Journal for ImmunoTherapy of Cancer 2017, 5(Suppl 3):89DOI 10.1186/s40425-017-0297-3

MEETING ABSTRACTS Open Access

32nd Annual Meeting and Pre-ConferencePrograms of the Society forImmunotherapy of Cancer (SITC 2017):Late-Breaking Abstracts

National Harbor, MD, USA. 8-12 November 2017

Published: 7 December 2017

Oral presentationsCellular Therapy Approaches

O35The transcription factor Myb enhances CD8+ T cell stemness andpolyfunctionality to promote curative antitumor immunitySanjivan Gautam1, Yun Ji1, Wei Zhu2, Jessica Fioravanti1, Jinhui Hu1,Neal Lacey1, James D Hocker1, John Le Gall1, Nga Voong1,William G Telford1, Philip Brohaun2, Avinash Bhandoola3, Hai-Hui Xue4,Rahul Roychoudhuri4, Nicholas P Restifo1, Brandon Higgs2,Timothy P Bender5, Luca Gattinoni11National Cancer Institute, Bethesda, MD, USA; 2Medimmune,Gaithersburg, MD, USA; 3Carver College of Medicine, University of Iowa,Iowa City, IA, USA; 4Cambridge University, Cambridge, UK; 5Univeristy ofVirginia, Charlottesville, VA, USACorrespondence: Luca Gattinoni (Luca_Gattinoni@nih.gov)Journal for ImmunoTherapy of Cancer 2017, 5(Suppl 3):O35

BackgroundFollowing antigen encounter, CD8+ T cells differentiate into effectorand memory T cells to mediate pathogen clearance and provide life-long immunity. Although our understanding of the molecular mecha-nisms regulating CD8+ T cell fate has expanded dramatically overrecent years, the precise transcriptional programs underlying thisprocess remains incompletely resolved. Myb is a transcription factorknown to play a major role in stem cell and progenitor renewal andhomeostasis, but its function in mature T cell differentiation isunknown. In this study, we demonstrate the role of Myb in CD8+ Tcell differentiation and antitumor function.MethodsWe employed CD8+ T cells isolated from pmel-1 mice (whichrecognize the shared melanoma-melanocyte differentiation antigengp100) carrying loxP-flanked Myb alleles and a fusion of Cre recom-binase and the estrogen receptor T2 moiety, which retains Cre in thecytosol until tamoxifen is administered (pmel-1 Mybfl/flCre-ERT2cells). Treating these mice with tamoxifen for several days immedi-ately prior to CD8+ T cell isolation ensured that pmel-1 Myb−/− T cellshad undergone thymic development similar to their ERT2-Cre nega-tive counterparts. pmel-1 Myb−/− or pmel-1 Myb+/+ cells were adop-tively transferred into wild-type mice infected with a recombinantstrain of vaccinia virus encoding gp100 and antigen-specific CD8+ Tcell expansion and long-term persistence was monitored overtime.Evaluation of tumor treatment efficacy of CD8+ T cells was performedin the pmel-1 model of adoptive cell therapy in the treatment oflarge established B16 melanomas.ResultsWe demonstrate that Myb expression is progressively downregulatedwith T cell differentiation. We found that Myb deficient T cells were

© The Author(s). 2017 Open Access This articInternational License (http://creativecommonsreproduction in any medium, provided you gthe Creative Commons license, and indicate if(http://creativecommons.org/publicdomain/ze

more prone to differentiate into short-lived KLRG1hi effector cellsresulting in a severe impairment of CD62Lhi stem cell-like memorycell formation, indicating that Myb is an essential regulator of T cellstemness. Conversely, enforced expression of Myb enhanced gener-ation of CD62Lhi memory cells, T cell polyfunctionality and recallresponses, suggesting that these cells might be therapeuticallysuperior for adoptive T cell therapy of tumors. Accordingly, Myboverexpressing T cells mediate enhanced antitumor immunity andpromoted curative and long-lasting responses against large estab-lished vascularized tumors.ConclusionsThese findings identify Myb as a master regulator of CD8+ T cellstemness and highlight the remarkable therapeutic potential ofmaneuvers aimed at increasing Myb activity in CD8+ T cells.

Clinical Trials (Completed)

O36First in human study with the CD40 agonistic monoclonal antibodyAPX005M in subjects with solid tumorsMelissa Johnson1, Marwan Fakih2, Johanna Bendell1, David Bajor3,Mihaela Cristea2, Thomas Tremblay4, Ovid Trifan4, Robert Vonderheide51Sarah Cannon Research Institute/Tennessee Oncology, Nashville, TN,USA; 2City of Hope, Duarte, CA, USA; 3Case Western Reserve UniversitySchool of Medicine, Cleveland, OH, USA; 4Apexigen, Inc., San Carlos, CA,USA; 5Abramson Cancer Center, Perelman School of Medicine, Universityof Pennsylvania, Philadelphia, PA, USACorrespondence: Ovid Trifan (otrifan@apexigen.com)Journal for ImmunoTherapy of Cancer 2017, 5(Suppl 3):O36

BackgroundImmune activating antibodies are being explored as the next gener-ation of immuno-oncology therapeutics. Activation of CD40 can stimu-late both innate and adaptive immune responses against cancer,making it an ideal target for the immune activating approach. CD40engagement with its ligand CD154 leads to antigen presentation,maturation and expression of co-stimulatory molecules and cytokineproduction by antigen presenting cells (APC), which are requisite foroptimal antigen-specific T-cell activation. Apexigen is developingAPX005M – a humanized IgG1 CD40 agonistic antibody that binds withhigh affinity to human CD40 (Kd=0.12nM) and carries an S267E muta-tion in the Fc region. APX005M recognizes a unique epitope that over-laps with the CD40 ligand binding sites and uses FcRγIIb to cluster andactivate CD40 thus mimicking CD154 engagement.MethodsIn a “first in human” Phase 1 dose escalating clinical trial, APX005Mwas administered every 21 days at doses ranging from 0.0001 mg/kgto 1 mg/kg to 30 adult subjects with solid tumors. Primary objectives

le is distributed under the terms of the Creative Commons Attribution 4.0.org/licenses/by/4.0/), which permits unrestricted use, distribution, andive appropriate credit to the original author(s) and the source, provide a link tochanges were made. The Creative Commons Public Domain Dedication waiverro/1.0/) applies to the data made available in this article, unless otherwise stated.

Journal for ImmunoTherapy of Cancer 2017, 5(Suppl 3):89 Page 2 of 14

were to evaluate the safety of APX005M, and to determine themaximum tolerated dose (MTD) and the recommended phase 2dose (RP2D).ResultsAPX005M demonstrated a dose-dependent APC activation (increasesin expression of CD54, CD70, CD80, CD86, HLA-DR), dose dependentT cell activation and increases in circulating levels of IL-12, INF-γ,TNFα and IL-6. Five subjects had prolonged stable disease. OverallAPX005M has been well tolerated; the majority of AEs were mild tomoderate in severity, and the majority of serious AEs were consid-ered unrelated to APX005M. The dose limiting toxicity of grade ≥ 3cytokine release syndrome was observed in subjects receiving doses≥ 0.6 mg/kg. The maximum administered dose of APX005M was 1mg/kg. The dose of 0.3 mg/kg of APX005M was selected as the RP2Dand represents the dose with maximum pharmacodynamic effectswithout grade > 2 toxicities. Increases in the dose of APX005M led toapproximately dose-proportional increases in maximum serum con-centration (Cmax) and area under the curve (AUC). No accumulationof APX005M was observed with every 21 day dosing.ConclusionsAPX005M produces dose-dependent activation of APCs and T cells atdoses that are well tolerated. Toxicities generally associated with theon-target cytokine release are observed at doses above the dosesthat are required to activate APCs and T-cells. APX005M exhibits ahighly differentiated and ideal profile for further clinical developmentas a single agent or in combination with other treatment modalitiesincluding immunomodulatory agents.

Clinical Trials (In Progress)

O37Nivolumab in mismatch-repair deficient (MMR-d) cancers:NCI-MATCH Trial (Molecular Analysis for Therapy Choice) arm Z1Dpreliminary resultsNilofer Azad1, Michael Overman2, Robert Gray3, Jonathan Schoenfeld4,Carlos Arteaga5, Brent Coffey6, David Patton7, Shuli Li8, Lisa McShane7,Larry Rubenstein7, Lyndsay Harris7, Robert Comis9, Jeffrey Abrams6,Paul M. Williams6, Edith Mitchell11, James Zweibel6, Elad Sharon7,Howard Streicher7, Peter J. Dwyer12, Stanley Hamilton2, Barbara Conley7,Alice P. Chen13, Keith Flaherty141Johns Hopkins University, Baltimore, MD, USA; 2MD Anderson, Houston,TX, USA; 3Dana Farber Institute, Boston, MA, USA; 4Brighan and Women'sCancer Center, Boston, MA, USA; 5Vanderbilt, Nashville, TN, USA;6National Institute of Health, Rockville, MD, USA; 7NCI, Rockville, MD,USA; 8Harvard, Boston, MA, USA; 9ECOG-ACRIN, Philadelphia, PA, USA;11Thomas Jefferson University, Philadelphia, PA, USA; 12University ofPennsylvania, Philadelphia, PA, USA; 13DTC National Cancer Institute,Bethesda, MD, USA; 14Massachusetts General Hospital, Boston, MA, USACorrespondence: Nilofer Azad; Stanley Hamilton(shamilto@mdanderson.org)Journal for ImmunoTherapy of Cancer 2017, 5(Suppl 3):O37

BackgroundThe NCI-MATCH (Molecular Analysis for Therapy Choice) trial is thelargest national study to date (1173 sites) for patients with relapsed/refractory solid tumors, lymphomas and myelomas, assigning rationaltargeted therapy based on individual tumor molecular alterations.Patients with mismatch repair-deficiency (MMR-d) may benefit fromimmune checkpoint inhibitor therapy secondary to increased muta-tional burden compared to MMR-proficient tumors. The anti-PD-1 in-hibitor nivolumab has previously shown antitumor activity in MMR-dcolorectal cancer; we hypothesized that nivolumab would haveactivity in patients with non-colorectal MMR-d cancers.MethodsEligibility for NCI-MATCH included relapsed/refractory cancers, goodend-organ function, and ECOG performance status of ≤ 1. Patients en-rolled were screened for molecular alterations by centralized testing onfresh biopsy tissue. MMR-d was defined by loss of nuclear expression ofMLH1 or MSH2 by immunohistochemistry. Patients with MMR-d colo-rectal cancer were excluded. Patients received nivolumab 3 mg/kgq2weeks (28-day cycles) and 480 mg q4weeks past cycle 4. Disease

reassessment was performed q2cycles. The primary endpoint of thestudy was RECIST 1.1 overall response rate (ORR). 35 enrolled patientswere planned with the ORR compared against a null value of 5%. If theobserved ORR was ≥5/31 (16%), the agent would be considered prom-ising and worthy of further testing. The proposed design had power of91.8% to find an agent promising assuming true OR rate was 0.25.Results4864 enrolled patients had interpretable results for MMR-d. 99 patientswere MMR-d, 63 patients were assigned to nivolumab treatment, and 47patients were treated (35:preplanned and 12:expansion). We report the pre-liminary results of the first 35 enrolled (70% MLH1 loss, 30% MSH2 loss).Minimum follow-up time for all patients was >6 months, median age was60 y/o, and median prior therapies was 3. Common histologies includedendometrioid endometrial (EEA: 10), prostate (6), and breast (3) cancer. 10pts remain on treatment; 7 stopped treatment for AEs; 12 for progressivedisease. The confirmed ORR was 24% (8/33 patients) with an additional 9/33 (27%) patients with stable disease. Three additional patients had uncon-firmed responses [PD at next scan(1), off study prior to reassessment(1),and no follow-up scan yet(1)]. The disease histologies for the PR wereprostate(3), EEA(2), breast(1), parathyroid(1), and gallbladder cancer(1). Esti-mated 6-month PFS was 43% and median OS has not been reached at thisearly time-point. Toxicity was predominantly low-grade.ConclusionsWe report the first results of a substudy of the NCI-MATCH trial.Nivolumab has promising activity in MMR-d, non-colorectal cancers.Trial RegistrationNCT02465060

