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Laboratory of Tumor Immunology and Biology

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Overview

I. LABORATORY MISSION STATEMENT
II. LABORATORY ORGANIZATION
III. SCIENTIFIC OVERVIEW/RECENT ACCOMPLISHMENTS
IV. ADMINISTRATIVE OVERVIEW
V. LIST OF CLINICAL RESEARCH PROTOCOLS AT THE CENTER FOR CANCER RESEARCH, NIH


I. LABORATORY MISSION STATEMENT

The Laboratory of Tumor Immunology and Biology (LTIB), CCR, functions as a multidisciplinary and interdisciplinary translational research programmatic effort with the goal of developing novel immunotherapies for cancer. The LTIB strategic plan focuses on the development of novel immunotherapeutics for human carcinomas, not only as monotherapies, but more importantly, in combination with other immune-mediating modalities, and other conventional or experimental therapies, as part of an immuno-oncology programmatic effort. Within this effort are several research groups, a clinical trials group, two independent tenure track investigators, and multiple collaborations with intramural and extramural scientific and clinical investigators and with investigators in the private sector. The program takes advantage of the uniqueness of the NCI intramural program in that it spans high-risk basic discovery research in immunology and tumor biology, through preclinical translational research, to paradigm-shifting clinical trials. Focus is placed on the design and development of novel 'off-the-shelf' recombinant (rec.) vaccines and immunomodulators that can be used in clinical studies at numerous institutions, and do not involve costly and labor-intensive ex vivo manipulations that can be carried out in only one or two centers. This is accomplished via Cooperative Research and Development Agreements (CRADAs) with partners in the private sector that provide agents for preclinical studies in appropriate animal models that we have developed and in human in vitro systems. The immunotherapeutics that we have developed have also enabled the collaborations with other clinical investigators at extramural Cancer Centers.

II. LABORATORY ORGANIZATION


Office of the Chief: Dr. J. Schlom (Senior Investigator, Chief). This office is responsible for the administrative functions of the LTIB, such as travel, personnel actions, training, meetings, manuscript editing, purchasing, etc.
Recombinant Vaccine Group: Dr. J. Hodge (Tenure Track Scientist), Head. This group investigates how non-immune‒based therapies affect tumor cells and specific components of the immune system. An emphasis is placed on the mechanisms of how standard-of-care and new experimental therapies alter tumor cells to render them more susceptible to immune-based therapies. These studies form the rationale for novel immune- and non-immune‒based combination clinical trials.
Immunoregulation Group: Dr. C. Palena (Tenure Track Scientist), Head. This group investigates mechanisms of tumor progression, including mechanisms of metastasis and tumor resistance to therapies, and how immune-based therapies can be employed as therapeutics directed against such tumor-cell phenotypes. These studies have led to the identification and analyses of transcription factors that are drivers of the phenomenon of epithelial-to-mesenchymal transition (EMT) and to ongoing clinical studies employing vaccines directed against one of these gene products.
TRANSLATIONAL RESEARCH program (J. Schlom)
This program consists of 4 research groups and a clinical trials group.
Cytokine Group: Dr. J. Greiner (Staff Scientist), Head. This group investigates the mechanisms by which cytokines and other immune modulators affect the host immune system and the tumor microenvironment for use in combination with immunotherapeutics and other forms of cancer therapy.
Cellular Immunology Group: Dr. KY Tsang (Senior Staff Associate), Head. This group is involved in studies to identify and modify tumor-associated antigens to enhance their immunogenicity in cancer patients in vaccine-mediated immunotherapy. The group also studies patients' immune responses to provide critical information toward the development of more effective immunotherapeutic approaches to cancer.
Molecular Immunology Group: Dr. B. Farsaci (Research Fellow), Head. Emphasis is placed on the identification of specific immune cell subsets that can help identify cancer patients most likely to benefit from immunotherapy. This group also studies the tumor microenvironment and specific immune cell subsets in the periphery, pre- and post-immunotherapy, to identify potential correlations with clinical responses of patients treated with immunotherapies as monotherapy or combination therapy.
Immunotherapeutics Group: Dr. J. Schlom (Senior Investigator), Head. This group focuses on the design and development of novel cancer immunotherapeutics such as cancer vaccines, checkpoint inhibitors and other immune modulators for use as monotherapies or in combination with standard-of-care and experimental non-immune‒based therapeutics. This is accomplished via collaborative efforts with laboratory and clinical investigators in other Branches/Laboratories at the NCI, at extramural Cancer Centers, and in the private sector.
Clinical Trials Group: Dr. C. Heery (Staff Clinician), Director. This group designs and conducts science-driven clinical studies as a consequence of hypothesis-driven preclinical studies in the laboratory. Dr. Heery works closely with Drs. J. Gulley and R. Madan (Genitourinary Malignancies Branch, both Adjunct Investigators in the LTIB) and with me and other LTIB members as a well-integrated immunotherapy team. This group also serves as the conduit for collaborative trials with clinical investigators in other Branches of the CCR, NCI and at numerous extramural Cancer Centers.


