ALBERT

Description: Background: Diffuse large B-cell lymphoma (DLBCL) is a genetically heterogeneous disease of malignant B cells most often classified by tumor gene expression and/or mutations. DLBCL is also characterized by a tumor microenvironmental influence that has not been well described. Immuno-oncology-targeting agents such as immune checkpoint inhibitors have limited clinical activity in DLBCL, highlighting the need for a better understanding of the DLBCL tumor microenvironment for rational drug development, combinations, and disease stratification. Here, we systematically characterize the immune composition of more than 100 DLBCL tumors using 2 imaging technologies and provide insight into the complexity of DLBCL disease biology. Methods: A total of 110 cases of newly diagnosed DLBCL were analyzed by multiplex immunohistochemistry (IHC; n=70) and multiplexed ion beam imaging (MIBI) (n=40), each with 10 common markers (CD20, CD3, CD8, Foxp3, CD56, CD163, CD11c, CD56, PD-1, PD-L1) and a few platform-specific markers. Both IHC and MIBI images were digitalized to generate marker-positive cell counts (including single, double, or triple positivity), cell density (cell count/mm2), and population fraction (% of total nucleated cells). Marker density was analyzed for the major components of tumor-infiltrating cell types and correlation between any pair of markers. In addition, RNAseq data and fluorescence in situ hybridization (FISH) data on MYC, BCL-2, and BCL-6 translocation were generated. Results: In the IHC cohort, T cells (CD3+), dendritic cells (DCs; by CD11c+), and macrophages (CD163+)were the major immune components, with median population fractions of 22%, 16%, and 2.7%, respectively. Natural killer cells (CD56+CD20−) were a minor component at a median of 0.1%. A significant negative correlation was observed between tumor cells (CD20+) and CD4+ (Spearman ρ = −0.47; P = 1.3 × 10−04), and CD8+ T cells (Spearman ρ = −0.42; P = 1.4 × 10−03) cells, and an unexpectedly negative correlation between DCs (CD11c+) and macrophages (CD163+, r = −0.63; P = 9.8 × 10−06) was found. Similar to follicular lymphoma, 2 PD-1+ T-cell populations were identified: PD-1bright and PD-1dim. The PD-1bright cells co-stained with CXCR5, indicating T follicular helper cells (Tfh). The PD-1dim were expressed on exhausted effector cells that co-stained with Tim3 or Lag3. The median population fraction of Tim3+ or Lag3+ among T cells was 25%, whereas that of PD-1dim among T cells was 0.2%, indicating that PD-1 was not a useful marker for exhausted T cells. PD-L1 was predominantly found on DCs and macrophages, and the median population fraction of PD-L1+ among tumor cells was only 6.2%. By unsupervised hierarchical clustering on marker density, 3 major immune-infiltration patterns (P1, P2, and P3) were identified. The first 2 segments (P1 and P2) were 20% and 25% of the total cases, respectively. Both were characterized by high T-cell, macrophage, and DC infiltration. P1 was enriched for PD-1+ T cells, whereas P2 was void of any PD-1+ cells. The third segment (P3) that comprised 55% of the cases was predominantly tumor cells with low T-cell, macrophage, and DC infiltration. PD-L1+ cells were primarily found in segments P1 and P2 but rare in segment P3. Additional analysis on the associations between the 3 immune-infiltration patterns and prognostic DLBCL molecular features such as cell-of-origin, double-hit gene signature, and double-hit FISH will also be presented. Conclusions: These data show the complexity of DLBCL disease biology and show classification of DLBCL at the immune-infiltration level as 3 distinct patterns. The overall low expression of PD-1+ T cells and the restricted pattern of PD-L1+ tumor cells provide a possible explanation for the lack of clinical activity of PD-1/PD-L1 blockade in DLBCL. We also observed other exhausted T cells expressing Lag3 and Tim3, suggesting alternative therapeutic opportunities in stratified populations. These data also highlight the opportunity to develop rational immuno-oncology-targeted agents based on the immune infiltration pattern of DLBCL and selection of patients who may respond more favorably to particular agents. Disclosures Huang: Celgene Corporation: Employment, Equity Ownership. Nakayama:Celgene Corporation: Employment, Equity Ownership. Stokes:Celgene Corporation: Employment, Equity Ownership. Towfic:Celgene Corporation: Employment, Equity Ownership. Lee:Celgene Corporation: Employment, Equity Ownership. Ren:Celgene Corporation: Employment, Equity Ownership. Marella:Celgene Corporation: Employment, Equity Ownership. Wang:Celgene Corporation: Employment, Equity Ownership. Hagner:Celgene Corporation: Employment, Equity Ownership, Patents & Royalties. Couto:Celgene Corporation: Employment, Equity Ownership, Patents & Royalties. Newhall:Celgene Corporation: Employment, Equity Ownership. Gandhi:Celgene Corporation: Employment, Equity Ownership, Patents & Royalties.

