Phase 1 Study of Adjuvant Allogeneic Granulocyte-Macrophage Colony-Stimulating Factor-Transduced Pancreatic Tumor Cell Vaccine, Low-Dose Cyclophosphamide, and Stereotactic Body Radiation Therapy Followed by FOLFIRINOX in High-Risk Resected Pancreatic Ductal Adenocarcinoma.

Purpose: Local and distant progression remains common following resection of resectable pancreatic ductal adenocarcinoma (PDAC) despite adjuvant multiagent chemotherapy. We report a prospective institutional phase 1 trial incorporating adjuvant GVAX vaccine, low-dose cyclophosphamide (Cy), and stereotactic body radiation therapy (SBRT) followed by FOLFIRINOX (FFX) among patients who underwent resection of high-risk PDAC.

Patients And Methods: The study design was a modified 3+3.

T cell receptor repertoire features associated with survival in immunotherapy-treated pancreatic ductal adenocarcinoma.

Background: Immune checkpoint inhibitors provide significant clinical benefit to a subset of patients, but novel prognostic markers are needed to predict which patients will respond. This study was initiated to determine if features of patient T cell repertoires could provide insights into the mechanisms of immunotherapy, while also predicting outcomes.

Methods: We examined T cell receptor (TCR) repertoires in peripheral blood of 25 metastatic pancreatic cancer patients treated with ipilimumab with or without GVAX (a pancreatic cancer vaccine), as well as peripheral blood and tumor biopsies from 32 patients treated with GVAX and mesothelin-expressing Listeria monocytogenes with or without nivolumab.

Quantitative Multiplex Immunohistochemistry Reveals Myeloid-Inflamed Tumor-Immune Complexity Associated with Poor Prognosis.

Here, we describe a multiplexed immunohistochemical platform with computational image processing workflows, including image cytometry, enabling simultaneous evaluation of 12 biomarkers in one formalin-fixed paraffin-embedded tissue section. To validate this platform, we used tissue microarrays containing 38 archival head and neck squamous cell carcinomas and revealed differential immune profiles based on lymphoid and myeloid cell densities, correlating with human papilloma virus status and prognosis. Based on these results, we investigated 24 pancreatic ductal adenocarcinomas from patients who received neoadjuvant GVAX vaccination and revealed that response to therapy correlated with degree of mono-myelocytic cell density and percentages of CD8 T cells expressing T cell exhaustion markers.

Targeting neoantigens to augment antitumour immunity.

The past decade of cancer research has been marked by a growing appreciation of the role of immunity in cancer. Mutations in the tumour genome can cause tumours to express mutant proteins that are tumour specific and not expressed on normal cells (neoantigens). These neoantigens are an attractive immune target because their selective expression on tumours may minimize immune tolerance as well as the risk of autoimmunity.

Priming the pancreatic cancer tumor microenvironment for checkpoint-inhibitor immunotherapy.

Single agent immunotherapy is effective against several cancers, but has failed against poorly immunogenic cancers, including pancreatic cancer. Evaluation of pancreatic tumors following treatment with an experimental vaccine (Lutz et al. Cancer Immunology Research 2014) suggests that vaccination primes the tumor microenvironment (TME) for checkpoint-inhibitor immunotherapy, and supports a new platform for evaluating checkpoint-inhibitors in poorly immunogenic cancers.

Safety and survival with GVAX pancreas prime and Listeria Monocytogenes-expressing mesothelin (CRS-207) boost vaccines for metastatic pancreatic cancer.

Purpose: GVAX pancreas, granulocyte-macrophage colony-stimulating factor-secreting allogeneic pancreatic tumor cells, induces T-cell immunity to cancer antigens, including mesothelin. GVAX is administered with low-dose cyclophosphamide (Cy) to inhibit regulatory T cells. CRS-207, live-attenuated Listeria monocytogenes-expressing mesothelin, induces innate and adaptive immunity.

Cancer immunoprevention--the next frontier.

Cancer immunotherapy is a rapidly developing field, but limited in its success by a high tumor burden and immune tolerance. In contrast, immunoprevention has the potential to prevent cancer before the development of immune tolerance, and to prevent cancer recurrence in the setting of minimal residual disease. Although immunoprevention for viral-induced cancers has been successful in the setting of hepatitis B and human papillomavirus vaccination, primary prevention of nonviral-induced cancers is in its infancy.

Immunotherapy converts nonimmunogenic pancreatic tumors into immunogenic foci of immune regulation.

Pancreatic ductal adenocarcinoma (PDAC) is considered a "nonimmunogenic" neoplasm. Single-agent immunotherapies have failed to demonstrate significant clinical activity in PDAC and other "nonimmunogenic" tumors, in part due to a complex tumor microenvironment (TME) that provides a formidable barrier to immune infiltration and function. We designed a neoadjuvant and adjuvant clinical trial comparing an irradiated, granulocyte-macrophage colony-stimulating factor (GM-CSF)-secreting, allogeneic PDAC vaccine (GVAX) given as a single agent or in combination with low-dose cyclophosphamide to deplete regulatory T cells (Treg) as a means to study how the TME is altered by immunotherapy.

A2A receptor signaling promotes peripheral tolerance by inducing T-cell anergy and the generation of adaptive regulatory T cells.

Tissue-derived adenosine, acting via the adenosine A(2A) receptor (A(2A)R), is emerging as an important negative regulator of T-cell function. In this report, we demonstrate that A(2A)R stimulation not only inhibits the generation of adaptive effector T cells but also promotes the induction of adaptive regulatory T cells. In vitro, antigen recognition in the setting of A(2A)R engagement induces T-cell anergy, even in the presence of costimulation.

OX40 costimulation synergizes with GM-CSF whole-cell vaccination to overcome established CD8+ T cell tolerance to an endogenous tumor antigen.

T cell costimulation via OX40 is known to increase CD4+ T cell expansion and effector function and enhances the development of T cell memory. OX40 costimulation can also prevent, and even reverse, CD4+ T cell anergy. However, the role of OX40 in CD8+ T cell function is less well defined, particularly in the setting of immune tolerance.

Mesothelin-specific CD8(+) T cell responses provide evidence of in vivo cross-priming by antigen-presenting cells in vaccinated pancreatic cancer patients.

Tumor-specific CD8(+) T cells can potentially be activated by two distinct mechanisms of major histocompatibility complex class I-restricted antigen presentation as follows: direct presentation by tumor cells themselves or indirect presentation by professional antigen-presenting cells (APCs). However, controversy still exists as to whether indirect presentation (the cross-priming mechanism) can contribute to effective in vivo priming of tumor-specific CD8(+) T cells that are capable of eradicating cancer in patients. A clinical trial of vaccination with granulocyte macrophage-colony stimulating factor-transduced pancreatic cancer lines was designed to test whether cross-presentation by locally recruited APCs can activate pancreatic tumor-specific CD8(+) T cells.

HER-2/neu-specific monoclonal antibodies collaborate with HER-2/neu-targeted granulocyte macrophage colony-stimulating factor secreting whole cell vaccination to augment CD8+ T cell effector function and tumor-free survival in Her-2/neu-transgenic mice.

HER-2/neu is overexpressed in several cancers including 30% of breast carcinomas, and correlates with a poor outcome. HER-2/neu-transgenic (neu-N) mice that overexpress the non-transforming rat neu develop spontaneous mammary carcinomas and demonstrate immunotolerance to the neu protein similar to that observed in patients with neu-expressing cancers. In neu-N mice, neu-targeted vaccination induces weak T cell and negligible Ab responses sufficient to delay but not eradicate transplanted neu-expressing tumor.