O38Nivolumab + Ipilimumab (N+I) vs Sunitinib (S) for treatment-naïveadvanced or metastatic renal cell carcinoma (aRCC): results fromCheckMate 214, including overall survival by subgroupsRobert J. Motzer1, Nizar M. Tannir2, David F. McDermott3,Osvaldo Arén Frontera4, Bohuslav Melichar5, Elizabeth R. Plimack6,Philippe Barthelemy7, Saby George8, Victoria Neiman9, Camillo Porta10,Toni K. Choueiri11, Thomas Powles12, Frede Donskov13, Pamela Salman14,Christian K. Kollmannsberger15, Brian Rini16, Sabeen Mekan17,M. Brent McHenry17, Megan Wind-Rotolo17, Hans J. Hammers18,Bernard Escudier191Memorial Sloan Kettering Cancer Center, New York, NY, USA; 2Universityof Texas, MD Anderson Cancer Center Hospital, Houston, TX, USA; 3BethIsrael Deaconess Medical Center, Dana-Farber/Harvard Cancer Center,Boston, MA, USA; 4Centro Internacional de Estudios Clinicos, Santiago,Chile; 5Palacky University, and University Hospital Olomouc, Olomouc,Czech Republic; 6Fox Chase Cancer Center, Philadelphia, PA, USA;7Hôpitaux Universitaires de Strasbourg, Strasbourg, France; 8Roswell ParkCancer Institute, Buffalo, NY, USA; 9Davidoff Cancer Center, RabinMedical Center, Petah Tikva, Israel, and Tel Aviv University, Tel Aviv,Israel; 10IRCCS San Matteo University Hospital Foundation, Pavia, Italy;11Dana-Farber Cancer Institute, Brigham and Women’s Hospital, andHarvard Medical School, Boston, MA, USA; 12Barts Cancer Institute,Cancer Research UK Experimental Cancer Medicine Centre, Queen MaryUniversity of London, Royal Free NHS Trust, London, UK; 13AarhusUniversity Hospital, Aarhus, Denmark; 14Fundación Arturo López Pérez,Santiago, Chile; 15British Columbia Cancer Agency, Vancouver, BritishColumbia, Canada; 16Cleveland Clinic Taussig Cancer Institute, Cleveland,OH, USA; 17Bristol-Myers Squibb, Princeton, NJ, USA; 18Sidney KimmelComprehensive Cancer Center, Johns Hopkins, Baltimore, MD, USA;19Gustave Roussy, Villejuif, FranceCorrespondence: Robert J. Motzer (motzerr@mskcc.org)Journal for ImmunoTherapy of Cancer 2017, 5(Suppl 3):O38

BackgroundWe report results from the phase III CheckMate 214 study of N+I ver-sus S for treatment-naïve aRCC.MethodsAdults with clear-cell aRCC, measurable disease, Karnofsky performancestatus ≥70, and available tumor tissue were eligible. Patients were ran-domized 1:1 (stratified by IMDC score; region) to N 3 mg/kg + I 1mg/kgevery 3 weeks for four doses followed by N 3 mg/kg every 2 weeks, or

Journal for ImmunoTherapy of Cancer 2017, 5(Suppl 3):89 Page 3 of 14

S 50 mg daily orally for 4 weeks (6-week cycles). Co-primary endpointswere objective response rate (ORR), progression-free survival (PFS) perindependent committee (IRRC), and overall survival (OS), all in inter-mediate- and poor-risk patients. Overall α for treatment effect was 0.05(allocated as 0.001 ORR, 0.009 PFS, 0.04 OS).Results1,096 patients were randomized (N+I: n=550; S: n=546); 425 (N+I) and422 (S) with intermediate/poor risk. With ~17.5 months minimum follow-up, confirmed ORR in intermediate/poor-risk patients was 41.6% (9.4%complete response [CR]) vs 26.5% (1.2% CR) for N+I vs S (P<0.0001); me-dian duration of response was not reached (NR; 95% CI, 21.82-NR) vs 18.2months (95% CI, 14.82-NR), respectively (Table 1). Median PFS with N+I vsS in intermediate/poor-risk patients was 11.6 vs 8.4 months (hazard ratio[HR] 0.82, P=0.0331, Table 1). At the first prespecified interim OS analysis,the Data Monitoring Committee recommended stopping the study earlyfor statistically significant superiority in OS with N+I vs S (median notreached vs 26.0 months [HR 0.63], P<0.0001, Table 1). ORR favored N+Iover S in intermediate/poor-risk patients irrespective of baseline tumorPD-L1 expression, while a PFS benefit with N+I vs S was seen only inpatients with PD-L1 ≥1%. OS favored N+I over S across all prespecifiedsubgroups (data to be presented), including baseline PD-L1 expressionstatus. In all treated patients, drug-related AEs occurred in 509/547 (93%any grade, 46% grade 3-4) with N+I vs 521/535 (97% any grade, 63%grade 3-5) with S, including 22% vs 12% with AEs leading to discontinu-ation. Death occurred in 159 N+I arm patients (7 [1%] drug-related) and202 S arm patients (4 [1%] drug-related).ConclusionsThis phase III study showed statistically significant OS benefit, significantlyhigher ORR, and numerically longer PFS for N+I vs S with a manageablesafety profile in intermediate- and poor-risk patients with aRCC, support-ing the use of N+I as a new first-line standard-of-care treatment optionfor these patients. OS benefit with N+I was seen irrespective of baselinePD-L1 status and was observed consistently across other subgroups.Trial RegistrationClinicalTrials.gov Identifier: NCT02231749

Table 1 (abstract O38). See text for description

Intermediate/poor risk

N+I S N+IPD-L1<1%

SPD-L1<1%

N+IPD-L1≥1%

SPD-L1≥1%

N=425 N=422 N=284(74%)a

N=278(71%)a

N=100(26%)a

N=114(29%)a

ORR per IRRC,n (%) [95% CI]

177 (42)[37-47]

112 (27)[22-31]

106 (37)[32-43]

79 (28)[23-34]

58 (58)[48-68]

25 (22)[15-31]

P<0.0001 Odds ratio(95% CI)=1.50(1.04-2.17)b

Odds ratio(95% CI)=4.92(2.61-9.34)b

Median PFS perIRRC, months(95% CI)

11.6(8.7-15.5)

8.4(7.0-10.8)

11.0(8.1-14.9)

10.4(7.5-13.8)

22.8(9.4-NR)

5.9(4.4-7.1)

HR (CI) 0.82 (99.1% CI,0.64-1.05)

1.00 (95% CI,0.80-1.26)

0.46 (95% CI,0.31-0.67)

P=0.0331 P=0.9672b P<0.0001b

Median OS,months (95% CI)

NR(28.2-NE)

26.0(22.1-NE)

NE(28.2-NE)

NE(24.0-NE)

NE 19.6(14.8-NE)

HR (CI) 0.63 (99.8% CI,0.44-0.89)

0.73 (95% CI,0.56-0.96)

0.45 (95% CI,0.29-0.71)

P<0.0001 P=0.0249b P=0.0006b

aPercentage based on number of PD-L1 evaluable patients. bExploratory unstratifiedanalysis. NE, not estimable

O39Phase I study of E7046, a novel PGE2 receptor type 4 inhibitor, inpatients with advanced solid tumors with high myeloid infiltrate:effects on myeloid- and T-lymphoid cell-mediatedimmunosuppressionAurelien Marabelle1, Aparna Parikh2, Geoffrey Shapiro3, Andrea Vargas1,Aung Naing4, Funda Meric-Bernstam4, Larisa Reyderman5, Xingfeng Bao5,Terri Binder5, Min Ren5, Amy Siu5, Lucy Xu5, Mingjie Liu5, Satish Dayal5,Vijay Bhagawati-Prasad5, Ilian Tchakov5, Takashi Owa5, Chean Eng. Ooi5,David Sanghyun Hong41Gustave Roussy Institute, Villejuif, France; 2Massachusetts GeneralHospital, Boston, MA, USA; 3Dana-Farber Cancer Institute, Boston, MA,USA; 4The University of Texas MD Anderson Cancer Center, Houston, TX,USA; 5Eisai Inc., Woodcliff Lake, NJ, USACorrespondence: Larisa Reyderman (larisa_reyderman@eisai.com)Journal for ImmunoTherapy of Cancer 2017, 5(Suppl 3):O39

BackgroundE7046 is a selective inhibitor of the prostaglandin E2 (PGE2) receptor-type-4, EP4, which transduces potent immunosuppressive activity ofPGE2 in both myeloid cells and T-lymphoid cells in the tumor micro-environment. In preclinical studies, E7046 reversed PGE2-mediatedinhibition of monocyte differentiation towards anti-tumorigenic anti-gen presenting cells and facilitated tumoral recruitment andactivation of cytotoxic T-cells. Here, we present initial clinical, phar-macokinetic and pharmacodynamic results from a first-in-humanstudy of single agent E7046 in patients with selected cancer typeshaving high myeloid cell infiltration.MethodsE7046 was administered orally, once-daily, in 21-day cycles in se-quential dose-escalating cohorts of 6 pts each at 125, 250, 500and 750mg. Tumor responses were evaluated by irRECIST andmetabolic responses by 18FDG-PET. Modulation of immune re-sponse was assessed in pre- and post-treatment tumor biopsiesby immunohistochemistry, and in blood samples by TaqMan LowDensity Array and Meso Scale Discovery assays. Blood sampleswere collected for PK analysis.ResultsThirty patients were treated with no dose-limiting toxicities observed.The most common adverse events were fatigue (37%), diarrhea(33%), and nausea (30%). Grade 3/4 AEs in >1 patient were abdom-inal pain (3 patients, at 250 mg, 750 mg) and vomiting (2 patients, at125 mg, 250 mg). Grade 3/4 treatment-related AEs occurred in 4 pa-tients (rash in 2 patients, and diarrhea, allergic reaction, anaphylaxis,hypersensitivity, and hyperuricemia, in 1 patient each). Four patientsdiscontinued treatment due to an AE (bowel obstruction, allergic re-action, abdominal pain, acute renal failure). No objective tumor re-sponses were reported. Duration of treatment of ≥20 wks with bestresponse of stable disease (SD) was observed in 5 patients, 3 of thesehad partial metabolic responses. E7046 exposure was dose-proportional up to the 500 mg dose with a plateau at 750 mg. Elim-ination half-life (11 hr) justified once-daily dosing. Treatment withE7046 significantly increased tumor CD3+ and CD8+ T-cell infiltrationand expression of the T-effector cell-recruiting chemokine CXCL10 inblood. Gene expression analysis in blood showed modulation of EP4signaling genes (including IDO1, EOMES, PD-L1). Longer duration oftherapy with SD was associated with higher baseline tumor infiltrateof CD8+ T-cells and CD163+ macrophages.ConclusionsE7046 demonstrated favorable tolerability profile with preliminaryevidence of anti-tumor activity and immune modulation in tumorand peripheral blood. MTD was not reached. Further studies testingE7046 in combination with other agents are planned.Trial RegistrationNCT-02540291

Journal for ImmunoTherapy of Cancer 2017, 5(Suppl 3):89 Page 4 of 14

O40Interim safety analysis of Cancer Immunotherapy Trials Network –12 (CITN-12): A phase 1 study of Pembrolizumab in patients withHIV and relapsed, refractory or disseminated malignanciesThomas S. Uldrick1, Priscila H. Gonçalves1, Steven P. Fling2,Karen Aleman1, Brinda Emu3, Marc S. Ernstoff4, Ashley Jackson4,Judith Kaiser2, Holbrook E. Kohrt5, Andreanne Lacroix2, MatthewLindsley1, Lisa M. Lundgren2, Kathryn Lurain1, Matthew Madura3,James S. Outland6, Chris Parsons6, Elad Sharon1, Robert Yarchoan1,Martin A. “Mac” Cheever21National Cancer Institute, Bethesda, MD, USA; 2Fred Hutchinson CancerResearch Center, Seattle, WA, USA; 3Yale University, New Haven, CT, USA;4Roswell Park Cancer Institute, Buffalo, NY, USA; 5Stanford University,Palo Alto, CA, USA; 6Louisiana State University Health Science Center,New Orleans, LA, USACorrespondence: Thomas S. Uldrick (uldrickts@mail.nih.gov)Journal for ImmunoTherapy of Cancer 2017, 5(Suppl 3):O40

