ALBERT

Description: Background Treatment of relapsed/refractory multiple myeloma (RRMM) remains challenging as durable remissions are achieved in patient sub-groups only. Identifying patients that are likely to benefit prior to or early after starting relapse treatments remains an unmet need. MUKseven is a trial specifically designed to investigate and validate biomarkers for treatment optimization in a 'real-world' RRMM population. Design In the randomized multi-center phase 2 MUKseven trial, RRMM patients (≥2 prior lines of therapy, exposed to proteasome inhibitor and lenalidomide) were randomized 1:1 to cyclophosphamide (500 mg po d1, 8, 15), pomalidomide (4 mg days 1-21) and dexamethasone (40 mg; if ≥75 years 20 mg; d1, 8, 15, 21) (CPomD) or PomD and treated until progression. All patients were asked to undergo bone marrow (BM) and peripheral blood (PB) bio-sampling at baseline, cycle 1 day 14 (C1D14, on-treatment) and relapse. For biomarker discovery and validation, IGH translocations were profiled by qRT-PCR, copy number aberrations by digital MLPA (probemix D006; MRC Holland), GEP by U133plus2.0 array (Affymetrix), PD protein markers by IHC and PB T-cell subsets by flow cytometry for all patients with sufficient material. Primary endpoint was PFS, secondary endpoints included response, OS, safety/toxicity and biomarker validation. Original planned sample size was 250 patients but due to a change in UK standard of care during recruitment with pomalidomide becoming available, a decision was made to stop recruitment early. Results In total, 102 RRMM patients were randomized 1:1 between March 2016 and February 2018. Trial entry criteria were designed to include a real-world RRMM population, permitting transfusions and growth factor support. Median age at randomization was 69 years (range 42-88), 28% of patients had received ≥5 prior lines of therapy (median: 3). Median follow-up for this analysis was 13.4 months (95% CI: 12.0-17.5). 16 patients remained on trial at time of analysis (median number of cycles: 19.5; range 8-28). More patients achieved ≥PR with CPomD compared to PomD: 70.6% (95% CI: 56.2-82.5%) vs. 47.1% (CI: 32.9-61.5%) (P=0.006). Median PFS was 6.9 months (CI: 5.7-10.4) for CPomD vs. 4.6 months (CI: 3.5-7.4) for PomD, which was not significantly different as per pre-defined criteria. Follow-up for OS is ongoing and will be presented at the conference. High-risk genetic aberrations were found at following frequencies: t(4;14): 6%, t(14;16)/t(14;20): 2%, gain(1q): 45%, del(17p): 13%. Non-high risk lesions were present as follows: t(11;14): 22%, hyperdiploidy: 44%. Complete information on all high-risk genetic markers was available for 71/102 patients, of whom 12.7% had double-hit high-risk (≥2 adverse lesions), 46.5% single-hit high-risk (1 adverse lesion) and 40.8% no risk markers, as per our recent meta-analysis in NDMM (Shah V, et al., Leukemia 2018). Median PFS was significantly shorter for double-hit: 3.4 months (CI: 1.0-4.9) vs. single-hit: 5.8 months (CI: 3.7-9.0) or no hit: 14.1 months (CI: 6.9-17.3) (P=0.005) (Figure 1A). GEP was available for 48 patients and the EMC92 high-risk signature, present in 19% of tumors, was associated with significantly shorter PFS: 3.4 months (CI: 2.0-5.7) vs. 7.4 (CI: 3.9-15.1) for EMC92 standard risk (P=0.037). Pharmacodynamic (PD) profiling of cereblon and CRL4CRBN ubiquitination targets (including Aiolos, ZFP91) in BM clots collected at baseline and C1D14 is currently ongoing. Preliminary results for the first 10 patients demonstrate differential change of nuclear Aiolos (Figure 1C), with a major decrease in Aiolos H-scores in 7/10 patients from baseline to C1D14 and reconstitution at relapse. T-cell PB sub-sets were profiled at baseline and C1D14 by flow cytometry. Specific sub-sets increased with therapy from baseline to C1D14, e.g. activated (HLA-DR+) CD4+ T-cells, as reported at last ASH. CD4+ T-cell % at baseline was associated with