SCIENTIFIC OVERVIEW

Recent Accomplishments

We have continued our preclinical and clinical investigations of two diverse recombinant (rec.) vaccine platforms (each with demonstrated unique properties): (a) rec. poxviral vectors containing the transgenes for one or more tumor-associated antigens (TAAs) and three T-cell costimulatory molecules (designated TRICOM); and (b) heat-killed rec. Saccharomyces cerevisiae (yeast) containing TAA protein via the insertion of a yeast plasmid.

We have further interrogated the transcription factor brachyury, which is a major driver of the epithelial-to-mesenchymal transition (EMT) process in human carcinoma cells, as a novel vaccine target. A rec. yeast-brachyury vaccine has been developed and a first-in-human clinical trial is underway.

We have analyzed biopsies of human lung and breast carcinomas and have found overexpression of brachyury mRNA and protein in carcinomas vs. normal adult tissues with the exception of testes and staining in some thyroids. Expression of brachyury has been shown to be increased in higher grade tumors and metastases. Brachyury expression was shown to be significantly and independently associated with a high risk of recurrence (P=0.0027) in breast cancer patients treated with tamoxifen.

We have described the association of brachyury with features of stemness. These studies included the comprehensive characterization of the role of brachyury in the control of E-cadherin transcription and its cooperation with other drivers of EMT (snail, slug).

We have characterized the pattern of cytokines, chemokines, and growth factors secreted by tumor cells undergoing EMT and demonstrated that the chemokine IL-8 might function in an autocrine and/or paracrine fashion to initiate and/or maintain EMT in human carcinomas.

We have described the role of TGF-β1 signaling in the control of brachyury expression in tumors and have shown that blockade of autocrine TGF-β1 with a small molecule inhibitor of TGFβ-R1 can (a) reduce brachyury, (b) revert tumor features of EMT, and (c) increase sensitivity to chemotherapy.

We have demonstrated that the level of brachyury expression in human carcinoma cells directly correlates with resistance to cytotoxic treatments, including chemotherapy and radiation, and that treatment in vitro or in vivo with cycles of chemotherapy selects for a population of highly mesenchymal, invasive and brachyury positive tumor cells.

Mechanistic studies demonstrated that brachyury promotes a stall in tumor cell cycle progression by repressing the expression of the cell cycle regulatory protein p21Cip1. We subsequently showed that reconstitution of p21Cip1 expression is able to alleviate chemotherapy resistance of brachyury-high tumor cells.

We have made the paradoxical observation that reducing, rather than increasing, the level of the target brachyury in some carcinoma cells enhances their cytotoxic response to brachyury-specific T cells. This observation was expanded to demonstrate that tumor cells with very high levels of brachyury may be less sensitive to various immune effector cells, including antigen-specific T cells, NK, LAK cells or the immune mediators FasL and TRAIL, than tumor cells with intermediate or low levels of brachyury. Studies are ongoing to identify strategies aimed at reducing brachyury and mesenchymal features to render tumor cells more susceptible to immune attack.