BackgroundAnti-PD-1 and anti-PD-L1 antibodies are approved for multiple indi-cations and are becoming mainstays of cancer therapy. However,patients with HIV have been excluded from clinical trials evaluatingthese agents largely due to safety concerns.MethodsCITN-12 is a multicenter study of pembrolizumab in patients withHIV and advanced cancers not curable by standard therapies.Three parallel cohorts are accruing based on CD4+ counts; 1:100-199, 2: 200-350, and 3: >350 cells/uL. Additional eligibility cri-teria: >4 weeks antiretroviral therapy (ART), HIV viral load <200copies/mL, no uncontrolled infections including hepatitis B and C,ECOG performance status 0-1. Treatment: pembrolizumab 200mgintravenously every 3 weeks for up to 2 years. The primary ob-jective is to assess safety and tolerability by summarizing adverseevents (AEs) graded by CTCAEv4 and evaluating HIV viral loadand CD4+ counts. Immune mediated adverse events are man-aged using standard guidelines. We performed an interim analysisof treatment emergent adverse events at least possibly related topembrolizumab (rTEAEs), serious AEs, and HIV viral load and CD4+ counts on therapy.Results17 patients; Cohort 1 (4), Cohort 2 (9), Cohort 3 (4); were accruedstarting April 2016 and followed through May 2017. Characteristics: 1woman, 16 men; median age 56 years (range 43-77); white (13),African American (3), Hispanic (1); HIV viral load <20 copies/mL(94%). Cancers: non-Hodgkin lymphoma (3), Kaposi sarcoma (1), analcancer (5), head and neck (1), lung (2), bladder (1), hepatocellular (1),pancreatic (1), cholangiocarcinoma (1). Median number prior therap-ies 1 (range 0-4), prior radiation (71%). Safety observed over a totalof 100 cycles, median 4 (range 1-20). 82 rTEAEs were observed andcomparable between cohorts. 93% were grade 1-2. Ten primary ser-ious AEs were observed, 2 possibly attributable to pembrolizumab,both occurring in the setting of progressive malignancy. Immunemediated AEs managed with levothyroxine or prednisone includedsubclinical hypothyroidism 6 (35%), pneumonitis (2) and liver test el-evations (2). Median CD4+ counts increased over time, changes didnot reach statistical significance. HIV remained suppressed on ART inall patients.ConclusionsPembrolizumab has an acceptable safety profile to date in CITN-12.Standard therapy with anti-PD1 is appropriate for FDA-approved indi-cations in patients with HIV. Patients with HIV who meet appropriateimmune eligibility criteria for a given cancer should be included inimmunotherapy studies. Further evaluation of checkpoint inhibitorsin HIV-associated tumors is justified.Trial Registrationclinicaltrials.gov NCT02595866

Combination Therapy (IO/IO, IO/Standard of Care,IO/Other)

O41Preliminary antitumor and immunomodulatory activity of BMS-986205, an optimized indoleamine 2,3-dioxygenase 1 (IDO1)inhibitor, in combination with nivolumab in patients withadvanced cancersJason J. Luke1, Karen Gelmon2, Russell K. Pachynski3, Jayesh Desai4, VictorMoreno5, Josep M. Tabernero6, Carlos A. Gomez-Roca7, Quincy Chu8,Paul Basciano9, Penny Phillips9, Li Zhu9, Zhaohui Liu9, Lillian L. Siu101University of Chicago Medical Center, Chicago, IL, USA; 2University ofBritish Columbia, BC Cancer Agency, Vancouver, British Columbia,Canada; 3Washington University School of Medicine, St. Louis, MO, USA;4Peter MacCallum Cancer Centre and Royal Melbourne Hospital,Melbourne, Australia; 5START Madrid-FJD, Hospital UniversitarioFundación Jiménez Díaz, Madrid, Spain; 6Vall d’Hebron UniversityHospital, Barcelona, Spain; 7Institut Universitaire du Cancer, Oncopole,Toulouse, France; 8Cross Cancer Institute, University of Alberta/AlbertaHealth Services, Edmonton, Alberta, Canada; 9Bristol-Myers Squibb,Princeton, NJ, USA; 10Princess Margaret Cancer Centre, Toronto, Ontario,CanadaCorrespondence: Jason J. Luke (jluke@medicine.bsd.uchicago.edu)Journal for ImmunoTherapy of Cancer 2017, 5(Suppl 3):O41

BackgroundCheckpoint inhibitors have transformed cancer care, but extendingthose benefits to more patients requires additional approaches. IDO1allows tumor escape through kynurenine production, whichdecreases immune cell tumor infiltration/function and increases regula-tory T-cell numbers. Anti─PD-1 treatment upregulates IDO1, supportinga rationale for combining nivolumab (anti–PD-1) with an IDO1 inhibitor.BMS-986205 is a selective, potent, once-daily, oral IDO1 inhibitor with apotentially best-in-class pharmacokinetic/pharmacodynamic/safetyprofile in combination with nivolumab that was previously disclosed(NCT02658890) [1]. Here we present updated safety and preliminaryefficacy and pharmacodynamic data.MethodsDose-escalation methods were previously described [1]. During co-hort expansion in this phase 1/2a open-label study, patients with ad-vanced cancers were treated with BMS-986205 100 or 200 mg orallyonce daily + nivolumab 240 mg IV Q2W or 480 mg IV Q4W. Objec-tives included safety, preliminary antitumor activity, and pharmaco-dynamics (including immunomodulatory assays).

ResultsAs of the July 20, 2017, data cutoff, safety data were available for 216patients across the study. Maximum tolerated dose during escalationwas 200 mg; at 400 mg, 2/4 patients experienced dose-limiting toxic-ities (grade 3 AST/ALT increased; grade 2 anemia, fatigue). Treatment-related AEs occurred in 47% of patients (11% grade 3/4), and 4 patients(2%) discontinued due to study drug toxicity; the safety profile wasgenerally consistent with that previously reported for nivolumab mono-therapy. In the bladder cancer cohort, among 15 heavily pretreated pa-tients (39% received ≥2 prior regimens), 5 partial responses (PRs), 3stable disease (SD), and 6 progressive disease (PD, including a patientwith prior anti–PD-[L]1 therapy) were reported, with 1 death prior to as-sessment. In the cervical cancer cohort, among 17 heavily pretreatedpatients (52% received ≥2 prior regimens), 3 PRs, 5 SD, and 7 PD werereported, with 2 deaths prior to assessment. Within 39 paired pre- vson-treatment tumor samples across various tumor types, BMS-986205plus nivolumab decreased kynurenine and increased the percentage ofproliferating CD8+ T cells.

ConclusionsBMS-986205 plus nivolumab was well tolerated, increased proliferat-ing CD8+ T cells in tumors, and demonstrated preliminary antitumor

Journal for ImmunoTherapy of Cancer 2017, 5(Suppl 3):89 Page 5 of 14

activity. Updated efficacy, safety, and pharmacodynamic data will bepresented.Trial RegistrationClinicalTrials.gov, NCT02658890ConsentNot applicable

References1. Siu L, et al. AACR 2017, abstract CT116.

O42First-in-human phase 1 dose escalation and expansion of a novelcombination, anti–CSF-1 receptor (cabiralizumab) plus anti–PD-1(nivolumab), in patients with advanced solid tumorsZev Wainberg1, Sarina Piha-Paul2, Jason Luke3, Edward Kim4,John Thompson5, Nicklas Pfanzelter6, Michael Gordon7, Drew Rasco8,Amy Weise9, F. Stephen Hodi10, Sandeep Inamdar11, Serena Perna12,Christy Ma11, Janine Powers11, Michael Carleton12, Hong Xiang11,Lei Zhou11, Helen Collins11, Yeonju Lee11, James Lee13,Jennifer Johnson14, Carolyn Britten15, Majid Ghoddusi111UCLA School of Medicine, Santa Monica, CA, USA; 2The University ofTexas MD Anderson Cancer Center, Houston, TX, USA; 3The University ofChicago Medicine, Chicago, IL, USA; 4UC Davis Comprehensive CancerCenter, Sacramento, CA, USA; 5Seattle Cancer Center Alliance, Seattle,Washington, CA, USA; 6Rush University Medical Center, Chicago, IL, USA;7HonorHealth Scottsdale Shea Medical Center, Scottsdale, AZ, USA;8South Texas Accelerated Research Therapeutics, San Antonio, TX, USA;9Karmanos Cancer Center, Detroit, MI, USA; 10Dana-Farber CancerInstitute, Boston, MA, USA; 11FivePrime Therapeutics, South SanFrancisco, CA, USA; 12Bristol-Myers Squibb, Lawrenceville, NJ, USA;13University of Pittsburg Medical Center, Pittsburg, PA, USA; 14ThomasJefferson University Hospital, Philadelphia, PA, USA; 15Medical Universityof South Carolina, Charleston, SC, USACorrespondence: Sandeep Inamdar (sandeep.inamdar@fiveprime.com)Journal for ImmunoTherapy of Cancer 2017, 5(Suppl 3):O42

BackgroundResistance to immunotherapy may be related to activity of severalimmunosuppressive cell types. Depletion of tumor-associatedmacrophages (TAMs) may promote a pro-inflammatory state, in-creasing antitumor T-cell responses. Cabiralizumab, a humanizedIgG4 monoclonal antibody, binds to CSF-1 receptor and blockscytokine signaling that is needed for TAM activation and survival,leading to TAM depletion. The combination of cabiralizumab plusanti–PD-1 may work synergistically by modifying the immunosup-pressive tumor environment while simultaneously suppressing thePD-1 checkpoint pathway. This is the first clinical disclosure ofsafety, pharmacokinetics, and pharmacodynamics of this novelcombination, along with preliminary evidence of antitumor activ-ity in pancreatic cancer (NCT02526017).MethodsIn phase 1a dose escalation, patients with advanced solid tumors weretreated with cabiralizumab 1, 2, 4, and 6 mg/kg alone or combined withnivolumab 3 mg/kg, both given IV Q2W, in a 3+3+3 design.

ResultsAs of August 1, 2017, 205 patients were treated with the combination.Most received cabiralizumab 4 mg/kg Q2W plus nivolumab 3 mg/kgQ2W. Cabiralizumab, alone or with nivolumab, demonstrated target-mediated clearance and dose-dependent increase in exposure, andpharmacodynamic activity as evidenced by reduced circulating CD14+

CD16+ nonclassical monocytes. Grade 3–5 treatment-related AEs(TRAEs) attributed to cabiralizumab occurred in 43% of patients, with13% of patients discontinuing due to AEs. Elevations in creatinine phos-phokinase (14%) and AST (5%) were among the most common grade 3

TRAEs but were secondary to cabiralizumab’s depletion of macro-phages, which would otherwise metabolize these enzymes, and werereversible without significant clinical sequelae. Among the cohort ofprior chemotherapy–treated and immunotherapy-naive patients withpancreatic cancer, 31 were efficacy evaluable. There were 3 confirmedpartial responses in microsatellite-stable patients (293, 275+, and 168+days on study) and 1 prolonged stable disease (182 days); 1 patienttreated beyond progressive disease experienced >40% reduction inbaseline target lesions (247 days on study). The 6-month diseasecontrol rate was 13%, and objective response rate was 10%. Studies ina larger pancreatic cohort and other tumor types are ongoing, and pre-liminary translational biomarker data will be presented.ConclusionsCabiralizumab plus nivolumab, a mechanistically novel immunotherapycombination, demonstrated a tolerable safety profile across several co-horts and promising preliminary antitumor activity in pancreatic cancer.These results also show a potential immunotherapeutic strategy totreat patients with tumors resistant to anti–PD-1 blockade.Trial RegistrationNCT02526017

Tumor Microenvironment (Mechanisms andTherapies)