shorter PFS in these analyses in a multi-variable Cox regression model (P=0.005). PD and T-cell biomarker results will be updated and integrated with molecular tumor characteristics and outcome. Discussion Our results demonstrate that molecular markers validated for NDMM predict treatment outcomes in RRMM, opening the potential for stratified delivery of novel treatment approaches for patients with a particularly high unmet need. Additional immunologic and PD biomarkers are currently being explored. Disclosures Croft: Celgene: Other: Travel expenses. Hall:Celgene, Amgen, Janssen, Karyopharm: Other: Research funding to Institution. Walker:Janssen, Celgene: Other: Research funding to Institution. Pawlyn:Amgen, Janssen, Celgene, Takeda: Other: Travel expenses; Amgen, Celgene, Janssen, Oncopeptides: Honoraria; Amgen, Celgene, Takeda: Consultancy. Flanagan:Amgen, Celgene, Janssen, Karyopharm: Other: Research funding to Institution. Garg:Janssen, Takeda, Novartis: Other: Travel expenses; Novartis, Janssen: Research Funding; Janssen: Honoraria. Couto:Celgene Corporation: Employment, Equity Ownership, Patents & Royalties. Wang:Celgene Corporation: Employment, Equity Ownership. Boyd:Novartis: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Takeda: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; Celgene: Consultancy, Honoraria. Pierceall:Celgene: Employment. Thakurta:Celgene: Employment, Equity Ownership. Cook:Celgene, Janssen-Cilag, Takeda: Honoraria, Research Funding; Janssen, Takeda, Sanofi, Karyopharm, Celgene: Consultancy, Honoraria, Speakers Bureau; Amgen, Bristol-Myers Squib, GlycoMimetics, Seattle Genetics, Sanofi: Honoraria. Brown:Amgen, Celgene, Janssen, Karyopharm: Other: Research funding to Institution. Kaiser:Takeda, Janssen, Celgene, Amgen: Honoraria, Other: Travel Expenses; Celgene, Janssen: Research Funding; Abbvie, Celgene, Takeda, Janssen, Amgen, Abbvie, Karyopharm: Consultancy.

Description: Background: Cereblon (CRBN) is a substrate receptor of the Cullin 4 E3 ubiquitin ligase complex CRL4CRBN and is the molecular target of the IMiD® immunomodulatory drug lenalidomide. It has been shown that cereblon is required for the anti-proliferative activity of lenalidomide in multiple myeloma (MM) and that reduction of CRBN expression is associated with resistance to IMiD® compounds. Methods: RNA-seq analysis was performed on 12 paired MM patients samples of sorted CD138+ cells obtained prior to lenalidomide treatment initiation and after development of resistance. Transcriptome sequence data was generated on an Ion Torrent Proton sequencer with at least 70 million reads per sample. The STAR aligner was used to align raw reads to the Ensembl74 reference annotation. The HTseq and eXpress algorithms were used to quantify gene and transcript counts, respectively, and the Sailfish algorithm was used to validate eXpress transcript counts. The Deseq2 algorithm was used to determine differential expression at gene and transcript levels between paired samples. Results: Of 272 genes observed to change significantly in expression at relapse (FDR 〈 0.05), a majority (169) were up-regulated. Inter-pathway similarity analysis based on gene set enrichment analysis (GSEA; canonical pathways) suggested 4 distinct processes were down-regulated at relapse, including Notch Signaling, Interferon Signaling and G-coupled protein receptor signaling. Conversely, patients exhibited a single dominant up-regulated process associated with proliferation. Additional GSEA analysis on more specific gene categories revealed up-regulation of the Proliferation gene cluster described in the University of Arkansas for Medical Science (UAMS) classification for newly diagnosed MM (6 of 2599 gene sets tested; FDR

Description: Key Points Pomalidomide leads to rapid immune activation in vivo correlating with clinical outcome in relapsed myeloma. Baseline expression of ikaros/aiolos protein in tumor cells is not predictive of outcome.