Description: BACKGROUND: Loss of immune surveillance is critical in the pathogenesis of multiple myeloma (MM) and the progression from smoldering to symptomatic MM. To date, no clear efficacy signal has been observed with programmed-death 1 and programmed death ligand-1 inhibitors in patients with MM. General immune dysfunction in MM is well documented, but the evolving immune landscape in relapsed/refractory MM (RRMM) vs newly diagnosed MM (NDMM) is less well characterized. This study aimed to characterize immune profiles in peripheral blood and bone marrow from patients with NDMM and RRMM. METHODS: Peripheral blood samples were collected from 35 NDMM and 146 RRMM patients and 36 age-matched healthy volunteers (HVs). Cell surface and intracellular antigen staining using fluorochrome labeled antibodies was performed on a BD FACSCanto II flow cytometer. Bone marrow aspirates were collected from 26 NDMM and 73 RRMM patients, and the transcriptome was assessed by mRNA-Seq. RESULTS: In peripheral blood, T-cell populations differed between HVs and NDMM and RRMM patients. Absolute numbers of lymphocytes were higher in HVs than in NDMM and RRMM, regardless of the MM disease state. Absolute numbers of total CD4+ T cells and naïve CD4+ T cells were lower in RRMM patients, whereas CD4+ effector memory T cells as a proportion of total CD4+ T cells were increased in RRMM patients. Blood from RRMM patients also contained increased levels of proliferating CD4+ T cells, as evidenced by Ki67, ICOS, and HLA-DR, compared with blood from NDMM patients; HVs had values much closer to those from NDMM than from RRMM patients, suggesting a trend influenced by disease state or therapeutic intervention. In bone marrow, immunologic gene expression signatures were elevated in NDMM vs RRMM patients; the differences were similar to those in peripheral blood. Using limma to model the differential expression of all measured genes between NDMM and RRMM, we identified 367 genes that were elevated in NDMM patients vs 52 in RRMM patients. Gene set analyses using Molecular Signatures Database immunologic signatures (C7) applied to those 367 genes showed that naïve T-cell genes were increased in the bone marrow of NDMM vs RRMM patients. Gene set enrichment analysis with limma, using 489 gene sets from xCell representing 64 cell types and controlling for differences in tumor burden, indicated that macrophage, monocyte, and neutrophil genes were upregulated and T cells, particularly naïve CD4+ T cells, were downregulated in RRMM patients. Immunohistochemistry results from bone marrow biopsies showed increased programmed death-ligand 1 expression on tumor and infiltrating immune cells and increased CD8 infiltration into bone marrow in RRMM vs NDMM patients. Multiparameter immunofluorescence is underway to confirm these findings and further understand the tumor immune microenvironment in patient subsets. As expected, baseline RRMM immune cell populations depended on prior lines of therapy. Daratumumab-exposed RRMM patients had elevated total CD8+ T cells in peripheral blood but decreased CD38+, CD4+, and CD8+ T cells, as well as decreased total natural killer cells, compared with the daratumumab-naïve patients. Transcriptome analyses of bone marrow from daratumumab-exposed RRMM patients revealed increased T-cell gene expression signatures relative to marrow from daratumumab-naïve patients. Additionally, pomalidomide-exposed RRMM patients had increased activated CD4+ and CD8+ T cells vs pomalidomide-naïve patients. CONCLUSIONS: These data indicate that RRMM patients have peripheral blood and bone marrow environments with highly differentiated T-cell populations, whereas NDMM patients show elevated T-cell levels with proliferative capacity. Furthermore, the bone marrow of RRMM patients is enriched with neutrophils and macrophages; investigation is ongoing to determine if these cell types contribute to an immunosuppressive tumor microenvironment. Understanding immune system function based on disease progression, patient segments, and prior lines of therapy is imperative as treatment of MM improves, and it may inform the administration and sequence of next generation immunotherapeutics and identify predictive biomarkers for optimal treatment selection. Disclosures Pietz: Celgene Corporation: Employment. Tometsko:Celgene Corporation: Employment, Equity Ownership. Copeland:Celgene Corporation: Employment, Equity Ownership. Whalen:Celgene Corporation: Employment, Equity Ownership. Schmitz:Celgene Corporation: Employment, Equity Ownership. Thompson:Celgene Corporation: Employment, Equity Ownership. Agarwal:Celgene Corporation: Employment, Equity Ownership. Foy:Celgene Corporation: Employment, Equity Ownership. Buchholz:Celgene Corporation: Employment. Komashko:Celgene Corporation: Employment. Dell'Aringa:Celgene Corporation: Employment, Equity Ownership. Fox:Celgene Corporation: Employment, Equity Ownership. Newhall:Celgene Corporation: Employment.