O43Monotherapy dose escalation clinical and translational data fromfirst-in-human study in advanced solid tumors of IPI-549, an oral,selective, PI3K-gamma inhibitor targeting tumor macrophagesDavid Hong1, Anthony Tolcher2, Ryan Sullivan3, Geoffrey Shapiro4,Bartosz Chmielowski5, Antoni Ribas5, Les Brail6, Joseph Pearlberg6,Suresh Mahabhashyam6, Lucy Lee6, Claudio Dansky Ullmann6,Brenda O'Connell6, Jeffery Kutok6, Michael Postow7, Jedd Wolchok71UT MD Anderson Cancer Center, Houston, TX, USA; 2START, SanAntonio, TX, USA; 3Massachusetts General Hospital, Boston, MA, USA;4Dana Farber Cancer Institute, Boston, MA, USA; 5University of California,Los Angeles, Santa Monica, CA, USA; 6Infinity Pharmaceuticals, Inc.,Cambridge, MA, USA; 7Memorial Sloan Kettering Cancer Center, NewYork, NY, USACorrespondence: Jeffery Kutok (jeff.kutok@infi.com)Journal for ImmunoTherapy of Cancer 2017, 5(Suppl 3):O43

BackgroundIPI-549 is a potential first-in-class, oral, selective PI3K-gamma inhibitorbeing developed as an immuno-oncology therapeutic in multiplecancer indications. Preclinical research demonstrated that IPI-549 re-sults in transcriptional reprogramming M2, pro-tumor macrophagesto the M1, anti-tumor phenotype. In preclinical tumor models, IPI-549was active as a monotherapy and was able to overcome checkpointinhibitor (CPI) resistance in CPI-insensitive models. These preclinicaldata provide a strong rationale for the ongoing Phase 1/1b study.MethodsThis study (NCT02637531) is being conducted to evaluate the safety, tol-erability, pharmacodynamics and pharmacokinetics to determine the rec-ommended dose and activity of IPI-549 as monotherapy and incombination with nivolumab in patients with advanced solid tumors. Thestudy design includes four parts: 1) monotherapy dose escalation 2) com-bination dose escalation of IPI-549 with nivolumab 3) monotherapy ex-pansion, and 4) combination expansion in specific tumor types with denovo or acquired resistance to checkpoint inhibitors. Pre- and on-treatment blood samples are being obtained in all patients to performflow cytometry, gene expression, and serum cytokine and chemokineanalysis to better understand the biological effect of IPI-549 on immunecells and to identify correlations with any clinical response. Pre- and on-treatment biopsies are being mandated in the expansion cohorts toevaluate the effect of IPI-549 on the tumor microenvironment.

Journal for ImmunoTherapy of Cancer 2017, 5(Suppl 3):89 Page 6 of 14

ResultsA total of 19 patients have been enrolled (18 evaluable) in the mono-therapy dose escalation phase (10, 15, 20, 30, 40, 60 mg qd). No DLTs,or drug related SAEs have been observed. The majority of treatment-emergent adverse events were low grade (grade 1-2). The most com-mon (≥2 patients) drug related treatment-emergent adverse events arealanine aminotransferase increase, rash maculo-papular, white bloodcell count decrease, and headache. Durable clinical benefit has beenobserved, with 8 patients able to remain on treatment ≥16 weeks, in-cluding 2 patients on study for ≥52 weeks. The PK profile of IPI-549 hasfavorable characteristics including dose proportionality. PD analysisdemonstrates full and sustained suppression of PI3K-γ at 60 mg qd.Translational studies performed on peripheral blood demonstrated in-creased activation of circulating myeloid cells in patient subsets, as wellas, evidence of interferon-gamma mediated immune stimulation afterIPI-549 treatment. Detailed PK, PD, translational, safety, and efficacydata will be presented.ConclusionsThe monotherapy dose escalation has completed enrollment,demonstrating favorable tolerability, evidence of immune modulation,and PK/PD defining 60 mg qd as the monotherapy expansion dose. Themonotherapy expansion phase in solid tumors is actively enrolling.

Poster presentationsBiomarkers and Immune Monitoring

P509Modelling oscillatory human immune system dynamics of point-of-care biomarkers for targeting/sequencing vaccine immuno-chemotherapy in advanced melanomaBrendon Coventry, Carrie Cooper, Mohsen Dorraki, Andrew Allison,Azhar Iqbal, Derek AbbottUniversity of Adelaide, Adelaide, AustraliaCorrespondence: Brendon Coventry(brendon.coventry@adelaide.edu.au)Journal for ImmunoTherapy of Cancer 2017, 5(Suppl 3):P509

BackgroundVaccine immunotherapy for advanced melanoma has demonstratedlong-term survival (>15 years) and Complete Responses (CR=17%)1.Recent clinical responses from 3-5 years using anti-PD-1, anti-CTLA4and other immunotherapies represent major advances over standardcytotoxic chemotherapies with 1-2% ≥1 year survivals. However,even with the best approved immunotherapies most patients still donot obtain CR's or achieve long-term survival2. Toxicity remains aserious problem2. Pre-treatment identification of responders andnon-responders remains truly enigmatic. Optimal coordination withthe individual patient's dynamic immune response has been pro-posed to better target treatment3.MethodsPatients with advanced melanoma received vaccine immunotherapyalone, or immuno-chemotherapy, and daily immune point-of-caremonitoring with serum C-reactive protein as an inflammatory bio-marker. The null hypothesis was stability. Immune oscillatory behav-ior was tested mathematically. Advanced mathematical analysis wasperformed to determine the validity of the null hypothesis.ResultsOscillatory biochemical inflammatory marker behavior was identifiedin most patients during therapy, and investigated for correlation withclinical outcome. Monitoring periods containing ≥5 measurements,and of at least 3 in number, are required for statistically defining os-cillatory cyclical behavior in humans with cancer.ConclusionsThe implications of these findings are that immunomodulatory ther-apies (eg. pathway inhibitors, cytotoxics, radiation & perhaps surgery)may require individualized tailoring to coordinate with immune sys-tem phase dynamics at delivery to direct immune control and influ-ence clinical efficacy. These findings of immune fluctuation might

explain why predictive biomarker identification has been so elusivelyproblematic, and why toxicity is often variable and unpredictable.Trial RegistrationAustralian Clinical Trials Registry [ACTRN] 12605000425695

References1. Coventry BJ, Lilly C, Hersey P, Michele A, Bright R, et al. Prolonged repeated

vaccine immuno-chemotherapy induces long-term clinical responses and sur-vival for advanced metastatic melanoma. J Immunother. Cancer 2014; 2: 9-17.

2. Coventry BJ, Baum D, Lilly CA, et al. Long-term survival in advancedmelanoma patients using repeated therapies: successive immunomodu-lation improving the odds? Cancer Manag. Res. 2015 Apr 29; 7:93-103.

3. Coventry BJ, Ashdown ML, Quinn MA, Markovic SN, Yatomi-Clarke, RobinsonAP, et al. CRP identifies homeostatic immune oscillations in cancer patients:potential treatment targeting tool? J Transl Med 2009; 7: 102. Review.

P510Multitumor profiling of lymphocyte activation gene 3 (LAG-3) andassociation with immune cell phenotypesRobin Edwards1, Cyrus Hedvat1, John Cogswell1, Darren Locke1,George Lee1, Vipul Baxi1, Patrik Vitazka1, Peter Szabo1, Chelsea Jin1,Dimple Pandya1, Keyur Desai1, Roland Meier1, Matt Maurer1,Donald Jackson1, Petra B Ross-MacDonald1, Megan Wind-Rotolo1,Abdel Saci1, Parminder Mankoo1, Jean-Marie Bruey1,Christopher Harbison1, Mark Selby1, Alan Korman1, Kent Thudium1,Riyue Bao2, Janis M. Taube3, Jason Luke21Bristol-Myers Squibb, Princeton, NJ, USA; 2University of Chicago MedicalCenter, Chicago, IL, USA; 3Johns Hopkins University School of Medicine,Sidney Kimmel Comprehensive Cancer Center and Bloomberg-KimmelInstitute for Cancer Immunotherapy, Baltimore, MD, USACorrespondence: Robin Edwards (robin.edwards2@bms.com); PeterSzabo (peter.szabo@bms.com)Journal for ImmunoTherapy of Cancer 2017, 5(Suppl 3):P510

BackgroundLAG-3 negatively regulates T-cell activation, is expressed onexhausted T cells, and may promote regulatory T-cell activity. By lim-iting antitumor T-cell activation, LAG-3 may contribute to immuno-therapy nonresponsiveness, as observed in patients with melanomawho progressed during prior anti-PD-(L)1 therapy [1]. Here wedescribe first results from comprehensive multitumor profiling usingquantitative immunohistochemistry (IHC) to characterize expressionof LAG-3 and its ligand, MHCII, in the context of inflammationmarkers, as well as a bioinformatic investigation of LAG-3 using TheCancer Genome Atlas (TCGA).MethodsUrothelial, gastric, non-small cell lung cancer, renal cell carcinoma(RCC), squamous cell carcinoma of the head and neck, and melan-oma tumor specimens (N=245) were stained by IHC for LAG-3, CD8,FOXP3, CD68, CD163, PD-L1, and MHCII. The proportion of total nu-cleated cells in the tumor microenvironment expressing a givenmarker was determined using image analysis, and unsupervisedclustering was used to identify subgroups within tumor types. A160-gene T-cell-inflamed signature was applied to TCGA RNA-sequencing data to assess correlations between LAG-3 and IFNγ-induced gene expression.ResultsUnsupervised clustering of IHC results revealed inflammation-high,-moderate, and -low subgroups, and LAG-3 expression generally cor-related with the level of inflammation: CD8 (r=0.65); CD68, CD163,and FOXP3 (r=0.49-0.53). MHCII tumor-cell expression was observedin inflammation-high and -low tumors and did not correlate with PD-L1 positivity, whereas LAG-3 was significantly higher in tumors withMHCII expression ≥1% vs <1% (P=0.001). In 6 individual tumors withheterogeneous MHCII tumor-cell expression, LAG-3 was higher inMHCIIhi (>70%) vs MHCIIlo (<10%) regions (P range=0.001-0.070).

Journal for ImmunoTherapy of Cancer 2017, 5(Suppl 3):89 Page 7 of 14

TCGA analysis was consistent with IHC analyses, demonstrating astrong correlation of LAG-3 mRNA expression with CD8, PD-1, andCTLA-4 (r=0.81; r=0.87; r=0.69), moderate correlation with PD-L1 andMHCII (r=0.47; r=0.58), and correlation of LAG-3, CD8, and PD-1mRNA expression with T-cell-inflamed gene signatures across tumortypes. Exploratory analyses of clinical trials in RCC and melanomashowed increased mean LAG-3 mRNA expression after nivolumab(anti-PD-1) treatment.ConclusionsLAG-3 expression correlates with tumor inflammation and isenriched in tumors with MHCIIhi tumor cells. Preliminary datasuggest that preferential localization of LAG-3-expressing leuko-cytes to MHCIIhi tumor regions potentially serves as a mechanismfor LAG-3 checkpoint pathway activation. These findings, and theobservation that nivolumab may induce LAG-3 expression, under-score the importance of studies to define predictive biomarkerprofiles for relatlimab (anti-LAG-3) therapy in PD-1-naive and-progressed patients.

References1. Ascierto, et al. J Clin Oncol. 2017; 35(suppl) [abstract 9520].