Description: Background: Multiple myeloma clinical trial CC-4047-MM-014 (NCT01946477) is a Phase II study designed to test the safety and efficacy of pomalidomide and low-dose dexamethasone alone (arm A) or in combination with daratumumab, an anti-CD38 antibody, (arm B) subjects with relapsed or refractory multiple myeloma who have received a first or second line treatment of lenalidomide-based therapy. Immunomodulatory agents (IMiD® compounds) continue to be the backbone of multiple myeloma therapy especially when combined with monoclonal antibodies, more specifically pomalidomide had been shown previously to enhance T cell- and NK cell-mediated immunity. We sought to characterize on-treatment pharmacodynamic changes of immune biomarkers associated with POM + LoDEX + DARA administration (arm B) using multicolor flow cytometry panels designed to characterize T-cell subsets and CD38+ expressing cells. IMiD agents are the backbone of combination regimens in the treatment of patients with newly diagnosed or relapsed and/or refractory multiple myeloma. The anti-myeloma properties of these agents derive from a dual mechanism of pro-apoptotic effects on tumor cells as well as enhanced immune stimulation. An understanding of how IMiD agents interact with new monoclonal antibodies to modify patient immune profiles offers key insights into the role of such in innate and adaptive immunity in determining patient outcomes. Methods and Results: Peripheral blood samples were collected at screening, Cycle1 Days 1, 8, and 15, and Cycle 2 Days 1 and 15 to monitor pharmacodynamic changes in populations of T cells, NK cells, monocytes and MDSCs by flow cytometry. From 112 patients enrolled in Arm B, 98 patients had baseline and post-treatment specimens available for these analyses. As expected, combination treatment with POM + LoDEX + DARA led to decreased peripheral counts of CD56+CD16+ NK cells as well as CD4+CD38+ and CD8+CD38+ T cell subpopulations. Decreased counts were also noted in CD3-CD19+ B cells. In contrast, total counts of CD14+ monocytes and CD3+CD4+ or CD3+CD8+ T cells were stably maintained and pronounced increases were observed in proliferating CD4+Ki-67+ and CD8+Ki-67+ T cells. Further, when examined as a percent of total counts, increases were observed in CD14+ monocytes, CD3+CD4+ and CD3+CD8+ T-cells, with decreases in CD3-CD19+ B-cells and CD3-CD56+CD16+ NK cells. Correlation of these pharmacodynamic changes with clinical outcomes will be presented. In addition, baseline immune profiling of specific cell population subsets and associations with best overall response and progression-free survival is currently being analyzed. Conclusions: The triplet regimen POM + LoDEX + DARA has shown notable clinical activity with deep and durable responses in relapsed multiple myeloma patients progressed and are or refractory to lenalidomide. Immune characterization here is consistent with a model for clinical activity in which the loss of CD56+CD16+ NK cells along with a concomitant immune suppression by loss of CD38+CD4+ and CD38+CD8+ T- cells is offset by an increase in proliferating cytotoxic CD4+Ki-67+ and CD8+Ki-67+ T-cell populations. Our results demonstrate that patients treated with the POM + LoDEX + DARA combination do not demonstrate impairment in the innate and adaptive immune compartments and, in contrast, show significant proliferative activity in the subsets of CD4, CD8 and NK cells following treatment. Pomalidomide had been shown previously to enhance T cell- and NK cell-mediated immunity; these data are consistent with a mechanism of action in which pomalidomide administration