZKF, IRF4). The amplicons are spread across 21 chromosomes, allowing the identification of copy-number changes in these regions. Results: We have sequenced 38 MM cases (150 will be presented) with paired tumor-germline DNA samples, using only 20ng of DNA for library preparation. Patients (Pts) included 29 untreated and 9 MM pts with multi drug refractory disease. Coverage depth averaged 964X. Hyperdiploid MM was successfully identified in 45% of cases, del(13q) in 34%, del(1p) in 18%, del(17p) in 8% and gain of 1q in 13%. Array CGH in representative cases confirmed concordance with semiconductor sequencing. Overall, 71 exonic missense and 3 nonsense mutations were detected, and 7 frameshift indels. In 89% of the pts a mutation in at least one M3P2.0 gene was identified (range 1-8). 92% of mutations were predicted damaging (Provean, Polyphene-2 or SIFT). Most commonly mutated were KRAS (37%), NRAS (21%), BRAF (13%), TP53, CDKN1B, DIS3 (each 11%), FAM46C, STAT3, and IRF4 (each 8%). The MEK-ERK pathway was mutated in 61% of cases and in 3 cases more than one gene in this pathway (NRAS, KRAS, BRAF) was simultaneously mutated. Six mutations in BRAF were identified in 5 untreated pts, 3 of them known to be activating and targetable (Val600E). Other commonly mutated pathways were the NFKB pathway in 24% of pts and the Cyclin D pathway, mutated in 16% of cases. Genes of the cereblon pathway (CRBN, IRF4, IKZF3), essential for the action of lenalidomide (len) were mutated in 5 Pts. One newly diagnosed and len refractory Pt harbored a subclonal CRBN mutation (Asn316Lys, allelic fraction [AF] 20%) as well as 4 clonal IRF4 mutations within the DNA binding domain of the gene (Lys89Asn (AF 78%), Lys77Glu, Ser48Arg and Cys49Ser (AF 80% each). Another IRF4 mutated (Lys123Arg, AF 90%) hemodialysis dependent Pt was responsive to dose adapted treatment of len and dexamethasone (dex). Mutations in the C2H2-type 3 region of IKZF3 in a len resistant (Gly191Arg, AF 48%) pt occured as well as in a len and dex responsive (Arg242Gly, AF 52%) Pt. Furthermore, we identified a truncating XBP1 mutation (p.Leu232*, 97% AF) in a Pt refractory to bortezomib. One patient harbored a mutation in the steroid receptor NR3C1 (Pro255Leu, 22% variant reads). Finally, integrated mutation and copy-number data identified biallelic deletions of CDKN2C and FAM46C in a multi drug refractory Pt. Mutation and/or copy-number losses in both alleles were found in DIS3 in 4 Pts, in CYLD, TP53 and TRAF3 in 2 Pts and in CARD11, CDKN2A, CDKN1B, RB1and STAT3 in one Pt each. Conclusion: In summary, we report the initial results from 38 MM Pts using a custom MM sequencing panel which employs small amounts of DNA requiring very few cells and providing deep coverage in clinically meaningful timeframes. Our findings frequently include prognostically significant information, actionable targets and mutations in genes related to drug resistance. Targeted mutation profiling will likely become part of the clinical workup in MM and our M3P2.0 mutation panel is a suitable tool to provide information needed to guide precision therapy and to set the basis for individually tailored treatment decisions. 1. Kortuem KM. et al. Development Of a 47 Gene Sequencing Panel For Common Mutations Present In Multiple Myeloma: Preliminary Results In 77 p53 Deleted Patients, ASH 2013. Disclosures Stewart: Celgene: Consultancy; Bristol Myers Squibb: Consultancy; Array BioPharma: Consultancy; Sanofi: Consultancy; Takeda Pharmaceuticals International Co.: Research Funding; Novartis: Consultancy. Bruins:OncoSpire: Salary support Other. Vasmatzis:OncoSpire: Salary Support Other. Kumar:Celgene: Consultancy, Research Funding; Millennium: The Takeda Oncology Co.: Consultancy, Research Funding; Onyx Pharmaceuticals: Consultancy, Research Funding; Sanofi-Aventis: Consultancy, Research Funding; Array BioPharma: Consultancy, Research Funding; Janssen: Consultancy, Research Funding; Skyline Diagnostics: Membership on an entity's Board of Directors or advisory committees. Fonseca:Medtronic, Otsuka, Celgene, Genzyme, BMS, Lilly, Onyx, Binding Site, Millennium, AMGEN: Consultancy, patent for the prognostication of MM based on genetic categorization of the disease. He also has sponsored research from Cylene and Onyx Other, Research Funding. Bergsagel:MundiPharma: Research Funding; OncoEthix: Research Funding; Constellation Pharmaceutical: Research Funding; Novartis: Research Funding.