P511Evaluating immune responses of patients receiving the DPV-001cancer vaccineChristopher Paustian1, Yoshinobu Koguchi2, Adi Mehta3,Fridtjof Lund-Johansen3, Sam Bookhardt1, Purvish Patel4,Danielle Svancara4, Tarsem Moudgil2, Christopher Dubay2,William Redmond2, Carlo Bifulco2, Kyle Happel5, Brian Boulmay5,Augusto Ochoa5, Brenda Fisher2, Eileen Mederos5, Hong Ming Hu1,Traci Hilton1, Bernard Fox1, Walter Urba2, Rachel Sanborn21UbiVac, Portland, OR, USA; 2Robert W. Franz Cancer Center, Earle A.Chiles Research Institute, Providence Cancer Center, Portland, OR, USA;3Oslo University Hospital Rikshospitalet, Oslo, Norway; 4Quanterix,Lexington, MA, USA; 5LSUHSC School of Medicine, New Orleans, LA, USACorrespondence: Traci Hilton (traci.hilton@ubivac.com)Journal for ImmunoTherapy of Cancer 2017, 5(Suppl 3):P511

BackgroundDPV-001 DRibble® is a dendritic cell-targeted microvesicle (proteasomeblocked autophagosome) vaccine derived from adenocarcinoma andmixed histology cancer cell lines. It contains multiple TLR agonists and>130 potential NSCLC antigens, many as prospective altered-peptideligands or neoantigens. We hypothesize that the efficacy of DRibbles’vaccination can be attributed to tumor-derived short-lived pro-teins (SLiPs) and defective ribosomal products (DRiPs). SLiPs andDRiPs are typically not processed and presented by professionalantigen presenting cells therefor the host may be less tolerant.The large number of potential antigens in the vaccine necessitatenew techniques to monitor responses.MethodsPatients received induction cyclophosphamide, then 7 vaccines at 3-week intervals. First vaccine was given intranodally; subsequent vac-cines intradermally. Patients were randomized to receive DRibblealone (A), or with imiquimod (B) or GM-CSF (C). PBMCs and serumwere collected at baseline and at each vaccination to assess changesin antibodies (Protoarray, microsphere affinity proteomics (MAP)) andcytokines (Quanterix), peripheral lymphocytes populations (flow cy-tometry) and TCR repertoires (Adaptive immunoSEQ).Results13 pts were enrolled (Arm A: 5; B: 4; C: 4). Serum cytokines (IL1β, IL8,IFNα, IFNγ, IL6, IL17 and TNFα) were measured and normalized andthe sum plotted against time. The slope of the resultant trend linewas used as an indicator of either increased (positive slope) or

decreased (negative slope) systemic inflammation. DPV-001 alonedid not change net cytokine load while the addition of the adjuvantimmiquimod increased, and the addition of GM-CSF significantly less-ened the slope. Vaccination induced or increased IgG Ab responsesagainst targets over-expressed by NSCLC, correlating with activatedTh1 cells in whole blood samples. New or augmented Ab responseswere observed with continued vaccination. Pts receiving DPV-001had a significant (p<0.04) increase in total (CD4 + CD8) TCRs that in-creased 10 fold over baseline compared to normal controls (inde-pendent from trial, n=3) and the increase in CD4 clones was similarto that seen following Ipilimumab (melanoma pts, independent fromtrial, n=9). Patients receiving DPV-001 alone had the largest increasein CD8 T cell clones.ConclusionsVaccination with DPV-001 increased the number of strong anti-body responses to antigens commonly over-expressed in NSCLCand expanded populations of T cells. DPV-001 alone provided thegreatest increase in CD8 TCRs. Interval monitoring of PBMCs/serum identified the complexity of the immune response to thisvaccine and suggests possibilities to boost or sustain immunity.Trial Registration

NCT01909752.

P512Deep immunoprofiling of rare T-cell populations from clinicalsamplesMark Knappenberger1, Sri Krishna1, Kit Fuhrman2, Cheryl Tan2,Douglas Hinerfeld2, Karen S. Anderson11The Biodesign Institute at Arizona State University, Tempe, AZ, USA;2Nanostring Technologies, Inc., Seattle, WA, USACorrespondence: Karen S. Anderson (karen.anderson.1@asu.edu)Journal for ImmunoTherapy of Cancer 2017, 5(Suppl 3):P512

BackgroundThe complexity and heterogeneity of the immune system combinedwith its central role in tumor biology necessitates sophisticated analyt-ical approaches to reveal molecular mechanisms, novel therapeutictargets and clinically relevant biomarkers. T-cells have significant func-tional variation in activation states. However, the rare frequency ofantigen-specific CD8+ cells, for example, limits transcriptomic andproteomic analysis to identify biomarkers of exhaustion and activation.MethodsUtilizing a novel integrated workflow, we performed both proteomicand transcriptomic analysis of very rare populations of T-cells. Nega-tively selected CD3+ cells were derived from whole PBMCs and stimu-lated in vitro with allogeneic, CD40L-activated, viral-antigen presentingB cells for 8 days. The stimulated cell population was stained with HLA-A02:01 MHC Pentamers specific for Influenza A M158-66 (GILGFVFTL).The cells were then simultaneously labeled with fluorescent markersand 30 different DNA barcoded antibodies. Using the fluorescentmarkers, antigen-specific and naïve CD8+ T-cells were sorted, lysed,and then the antibody-bound DNA barcodes and the released cellularRNA’s were simultaneously measured using the NanoString nCounter®system and analyzed using the nSolver™ software.ResultsBy integrating flow cytometry with downstream analysis on the NanoStringnCounter system, 30 proteins and 770 RNAs were quantitatively measuredon the nCounter from as few as 400 petamer-positive T-cells. Using thenSolver Advanced Analysis software, differences in gene and proteinexpression between Influenza A M158-66 specific CD8+ T cells and apentamer-negative CD8+ T cell population were quantitatively measured.M158-66 specific cells showed upregulation of extracellular markers ofexhaustion and activation consistent with similar proteomic studiesincluding 4-1BB, CD27, CD45, and ICOS. Additionally, normalized

Journal for ImmunoTherapy of Cancer 2017, 5(Suppl 3):89 Page 8 of 14

mRNA counts from each population revealed increased presence oftranscripts coding for Granzyme B, CD225, Interleukin-32, STAT1, andTCF7 in the Influenza-specific CD8+ cells.ConclusionsThe rarity and functional importance of immune cell subsets in clin-ical samples has necessitated the development of new analyticalmethodologies that permit quantitative multiplexed immunoprofil-ing of RNA and protein expression. Using the nCounter platformdownstream of cell sorting uniquely allows simultaneous high-plexanalysis of protein and RNA from small numbers of targeted cells.In addition to the data we present on pentamer-positive antigen-specific T-cells, this method can be applied to any number of im-mune cell populations.ConsentWritten informed consent was obtained from the patient for publica-tion of this abstract and any accompanying images. A copy of thewritten consent is available for review by the Editor of this journal.

Cancer Vaccines

P513Sustained complete response to Nivolumab in a HPV16+ head andneck cancer patient after treatment with MEDI0457 (INO-3112), aDNA immunotherapy targeting HPV16/18Charu Aggarwal1, Roger Cohen1, Matthew Morrow2, Kimberly Kraynyak2,Dawson Knoblock2, Joshua Bauml1, Gregory Weinstein1, Jian Yan2,Drishty Mangrolia2, Sandra Oyola2, Susan Duff2, David Weiner3, Ildi Csiki2,Mark Bagarazzi21Perelman School of Medicine at the University of Pennsylvania,Philadelphia, PA, USA; 2Inovio Pharmaceuticals, Plymouth Meeting, PA,USA; 3Wistar Institute, Philadelphia, PA, USAJournal for ImmunoTherapy of Cancer 2017, 5(Suppl 3):P513

BackgroundWe report outcomes of a patient (pt) with HPV16+ head and necksquamous cell cancer (HNSCCa) who underwent treatment with 4doses of MEDI0457 as part of a pilot prospective clinical trial. Diseaseprogression was noted approx. 7 months after completion of adju-vant chemoradiation (due to extracapsular extension) followingdefinitive surgery. The pt was subsequently treated with nivolumab(nivo) and was noted to have a Complete Response (CR) at 6 weeksby RECIST. We performed correlative immune analysis for this pt tounderstand the mechanism underlying this response.MethodsThis Phase I/IIa trial included pts with p16+ locally advanced HNSCCa.MEDI0457 was delivered IM followed by electroporation with theCELLECTRA® device, Q3 weeks x 4 doses. Trial methods and resultshave been previously reported (Aggarwal C et al JImmunotherCan-cer. 2015;3(Suppl2):P426). Humoral and whole PBMC immuneresponses were assessed by ELISA and IFNg ELISpot, respectively.CD8+T cell activity and PD1 were assessed by flow cytometry (FC).Tissue immune responses were assessed by IHC.ResultsPt is a 66 yr old Caucasian male with HPV16+ Stage IVA (T2N2b) ton-sillar SCCa. He received one dose of MEDI0457 before definitive sur-gery, and three doses post-operatively. Tissue immune assessmentshowed decrease in both CD8+ and FoxP3+ infiltrates. Assessment ofpeak antibody and IFNg ELISpot responses showed titers of 1:150and 0 for HPV16 E6 and E7 antigens, respectively, and an elevationof 7 SFU/106 PBMC for each antigen. However, analysis of HPV16 spe-cific CD8+T cells prior to and post dosing with MEDI0457 showed denovo induction of CD8+ Tcells cells expressing PD-1 (1.8% of all CD8+ Tcells), as well as cells co-expressing PD-1, granzyme A, granzymeB and perforin (0.70% of all CD8+ Tcells). The pt was noted to have

CR after 4 nivo doses, and remains in complete clinical remission 14months after initiation of nivo.ConclusionsThe data above suggest that the pt responded immunologically totreatment with MEDI0457 as evidenced by the expansion of antigenspecific CD8+T cells noted by FC. The expression of PD1 on the CD8+ Tcells cells may have allowed them to be subsequently inhibitedby binding to tumor cells expressing PD-L1. Nivo may have relievedthis inhibition, allowing for an outgrowth of functional HPV16-specific CTLs, contributing to the sustained CR. An ongoing trial withMEDI0457 and durvalumab in HPV+ HNSCCa is evaluating the clinicaland immunologic efficacy of the combination treatment. Clinical trialinformation: NCT02163057.

Cellular Therapy Approaches

P514Utilizing T-cell activation signals 1, 2 and 3 for tumor-infiltratinglymphocytes (TIL) expansion: the advantage over the sole use ofinterleukin-2 in cutaneous and uveal melanomaMarie-Andree Forget, Rene J. Tavera, Young Uk Kim, Ankit Bhatta,Donastas Sakellariou-Thompson, Caitlin A. Creasy, Orenthial J. Fulbright,Renjith Ramachandran, Shawne T. Thorson, Esteban Flores, Arely Wahl,Sapna P. Patel, Patrick Hwu, Rodabe N. Amaria, Chantale Bernatchez,Cara HaymakerMDACC, Houston, TX, USACorrespondence: Marie-Andree Forget (mforget@mdanderson.org)Journal for ImmunoTherapy of Cancer 2017, 5(Suppl 3):P514

BackgroundMDACC has been conducting clinical trials using adoptive transfer ofautologous tumor-infiltrating lymphocytes (TIL) in the context ofmetastatic melanoma for more than a decade [1]. The art of TIL ex-pansion lies in a two-phase process. The initial phase utilizes high-doses of IL-2 (signal 3) and results in a 62% successful TIL growthrate averaged over the past 11 years (n=1135) with 68% for the last5 years. The second phase is the rapid expansion process (REP) andrelies on TCR activation (signal 1) and co-stimulation (signal 2)followed by high-doses of IL-2 (signal 3). This leads to successful ex-pansion in the vast majority of cases.MethodsIt was recently demonstrated that uveal melanoma is infiltratedwith CD8+ TIL. However, the initial TIL expansion (pre-REP) fromuveal melanoma tumors does not lead to comparable TIL growthwith IL-2 alone as seen from cutaneous melanoma [2]. Oncecultures from both types of melanoma reach the REP phase, ouranecdotal observations concluded that there was no difference inexpansion. Therefore, we hypothesized that TCR activation in the1st phase of expansion combined with an agonistic stimulation ofCD137/4-1BB (Urelumab) to protect the TIL from over differenti-ation in this initial TCR stimulation would favor reliable expansionof CD8+ TIL.ResultsThis novel 3-signal approach resulted in a faster and more con-sistent expansion of TIL, up to 100% for both types of melanoma.For cutaneous melanoma, numbers were comparable to or higherthan the traditional high-dose IL-2 method and favored expan-sion of CD8+ TIL. Importantly, this new method allowed for bet-ter/enhanced pre-REP expansion of TIL from uveal melanomawhich, in turn, would allow for this patient population to haveaccess to TIL therapy. Finally, providing the 3-signal attributed toT-cell activation led to expansion of TIL capable of recognizingtheir tumor counterpart in cutaneous as well as uveal melanomaas determined using IFNg ELISPOT.

Journal for ImmunoTherapy of Cancer 2017, 5(Suppl 3):89 Page 9 of 14

ConclusionsThis new methodology for the initial phase of TIL expansion addressesone of the major critiques for TIL therapy - the time needed for properexpansion of a suitable product. It brings consistency in successfulgrowth as well as a new opportunity for challenging malignancies suchas uveal melanoma.