facilitates the ability to overcome immunosuppressive effects of Dara and LoDex. Potential associations of immune biomarkers with patient outcomes is ongoing and will be updated. Disclosures Pierceall: Celgene Corporation: Employment, Equity Ownership. Bahlis:Janssen: Consultancy, Honoraria, Research Funding; Celgene: Consultancy, Honoraria, Research Funding; Amgen: Consultancy, Honoraria, Research Funding. Siegel:Merck: Consultancy, Honoraria, Speakers Bureau; Celgene: Consultancy, Honoraria, Research Funding, Speakers Bureau; Karyopharm: Consultancy, Honoraria; Amgen: Consultancy, Honoraria, Speakers Bureau; BMS: Consultancy, Honoraria, Speakers Bureau; Novartis: Honoraria, Speakers Bureau; Janssen: Consultancy, Honoraria, Speakers Bureau; Takeda: Consultancy, Honoraria, Speakers Bureau. Schiller:Astellas Pharma: Membership on an entity's Board of Directors or advisory committees, Research Funding; bluebird bio: Research Funding. Sebag:Amgen Canada: Membership on an entity's Board of Directors or advisory committees; Takeda Canada: Membership on an entity's Board of Directors or advisory committees; Janssen Inc.: Membership on an entity's Board of Directors or advisory committees; Celgene Canada: Membership on an entity's Board of Directors or advisory committees. Berdeja:Takeda: Research Funding; Genentech: Research Funding; Sanofi: Research Funding; Bristol-Myers Squibb: Research Funding; Celgene: Research Funding; Janssen: Research Funding; Glenmark: Research Funding; Amgen: Research Funding; Novartis: Research Funding; Poseida Therapeutics, Inc.: Research Funding; Bluebird: Research Funding; Teva: Research Funding. Ganguly:Amgen: Consultancy; Daiichi Sankyo: Research Funding; Janssen: Consultancy; Seattle Genetics: Speakers Bureau. Matous:Celgene: Consultancy, Honoraria, Speakers Bureau. Srinivas:VAHCSNJ: Employment. Bar:Celgene: Consultancy. Quick:CTI BioPharma: Research Funding. Fonseca:Celgene: Speakers Bureau. Reece:Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Amgen: Consultancy, Honoraria, Research Funding; Takeda: Consultancy, Honoraria, Research Funding; Merck: Honoraria, Research Funding; Otsuka: Research Funding. Serbina:Celgene: Employment. Zafar:Celgene: Employment. Agarwal:Celgene Corporation: Employment, Equity Ownership. Thakurta:Celgene Corporation: Employment, Equity Ownership.

Description: Background: CC-122 modulates the CRL4 E3 ligase complex, which results in recruitment and degradation of Aiolos and Ikaros. This results in cell autonomous anti-lymphoma and immunomodulatory effects on T and NK-cell function; such as increased expression of activation markers and cytokine production such as IFN-γ and TNF-α (Gandhi, ASH 2012). Single agent CC-122 is currently in a Phase I clinical trial for diffuse large B-cell lymphoma (DLBCL), multiple myeloma, and solid tumors (NCT01421524) and in combination with obinutuzumab (GA101) in DLBCL and indolent non-Hodgkin lymphoma (iNHL) (NCT02417285). We sought to understand the effects of combining CC-122 with anti-CD20 monoclonal antibody obinutuzumab (GA101) in in vitro and in vivo models of DLBCL and follicular lymphoma (FL). Methods: Apoptosis and cell toxicity was measured by Annexin V/ToPro-3 flow cytometry and CellTiter Glo luciferase assays, respectively. Antibody dependent cellular cytotoxicity (ADCC) was measured by anti-CD3 stimulated peripheral blood mononuclear cells (PBMCs) treated with vehicle or 100 nM CC-122 for 3 days. Prior to co-culture, target tumor cells were incubated with vehicle or GA101 for 1 hour, washed and incubated with treated PBMCs for an additional 4 hours followed by an apoptosis