Abstract Abstract 1285 Introduction: Recent studies have now demonstrated that both genic and global hypomethylation characterizes the multiple myeloma (MM) epigenome. We previously conducted a study to measure changes in DNA methylation at approximately 1500 CpG (GoldenGate Methylation BeadArray, Illumina) loci in 193 MM samples used in the Multiple Myeloma Research Consortium Genomics Initiative. The purpose of this study was to determine the extent to which DNA methylation changes in MM correlate to changes at the gene expression level. Methods: To evaluate this correlation we performed three independent analyses. In the first approach we analyzed matching gene expression and DNA methylation data using a Pearson correlation to assess the linear relationship between the datasets. In the second approach methylation and gene expression data from 193 matching samples were quantile-normalized and standardized across genes and samples. Methylation data was then discretized into three groups (methylated, unchanged, unmethylated) according to the mean and standard deviation of the values for each probe on the array. We then computed a t-test to compare the gene expression differences for each gene represented on the methylation array between samples in the methylated and unmethylated groups. We also performed a class enrichment analysis to assess DNA methylation/gene expression correlations that might be associated with hyperdiploidy or molecular subtype. In the third approach we performed RT-PCR and methylation pyrosequencing to validate results in a subset of samples used for the analysis and in an independent cohort comprised of 50 MM samples. Results: By Pearson correlation, only 31 (2.1%) CpG loci (corresponding to 24 unique genes) had a gene expression probe with a statistically significant correlation. Using the discretization approach, we identified 382 loci (25.3%, 309 unique genes) with methylation-expression correlations. Although we identified more correlations by discretizing the data, methylated and unmethylated samples were represented by an average of only 30 and 27 samples per group. We identified correlations where the directionality of methylation and expression values were either in the opposite (negative) or same direction (positive). Among the genes identified, the tumor suppressor genes CDKN2A and DLC1 interestingly demonstrated a positive correlation (methylated and expressed) and the IGF1R and IL17RB genes were negatively correlated (unmethylated and expressed). A class enrichment analysis revealed that samples with DLC1, CDKN2A, IGF1R or IL17RB methylation were associated with hyperdiploid MM. Conversely, samples that were unmethylation for these genes were generally non-hyperdiploid. These findings were validated by RT-PCR and methylation pyrosequencing. Conclusion: Overall, our findings demonstrated, albeit in a limited number of genes, that DNA methylation changes are weakly associated to gene expression. These data suggest that CpG methylation may have other functional consequences such as predisposing the genome to global gene transcriptional changes or chromosomal instability. While future studies are needed to determine the exact role of DNA methylation, we identified a number of genes regulated by an epigenetic mechanism with important clinical and biological implications to MM and warrant further study. Disclosures: No relevant conflicts of interest to declare.