References1. Radvanyi, et al. Clinical Cancer Research. 20122. Qin, et al. Oncoimmunology. 2017

P515Novel cryopreserved tumor infiltrating lymphocytes (LN-144)administered to patients with metastatic melanoma demonstratesefficacy and tolerability in a multicenter Phase 2 clinical trialAmod Sarnaik1, Jason Chesney2, Harriet Kluger3, Brendan Curti4, OmidHamid5, Jose Lutzky6, Maria Fardis7, Igor Gorbatchevsky7, Sam Suzuki7,Bente Larsen7, Nancy L. Samberg7, John Kirkwood81Moffit Cancer Center, Tampa, FL, USA; 2James Graham Brown CancerCenter, Louisville, KY, USA; 3Yale Cancer Center, New Haven, CT USA;4Earle A. Chiles Research Institute, Providence Cancer Center, Portland,OR, USA; 5The Angeles Clinic and Research Institute, Los Angeles, CA,USA; 6Mount Sinai Comprehensive Cancer Center, Miami Beach, FL, USA;7Iovance Biotherapeutics, Inc., San Carlos, CA, USA; 8University ofPittsburgh Medical Center, Hillman Cancer Center, Pittsburgh, PA, USACorrespondence: Igor Gorbatchevsky(igor.gorbatchevsky@iovance.com)Journal for ImmunoTherapy of Cancer 2017, 5(Suppl 3):P515

BackgroundThe safety and efficacy of adoptive cell therapy (ACT) with non-cryopreserved tumor infiltrating lymphocytes (TIL) has been studied inhundreds of patients with metastatic melanoma. This multicenterclinical trial was initiated with centrally manufactured TILs (LN-144) asnon-cryopreserved and cryopreserved infusion products. Our novelmanufacturing process for the non-cryopreserved LN-144 is used inCohort 1, and a shortened 3 weeks, cryopreserved LN-144 is used in Co-hort 2. The Cohort 2 manufacturing offers a significantly shorterprocess, which allows for flexibility of patient scheduling and dosing.The shorter manufacturing process reduces the wait time for the pa-tient to receive their LN-144 product and adds convenience to logisticsand delivery to the clinical sites.MethodsC-144-01 is a prospective, multicenter study evaluating metastatic mel-anoma patients who receive LN-144. Following a non-myeloablativelymphodepletion with Cy/Flu preconditioning regimen, patients receivea single infusion of LN-144 followed by the administration of IL-2(600,000 IU/kg) up to 6 doses. Patients are evaluated for objective re-sponse as a primary endpoint for up to 24 months.ResultsWe characterize the cryopreserved LN-144 administered to a secondcohort of patients, Cohort 2 following the same pre- and post-TIL in-fusion treatment regimen as used for Cohort 1.Cohort 2 patients were heavily pretreated with increased number of priorlines with all patients having anti-CTLA-4 and anti-PD-1 therapies, and lar-ger tumor burden (mean SOD: 15.3, 10.9 cm for Cohorts 2, 1). Mediannumber of prior systemic therapies were 4 and 3 for Cohorts 2 and 1,respectively. An initial analysis of safety data demonstrates comparabletolerability of cryopreserved LN-144. The safety profile for Cohort 1 pa-tients receiving the non-cryopreserved LN-144 continues to be accept-able for this late stage patient population. The most common TEAEsobserved in both cohorts by frequency are nausea, anaemia, febrile neu-tropenia, neutrophil count decreased, platelet count decreased. Early re-view of efficacy data indicates anti-tumor activity, including PRs, to theTIL therapy observed in patients treated in Cohort 2.

ConclusionsThis represents the first clinical trial in a multicenter setting with cen-trally manufactured TIL assessing a novel process for cryopreservedproduct with a significantly shorter process (~3 weeks). Preliminary re-sults indicate cryopreserved LN-144 as a novel, well tolerated thera-peutic option for patients with metastatic melanoma who have failedmultiple prior therapies, including checkpoint inhibitors. The cryopre-served LN-144 provides greater flexibility for patients and caregiversand allows for more immediate treatment for patients with such highunmet medical need.Trial RegistrationNCT02360579.

P516An evaluation of autologous tumor-reactive TIL generation fromhead and neck squamous cell cancersAshish Patel1, Bryan Bell2, Bernard Fox2, Carlo Bifulco2, Walter Urba2,Tarsem Moudgil2, Shawn Jenson2, Christopher Paustian3, Zipei Feng2,Carmen-Ballesteros Merino2, Rom Leidner4, Christopher Dubay2,Brenden Curti2, Hong-Ming Hu21PPMC, Portland, OR, USA; 2E.A.Chiles Research Institute, Portland, OR,USA; 3UbiVac, Portland, OR, USA; 4Providence Cancer Center, Portland,OR, USACorrespondence: Bernard Fox (bernard.fox@providence.org)Journal for ImmunoTherapy of Cancer 2017, 5(Suppl 3):P516

BackgroundHead and neck squamous cell carcinoma (HNSCC) remains a signifi-cant unmet medical need. While checkpoint blockade has providedimproved outcomes for some patients, the majority of patients donot benefit. We hypothesize that the lack of clinical benefit is sec-ondary to the absence of tumor-specific T cells that can expand andmediate tumor destruction. To begin to address this hypothesis wehave investigated the percentage of HNSCC from which we can gen-erate TIL reactive with the autologous tumor.MethodsOver the past 5 years we have collected and processed more than300 HNSCC specimens. When sufficient tumor material was available,tumor-infiltrating lymphocytes (TIL) and primary tumor cultures wereinitiated from enzyme digests (collagenase, thermolysin and DNAase)of freshly resected surgical samples. TIL cultures were assessed forgrowth and autologous tumor reactivity measured by IFN-g release.IFN-g was measured by ELISA. Once established, tumor cell lineswere characterized for phenotypic markers by flow cytometry.ResultsFor 242 tumor samples with sufficient tumor, 51 (21%) were identi-fied as being contaminated. TIL were generated from 82 (42%) of theremaining 191 tumors. Of the 59 where testing is complete, 46 TIL(77.9%) were autologous tumor-reactive. Overall, we were able togenerate TIL from 33% of tumors tested. We identified TIL cultureswith a range of autologous tumor reactivity that ranged from verystrong to no cytokine-release following stimulation with autologoustumor. At least 20 (10.2%) cell lines were established from the HNSCCsamples. A majority of these tumor cell lines contain cells thatexpress CD44, a marker of cancer stem cells.ConclusionsTumors from one-third (33%) of the 191 patients evaluated con-tained TIL that could be expanded and recognize autologous tumorcells. This may correspond to the patients that benefit from immuno-therapy with checkpoint blockade or T cell agonists. The remainingpatients may require vaccines or other therapies that will prime Tcells that can recognize autologous cancer cells. Our group is prepar-ing to undertake a clinical trial of vaccine plus anti-OX40 in patientswith HNSCC. Current efforts are examining whether multiplex IHC willbe useful in identifying tumors that contain tumor-reactive TIL.

Journal for ImmunoTherapy of Cancer 2017, 5(Suppl 3):89 Page 10 of 14

P517Regional intraventricular delivery of HER2-specific CAR T cellstargets breast cancer metastasis to the brainSaul Priceman1, Dileshni Tilakawardane1, Brook Jeang1, John Murad1,Anthony Park1, Wen-Chung Chang1, Julie Ostberg1, Josh Neman2,Rahul Jandial1, Jana Portnow1, Stephen Forman1, Christine Brown11City of Hope National Medical Center, Duarte, CA, USA; 2University ofSouthern California, Los Angeles, CA, USACorrespondence: Christine Brown (cbrown@coh.org)Journal for ImmunoTherapy of Cancer 2017, 5(Suppl 3):P517

BackgroundMetastasis to the brain from breast cancer remains a significantclinical challenge, and may be targeted with CAR-based immuno-therapy. CAR design optimization for solid tumors is crucial dueto the absence of truly restricted antigen expression and poten-tial safety concerns with “on-target off-tumor” activity. Here, wehave optimized human epidermal growth factor receptor-2(HER2)-CAR T cells for the treatment of breast to brain metasta-ses, and determined optimal second generation CAR design androute of administration for xenograft mouse models of breastmetastatic brain tumors, including multifocal and leptomeningealdisease.MethodsHER2-CAR constructs containing either CD28 or 4-1BB intracellularco-stimulatory signaling domains were compared for functional activ-ity in vitro by measuring cytokine production, T cell proliferation, andtumor killing capacity. We also evaluated HER2-CAR T cells deliveredby intravenous, local intratumoral, or regional intraventricular routesof administration using in vivo human xenograft brain metastaticbreast cancer models.ResultsHere, we have shown HER2-CARs containing the 4-1BB intracel-lular co-stimulatory domain confer improved antigen-selectivetumor targeting with reduced T cell exhaustion phenotype andenhanced antigen-dependent proliferative capacity compared toHER2-CARs containing the CD28 co-stimulatory domain. Localintracranial delivery of HER2-CARs showed in vivo anti-tumor ef-ficacy in an orthotopic xenograft model using a tumor line gen-erated from a breast cancer patient with brain metastasis.Importantly, we demonstrated robust anti-tumor activity follow-ing regional intraventricular delivery of HER2-CAR T cells fortreatment of multifocal brain metastases and leptomeningealdisease.ConclusionsOur study shows the importance of CAR design in defining an opti-mized CAR T cell, and highlights intraventricular delivery of HER2-CAR T cells for treating multifocal brain metastases.

Combination Therapy (IO/IO, IO/Standard of Care,IO/Other)

P518Generation of non-reprogrammable, dysfunctional CD8+ T-cellsfollowing anti-PD-1 therapy in the presence of low antigenpriming is a cause of failure of the treatmentVivek Verma1, Rajeev Shrimali1, Shamim Ahmad1, Winjie Dai1, HuaWang1, Sumin Lu1, Pankaj Gaur1, Scott A. Hammond2, MikayelMkrtichyan1, John E. Janik1, Seema Gupta1, Samir N. Khleif11Augusta University, Augusta, GA, USA; 2MedImmune LLC, Gaithersburg,MD, USACorrespondence: Samir N. Khleif (skhleif@augusta.edu)Journal for ImmunoTherapy of Cancer 2017, 5(Suppl 3):P518

BackgroundCurrently, several clinical trials utilizing anti-PD-1 for cancer ther-apy are ongoing either alone or in combination with other im-mune modulators [1]. However, despite a durable response insome patients, monotherapy with anti-PD-1 fails in significantnumber of patients. Hence, understanding of the mechanismsthat lead to failure of anti-PD-1 as an anti-cancer agent wouldhelp to harness its full potential.MethodsEffects of PD-1 blockade, prior or together with tumor-specific vac-cine, on tumor growth and survival were evaluated in TC-1 and B16tumor mouse models. Immune responses were determined in TC-1tumors in a time-dependent manner. In vitro mechanistic studieswere carried out in pMel-1 CD8+ T-cells.ResultsWe show that in the immunosuppressive microenvironment of thetumor, anti-PD-1 treatment leads to induction of PD1highCD38high

non-reprogrammable CD8+ T-cells [2]. These cells are generatedearly after first anti-PD-1 treatment and remain unresponsive tosubsequent antigenic stimulation indicating their dysfunctionalstate. Using in vitro assays, we found that treatment with anti-PD-1prior to T-cell priming abrogates the ability of T-cells to upregulateCD40L and increase IFNg, and leads to significant cell death byapoptosis and failure to generate memory cells. On the other hand,anti-PD-1 therapy given concomitantly with strong T-cell antigenpriming by vaccine produces a robust anti-tumor immune responseaccompanied with the generation of reprogrammable (plastic)PD1highCD38high cells that get activated, generating effector func-tions and immune memory.ConclusionsOur data provide a plausible explanation for the inability ofanti-PD-1 therapy to generate effective anti-tumor effects insome patients especially with non-immunogenic tumors. Thissuggests that the development of combination therapies thatwould increase the immunogenicity of tumors might enhancethe efficacy of anti-PD-1 therapy. These results also suggest thatrecurrent patients that have undergone anti-PD-1 therapy earliermay not respond to combination therapies that further activate/stimulate the TCR signaling. Therefore, these findings have im-portant implications in the design of future trials employingcombination therapy with anti-PD-1 to achieve clinical success.