assay. DOHH2 and OCI-LY10 xenograft models were analyzed in C.B-17/Icr-Prkdcscid/IcoIcr mice, which retain NK cells, and CC-122 was dosed at 30 mg/kg, qd days (days 1-5 out of a 7 day schedule). Results: In the DOHH2 FL cell line, the percentage of Annexin V and ToPro-3 positive DOHH2 cells treated with 40 nΜ CC-122 or 1000 ng/mL GA101 was 35% and 40%, respectively. The combination of CC-122 and GA101 resulted in a synergistic enhancement with 82% cell death (theoretical additivity = 61%). Treatment of RL FL cells with 40 nΜ CC-122 or 2000 ng/mL GA101 resulted in 14% and 12% apoptotic cells, respectively. CC-122 combined with GA101 showed a synergistic enhancement of 44% cell death (theoretical additivity = 24.2%). In ADCC assays, DOHH2 cells incubated with vehicle treated PBMCs demonstrated 14% apoptosis. DOHH2 cells treated with 1000 ng/ml GA101 and vehicle treated PBMCs exhibited 42% apoptosis. The addition of CC-122 (100 nM) treated PBMCs to GA101 treated DOHH2 cells increased the level of ADCC to 57%. Similarly, CC-122 treatment of PBMCs co-cultured with GA101 treated RL cells led to increased levels of apoptosis by ADCC (75.7%) compared to DMSO treated PBMC with GA101 treated RL cells (62.8%) and vehicle treated co-cultures (33.9%). In a DOHH2 xenograft model, the mean tumor volume (MTV) for vehicle treated controls was 2818 mm3 at the conclusion of the study, compared to CC-122 MTV of 1568 mm3 (44% tumor growth inhibition (TGI)). GA101 monotherapies at 0.5 and 3 mg/kg once weekly yielded dose-related MTVs of 1576 mm3 (44% TGI) and 826 mm3 (71% TGI), respectively. CC-122 in combination with GA101 at 0.5 mg/kg resulted in a MTV of 694 mm3 (75% TGI), whereas the combination of CC-122 with GA101 at 3 mg/kg yielded a MTV of 493 mm3 (83% TGI). All regimens produced TGI that was statistically different from vehicle treated controls (p≤0.001). In 2 DLBCL cell lines (OCI-LY10, ABC-DLBCL and WSU-DLCL2, GCB-DLBCL), CC-122 treatment induced apoptosis with an IC50 ranging from 100 to 300 nΜ. Cell toxicity of either single agent CC-122, GA101 or a combination of the two was measured. OCI-LY10 and WSU-DLCL2 cells treated with 40 nΜ CC-122 reduced viability by 20% and 15%, respectively. OCI-LY10 and WSU-DLCL2 cells treated with 2000 ng/mL GA101 reduced viability by 46% and 62%, respectively. The combination of CC-122 with GA101 in either cell line resulted in additive effects of 58% and 68%, respectively. In the OCI-LY10 xenograft model, CC-122 demonstrated no significant reduction in MTV compared to vehicle. Single agent GA101 at 0.5 and 2.5 mg/kg once weekly yielded dose-related reduction in TGI's of 30.5% and 49.2%, respectively. CC-122 in combination with GA101 at 0.5 mg/kg resulted in 47% TGI), whereas the combination of CC-122 with GA101 at 2.5 mg/kg yielded a 94.5% TGI. Conclusion: Together, these data demonstrate that CC-122 has potent cell autonomous and immunomodulatory activities and that the addition of GA101 provides a synergistic effect in FL and is additive in DLBCL when compared to either as single agents. These data provide pre-clinical proof of concept that a combination of CC-122 and GA101 in the treatment of DLBCL and iNHL may be clinically beneficial. Disclosures Chiu: Celgene: Employment, Equity Ownership. Hagner:Celgene: Employment, Equity Ownership. Pourdehnad:Celgene: Employment, Equity Ownership. Daniel:Celgene: Employment, Equity Ownership. Chopra:Celgene: Employment, Equity Ownership. Klippel:Celgene Corporation: Employment, Equity Ownership. Klein:Roche: Employment. Thakurta:Celgene Corporation: Employment, Equity Ownership. Gandhi:Celgene: Employment, Equity Ownership.