Description: Background: The availability of chimeric antigen receptor (CAR)-modified T cells (CAR T) has profoundly increased therapeutic options for patients (pts) with B cell malignancies, including DLBCL. Liso-cel is an investigational, anti-CD19, defined composition, 4-1BB, CAR T cell product administered at a target dose of CD4+ and CD8+ CAR T cells. To understand tumor microenvironmental (TME) factors affecting short-term and durable responses in pts with R/R DLBCL who received liso-cel in the TRANSCEND NHL 001 study, we conducted multiplexed IF analyses of 111 DLBCL biopsies for 83 pts obtained at baseline (n=58) and approximately 11 days (D11) (n=53; 28 paired) after liso-cel infusion (NCT02631044). Methods: We employed three 5-plex IF panels, consisting of antibodies detecting (1) B cell (CD19, CD20) and T cell lineage (CD4, CD8, EGFR) markers, (2) immunosuppressive markers (CD163, FoxP3, CD73, IDO1, PD-L1), and (3) functional markers (CD3, Ki67, GZMB, PD-1, EGFR). Liso-cel expresses a truncated EGFR (EGFRt), and fluorescent anti-EGFR was used to identify CAR T cells within the tumor biopsies. We also performed bulk tumor RNA profiling for an overlapping subset of 50 baseline biopsies and 37 D11 biopsies (11 paired). We investigated the association of differences in marker densities for pts with best overall response (BOR) of complete response (CR), and progressive disease (PD). Baseline and D11 biopsy findings were correlated with early responses at ~1 month (M1) posttreatment (PD n=16; CR n=42) and durable responses at ~9 months (M9) posttreatment (PD n=76; CR n=32; 55 pts evaluated at both M1 and M9). We investigated how baseline and D11 densities, with spatial distinction between tumoral and peritumoral regions, correlated with early and durable responses. All comparisons describe differences in median densities, and have statistical significance reported with uncorrected P values assessed via the (unpaired) Wilcoxon-Mann-Whitney nonparametric test. Results: Signals in baseline biopsies that correlated with early (M1) response differed from those that correlated with durable (M9) CR. A 21% higher baseline presence of PD-1+ T cells was associated with pts who achieved early CR at M1 vs pts who had PD at M1 (P=0.007). Pts with durable CR at M9 had 39% lower baseline levels of CD163+ macrophages (P=0.019) and 270% higher levels of CD73+ cells (P=0.028) than those with PD at M9. On-treatment (D11) tumors of pts with both early and durable CR had 28% higher levels of EGFRt+ (CAR T) CD8+ T cells (P=0.022), and 810% higher EGFRt- (non-CAR T) CD4+ (but notably, not CD8+; P=0.28) T cells (P=0.009). We also investigated changes in marker densities between baseline and on-treatment (D11) biopsies, and found that pts with durable CR at M9 had decreased on-treatment B cell densities (P=0.029), and increased densities of CD8+ GZMB+, Ki67+, and/or PD-1+ CAR (P=0.001) as well as non-CAR T (P=0.017) cells. Pts with durable CR also had a 29% increase in tumor-associated CD163+ macrophages at D11 relative to baseline (P=0.033). While the accessibility of spatial arrangements and multilabeled cells from IF enables a more nuanced picture of the TME, many of the general trends described above are concordant with those observed in bulk tumor RNA sequencing. Lower baseline expression of CD163 (P=0.021) and higher expression of CD73 (P=0.054) were seen in pts with durable CR. Additionally, elevated on-treatment (D11) expression of CD3E, CD4, and liso-cel (P

Description: Key Points AMG 330 cytotoxicity against AML cells is proportional to the level of CD33 expression but is not affected by ABC transporter activity. AMG 330 cytotoxicity is amenable to modulation and augmentation by clinically available drugs such as histone deacetylase or DNA methyltransferase I inhibitors.