Abstract Abstract 420 Primary central nervous system lymphoma (PCNSL) is a rare and aggressive non-Hodgkin lymphoma that is confined to the CNS because of a poorly understood neurotropism. Most of PCNSL (90%) are part of the immune-privileged site-associated DLBCL (IPDLBCL). IPDLBCL consist in late–germinal center or post–germinal center lymphoid cells but that show very distinct characteristics that separate them from systemic DLBCL. It is still a matter of debate whether the PCNSL differ from nodal DLBCL with respect to molecular features and pathogenesis and also if there is a genomic signature specific of PCNSL. Only few genetic studies have been performed in PCNSL, partly due to the rarity of the tumors and the limited amount of available tissue. To gain insight into the genomic basis of PCNSL, we performed an integrated, high-throughput, genomic analysis in 17 immunocompetent, EBV- and HIV- cases. B-cell differentiation status was characterized by immunostains for CD10, MUM-1, and BCL-6. Either frozen samples or formalin fixed embedded paraffin sections from 17 PCNSL were studied by array-based comparative genomic hybridization (aCGH) using Sureprint G3 (1 million probes) array. Massively parallel whole-exome sequencing was performed in 4 of these cases. Additionally, 2 cases were analyzed by mate-pair whole genome sequencing searching for chromosomal breakpoints. Sanger DNA sequencing was used for validation. All cases were characterized by complex genomic aberrations with a median of 21 copy-number abnormalities (CNA, range 10–49), 4 structural abnormalities, 6 frameshift indels and 99 nonsynonymous exonic mutations. Focal deletion affecting CDKN2A (9p21) was the most common CNA, found in 14 of 17 cases (82%); with 6 of these cases (35%) having homozygous deletion. The second most frequent CNA involved the HLA genes (6p21), found in 11 of 17 (65%) cases; 4 of them (23%) with homozygous deletions. We identified recurrent CNA and mutations in several genes previously found in systemic DLBCL. Thus, PRDM1 (BLIMP1) was deleted or mutated in 47% of cases and the translocation IgH-BCL6 was found in 30% of PCNSL. Furthermore, recurrent mutations were found in NF-kB genes CD79B (75%, 3 of 4 cases analyzed), MYD88 (70%, 7 of 10), TNFAIP3 (50%, 2 of 4) and CARD11 (50%, 2 of 4). Additionally, recurrent abnormalities were found in B2M, BCL7A, CD58, CIITA, ETV6, GNA13, PAX5, TMEM30A and TP53. Nevertheless, we identified several recurrent genetic alterations not described in systemic DLBCL. TOX (a regulator of T-cell development) and TBL1XR1 (a negative regulator of the NF-kB and Wnt pathways) were either deleted or mutated in 30% of PNCSL, something not previously described in systemic DLBCL. Additionally, chromosomal breakpoints either in DLGAP1 or DLGAP2 (play a role in neuronal cell signaling) were found in 18% of PCNSL but not in systemic DLBCL. Moreover, mutations in ATM (master controller of cell cycle checkpoint), BAI3 (inhibitor of brain angiogenesis), BTG2 (cell cycle arrest), KDM6B (histone demethylase), PKC family members PRKCD/PRKCDE, genes from the histone cluster, the protocadherin family and the WD repeat domain were found in 10% to 50% of PCNSL. Pathway analysis including the most commonly affected genes in PCNSL showed an enrichment of networks associated with immune response, NF-kB pathway, proliferation, regulation of the apoptosis and lymphocyte differentiation and activation. In summary, we show evidence of a highly complex genome and identified a subset of genes with potential relevance in PCNSL pathogenesis. The genomic profile described here reinforces the existence of a specific molecular signature in PCNSL, thus helping to genetically differentiate this entity from the nodal DLBCL and related lymphomas. Disclosures: Stewart: Millenium: Consultancy, Honoraria, Research Funding; Onyx: Consultancy; Celgene: Consultancy. Fonseca:Medtronic: Consultancy; Otsuka: Consultancy; Celgene: Consultancy; Genzyme: Consultancy; BMS: Consultancy; Lilly: Consultancy; Onyx: Consultancy; Binding site: Consultancy; Millenium: Consultancy; AMGEN: Consultancy; Celgene : Research Funding; Onyx: Research Funding; prognostication of MM based on genetic categorization of the disease: Prognostication of MM based on genetic categorization of the disease Patents & Royalties.