Description: Background: Preclinical studies indicate that lenalidomide (LEN) and POM are not cross-resistant (Ocio et al Leukemia, 2015) and that POM remains active in LEN-resistant myeloma cells (Lopez-Girona et al Leukemia, 2012). Likewise, POM + LoDEX showed comparable efficacy in patients (pts) refractory to LEN administered as last prior Tx vs the full population in subanalyses of the clinical trials MM-002 and MM-003 (San Miguel et al Lancet Oncol, 2013; Richardson et al Blood, 2014). To confirm these observations, we initiated a single-arm, phase 2 trial evaluating POM + LoDEX immediately following second-line LEN-based Tx in advanced RRMM (MM-014; NCT01946477). Methods: Eligible pts (aged ≥ 18 yrs) had received 2 prior lines of Tx, with ≥ 2 cycles of LEN-based Tx in the second line. Pts must have had documented progressive disease (PD) during or after their last antimyeloma Tx and Eastern Cooperative Oncology Group (ECOG) performance status ≤ 2. POM was administered 4 mg/day on days 1-21 of a 28-day cycle with LoDEX 40 mg/day (20 mg/day for pts aged 〉 75 yrs) on days 1, 8, 15, and 22 until PD or discontinuation for any reason. Pts received mandatory thromboprophylaxis. The primary end point was overall response rate by modified International Myeloma Working Group criteria (including minor response). Secondary end points included progression-free survival, overall survival, time to progression, safety, and duration of response. Exploratory end points were included to identify molecular, immune, and cellular biomarkers that might inform POM + LoDEX response, resistance, or mechanism of action. Results: As of March 20, 2015, 27 of the 85 planned pts were enrolled and received POM + LoDEX. Twelve pts remain on Tx, whereas 15 have discontinued, due to PD (n = 7) and withdrawal (n = 5), but not adverse events (n = 0). Males comprised 59% of pts; 85% were white and the median age was 69 yrs (range, 44-85 yrs), with 67% of pts aged ≥ 65 yrs. The median time since diagnosis was 3.9 yrs (range, 1.3-13.3 yrs), and 59% of pts received prior stem cell transplant. Most pts (81%) were refractory to the most recent prior LEN-containing Tx, and the median duration of the most recent prior LEN Tx was 8.3 mos (range, 0.3-56.3 mos). The 19% of pts who were not refractory to the most recent prior LEN-containing Tx remain on Tx. Pts predominantly had ECOG performance status 0 or 1 (30% and 63%, respectively) vs 2 (7%). Of the 19 pts with International Staging System assessment reported, most were stage I (n = 7) or II (n = 11) vs III (n = 1). Efficacy and safety data will be presented. Conclusions: The MM-014 study is assessing the efficacy and safety of POM + LoDEX in pts with RRMM who have received second-line LEN-based Tx. MM-014 is designed to confirm and expand the results from MM-002 and MM-003 with translational data. Clonality and biomarkers, including Aiolos, Ikaros, IRF-4, and c-Myc, will be evaluated to determine association with POM + LoDEX synergy, high-risk MM-associated genetic aberrations, clonal evolution, and minimal residual disease. Disclosures Siegel: Celgene Corporation: Speakers Bureau; Amgen: Speakers Bureau; Takeda: Speakers Bureau; Merck: Speakers Bureau; Novartis: Speakers Bureau. Schiller:Celgene Corporation: Research Funding. Song:Celgene Canada: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Stockerl-Goldstein:Celgene Corporation: Speakers Bureau; Onyx: Speakers Bureau. Kaya:Novartis: Honoraria, Speakers Bureau; Millennium: Honoraria, Speakers Bureau; Celgene: Honoraria, Speakers Bureau; Onyx: Honoraria, Speakers Bureau; Amgen: Honoraria, Speakers Bureau. Sebag:Amgen: Honoraria; Celgene: Honoraria; Novartis: Honoraria; Janssen: Honoraria. Reu:Takeda/Millennium: Research Funding; Novartis: Research Funding; Celgene: Research Funding. Mouro:Celgene Corporation: Employment, Equity Ownership. Sturniolo:Celgene Corporation: Employment. Srinivasan:Celgene Corporation: Employment, Equity Ownership. Thakurta:Celgene Corporation: Employment, Equity Ownership. Nagarwala:Celgene Corporation: Employment, Equity Ownership. Bahlis:Johnson & Johnson: Speakers Bureau; Johnson & Johnson: Consultancy; Amgen: Consultancy; Celgene: Consultancy, Honoraria, Research Funding, Speakers Bureau; Johnson & Johnson: Research Funding.