Description: Bispecific T-cell engager (BiTE®) antibodies represent a promising tool for anti-leukemic immunotherapy. The CD19/CD3-bispecific antibody blinatumomab was shown to be active in refractory and relapse patients with B-precursor acute lymphoblastic leukemia (Topp et al, ASCO 2014). Transient, blinatumomab-mediated cytokine release syndrome has been linked to target cell numbers as this phenomenon is predominantly observed within the first treatment cycle. In our previous work, we demonstrated that the bispecific CD33/CD3 BiTE® antibody AMG 330 is able to induce activation and proliferation of residual autologous T-cells and effectively mediates lysis of primary acute myeloid leukemia (AML) cells (Krupka et al, Blood 2014; 123(3):356-65). We hypothesize that in AML patients with high initial leukocyte counts (WBC 〉 30.000/μl) a cytoreductive phase prior to AMG 330 therapy might be beneficial to reduce the incidence and severity of cytokine mediated toxicity. Ideally, the cytoreductive drug does not impair T-cell function or reduce target antigen expression level. In the current study, we evaluated the effect of cytarabine (20 µM), decitabine (5 µM), azacitidine (1 µM and 5 µM) and hydroxyurea (10 µM and 100 µM) on T-cell proliferation and function in close analogy to potential treatment algorithms for AML. Healthy donor (HD) T-cells were pre-incubated with the cytoreductive drugs for 72 hours. T-cells were CFSE-labeled and co-cultured with either HL60 or MV4-11 cells (effector cell:target (E:T) ratio 1:1) in the presence or absence of AMG 330 (5 ng/ml). After 3 days of co-culture, lysis of HL60 cells and T-cell proliferation was assessed by flow cytometry. Pretreatment of T-cells with cytarabine completely abrogated T-cell function (lysis of HL60 cells: untreated (UT): 96.9% vs 20 µM: 4.2%) and significantly impaired T-cell proliferation (UT: 31.2% vs 20 µM: 4.6%). These findings correlated to data using primary AML samples collected 3 and 6 days after discontinuation of cytarabine treatment. After a 3-day chemotherapy-free interval, we observed no relevant T-cell proliferation and lysis of AML cells upon the addition of AMG 330 to the ex-vivo long-term culture system (lysis of AML cells on day 12: 30%; fold change T-cell expansion 0.9). After a 6-day treatment-free interval, high T-cell proliferation and cytotoxicity against primary AML cells were observed (lysis of AML cells on day 12: 61%; fold change T-cell expansion: 3.1). In contrast to cytarabine, decitabine treatment only marginally impaired T-cell function. Similarly, pre-incubation with azacitidine did not convey a negative effect on T-cell function (lysis of HL60 cells: UT: 100% vs 1 µM: 94.9% vs 5µM: 86.8%; proliferation: UT: 90.9% vs 1 µM: 80% vs 5 µM: 66.8%). Pretreatment with hydroxyurea had the least impact on T-cell performance. It did not impair T-cell function (lysis of HL60 cells: UT: 100% vs 10 µM: 100% vs 100 µM: 100%) and proliferation compared to untreated controls (UT: 92.9% vs 100 µM 90.8% vs 10 µM 92.9%). As we have previously shown that the level of CD33 expression correlates to kinetics of AMG 330-mediated lysis (Krupka et.al, EHA 2014), we analyzed the effect of the cytoreductive agents on CD33 expression level in AML cell lines and primary AML cells. Five AML cell lines (HL60, MV4-11, PL21, OCI-AML3, KG1a) and a primary AML patient sample were cultured in the presence or absence of decitabine (5 µM and 50 µM), azacitidine (1 µM and 5 µM) or hydroxyurea (10 µM and 100 µM) for 72 hours. The change of CD33 expression level was evaluated by flow cytometry (median fluorescence intensity, MFI). No significant changes in CD33 expression level were observed after culture of AML cell lines and primary AML cells with decitabine or azacitidine. In contrast, hydroxyurea upregulated surface expression of CD33 on 2/5 cell lines (HL60 and PL21) in a dose dependent manner (HL 60 MFI Ratio: UT 134.9 vs 10 µM 171.3 vs 100 µM 210; PL21 MFI Ratio: UT 166.9 vs 10 µM 177.9 vs 100 µM 191.8). In summary, we could show that pretreatment with hydroxyurea did not impair T-cell function and proliferation. In addition, we observed an upregulation of CD33 expression on AML cell lines. As the BiTE® technology relies on T-cell function and target antigen expression level, sequential and combinatorial immuno-chemotherapeutic approaches need to address both issues. Our data support the use of hydroxyurea in AML patients that require cytoreduction prior to AMG 330 treatment. Disclosures Krupka: AMGEN Inc.: Research Funding. Kufer:AMGEN Research (Munich): Employment; AMGEN Inc.: Equity Ownership. Kischel:AMGEN Research (Munich): Employment; AMGEN Inc.: Equity Ownership. Zugmaier:AMGEN Inc.: Equity Ownership; AMGEN Research (Munich): Employment. Sinclair:AMGEN Inc.: Employment, Equity Ownership. Newhall:AMGEN Inc.: Employment, Equity Ownership. Frankel:AMGEN Inc.: Employment, Equity Ownership. Baeuerle:AMGEN Research (Munich): Employment; AMGEN Inc.: Equity Ownership. Riethmüller:AMGEN Inc.: Equity Ownership. Subklewe:AMGEN Inc.: Research Funding.