Abstract Abstract 201 Background: Pomalidomide at doses of 2 or 4 mg/d has demonstrated excellent activity in patients with relapsed multiple myeloma (MM). Between November 2007 and March 2012, we opened 6 sequential phase 2 trials and treated 345 patients with relapsed MM with pomalidomide at differing doses with weekly dexamethasone (Pom/dex). Results of 164 of these patients have been previously published. Here we describe long term follow up of these patients as well as results of an additional 181 patients with relapsed MM treated with the Pom/dex regimen. Methods: The six cohorts consisted of: Cohort 1 (N=60): relapsed MM with 1–3 prior regimens, 2 mg dose; Cohort 2 (N=34): lenalidomide (LEN) refractory, 2 mg dose; Cohort 3 (N=35): BZ)/LEN refractory, 2 mg dose; Cohort 4 (N=35): BZ/LEN refractory, 4 mg dose; Cohort 5 (N=60) LEN refractory, 1–3 prior regimens, 4 mg dose; and Cohort 6 (N=120) LEN refractory, 4 mg dose. Pomalidomide was given orally 2 mg daily or 4mg daily on days 1–28(cohorts 1–5) or 1–21 (cohort 6) of a 28-day cycle with oral dexamethasone given 40 mg daily on days 1, 8, 15 and 22. Response was assessed by the International Myeloma Working Group Uniform Response criteria. All patients received aspirin 325 mg daily for deep venous thrombosis (VTE) prophylaxis or full dose anticoagulation. Results: A total of 345 patients were enrolled across all 6 cohorts. One patient was ineligible and excluded from analysis. The median age was 64 years (32–88). The median time since diagnosis was 53 months. The median number of prior therapies was 3 (1–14). 147 (44%) had high-risk molecular markers by mSMART criteria. Prior therapies consisted of thalidomide 52%, lenalidomide 87%, bortezomib 75%, autologous stem cell transplant 70% and allogeneic transplant 3%. The median follow-up is 10.4 months (5.4–34 months). Sixty-seven percent are alive and 32% remain progression free. 46 patients are continuing to receive treatment. The most common toxicities (grade 3 or higher) were neutropenia (31%), anemia (16%), thrombocytopenia (12%), pneumonia (8%) and fatigue (8%). VTE was seen in 10 patients (3%). Outcomes are shown in Table 1. Across all 6 cohorts confirmed responses of partial response (PR) or better were seen in 34%. The response rate in all patients with mSMART high risk status was 30.6%. Responses and duration of response (DOR) in those with high risk molecular markers include: 17p– 19 of 56 (34%) DOR 8.2 months; t(4;14) 6 of 24 (25%) and DOR 4.8 months; t(14;16) 7 of 11(64%) and DOR 9.5 months; deletion 13 by cytogenetics 13 of 37 (35%) with DOR 8.2 months. In a multivariate analysis, only LDH > ULN, number of prior regimens, and prior BZ therapy were predictive of a shorter TTP and factors associated with a poor OS following initiation of pomalidomide therapy included B2M > 5.5, LDH > ULN,number of prior regimens, and prior BZ therapy. Conclusions: Pom/dex is active and well tolerated even in heavily pretreated patients and those with high risk molecular markers. Remissions are durable. Response rates and toxicity are similar between the 2 mg and 4 mg doses. Disclosures: Lacy: Celgene: Research Funding. Stewart:Celgene: Consultancy, Honoraria. Reeder:Celgene: Mayo Clinic receives funding from Celgene to support clinical trials Other, Research Funding.