Description: Background: CC-220 is a Cereblon (CRBN) binding compound currently under clinical investigation for systemic lupus erythematosus. Comparable to other Cereblon-binding agents, ex vivo treatment of CC-220 on B-cells, T-cells and monocytes leads to the degradation of the hematopoietic transcription factors Ikaros (IKZF1) and Aiolos (IKZF3).(1) Currently, CC-220 is being investigated in a phase Ib/IIa study CC-220-MM-001 (clintrial.gov trial #NCT02773030) as a single agent, or in combination with dexamethasone in relapsed/refractory multiple myeloma (RRMM) in patients who may have previously been exposed to pomalidomide. Here, we provide pre-clinical data and mechanistic rationale for the clinical development of CC-220 in heavily pre-treated RRMM. Results: In order to evaluate the ability of CC-220 effects on MM cells in vitro, we generated a large panel of MM cell lines (~69) that consist of 5 categories, including lenalidomide-sensitive (LS; n=26), intrinsically lenalidomide-resistant (ILR; n=7), acquired lenalidomide-resistant (ALR; n=12), acquired lenalidomide/dexamethasone-dual-resistant (ALDR; n=12), and acquired-pomalidomide-resistant (APR; n=12). Cell proliferation by 3H-thymidine incorporation at concentration between 0.01-100 μM was assessed by the area under the curve (AUC) for both CC-220 and pomalidomide. The average AUC was significantly reduced by 65% vs. 52% (p

Description: Background: Immunomodulatory drugs exhibit several anti-Multiple Myeloma (MM) activities including: growth arrest, antiangiogenesis, inhibition of tumor necrosis factor-alpha signaling and induction of apoptosis. The mechanism of action of the IMiD® compounds lenalidomide and pomalidomide that are responsible for these effects are starting to become clear. IMiD® compounds directly bind Cereblon (CBRN), a substrate receptor of the cullin ring E3 ligase (CRL4), and induce CRL4CRBN -mediated degradation of the zinc finger transcriptional repressors Aiolos and Ikaros by ubiquitin-mediated proteolysis. However, direct links between Aiolos or Ikaros degradation via the CRBN-Cul4 complex to the anti-MM activities of IMiD® drugs are poorly understood. Methods and Results: IMiD® compound-induced apoptosis in MM cells is associated with extended duration of treatment and increased caspase-8 activity, but the precise mechanism of caspase-8 activation and delayed onset of apoptotic effects in response to treatment are unknown. Here we show that both lenalidomide and pomalidomide induce caspase-8, but not capsase-9 activity, in multiple MM cell lines after 3 days of treatment and apoptosis after 4 days without inducing significant changes in total caspase-8, c-FLIP (a casapse-8 inhibitory molecule) or caspase-3 gene expression. Bioinformatic analysis of public datasets revealed that that the pro-apoptotic protein TRAIL may be induced by IMiD® compound treatment in a CRBN dependent manner. We confirmed in multiple cell lines that IMiD® compound treatment or knockdown of Aiolos or Ikaros induces TRAIL gene expression. Furthermore, IMiD® compound treatment in pomalidomide resistant cells that lack CRBN expression failed to induce TRAIL gene expression suggesting TRAIL induction is regulated through the established IMiD® drug mediated CRBN-Aiolos/Ikaros pathway. ChIP-PCR analysis confirmed that TRAIL is a direct transcriptional target gene of Aiolos and Ikaros in MM cells. Incubation of cells with a TRAIL neutralizing antibody was sufficient to partially attenuate IMiD® induced apoptosis, thus confirming the role of TRAIL in IMiD® drug induced MM cell apoptosis. Furthermore, TRAIL secretion into the media of IMiD® compound treated cells was significantly increased only after 2 days treatment explaining the delayed induction of apoptosis in treated cells. Interestingly, MM cell lines that are intrinsically resistant to the apoptotic effects of IMiD® compounds, despite degrading Aiolos and Ikaros in response to drug, displayed a decrease in TRAIL sensitivity. Conclusions: Taken together this data indicates that IMiD® drugs induce caspase-8 mediated apoptosis by directly inducing TRAIL gene expression via degradation of Aiolos and Ikaros. Additionally, this suggests that therapeutic interventions that can increase MM cell sensitivity to TRAIL might act synergistically with IMiD® compounds. Disclosures Amatangelo: Celgene Corporation: Employment, Equity Ownership. Bjorklund:Celgene Corporation: Employment, Equity Ownership. Gandhi:Celgene: Employment, Equity Ownership. Klippel:Celgene Corporation: Employment, Equity Ownership. Daniel:Celgene Corporation: Employment, Equity Ownership. Chopra:Celgene Corporation: Employment, Equity Ownership. Trotter:Celgene Corporation: Employment. Thakurta:Celgene Corporation: Employment, Equity Ownership.