Mechanistic studies demonstrated that mesenchymalized tumor cells are resistant to caspase-dependent lytic pathways while remaining normally sensitive to the cytotoxic effect of granzymes and perforin. We also showed that a reduction of the cell cycle CDK1 protein levels was responsible for the cytotoxic resistance of tumor cells with very high levels of brachyury. This defect could be countered by utilizing a small molecule inhibitor of WEE1, a kinase that negatively controls the activity of CDK1. This inhibitor is currently in the clinic and our results support potential future studies of combinations of immunotherapy and WEE1 inhibition.

The transcription factor Twist was shown by others to be a driver of the metastatic process in a murine breast carcinoma model. We have demonstrated in murine models that rec. Twist vaccines are capable of mediating anti-tumor therapy directed against an endogenous transcription factor driving the metastatic process.

The C-terminus of MUC1 (MUC1-C) has been shown by others to be an oncogene and is associated with drug resistance and poor prognosis for a range of human tumors. We have identified 7 novel enhancer agonist CD8 T-cell epitopes of the MUC1 C-terminus region. Recombinant vaccines expressing these agonists are being developed.

In collaboration with our CRADA partner, we are characterizing a tumor-targeting immunocytokine. NHS-IL12 is a fully human MAb that binds DNA/histone in necrotic tumor, which is fused to human IL-12 heterodimers. The agent was designed to reduce the toxicity of rec. IL-12 protein while maintaining its immuno-enhancing properties at the tumor site. We have shown that the immunocytokine has anti-tumor activity in a range of tumor models and have recently initiated a first-in-human clinical trial with NHS-IL12.

We are characterizing, in collaboration with our CRADA partner, an anti-PDL1 MAb that, unlike other anti-PDL1 MAbs, is capable of mediating ADCC of human carcinomas cells. We have initiated a first-in-human clinical trial with this anti-PDL1.

We are involved in studies of immunotherapeutics as part of an immuno-oncology platform.

We have determined that the use of relatively low doses of external beam radiation, insufficient to kill tumors, alter those tumor cells to render them more susceptible to T-cell-mediated lysis, termed immunogenic modulation.

We have now shown in murine models that irradiation of a primary tumor could facilitate systemic anti-tumor activity which mediated regression of distal antigen disparate tumors.

We have demonstrated that immunogenic modulation could be induced and exploited in an animal model utilizing vaccine and non-ionizing radiofrequency ablation of the primary tumor.

We have shown that radiation significantly increased cell-surface and total protein expression of the monoclonal antibody target HER2, and improved subsequent ADCC and sensitization to the antiproliferative effects of trastuzumab.

Utilizing a panel of human tumor cells in vitro, we have now examined the molecular mechanisms of immunogenic modulation and determined that radiation modulated components of the endogenous antigen-processing machinery (APM) chain and induced the expression of certain surface molecules resulting in increased MHC-peptide loading and subsequent T-cell recognition and killing.

We examined phenotypic and functional consequences of tumor cells that survive docetaxel chemotherapy. Killing by tumor-specific CD8+ CTL was significantly enhanced after docetaxel treatment and was mediated by calreticulin membrane translocation. These effects were also observed in chemotherapy resistant tumor cells.

We have now examined the role of androgen deprivation therapy on the phenotype of prostate cancer cells and shown that the combination therapy of an androgen receptor antagonist and a therapeutic vaccine targeting a driver of metastasis significantly improved survival in a murine spontaneous prostate cancer model.

We have now shown a differential functional effect of a small molecule inhibitor on naive versus memory T-cells. In vivo, this inhibitor was given after vaccination so as not to impair the induction of vaccine-mediated immunity, which resulted in a significant reduction of experimental pulmonary tumor nodules.

We have demonstrated in a murine lung carcinoma model that exploitation of differential homeostatic proliferation of T-cell subsets following chemotherapy can enhance the efficacy of vaccine mediated antitumor responses by exploiting differential reconstitution of Treg vs. effector T cell subsets.

We have now examined the consequence of dose scheduling of a targeted tyrosine kinase inhibitor (TKI, sunitinib) with vaccine on negative host immune response elements in the tumor microenvironment.