Abstract Abstract 4079 The treatment and natural history of asymptomatic or smoldering myeloma has been an area of intense preclinical and clinical study. Historical attempts to treat these patients have not demonstrated significant benefit, likely as a consequence of limited therapeutic options as well lack of attention to the vast heterogeneity contained within the diagnosis of smoldering myeloma. More recent risk criteria from both US and Spanish investigators have identified a cohort of smoldering myeloma patients at high risk for progression to myeloma in a short time. Recently the PETHEMA group has conducted a randomized clinical trial testing lenalidomide and dexamethasone vs observation among high risk smoldering patients and has demonstrated a clear benefit in terms of progression free survival and hints towards improvement in overall survival favoring early intervention. To further evaluate the potential benefit of early intervention in a high risk smoldering cohort, the ECOG myeloma group designed a phase II trial testing the safety and efficacy of single agent lenalidomide with the intent of broadening to a randomized phase III trial if toxicity was acceptable. We report here on the safety portion of the phase II trial. The phase II group of patients received lenalidomide at a dose of 25 mg days 1–21 every 28 days to evaluate the early toxicity and tolerance of this dosing. The dose of lenalidomide could be adjusted based on toxicity using a defined dose-modification guideline in the protocol. The primary endpoint for the safety study was the rate of any treatment-related grade 4–5 non-hematologic toxicity plus grade 3 non-hematologic toxicity that affects vital organ function (such as cardiac, hepatic, or thromboembolic events) observed within 6 cycles of treatment. The goal was to enroll 34 patients; if 9 or more patients experience toxicity as defined, then the study would not continue. In terms of eligibility, patients were to be diagnosed with asymptomatic high-risk smoldering multiple myeloma (SMM) within the past 12 months, as confirmed by both of the following: bone marrow plasmacytosis with >= 10% plasma cells or sheets of plasma cells and an abnormal serum free light chain ratio (<0.125 or >8.0) by serum FLC assay. Further, patients must have measurable levels of monoclonal protein (M-protein): >=1g/dL on serum protein electrophoresis or >=200 mg of monoclonal protein on a 24 hour urine protein electrophoresis. Patients must have no lytic lesions on skeletal surveys and no hypercalcemia. Among the 36 patients enrolled in the phase II study, 56% were female, and 44% were 65 years and older. Treatment and toxicity data at a minimum through cycle 6 is complete as of August 2, 2102. The last patient enrolled completed cycle 6 treatment on June 7, 2012. The median treatment duration of the entire cohort is 9 cycles (range 1–18 cycles), with 86% of patients completing at least 6 cycles of treatment. Ten patients are off treatment for the following reasons: disease progression (n=1), AE/complication (n=5), death (n=1) and patient withdrawal/refusal (n=3); 5 of the 10 patients ended treatment before completing 6 cycles. Of 36 patients assessed for toxicity, 8 patients [22.2%, 90% CI: (11.6%-36.5%)] experienced worst grade treatment-related non-hematologic toxicity of grade 3 or higher. Separately, 6 patients experienced unrelated non-hematologic toxicity of grade 3 or higher. Three patients [8.3%, 90% CI: (2.3%-20.2%)] experienced a serious adverse event as defined for the purposes of the phase II toxicity analysis (treatment-related grade 4–5 non-hematologic toxicity or grade 3 non-hematologic toxicity that affects vital organ function (such as cardiac, hepatic, or thromboembolic events). Based upon this analysis of the study, the phase II portion of the trial met the prespecified safety benchmark established to allow for phase III expansion, and accrual to the phase III portion of this study will begin. Efficacy data will be presented at the time of presentation. Disclosures: Lonial: Novartis: Consultancy; Millennium: Consultancy; Onyx: Consultancy; BMS: Consultancy; Celgene Corp: Consultancy; Merck: Consultancy. Off Label Use: Lenalidomide is not approved for treatment of smoldering MM. Fonseca:Medtronic: Consultancy; Otsuka: Consultancy; Celgene: Consultancy; Genzyme: Consultancy; BMS: Consultancy; Lilly: Consultancy; Onyx: Consultancy; Binding site: Consultancy; Millenium: Consultancy; AMGEN: Consultancy; Celgene : Research Funding; Onyx: Research Funding; prognostication of MM based on genetic categorization of the disease: Prognostication of MM based on genetic categorization of the disease, Prognostication of MM based on genetic categorization of the disease Patents & Royalties. Dhodapkar:Celgene: Research Funding; KHK: Research Funding.