Description: Background: Recent studies have demonstrated that AMG 330, a novel CD33/CD3-directed bispecific T-cell engaging (BiTE¨) antibody, is highly active against CD33+ AML cell lines and can potently lyse leukemic blasts from AML patients. Here, we have investigated the preclinical determinants for AMG 330 activity in primary newly diagnosed and relapsed/refractory human AML samples to prospectively understand factors that might contribute to clinical response or resistance. Patients and Methods: Frozen aliquots of Ficoll-isolated mononuclear cells from peripheral blood or bone marrow specimens were obtained from adults with AML who consented to their use for research purposes. CD33 expression on myeloblasts (identified by appropriate CD45 and side-scatter properties) and the percentage of endogenous CD3+ T-cells were quantified by flow cytometry. To determine drug-induced cytotoxicity, AML cells were incubated in culture medium containing various concentrations of AMG 330; in some experiments, exogenous T-cells (isolated via magnetic cell sorting from a healthy adult volunteer who underwent leukapheresis) were labeled with CellVue Burgundy and added at different effector:target (E:T) cell ratios. After 48 hours, cell numbers and drug-induced cytotoxicity, using DAPI to detect non-viable cells, were determined by flow cytometry; AML cells were identified by forward/side scatter properties and negativity for CellVue Burgundy dye. Specific drug-induced cytotoxicity was calculated as: 100 x (1 – live target cellstreated/live target cellscontrol), and presented as mean±SEM. Results: Forty-one of the 49 studied specimens were included in our analyses as they had 〉40% myeloblasts upon thaw and were 〉50% and 〉30% viable at baseline and after 48 hours, respectively. Median age of the patients was 65.3 (range: 23.9-80.0) years. The median percentage of myeloid blasts and CD3+ T-cells in the studied specimens was 87.1% (range: 55.1-97.0%) and 2.0% (range: 0-27.3%), respectively, and median sample viability after 48 hours in culture was 76.7% (range: 31.1-93.5%). These characteristics were similar between the newly diagnosed (n=21) and relapsed/refractory (n=20) AML specimens. In the absence of healthy donor T-cells, AMG 330 resulted in modest cytotoxicity (at 500 pg/mL: 11.8±2.5%) that was correlated with the amount of autologous T-cells (at 500 pg/mL; r=0.566; p=0.0001; Spearman's rank correlation test). On the other hand, AMG 330 exerted marked cytotoxic activity in several specimens with very low CD33 expression, and there was no correlation between AMG 330 cytotoxicity and CD33 expression (at 500 pg/mL; r=-0.048; p=0.77). In the presence of healthy donor T-cells, AMG 330 cytotoxicity was strictly dependent on the drug dose (e.g. p

Description: Introduction: Targeting immune cells in the tumor microenvironment is an attractive approach to improving antitumor activity of standard therapy in r/r hematologic malignancies. Durvalumab is a monoclonal antibody that blocks programmed cell death ligand-1 (PD-L1), allowing T cells to recognize and kill tumor cells. Methods: The FUSION NHL-001 study (NCT02733042) is a phase 1/2 study assessing safety and efficacy of durvalumab as monotherapy or in combination. Eligible patients (pts) must have had r/r DLBCL or FL after ≥1 systemic therapy requiring therapeutic intervention. Other inclusion criteria include ECOG performance status 0-2 and ≥1 CT-measurable lesion. Pretreatment tumor biopsies were collected to assess biomarkers of response to durvalumab combination therapies. Pts with r/r B-cell neoplasms were enrolled into 1 of 4 arms that included durvalumab monotherapy (Arm D) or in combination with lenalidomide ± rituximab (Arm A), ibrutinib (Arm B), or rituximab ± bendamustine (Arm C). Durvalumab was given at a fixed dose of 1500 mg every 4 weeks. The study consisted of 2 parts: dose finding (except