We have analyzed PBMCs from cancer patients both prior to and during standard-of-care therapies to determine whether specific regimens are suitable for use in combination with immunotherapeutics. Breast carcinoma patients undergoing treatment with docetaxel were shown to have some reduction in CD4+ and CD8+ T cells, but an even greater reduction in Tregs during therapy. PBMCs were evaluated from non-small cell lung cancer patients prior to and during cisplatin/vinorelbine therapy. No differences during therapy were seen in CD4+ T cells, but the level of Tregs was decreased, and the suppressive activity of Tregs was decreased in the majority of patients. Similar findings were observed in metastatic prostate cancer patients treated with docetaxel.

Clinical oncologists Drs. Gulley, Madan (Genitourinary Malignancies Branch, CCR) and Heery along with clinical fellows work closely with other members of the LTIB in a well-integrated immunotherapy team.

Prior Phase II studies with rV-, rF-PSA-TRICOM (PROSTVAC) vaccine as a monotherapy in patients with metastatic castration-resistant prostate cancer (mCRPC) have led to an ongoing Phase III study. This is an ongoing global 3-arm study in patients (n=1,200) with asymptomatic mCRPC who receive (a) PROSTVAC, (b) PROSTVAC + GM-CSF, (c) placebo (empty vector). The endpoint is overall survival (OS).

We have evaluated the growth rates of tumors in patients with mCRPC receiving PROSTVAC vaccine or several different chemotherapy regimens. These studies have revealed that, unlike chemotherapy, vaccine therapy can reduce the tumor growth rate leading to enhanced survival even in the absence of increases in progression-free survival.

We have completed a trial in patients with mCRPC of PROSTVAC vaccination with increasing doses of ipilimumab (anti-CTLA4). No adverse events beyond those seen with ipilimumab alone were observed. These findings provide evidence for the use of vaccine in combination with checkpoint inhibitors such as anti-PDL1.

Two randomized clinical studies have recently been initiated employing the novel FDA-approved androgen blockade agent enzalutamide +/- PROSTVAC vaccine. The first is in mCRPC patients with a TTP endpoint; the second trial is in non-metastatic patients with rising PSA where changes in PSA velocity at the discontinuation of enzalutamide will be evaluated.

A dual center study in which patients with metastatic breast cancer were randomized to docetaxel +/- PANVAC vaccine (rV-, rF-CEA-MUC1-TRICOM) has just been completed. We have used a multi-color FACS-based assay to define a 'peripheral immunoscore' monitoring immune cell subsets known in the literature to have specific immune stimulatory or regulatory functions.

We have completed a first-in-human Phase I study of rec. yeast-CEA vaccine in patients with metastatic disease and demonstrated safety to the generation of CEA-specific T-cell responses. This has led to the initiation of a Phase II study in patients with metastatic medullary thyroid cancer (MTC), where the primary endpoint is tumor growth rate following serum calcitonin, which is a marker for disease progression.

A clinical study has just opened in collaboration with Dr. P. Agarwal in the CCR Urologic Oncology Branch (UOB). BCG failure bladder cancer patients will be randomized to second-line BCG +/- PANVAC vaccine. The primary endpoint will be tumor extent and immune infiltrate in pre- vs. post-treatment biopsies.

Numerous immune analyses pre- vs. post-treatment have been/are being employed in clinical studies in an attempt to identify which patients would most likely benefit from a given immunotherapy, and to evaluate potential immune correlates of clinical benefit early in the treatment cycle. It is emphasized that any correlations with clinical outcome using any of the immune assays described must be considered only exploratory. True correlations will require the use of validated assays in larger randomized trials.

In addition to the use of the Elispot assay to define CD8+ responses in PBMCs to an immunodominant HLA-A2 epitope, we have now developed a FACS-based assay using 15-mer peptides reflecting entire TAA gene to simultaneously measure both CD4 and CD8 responses; this assay is not restricted by HLA allele.

We have developed assays to analyze numerous soluble factors in sera pre- and post-immunotherapy. In collaboration with Dr. J. Gildersleeve in the CCR, we have profiled anti-glycan antibodies using glycan arrays in several of our PROSTVAC trials; levels of Abs to specific glycans significantly correlated with overall survival.

