Extended evaluation of a phase 1/2 trial on dosing, safety, immunogenicity, and overall survival after immunizations with an advanced-generation Ad5 [E1-, E2b-]-CEA(6D) vaccine in late-stage colorectal cancer

Abstract A phase 1/2 clinical trial evaluating dosing, safety, immunogenicity, and overall survival on metastatic colorectal cancer (mCRC) patients after immunotherapy with an advanced-generation Ad5 [E1-, E2b-]-CEA(6D) vaccine was performed. We report our extended observations on long-term overall survival and further immune analyses on a subset of treated patients including assessment of cytolytic T cell responses, T regulatory (Treg) to T effector (Teff) cell ratios, flow cytometry on peripheral blood mononuclear cells (PBMCs), and determination of HLA-A2 status. An overall survival of 20 % (median survival 11 months) was observed during long-term follow-up, and no long-term adverse effects were reported. Cytolytic T cell responses increased after immunizations, and cell-mediated immune (CMI) responses were induced whether or not patients were HLA-A2 positive or Ad5 immune. PBMC samples from a small subset of patients were available for follow-up immune analyses. It was observed that the levels of carcinoembryonic antigen (CEA)-specific CMI activity decreased from their peak values during follow-up in five patients analyzed. Preliminary results revealed that activated CD4+ and CD8+ T cells were detected in a post-immunization sample exhibiting high CMI activity. Treg to Teff cell ratios were assessed, and samples from three of five patients exhibited a decrease in Treg to Teff cell ratio during the treatment protocol. Based upon the favorable safety and immunogenicity data obtained, we plan to perform an extensive immunologic and survival analysis on mCRC patients to be enrolled in a randomized/controlled clinical trial that investigates Ad5 [E1-, E2b-]-CEA(6D) as a single agent with booster immunizations.

[1]  Walter T. Lee,et al.  A Non-oncogenic HPV 16 E6/E7 Vaccine Enhances Treatment of HPV Expressing Tumors , 2012, Cancer Gene Therapy.

[2]  Hildegund C.J. Ertl,et al.  Adenoviruses as vaccine vectors , 2004, Molecular Therapy.

[3]  E. Gabitzsch,et al.  New Recombinant Ad5 Vector Overcomes Ad5 Immunity Allowing for Multiple Safe, Homologous Immunizations , 2012 .

[4]  K. Propert,et al.  Immune responses to adenovirus and adeno-associated virus in humans , 1999, Gene Therapy.

[5]  J. Schlom,et al.  Therapeutic cancer vaccines: current status and moving forward. , 2012, Journal of the National Cancer Institute.

[6]  P. Kantoff,et al.  Sipuleucel-T immunotherapy for castration-resistant prostate cancer. , 2010, The New England journal of medicine.

[7]  D. Niedzwiecki,et al.  Optimization of vaccine responses with an E1, E2b, E3 deleted Ad5 vector circumvents pre-existing anti-vector immunity , 2009, Cancer Gene Therapy.

[8]  Dongsheng Tu,et al.  K-ras mutations and benefit from cetuximab in advanced colorectal cancer. , 2008, The New England journal of medicine.

[9]  Brigitte E. Sanders-Beer,et al.  Control of SIV infection and subsequent induction of pandemic H1N1 immunity in rhesus macaques using an Ad5 [E1-, E2b-] vector platform. , 2012, Vaccine.

[10]  A. Amalfitano,et al.  Overcoming pre-existing adenovirus immunity by genetic engineering of adenovirus-based vectors , 2009, Expert opinion on biological therapy.

[11]  Martin A. Cheever,et al.  The Prioritization of Cancer Antigens: A National Cancer Institute Pilot Project for the Acceleration of Translational Research , 2009, Clinical Cancer Research.

[12]  H. Lyerly,et al.  Anti-tumor immunotherapy despite immunity to adenovirus using a novel adenoviral vector Ad5 [E1-, E2b-]-CEA , 2010, Cancer Immunology, Immunotherapy.

[13]  P. Schellhammer,et al.  Placebo-controlled phase III trial of immunologic therapy with sipuleucel-T (APC8015) in patients with metastatic, asymptomatic hormone refractory prostate cancer. , 2006, Journal of clinical oncology : official journal of the American Society of Clinical Oncology.

[14]  J. Hodge,et al.  Cancer vaccines targeting carcinoembryonic antigen: state-of-the-art and future promise , 2013, Expert review of vaccines.

[15]  M. Salazar,et al.  Prevention of influenza virus shedding and protection from lethal H1N1 challenge using a consensus 2009 H1N1 HA and NA adenovirus vector vaccine. , 2011, Vaccine.

[16]  M. Barry,et al.  Current advances and future challenges in Adenoviral vector biology and targeting. , 2007, Current gene therapy.

[17]  Frank R. Jones,et al.  Novel adenoviral vector induces T-cell responses despite anti-adenoviral neutralizing antibodies in colorectal cancer patients , 2013, Cancer Immunology, Immunotherapy.