Abstract Abstract 724 Background: Chromosome content identifies two pathogenic pathways, each occurring in about half of patients with MGUS and multiple myeloma (MM). Hyperdiploid MM (HRD) has 48–75 chromosomes with multiple trisomies selectively involving chromosomes 3, 5, 7, 9, 11, 15, 19 and 21; only 10% of these HRD tumors have primary IgH translocations and no frequent focal genetic mutations have been identified. In contrast primary IgH translocations are identified in over 70% of non-hyperdiploid MM (NHRD). Rearrangements of MYC have been detected by FISH in only 16% of untreated MM, but over 90% of MM cell lines, identifying a late role for MYC in the progression of MM. The introduction of a MYC transgene into a mouse strain predisposed to MGUS results in mice that uniformly develop MM, suggesting a distinct early role of MYC in the progression of MGUS to MM. We report here that rearrangements in a 4Mb region surrounding MYC are present in 70% of HRD, representing the most frequent focal genetic mutation in this genetic subtype of MM. Results: We analyzed the MMRC reference collection of gene expression (Affymetrix Hu133Plus2) and copy number (Agilent 244k CGH) data and performed FISH to identify MYC rearrangements with IgH or IgL loci in 218 patients with untreated and relapsed MM. We found MYC rearrangements in 48% of MM (identified only by FISH in 5%, only by aCGH in 33%, and by both FISH and aCGH in 10%), including 43% of untreated, and 51% of relapsed MM. Using a hyperdiploid index calculated from the median copy number of the chromosomes involved in trisomies we determined that rearrangements of MYC were present in 70% of the top third, 35% of the middle third, and 25% of the bottom third. Using the paired gene expression data we found that the expression of MYC was approximately two-fold higher in the samples with rearrangements compared to those without rearrangements (p<0.001) and about three-fold higher in MM tumors without rearrangements compared to MGUS (p<0001). Using paired RNA and DNA from the MMRC reference collection we determined in 22 informative patients that MYC rearrangements are associated with monoallelic expression of MYC (p<0.01), consistent with cis-dysregulation of MYC. Analysis of the various changes on aCGH, and fine mapping of the genetic architecture of the rearrangements using next generation sequencing identifies a promiscuous array of rearrangements that often result in the introduction of an enhancer within the MYC locus, resulting in its cis-dysregulation. Since they cannot be comprehensively identified by either CGH or FISH alone, more sensitive techniques, such as next generation sequencing approaches, will be required to comprehensively identify all MYC rearrangements in MM. Conclusions: Rearrangements of MYC are the most frequent focal genetic mutation in untreated MM and are particularly prevalent in hyperdiploid MM. While only one third involve an immunoglobulin locus, they all result in cis-dysregulated expression of MYC, and may be one mechanism responsible for the progression of MGUS to MM. Tumors lacking MYC rearrangements bi-allelically over-express MYC by a trans mechanism including potentially inactivating mutations of BLIMP1/PRDM1, or activating mutations of IRF4. We propose two largely non-overlapping pathogenic pathways in MM: HRD associated with frequent MYC rearrangements, and NHRD associated with frequent primary IgH translocations. The prevalence of MYC rearrangements increases with tumor progression, identifying a role for MYC both early and late in tumorigenesis. As therapies that have been reported to target MYC (e.g., IMiDs®, bortezomib, bromodomain inhibitors) are used in the clinic, it will be important to associate their effect with the presence or absence of MYC rearrangements. Disclosures: Bergsagel: Constellation Pharmaceuticals: Consultancy. Keats:Tgen: Employment.