We have analyzed post- vs. pre-serum samples for a range of cytokines as well as two potential immunomodulatory molecules. We have shown that soluble CD27 (sCD27) sera levels are decreased in carcinoma patients vs. healthy donors. mCRPC patients treated with PROSTVAC + ipilimumab showed a significant increase in sCD27 post-vaccination, which was associated with increased OS. In vitro studies demonstrated that sCD27 provides strong proliferative signals to lymphocytes.

We have now developed a multi-laser/multi-color FACS-based assay to analyze up to 50 different immune cell subsets in PBMCs pre- vs. post-treatment. There were associations with OS of several immune cell subsets pre-treatment with PROSTVAC + ipilimumab.

We have now developed the capability to conduct digital immunohistochemistry (IHC) analyses of biopsy specimens. In a recently completed trial of i.t./s.c. vaccination with PROSTVAC, 19/21 patients developed stable or reduced levels of serum PSA; there were statistical increases in CD4+ and CD8+ T cells, and decreases in Tregs in post- vs. pre-treatment biopsies. Immunotherapy trials have been initiated or are planned in prostate, bladder, and lung carcinomas in which pre- vs. post-treatment biopsies will be analyzed by digital IHC and compared with changes in specific immune cell subsets in the periphery.


IV. ADMINISTRATIVE OVERVIEW

We are involved in the training of numerous Postdoctoral and Clinical Fellows, and medical, college and high school students. We take mentoring very seriously, with frequent meetings with postdoctoral and clinical fellows and with Group Heads. Frequent meetings are held to plan experiments, review and discuss data, and to discuss future plans. Meetings are also held to discuss the preparation of oral presentations, poster presentations, and the writing of manuscripts. All laboratory members attend more formal weekly lab meetings in which planned and ongoing research is discussed. We have also instituted 'chalk-talk' meetings that are attended only by postdoctoral fellows, where each fellow gives a brief presentation without the use of slides on their current research and/or future plans. There are also invited seminar speakers, and attendance at the numerous seminars ongoing at the NIH is encouraged.
LTIB Scientists and Clinicians have maintained an active role in many NCI and NIH committees, as well as in national organizations. They have also been asked to give plenary lectures and/or to chair sessions in numerous national and international meetings.
TECHNOLOGY TRANSFER. LTIB Scientists continue to be very active in the area of Technology Transfer. Two new CRADAs have recently been established: one CRADA is with Bavarian Nordic (BN) on the use of rec. poxviral vectors for cancer therapy (non-prostate, non-melanoma, non-hematologic malignancies) and the other is with Merck/EMD-Serono on the therapeutic applications of immune modulators (including anti-PDL1 and the immunocytokine NHS-IL12). This is in addition to two other ongoing CRADAs: one with BN on rec. poxviral vectors for prostate cancer therapy/prevention, and the other with GlobeImmune for rec. Saccharomyces cerevisiae (yeast) vectors for cancer therapy.
COLLABORATIONS AND TEAM SCIENCE. Many of the translational efforts of the LTIB require a 'team science' approach and extensive collaborations and interactions with scientific and clinical investigators at (a) other Laboratories/Branches of the CCR, (b) other components of the NIH intramural program and Clinical Center, (c) numerous Cancer Centers throughout the U.S. and abroad, and (d) the private sector. There are extensive interactions between members of the LTIB research and clinical groups. There is a seamless transition from hypothesis-driven preclinical studies to science-based clinical trials. Through numerous Laboratory and informal meetings, clinicians are very much involved in the design of preclinical studies, and scientists are very much involved in the design of clinical studies. This encompasses both 'bench to bedside' and 'bedside to bench' components.
MENTORING. LTIB Scientists and Clinicians have mentored numerous Postdoctoral Fellows, Clinical Fellows, college, high school and medical studies, and also mentored senior staff members. Many of our former investigators have gone on to successful academic careers and are now Full Professors, Associate Professors, and Directors of Research in academic centers, and several have gone on to high level positions in the private sector.

LIST OF CLINICAL TRIALS
For more information, go to CCR Clinical Trials at NIH website or see "Links".