for Arm D) to establish the recommended phase 2 dose (RP2D) for each combination and dose confirmation. We present final subset analyses for pts with DLBCL and FL treated in Arms A, C, and D. Results: A total of 38 DLBCL and 22 FL pts were enrolled. Baseline characteristics are presented in Tables 1 and 2. Arm A was prematurely closed after an FDA announcement regarding safety concerns with combination of lenalidomide and checkpoint inhibitors in multiple myeloma; therefore, RP2D for lenalidomide ± rituximab could not be defined. However, 4 pts (DLBCL, n=1; FL, n=3) experienced dose-limiting toxicities (DLTs): febrile neutropenia (lenalidomide 10 mg + rituximab), headache, hepatitis, and thrombocytopenia (lenalidomide 20 mg + rituximab). One pt with DLBCL experienced DLT in Arm C (neutropenia) when treated with bendamustine 90 mg/m2 + rituximab. RP2D for bendamustine was established as 70 mg/m2. Durvalumab treatment (13 infusions) was completed for 10 (DLBCL, n=4; FL, n=6) pts (17%), 2 in Arm A and 8 in Arm C; the main reason for durvalumab withdrawal was disease progression. During the study, 38 pts (63%) experienced 81 serious adverse events (SAEs), most frequently related to infections (Figure 1). A total of 22 immune-mediated AEs (imAEs) related to durvalumab were reported in 13 pts (grade 1, 2, and 3 in 9, 7, and 6 cases, respectively): transaminitis and increased bilirubin (9 events), diarrhea (5 events), rash and pruritus (5 events), thyroid disorder (2 events), and infusion-related reaction (1 event). Two pts were treated with systemic steroids, both for grade 3 transaminitis. Others received symptomatic treatment. Ten pts experienced AEs that led to any drug discontinuation: 4 in Arm A (cerebral ischemia, febrile neutropenia, myalgia, hyponatremia), 3 in Arm C (transaminitis; neutropenia in 2 pts) and 3 in Arm D (drug reaction with eosinophilia and systemic symptoms, gastrointestinal perforation, prolonged QT). There were 6 grade 5 AEs, none considered related to study drugs. For pts with DLBCL (Table 3), overall response rate (ORR) was 18% and complete response rate (CRR) was 8%. Median progression-free survival (PFS) (Figure 2) was 2.5 months (95% CI, 1.25-5.13). There were 30 deaths on study (2, 19, and 9 pts in Arms A, C, and D, respectively), 24 (80%) related to disease progression. Median overall survival (OS) was 7.9 months (2.66-15.31). For pts with FL (Table 3), ORR was 59% and CRR was 27%. Median PFS (Figure 3) was 10.6 months (4.63-NE). There were 6 deaths on study (2 and 4 pts in Arms A and D, respectively); 3 (50%) were related to disease progression and 1 to second primary malignancy (bladder cancer, Arm A). Median OS was not reached. An interferon-γ signature comprising 4 genes, IFN-γ, CD274, LAG3, and CXCL9, trended higher with best ORR in pts with r/r DLBCL (N=30, P=0.06) and FL (N=18, P=0.01) independent of treatment arm (Arms A, C, and D included in analysis). Conclusions: Durvalumab as monotherapy or in combination in DLBCL and FL is tolerable without unexpected safety signals but requires close monitoring. Durvalumab alone or in combination appeared to add limited benefit to therapy for r/r DLBCL or FL. However, use of an interferon-γ gene signature may serve as a biomarker by which to enrich for r/r NHL pts that may be more responsive to anti-PD-L1-based therapy and will require further investigation. Disclosures Casulo: Gilead: Honoraria, Other: Travel, accommodation, expenses; Roche: Other: Travel, accommodation, expenses; Celgene: Research Funding. Santoro:MSD: Speakers Bureau; Lilly: Speakers Bureau; Sandoz: Speakers Bureau; BMS: Consultancy; Takeda: Speakers Bureau; BMS: Speakers Bureau; Abb-Vie: Speakers Bureau; Amgen: Speakers Bureau; Celgene: Speakers Bureau; AstraZeneca: Speakers Bureau; Pfizer: Consultancy, Speakers Bureau; Arqule: Consultancy, Speakers Bureau; Eisai: Consultancy, Speakers Bureau; Novartis: Speakers Bureau; Bayer: Consultancy, Speakers Bureau; Servier: Consultancy, Speakers Bureau; Roche: Speakers Bureau; Gilead: Consultancy, Speakers Bureau. Ando:Eisai: Research Funding. Le Gouill:Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel support; Roche-Genentech: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel support. Ruan:Celgene: Consultancy, Honoraria, Research Funding; AstraZeneca: Consultancy, Honoraria; Seattle Genetics: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria; Pharmacyclics LLC, an AbbVie company: Research Funding; Juno: Consultancy; Kite: Consultancy. Radford:Novartis: Consultancy, Honoraria; ADC Therapeutics: Consultancy, Research Funding; BMS: Consultancy, Honoraria; AstraZeneca: Equity Ownership, Research Funding; Seattle Genetics: Consultancy, Honoraria; Takeda: Consultancy, Honoraria, Research Funding; GSK: Equity Ownership. Arcaini:Celgene, Roche, Janssen-Cilag, Gilead: Other: Travel expenses; Gilead Sciences: Research Funding; Celgene: Speakers Bureau; Bayer, Celgene, Gilead Sciences, Roche, Sandoz, Janssen-Cilag, VERASTEM: Consultancy. Pinto:Roche: Speakers Bureau; Roche, Takeda: Other: Travel grants; EDO-Mundipharma: Patents & Royalties; Roche, MSD, Bristol-Myers Squibb, Servier: Honoraria; Servier, Roche, Bristol-Myers Squibb, MSD: Membership on an entity's Board of Directors or advisory committees. Izutsu:Eisai, Chugai, Zenyaku: Honoraria; Eisai, Symbio, Chugai, Zenyaku: Research Funding; Celgene: Consultancy; Chugai, Celgene, Daiichi Sankyo, Astra Zeneca, Eisai, Symbio, Ono, Bayer, Solasia, Zenyaku, Incyte, Novartis, Sanofi, HUYA Bioscience, MSD, Astellas Amgen, Abbvie, ARIAD, Takeda, Pfizer: Research Funding; Kyowa Kirin, Eisai, Takeda, MSD, Chugai, Nihon Medi-physics, Janssen, Ono, Abbvie, Dainihon Sumitomo, Bayer, Astra Zeneca, HUYA Japan, Novartis, Bristol-Byers Squibb, Mundi, Otsuka, Daiichi Sankyo, Astellas, Asahi Kasei: Honoraria. Rule:Astra-Zeneca: Consultancy, Honoraria; Gilead: Consultancy, Honoraria; Sunesis: Consultancy, Honoraria; Pharmacyclics: Consultancy, Honoraria; Celgene: Consultancy, Honoraria; Janssen: Consultancy, Honoraria, Research Funding; Roche: Consultancy, Honoraria, Research Funding; TG Therapeutics: Consultancy, Honoraria; Napp: Consultancy; Kite: Consultancy. Munoz:Pharmacyclics /Janssen: Consultancy, Research Funding, Speakers Bureau; Bayer: Consultancy, Speakers Bureau; Merck: Consultancy; Kyowa: Consultancy, Honoraria, Speakers Bureau; Seattle Genetics: Consultancy, Honoraria, Research Funding, Speakers Bureau; Celgene/Juno: Consultancy, Research Funding; Genentech: Consultancy, Research Funding, Speakers Bureau; Kite/Gilead: Consultancy, Research Funding, Speakers Bureau; Bristol-Myers Squibb: Consultancy; Alexion: Consultancy; Pfizer: Consultancy; Fosunkite: Speakers Bureau; AstraZeneca: Speakers Bureau; Portola: Research Funding; Incyte: Research Funding. Casadebaig:Celgene Corporation: Employment, Equity Ownership. Fox:Celgene Corporation: Employment, Equity Ownership. Rettby:Celgene Corporation: Employment, Equity Ownership. Dell'Aringa:Celgene Corporation: Employment, Equity Ownership. Delarue:Celgene Corporation: Employment, Equity Ownership. Newhall:Celgene Corporation: Employment, Equity Ownership. Czuczman:Celgene Corporation: Employment, Equity Ownership. Cartron:Roche, Celgene: Consultancy; Sanofi, Gilead, Janssen, Roche, Celgene: Honoraria. OffLabel Disclosure: Durvalumab is a PD-L1 blocking antibody indicated for the treatment of patients with 1) locally advanced or metastatic urothelial carcinoma who have disease progression during or following platinum-containing chemotherapy, or who have disease progression within 12 months of neoadjuvant or adjuvant treatment with platinum-containing chemotherapy, or 2) unresectable, stage 3 NSCLC whose disease has not progressed following concurrent platinum-based chemotherapy and radiation therapy.