References1. Page, et al. Immune modulation in cancer with antibodies. Annu Rev

Med. 2014; 65:185-202.2. Philip, M et al. Chromatin states define tumour-specific T cell dysfunction

and reprogramming. Nature. 2017; 545:452-6.

Emerging Models and Imaging

P519Artificial intelligence augmented phenotypic screens rapidly revealnovel macrophage biologyViswa Colluru (viswa.colluru@recursionpharma.com)Recursion Pharmaceuticals, Salt Lake City, UT, USAJournal for ImmunoTherapy of Cancer 2017, 5(Suppl 3):P519

BackgroundTumor Associated Macrophages have long been recognized as akey component of the tumor microenvironment and play acritical role in tumor progression. However, our ability to fully le-verage macrophages as treatment targets is hampered by the

Fig. 2 (abstract P519). Principal component analysis of phenotypicfeatures reveals meaningful clustering and novel relationshipsbetween polarizations

Journal for ImmunoTherapy of Cancer 2017, 5(Suppl 3):89 Page 11 of 14

complexity of immune phenotypes and low-dimensional screen-ing practices. At Recursion Pharmaceuticals, we combine target-agnostic phenotypic imaging experiments with artificial-intelligence and advanced data analytics to interrogate complexbiology in high-dimensional screens. We describe the applicationof our platform to the study of macrophage polarization states todeliver novel and actionable insights for immuno-oncology drugdiscovery.MethodsPMA activated THP1 cells were treated with the relevant polariz-ing cytokines for 48h prior to staining with the Cell Paintingmethod, which fluorescently labels 9 cellular components toprovide a morpho-functional snapshot of a cellular state in theform of ~1000 unique features. Cells were then imaged for fluor-escence across 5 channels to generate ~200 images per perturb-ation and processed through a custom cloud-based softwarepipeline enabled to run CellProfiler and proprietary artificialintelligence algorithms at scale. Secretome and transcriptomeprofiling were performed using a standard 65-plex Procartaplexpanel and a custom 50-plex Quantigene Plex assay kit respect-ively (ThermoFisher).ResultsOur data demonstrate unique, sensitive, and functionally mean-ingful high-dimensional phenotypes for each of the M0, M1, M2a,M2c, and M2-like (M-CSF) macrophage polarizations (Figs. 1 and2). Principal component analysis on the phenotypic features fur-ther suggests that the M1-M2-like-M2a-M2c macrophage statesare distinct polarizations and not part of an axis, as currentdogma holds. All polarizations were validated in orthogonaltumor relevant functional assays. Importantly, when compared totranscriptome and secretome analyses, our phenotypic approachis able to better differentiate between the different polarizationstates. We demonstrate near perfect distinguishability of the dif-ferent macrophage classes by a Machine Learning classifiertrained on phenotypic features (Fig. 3). A phenotypic screen of~2000 diverse small molecules rapidly uncovered at least 1 noveldrug class that modulates M-CSF induced polarization, and atleast 3 drug classes that outperform CSF-1R inhibition alone forprevention of a M2-like phenotype. We also identified, in thesame screen, putative compounds that could cause a M1-like re-polarization in M-CSF treated macrophages. Our entire screeningcampaign described here was executed in 3 weeks, highlightingthe efficiency with which imaging and artificial intelligence canbe used in drug discovery.ConclusionsIn conclusion, artificial intelligence augmented phenotypic approachesallow facile interrogation of complex phenotypic states at scale to driverapid discovery.

Fig. 1 (abstract P519). Cell painting reveals rich morphologicalprofiles of macrophage polarizations

Fig. 3 (abstract P519). Machine learning can be leveraged toclassify macrophage phenotypes with high confidence

Mechanisms of Efficacy or Toxicity

P520Tuberculosis following PD-1 blockade in a patient with Merkel cellcarcinoma (MCC): coincidence or causality?Elad Sharon1, Daniel Barber2, Ragini Kudchadkar3, Steven Fling4,Tracey Day5, David Ashkin6, Lisa Lundgren4, Martin Cheever4,Paul Nghiem7, Shunsuke Sakai21National Cancer Institute, Bethesda, MD, USA; 2National Institute ofAllergy and Infectious Diseases, Bethesda, MD, USA; 3Emory UniversitySchool of Medicine, Atlanta, GA, USA; 4Fred Hutchinson Cancer ResearchCenter, Seattle, WA, USA; 5Infectious Disease Research Institute, Seattle,WA, USA; 6University of Florida College of Medicine, Gainsville, FL, USA;7University of Washington, Seattle, WA, USACorrespondence: Elad Sharon (sharone@mail.nih.gov)Journal for ImmunoTherapy of Cancer 2017, 5(Suppl 3):P520

Journal for ImmunoTherapy of Cancer 2017, 5(Suppl 3):89 Page 12 of 14

BackgroundPreclinical data suggest that PD1 blockade may assist in eradicatinga variety of infections. In contrast, PD1 knockout mice are hyper-susceptible to mycobacterium tuberculosis (Mtb) infection, develop-ing necrotic pulmonary lesions with high bacterial loads. We reporttuberculosis in a patient treated with pembrolizumab for Merkel cellcarcinoma (MCC). We also characterize Mtb-specific immunity andbacteria isolated from a pulmonary lesion that arose after initiatingPD1 therapy.MethodsAn 83-year old man began a clinical trial of pembrolizumab in June2015 for advanced MCC. The patient had no risk factors and no testingfor latent tuberculosis was performed. CT scan after 12 cycles revealedknown sites of MCC decreasing in size or remaining stable, and a newright lower lobe pulmonary nodule was noted (1.1 x 1.6 cm). Thepatient underwent excision of the nodule in January 2016. Pathologyrevealed necrotizing granulomas staining for acid-fast bacilli. Cryopre-served PBMC obtained immediately prior to pembrolizumab and atcycles 5, 8, 11, and 14 were analyzed for antigen-specific CD4 and CD8T cell responses by intracellular cytokine staining after stimulation withPPD. Serum samples were also analyzed for IgG responses to a panel ofdifferent Mtb antigens. Mtb genotyping was performed.ResultsPD1 blockade in this individual was associated with significantly in-creased circulating Mtb-specific Th1 responses prior to developmentof the necrotic pulmonary tuberculoma. However, neither Th17 cellsnor CD8 T cells specific to Mtb were detectable in PBMC at any time.Circulating Foxp3+ Tregs did not change in number during pembroli-zumab treatment in this individual. Mtb-specific IgG levels, althoughdetectable, did not display significant changes before the develop-ment of the necrotic granuloma. TB genotyping also did not correl-ate with any known new clusters of TB in North America in therecent past. Collectively, these data show that the development oftuberculosis following PD1 blockade in this individual was selectivelyassociated with increases in Mtb-specific Th1 responses.ConclusionsFour previous cases of TB have been reported following PD-1 blockade.In this case, Mtb-specific Th1 responses increased after PD1 blockadewas initiated, and clinical tuberculosis arose subsequently. Importantly,this nodule was assumed to be an MCC metastasis, and would not havebeen recognized as due to Mtb if an excisional biopsy had not beenperformed. In conjunction with animal model data suggesting a plaus-ible mechanism, and the prior reported cases, these findings suggestthat Mtb is possibly a concern following PD1 blockade.Trial RegistrationNCT02267603

Mechanisms of Resistance to Immunotherapy

P521Imprime PGG, a novel phase 2 immunotherapeutic, enhances theanti-tumor activity of checkpoint inhibitors (CPI) and suppressesCPI-induced Indoleamine 2, 3-dioxygenase (IDO) expressionXiaohong Qiu, Anissa SH Chan, Adria B. Jonas, Michael E. Danielson,Nadine R. Ottoson, Kyle S. Michel, Steven M. Leonardo, Ross B. Fulton,Kathryn Fraser, Takashi O. Kangas, Mark Uhlik, Jeremy R. Graff, NanditaBoseBiothera Pharmaceuticals, Inc., Eagan, MN, USACorrespondence: Nandita Bose (nbose@biothera.com)Journal for ImmunoTherapy of Cancer 2017, 5(Suppl 3):P521

BackgroundAlthough checkpoint inhibitors (CPI) have shown unprecedented effi-cacy in cancer treatment, a significant fraction of patients eventuallydevelop resistance to CPI. Therefore, there is a growing need to identifyresistance mechanisms as well as rational combination strategies tocombat this resistance. Imprime PGG (Imprime), a novel yeast derivedβ-glucan pathogen-associated molecular pattern (PAMP), is being de-veloped as a combination agent with CPI in patient populations whohave failed single- agent CPI therapy. In pre-clinical mechanistic studies,Imprime has been shown to reprogram the immuno-suppressive

myeloid cells in the microenvironment and enhance the effectorfunctions of tumor infiltrating T cells. The objective of this study was tofocus on IDO1, one of the critical resistance mechanisms in the micro-environment that hinders T cell anti-tumor immunity.MethodsThe anti-tumor efficacy of Imprime in combination with anti-PD-1was evaluated in the murine colon cancer model MC38. Transcrip-tional changes in the tumor were assessed by QuantiGene Multiplexplatform. IDO1 gene expression in IFN-γ-stimulated human wholeblood post Imprime treatment was assessed by qRT-PCR. Tryptophanand kyneurinine levels were measured in the serum by LC/MS.ResultsIn the MC38 model, Imprime in combination with anti-PD-1 resultedin significantly reduced tumor growth as compared to anti-PD-1monotherapy. Consistent with our previous results, transcriptionalanalyses of tumor tissues showed that Imprime alone induced a M1skewing gene expression profile by modulating several genes includ-ing iNOS, TNF, CXCL10, Arg1, and CCL17. Anti-PD-1 treatment aloneup-regulated several genes affecting T cell functionality, such as IFN-γ, PD-L1 and GzmB. Interestingly, anti-PD-1 treatment also resulted inincreased expression of several immuno-suppressive genes, such asIL10, Arg1, and most notably, IDO1. Furthermore, IDO1 expressionwas inversely correlated with tumor volume, suggesting IDO1 up-regulation is a counter-regulatory mechanism induced in the tumorand/or myeloid cells in response to enhanced IFN-γ production byanti-PD-1-treated tumor-infiltrating T-cells. Interestingly, this anti-PD-1 mediated IDO1 induction was dampened significantly by theaddition of Imprime to anti-PD-1. Flow cytometry showed thatImprime treatment affected IDO expression in the Ly6Chi monocytesand macrophages but not in tumor cells. In human whole blood, IFN-γ- treatment increased the transcriptional level of IDO1 and the ratioof tryptophan to kyneurinine, but Imprime treatment significantlyinhibited this IFN-γ-induced IDO1 increase.ConclusionsThese results collectively demonstrate that Imprime treatment canenhance efficacy of anti-PD-1 treatment and may do so by restrictingcompensatory immuno-suppressive mechanisms mediated by mye-loid cells.