Completed:
A phase I/II pilot study of sequential vaccinations with rFowlpox-PSA (L155)-TRICOM (PROSTVAC-F/TRICOM) alone, or in combination with rVaccinia-PSA (L155)-TRICOM (PROSTVAC-V/TRICOM), and the role of GM-CSF in patients with prostate cancer [03-C-0176]

A phase I trial of a PSA-based vaccine and an anti-CTLA-4 antibody in patients with metastatic androgen-independent prostate cancer [05-C-0167]

A randomized phase 2.5 Study of 153Sm-EDTMP (Quadramet) with or without a PSA/TRICOM vaccine in men with androgen-insensitive metastatic prostate cancer [07-C-0106]

A phase I feasibility study of an intraprostatic PSA-based vaccine in prostate cancer patients with local failure following radiotherapy or clinical progression on androgen-deprivation therapy in the absence of local definitive therapy [05-C-0017]

An open label pilot study to evaluate the safety and tolerability of PANVAC-V (vaccinia) and PANVAC-F (fowlpox) in combination with sargramostim in adults with metastatic carcinoma [04-C-0246]

Randomized pilot phase II study of docetaxel alone or in combination with PANVAC-V (vaccinia) and PANVAC-F (fowlpox) in adults with metastatic breast cancer [05-C-0229]

An open-label phase I study to evaluate the safety and tolerability of a vaccine (GI-6207) consisting of whole, heat-killed recombinant Saccharomyces cerevisiae (yeast) genetically modified to express CEA protein in adults with metastatic CEA-expressing carcinoma [09-C-0101]

Open:
A randomized, double-blind, phase III efficacy trial of PROSTVAC-V/F +/- GM-CSF in men with asymptomatic or minimally symptomatic metastatic, castrate-resistant prostate cancer [11-C-0262]

A randomized phase II trial combining vaccine therapy with PROSTVAC/TRICOM and flutamide vs. flutamide alone in men with androgen insensitive, non-metastatic (D0.5) prostate cancer [07-C-0107]

A randomized phase II trial combining vaccine therapy with PROSTVAC/TRICOM and enzalutamide vs. enzalutamide alone in men with metastatic castration resistant prostate cancer [13-C-0146]

A phase II trial of enzalutamide in combination with PSA-TRICOM in patients with non-metastatic castration sensitive prostate cancer [13-C-0153]

A randomized phase II study of L-BLP25 in combination with standard androgen deprivation therapy and radiation therapy for newly diagnosed, high risk prostate cancer patients [11-C-0247]

A pilot study of recombinant yeast CEA vaccine in patients with recurrent medullary thyroid cancer [13-C-0095]

An open-label phase I study to evaluate the safety and tolerability of GI-6301 a vaccine consisting of whole heat-killed recombinant Saccharomyces cerevisiae (yeast) genetically modified to express Brachyury protein in adults with solid tumors [12-C-0056]

First-in-human phase I trial of NHS-IL12 in subjects with metastatic solid tumors [11-C-0225]

A phase I, open-label, multiple-ascending dose trial to investigate the safety, tolerability, pharmacokinetics, biological and clinical activity of MSB0010718C (anti-PDL1) in subjects with metastatic or locally advanced solid tumors and expansion to selected indications [13-C-0063]

A randomized, prospective, phase II study to determine the efficacy of Bacillus Calmette-Guerin (BCG) given in combination with PANVAC versus BCG given alone in adults with high grade non-muscle invasive bladder cancer (NMIBC) who failed at least 1 induction course of BCG [14-C-0036]

Collection of blood, tissue and urine from patients with cancer [02-C-0179]

Follow-up study of subjects previously enrolled in immunotherapy studies utilizing gene transfer or other immunotherapeutic agents [04-C-0274]

In Review:
An open-label phase I study to evaluate the safety and tolerability of a modified vaccinia Ankara (MVA) based vaccine modified to express Brachyury and T-cell costimulatory molecules (MVA-Brachyury-TRICOM) [pending]

A phase II study of neoadjuvant rFowlpox-PSA (L155)-TRICOM (Prostvac-F/TRICOM) in combination with rVaccinia-PSA (L155)-TRICOM (Prostvac-V/TRICOM) in men with prostate cancer undergoing treatment with radical prostatectomy [pending]

Please see "Links" for a list of publications of the LTIB.

This page was last updated on 4/11/2014.