Description: Antibody-based immunotherapy represents a promising strategy to target and eliminate chemoresistant leukemic cells in acute myeloid leukemia (AML). In our previous work, the potency of the CD33/CD3-bispecific BiTE® antibody AMG 330 to activate and redirect T-cells to AML cells was evaluated in a long-term culture system using unmanipulated peripheral blood (PB) or bone marrow (BM) samples from AML patients. We were able to show effective elimination of AML cells by AMG 330-activated and -expanded residual autologous T-cells (n=13, Krupka et. al, Blood 2014 123(3):356-65). The goal of the present study was to identify and manipulate factors that interfere with AMG 330-mediated lysis of primary AML cells. In our ex-vivo long-term culture system (n= 32 primary diagnosis, 3 relapse), we observed that successful elimination of primary AML cells was predominantly influenced by the initial effector:target (E:T) ratio. Reduced short-term lysis efficacy was observed for patient samples with low E:T ratios (median lysis: E:T ratio 1:10 99.3%) after 4 days of culture. However, after 12 days of culture this effect was less prominent as effector T-cell numbers increased and lysis was observed even in cultures with very low initial E:T ratios (up to an E:T ratio of 1:80). Considering the ubiquitous expression pattern of CD33 within the myeloid compartment, the number of AMG 330 treatment days will be limited due to expected hematotoxicity. Therefore, AMG 330 efficacy might benefit by increasing the E:T ratio within a short time period. Programmed cell death-1 (PD-1) and its primary ligand PD-L1 are immune checkpoints that limit T-cell responses and may contribute to slower lysis kinetics during AMG 330 treatment. Therefore, we assessed PD-1 expression on T-cells and PD-L1 expression on primary AML cells. No constitutive expression of PD-1/PD-L1 on T-cells and corresponding AML cells was found at primary diagnosis (PD-1: n=23; PD-L1: n=193). Upon the addition of AMG 330 to our primary ex-vivo AML cultures, we observed a strong upregulation of PD-1 on activated T-cells, which correlated with the extent of T-cell proliferation (10/10). This was most prominent within the subpopulation of CD4+/CD45RA-/CCR7- effector memory T-cells. Furthermore, in response to AMG 330-mediated T-cell activation, we observed an upregulation of PD-L1 on primary AML cells (16/19). Data obtained from AML cell lines confirmed an upregulation of PD-L1 after co-cultivation with T-cells and AMG 330. This phenomenon was cytokine-mediated as the addition of IFNγ and TNFα also induced PD-L1 expression (n=6). Interestingly, we also observed a PD-L1 upregulation on T-cells upon activation with AMG 330, but to a much lower extent compared to primary AML cells (n=17; mean MFI ratio: T-cells: 4.7; AML cells: 12.1). Blockade of the PD-1/PD-L1 interaction through the addition of an inhibitory antibody induced an increase in T-cell proliferation in ex-vivocultures resulting in enhanced cytotoxicity against primary AML cells (lysis on day 18: with/without PD-1 blocking antibody: 75 vs 44%; fold change T-cell expansion: 6 vs 3). This was accompanied by a significant increase in IFNγ production (with/without PD-1 blocking antibody: 280 pg/ml vs 81 pg/ml). Complimentary experiments using primary AML cells and allogeneic T-cells at defined E:T ratios demonstrated that this effect is most prominent in co-cultures with a low percentage of T-cells within the primary sample (lysis on day 7 with/without PD-L1 blocking antibody: E:T ratio 1:1: 100% vs 94.5%; E:T ratio 1:5: 96.6% vs 82.7%; fold change T-cell expansion: E:T ratio 1:1: 3.1 vs 3.1; E:T ratio 1:5: 23.4 vs 9.8). Intriguingly, upon addition of lenalidomide to our primary AML cultures, we were also able to circumvent the immune inhibitory effect of the PD-1/PD-L1 interaction by a decrease in PD-L1 upregulation on primary AML cells. Our data show that AMG 330-mediated lysis of primary AML cells can be enhanced by inhibiting the PD-1/PD-L1 axis on T-cells and corresponding AML cells. The modulation of the PD-1/PD-L1 axis increased T-cell proliferation and accelerated attaining a beneficial E:T ratio. We hypothesize that PD-L1 upregulation on primary AML cells is a relevant immune escape mechanism employed by AML cells to escape cytokine-mediated immune responses. Prospective clinical trials will be needed to assess the relevance of our finding in AMG 330-treated AML patients. Disclosures Krupka: AMGEN Inc.: Research Funding. Kufer:AMGEN Inc.: Equity Ownership; AMGEN Research (Munich): Employment. Kischel:AMGEN Inc.: Equity Ownership; AMGEN Research (Munich): Employment. Zugmaier:AMGEN Research (Munich): Employment; AMGEN Inc.: Equity Ownership. Sinclair:AMGEN Inc.: Employment, Equity Ownership. Newhall:AMGEN Inc.: Employment, Equity Ownership. Frankel:AMGEN Inc.: Employment, Equity Ownership. Baeuerle:AMGEN Research (Munich): Employment; AMGEN Inc.: Equity Ownership. Riethmüller:AMGEN Inc.: Equity Ownership. Subklewe:AMGEN Inc.: Research Funding.