Microbiome

P522Clostridium species control primary liver cancer and livermetastasis via bile acids/CXCL16/CXCR6 mediated NKT cellimmunityChi Ma, Miaojun Han, Bernd Heinrich, Qiong Fu, Qianfei Zhang, MasakiTerabe, Jay Berzofsky, Xin Wei Wang, Giorgio Trinchieri, Tim GretenNCI, Bethesda, MD, USACorrespondence: Tim Greten (tim.greten@nih.gov)Journal for ImmunoTherapy of Cancer 2017, 5(Suppl 3):P522

BackgroundGut commensal bacteria have been described as important regulatorsof anti-tumor immunity. Primary liver tumors and liver metastasis repre-sent the leading cause of cancer-related death [1]. The liver is exposedto gut bacteria, and gut sterilization has profound effects on hepatocel-lular carcinoma (HCC) development [2, 3]. However, the role of gutbacteria in anti-tumor surveillance in the liver is poorly understood.MethodsGut commensal bacteria were depleted by feeding mice with anti-biotic cocktail in drinking water, or using Germ-free mice. PrimaryHCC was induced in liver-specific MYC transgenic mice. Liver metas-tasis was induced by intrasplenic injection of B16 melanoma tumorscells or i.v. injection of A20 lymphoma or EL4 thymoma tumor cellsinto C57BL/6 or BALB/c mice. Immune cell monitoring was performedby flow cytometry analysis. Stool bacteria was analyzed by 16S rRNAsequencing. Patient liver bile acids were measured by Metabolon'sDiscover HD4 Platform.ResultsDepleting gut commensal bacteria induced a liver-selective anti-tumor effect using both primary MYC-HCC model or A20 or EL4 liver

Journal for ImmunoTherapy of Cancer 2017, 5(Suppl 3):89 Page 13 of 14

metastasis models. An increase of hepatic CXCR6+ NKT cell numberand function was observed, independent of mouse strain, gender orpresence of liver tumors. In vivo functional studies confirmed thatNKT cells mediated a tumor inhibition in the liver. Further investiga-tion showed that NKT cell accumulation was regulated by CXCL16expression of liver sinusoidal endothelial cells, which was controlledby Clostridium species-mediated primary-to-secondary bile acid con-version. Feeding mice with secondary bile acid w-MCA reversed boththe NKT accumulation and the inhibition of liver tumor growthcaused by depleting gut microbiome. In human livers, primary bileacid CDCA levels correlated with CXCL16 expression, and the oppos-ite was found with the secondary bile acid glycolithocholate (GLCA).ConclusionsGut bacteria such as Clostridium species control liver anti-tumorimmunesurveillance by altering bile acid composition, which regu-lates CXCL16 expression in LSECs, thus affects NKT cell level in theliver. This study shows that the gut microbiome utilizes bile acid me-tabolism to control anti-tumor immunity in the liver and opens novelopportunities to treat primary liver cancer as well as liver metastasis.

References1. Disibio, et al. Metastatic patterns of cancers: results from a large autopsy

study Arch Pathol Lab Med. 2008; 132:931-9.2. Dapito, et al. Promotion of hepatocellular carcinoma by the intestinal

microbiota and TLR4. Cancer Cell. 2012; 21:504-16.3. Yoshimoto, et al. Obesity-induced gut microbial metabolite promotes

liver cancer through senescence secretome. Nature. 2013; 499:97–101

Fig. 1 (abstract P523). Most highly down-regulated and up-regulatedgenes in LD skin toxicity from immune checkpoint therapy.

Fig. 2 (abstract P523). Representative case of lichenoid dermatitis(LD) skin toxicity to immune checkpoint therapy

Oncogenetics and Immunogenomics

P523Gene expression profiling of dermatologic toxicities from immunecheckpoint therapyJonathan Curry, Michael Tetzlaff, Alexandre Reuben, Robert Szczepaniak,Saira George, Carlos Torres-Cabala, Daniel Johnson, Victor Prieto, AdiDiabMD Anderson Cancer Center, Houston, TX, USACorrespondence: Jonathan Curry (jlcurry@mdanderson.org)Journal for ImmunoTherapy of Cancer 2017, 5(Suppl 3):P523

BackgroundCancer patients receiving antibodies abrogating immune check-points antibodies may develop a diverse array of histologic skinreactions to these therapies that can include immunobullous,spongiotic, and lichenoid dermatitis (LD), and infrequentlySteven Johnson Syndrome/Toxic Epidermal Necrolysis. The de-velopment of any type of these adverse immune-related cutane-ous reactions may be sufficiently severe to warrant cessation ofpotentially efficacious treatment regimen. There is therefore acritical need to understand the pathogenesis of dermatologictoxicities in order to devise rational therapies to manage themmore effectively.MethodsTotal RNA from formalin-fixed paraffin, embedded tissue from pa-tients who developed LD skin toxicity [n=3; mean age (range) =60.7 years] while receiving immune checkpoint therapy (nivolu-mab =1, pembrolizumab = 1, nivolumab + ipilimumab = 1) formetastatic melanoma and from benign lichenoid keratosis (BLK)in control patients [n=3; mean age (range) = 48.7 (37-56) years]

were profiled with the NanoString nCounter PanCancer ImmuneProfiling Panel interrogating the mRNA levels of 770 genes. Folddifferences in mRNA transcript levels were compared betweenthe two groups using two-sample tests and p-value < 0.05 wereconsidered significant.ResultsOf the 770 genes, significant log fold difference in gene expres-sion was observed between the two groups in 167 genes. Com-pared to the BLK control group (Fig. 2), the LD skin toxicitygroup (Fig. 3) showed down-regulation of 93 mRNAs (p < 0.05)and up-regulation of 74 mRNAs (p < 0.05). The ten most signifi-cantly down- and up-regulated transcripts in the LD skin toxicitygroup are listed (Fig. 1). Among the down-regulated genes areCCL27, CCL18, CD83, ILIRN, and IL2RA (Log2 fold change range:-1.81 to -1.17; all p values < 0.05). Among the up-regulated geneswere CD14, CXCL12, and CCL14 (Log2 fold change range: 1.28-2.52, all p values < 0.04).ConclusionsLD skin toxicity from immune checkpoint therapy exhibits anmRNA gene expression profile distinct from BLK. Despite showinghistopathologically identical reaction patterns between the LDskin toxicity from immune checkpoint therapy and BLK, we ob-served differences in the mRNA transcript levels of 167 genes.Down-regulation of CCL27, CCL18, XCL2, CD83, ILIRN, and IL2RAgenes implies dysregulation of normal homeostasis and immuneregulation in the skin. Up-regulation of genes that encodechemotactic molecules (e.g. CXCL12 and CCL14) functions to re-cruit distinct subsets of skin immunocytes specific to immunecheckpoint mediated LD and further suggest that abrogation ofthese signaling pathways may spare patients from developingthis type of skin toxicity.

Fig. 3 (abstract P523). Representative case of lichenoid dermatitis(LD) skin toxicity to immune checkpoint therapy.

Journal for ImmunoTherapy of Cancer 2017, 5(Suppl 3):89 Page 14 of 14

Oncolytic Viruses and Intratumoral Therapies

P524Clinical and biomarker analyses of a phase II study of intratumoraltavokinogene telseplasmid (pIL-12) plus pembrolizumab in stageIII/IV melanoma patients predicted to not respond to anti-PD-1Alain P. Algazi1, Katy K. Tsai1, Michael D. Rosenblum1, Robert Andtbacka2,Carmen Ballesteros-Merino3, Shawn Jensen3, Carlo B. Bifulco3,Bernard A. Fox3, SuFey Ong4, Alessandra Cesano4, Joseph Beechem4,Chris Twitty5, Jean S. Campbell5, Erica Browning5, Reneta Talia5,Shawna A. Shirley5, Mai H. Le5, Robert H. Pierce5, Sharron Gargosky5,Adil I. Daud11University of California, Oakland, CA, USA; 2University of Utah, Salt LakeCity, UT, USA; 3Providence Portland Medical Center, Portland, OR, USA;4NanoString Technologies, Inc., Seattle, WA, USA; 5OncoSec MedicalIncorporated, San Diego, CA, USACorrespondence: Chris Twitty (ctwitty@oncosec.com)Journal for ImmunoTherapy of Cancer 2017, 5(Suppl 3):P524

BackgroundMelanoma patients with a low frequency of PD-1hiCTLA-4hi TIL arepredicted to not respond to pembrolizumab, yet our previous interimanalysis demonstrated that the combination of intratumoral (IT) plas-mid IL-12 (tavokinogene telseplasmid; TAVO) and pembrolizumabyields robust clinical responses with an excellent safety profile.Updated clinical analyses (locked August 2017) from this multi-center, phase II, open-label trial including 2-year progression freesurvival (PFS) and DOR are presented. New biomarker data revealscoordinated anti-tumor immunological mechanisms in both thetumor microenvironment (TME) and in the peripheral blood.MethodsMelanoma stage III/IV patients with a low CD8+ TIL status (<25% PD-1hiCTLA-4hi) were treated with pembrolizumab (200mg every 3weeks) concurrently with electroporation of IT-TAVO on days 1, 5and 8 (6 week cycles). Tumor samples were profiled with multispec-tral immunohistochemistry (mIHC) and NanoString’s Human Immun-ology and the PanCancer IO360 Beta Version panels. PBMC wereanalyzed for immune phenotype (flow cytometry) as well as Nano-String’s PanCancer Immune Profiling RNA and Protein panels.ResultsProgression free survival (PFS) rates for this treatment were 62% at 6months and 57% at 18 months (median PFS not reached at 24 months)with a 48% BORR. DOR was not assessable as no responders have pro-gressed and no safety signals were observed with only 2/22 grade 3treatment-emergent adverse events. In responding patients, significantpost-treatment increases were observed in both the Th1-associatedgene expression of STAT4 and IL-12RB in biopsies, and frequencies ofCD8+PD-1+TIGIT+ and proliferating CD8+PD-1+ peripherally. Addition-ally, responding patients had a significant increase of TCR clonality inthe tumors compared to PBMCs with a reversed relationship in non-responding patients. Spatial analysis by mIHC revealed a significant in-crease of both PD-L1+ and FoxP3+ cells <15um from CD8+ T cells innon-responders. Exploratory analysis with Nanostring’s IO360 Beta Ver-sion panels highlighted underexpression of WNT2B and overexpressionof MICB in the pretreatment responder biopsies.

ConclusionsDurable responses and favorable PFS rates in likely PD-1 non responderscontinues to suggest that combination IT-TAVO-EP with pembrolizumab isan effective therapeutic modality with an excellent safety profile. Associatedbiomarker data highlights connected immunological mechanisms, wherebyintratumoral Th1-polarization, associated TCR clonality and limited suppres-sive cell types can drive robust anti-tumor responses (intratumoral and sys-temic) that positively impact this difficult to treat patient population.Trial RegistrationNCT02493361

Tumor Microenvironment (Mechanisms andTherapies)

P525Exploring tumor microenvironment and human bone marrowstromal cells by single cell sequencingShutong Liu, Ping Jin, Yindong Zhao, Jiaqiang Ren, Steven Highfill,Jinguo Chen, Rongye Shi, Hui Liu, David StroncekNational Institutes of Health, Rockville, MD, USACorrespondence: David Stroncek (dstroncek@mail.cc.nih.gov)Journal for ImmunoTherapy of Cancer 2017, 5(Suppl 3):P525

BackgroundProinflammatory stimulation can lead to phenotype changes inmarrow mesenchymal stromal cells (MSCs). We have been usingMSCs to study the role of stromal cells in the tumor microenvir-onment. Our previous study showed that IFN-γ (InterferonGamma) and TNF-α (Tumor Necrosis Factor Alpha) together resultin the synergist uniform polarization of MSCs toward primarilyTh1 phenotype, suggesting that tumor associated stromal cellsmay contribute to immune-mediated tumor killing. MSCs are het-erogeneous and contain both stromal cells and skeletal stem cellsthat are responsible for osteogenesis. Prolonged passages of MSCcan result in a change in phenotype associated with the loss ofthe skeletal stem cells. In this study, we used IFN-γ and TNF-α tostimulate different passages MSCSs. We hypothesize that if stro-mal cells remain in late passage and if late passage Th1polarization is similar to that of early passage, Th1 polarization islikely an intrinsic property of MSCs.MethodsMSCs from bone marrow of one healthy donor were cultured andtreated by IFN-γ (6.5ng/ml) and TNF-α (1.5ng/ml) at passages 2 (Bulkonly), 3 (Single cell only), 4, 6, 8, 9 and 10(Bulk only) for 24 hours.RNA or cells were harvested from treated and control MSCs formRNA Next Generation Sequencing (NGS) respectively.ResultsControl and stimulated MSCs NGS analysis found that the transcriptome ofall passages of stimulated MSCs changed. Differences in the transcriptomeof stimulated MSCs among different passages were observed, however, theexpression by stimulated MSCs of important immune modulatory genessuch as CXCL9, HLA-DRA, IL15 and IDO1 were up-regulated in all passagesbut their expression levels varied among passages.ConclusionsResults show that after stimulation, different passages have similarbut not identical gene expression changes. This suggests that im-mune modulation is an intrinsic property of MSCs, immune modula-tion may vary among MSCs types and some variability may existamong MSCs in different cancer types.ConsentWritten informed consent was obtained from the patient for publica-tion of this abstract and any accompanying images. A copy of thewritten consent is available for review by the Editor of this journal.

Publisher’s NoteSpringer Nature remains neutral with regard to jurisdictional claims in publishedmaps and institutional affiliations.