[18]  Novel Adenovirus type 5 vaccine platform induces cellular immunity against HIV-1 Gag, Pol, Nef despite the presence of Ad5 immunity. , 2009, Vaccine.

[19]  Brigitte E. Sanders-Beer,et al.  Induction and comparison of SIV immunity in Ad5 naïve and Ad5 immune non-human primates using an Ad5 [E1-, E2b-] based vaccine. , 2011, Vaccine.

[20]  M. Baseler,et al.  The Granzyme B ELISPOT assay: an alternative to the 51Cr-release assay for monitoring cell-mediated cytotoxicity , 2003, Journal of Translational Medicine.

[21]  M. Beyer,et al.  Regulatory T cells in cancer. , 2006, Blood.

[22]  S. Hammarström.  The carcinoembryonic antigen (CEA) family: structures, suggested functions and expression in normal and malignant tissues. , 1999, Seminars in cancer biology.

[23]  Marc Peeters,et al.  Open-label phase III trial of panitumumab plus best supportive care compared with best supportive care alone in patients with chemotherapy-refractory metastatic colorectal cancer. , 2007, Journal of clinical oncology : official journal of the American Society of Clinical Oncology.

[24]  B. Boehm,et al.  Granzyme B ELISPOT assay for ex vivo measurements of T cell immunity. , 2000, Journal of immunological methods.

[25]  J. Schlom,et al.  Vaccines against Human Carcinomas: Strategies to Improve Antitumor Immune Responses , 2010, Journal of biomedicine & biotechnology.

[26]  F. Grunert,et al.  Carcinoembryonic antigen gene family: Molecular biology and clinical perspectives , 1991, Journal of clinical laboratory analysis.

[27]  A. Amalfitano,et al.  A preliminary and comparative evaluation of a novel Ad5 [E1-, E2b-] recombinant-based vaccine used to induce cell mediated immune responses. , 2009, Immunology letters.

[28]  L. Schwartz,et al.  32 INVITED New response evaluation criteria in solid tumors: revised RECIST guideline version 1.1 , 2008 .

[29]  J. Schlom,et al.  Strategies for Cancer Vaccine Development , 2010, Journal of biomedicine & biotechnology.

[30]  P. Schellhammer,et al.  Integrated data from 2 randomized, double‐blind, placebo‐controlled, phase 3 trials of active cellular immunotherapy with sipuleucel‐T in advanced prostate cancer , 2009, Cancer.

[31]  J. Schlom,et al.  Identification of an enhancer agonist cytotoxic T lymphocyte peptide from human carcinoembryonic antigen. , 1997, Cancer research.

[32]  J. G. Cory,et al.  Use of an aqueous soluble tetrazolium/formazan assay for cell growth assays in culture. , 1991, Cancer communications.

[33]  K. Mansfield,et al.  International seroepidemiology of adenovirus serotypes 5, 26, 35, and 48 in pediatric and adult populations. , 2011, Vaccine.

[34]  John Sidney,et al.  Structural Features of Peptide Analogs of Human Histocompatibility Leukocyte Antigen Class I Epitopes That Are More Potent and Immunogenic than Wild-Type Peptide , 2001, The Journal of experimental medicine.

[35]  S. Mittal,et al.  Development of nonhuman adenoviruses as vaccine vectors , 2005, Vaccine.

[36]  Dongsheng Tu,et al.  Cetuximab for the treatment of colorectal cancer. , 2007, The New England journal of medicine.

[37]  J. Chamberlain,et al.  Improved Production of Gutted Adenovirus in Cells Expressing Adenovirus Preterminal Protein and DNA Polymerase , 1999, Journal of Virology.

[38]  A. Amalfitano,et al.  Isolation and characterization of packaging cell lines that coexpress the adenovirus E1, DNA polymerase, and preterminal proteins: implications for gene therapy , 1997, Gene Therapy.

[39]  J. Chamberlain,et al.  Production and Characterization of Improved Adenovirus Vectors with the E1, E2b, and E3 Genes Deleted , 1998, Journal of Virology.

[40]  E. Gabitzsch,et al.  An Ad5 [E1-, E2b-]-HER2/neu vector induces immune responses and inhibits HER2/neu expressing tumor progression in Ad5 immune mice , 2010, Cancer Gene Therapy.

[41]  N. Berinstein.  Carcinoembryonic antigen as a target for therapeutic anticancer vaccines: a review. , 2002, Journal of clinical oncology : official journal of the American Society of Clinical Oncology.

[42]  D. Niedzwiecki,et al.  Enumerating Antigen-Specific T-Cell Responses in Peripheral Blood: A Comparison of Peptide MHC Tetramer, ELISpot, and Intracellular Cytokine Analysis , 2005, Journal of immunotherapy.

[43]  H. Lyerly,et al.  Quantitating therapeutically relevant T-cell responses to cancer vaccines. , 2001, Critical reviews in immunology.