Description: Background: We previously reported that Lenalidomide combined with R-CHOP (R2CHOP) has significant activity in non-GCB (non-germinal center B-cell) subtype of DLBCL as defined by immunohistochemistry (IHC) using Hans algorithm (J Clin Oncol. 2015 Jan 20;33(3):251-7). However, defining non-GCB subtype of DLBCL by IHC as opposed to the "gold standard" gene expression profiling (GEP) is subject to technical limitations and its prognostic value has not reproduced in some recently published studies. In addition, recent reports questioned prognostic value of GEP in prospective clinical trials as opposed to initial reports from retrospective case series. To address these concerns, we assessed outcomes by cell of origin (COO) as determined via GEP using NanoString Lymphoma Subtyping Test (LST) on formalin-fixed paraffin-embedded (FFPE) tissue on patients enrolled in a phase 2 study of R2CHOP and an independent comparison cohort of patients treated with RCHOP alone. Methods: Eligible patients for R2CHOP phase 2 study MC078E were adults with newly diagnosed, untreated, stages II-IV CD20 positive DLBCL. Patients received oral lenalidomide 25 mg days 1-10 with standard dose R-CHOP every 21 days for 6 cycles. All patients received pegfilgrastim on day 2 of each cycle and aspirin prophylaxis. DLBCL molecular subtype was determined by GEP using NanoString LST, a multiplexed digital gene expression assay performed on the nCounter® Dx Analysis System and reported as GCB vs ABC vs unclassified. A comparison cohort of RCHOP treated DLBCL patients was generated from the prospectively enrolled Mayo Clinic component of the Lymphoma SPORE Molecular Epidemiology Resource (MER). MER patients meeting the same inclusion criteria as MC078E with available tissue were selected based via matching on age, stage, and IPI to the MC078E patients. Event-free survival was defined as time from diagnosis (MER) or study registration (MC078E) to progression, re-treatment, or death. EFS24 was defined as being event-free at 24 months. Associations between COO and outcome were assessed via log-rank tests due to censoring for EFS24. Results: 50 MC078E R2CHOP patients enrolled between 2008 and 2013,124 matched MER RCHOP patients diagnosed between 2003 and 2012 were assessed for COO. Median follow up in 70 patients still alive was 7.9 years (1.9-13.0) in RCHOP treated patients and 4.4 years (1.9-5.5) for 24 in R2CHOP treated patients still alive. Median age was 65 years (range 35-89) in RCHOP treated patients and 69 years (22-87) in R2CHOP patients (p=0.485). 53 RCHOP treated patients (43%) and 31 R2CHOP treated patients (62%) had intermediate-high or high IPI (p=0.021). COO was GCB, ABC, and unclassified DLBCL subtype in 80, 31 and 13 patients in the 124 RCHOP cohort and 33, 13 and 4 patients in the R2CHOP treated patients, respectively (see table). EFS24 was inferior for ABC (48%) compared to GCB DLBCL 71% in MER RCHOP treated patients (p=0.013). In contrast, in R2CHOP treated pts, EFS24 was not different between ABC vs GCB DLBCL 69% vs 67% (p= 0.674). Conclusion: Cell of origin classification of DLBCL determined by NanoString LST remains prognostic in a series of prospectively enrolled DLBCL patients treated with RCHOP. R2CHOP shows promising efficacy in ABC DLBCL as defined by NanoString LST, where the addition of lenalidomide to RCHOP appears to mitigate the negative impact of an ABC molecular subtype on the outcome. Table Table. Disclosures Nowakowski: Morphosys: Research Funding; Bayer: Consultancy, Research Funding; Celgene: Research Funding. Maurer:Kite Pharma: Research Funding; Celgene: Research Funding. Storhoff:NanoString Technologies, Inc.: Employment, Other: Stock option. Dennis:NanoString Technologies, Inc.: Employment, Other: Stock option. Gandhi:Celgene Corporation: Employment, Equity Ownership. Thakurta:Celgene: Employment, Equity Ownership. Hagner:Celgene Corporation: Employment, Equity Ownership. Rimsza:NCI/NIH: Patents & Royalties: L.M. Rimsza is a co-inventor on a provisional patent, owned by the NCI of the NIH, using Nanostring technology for determining cell of origin in DLBCL..