A phase I trial of preventive HIV vaccination with heterologous poxviral-vectors containing matching HIV-1 inserts in healthy HIV-uninfected subjects.

We evaluated replication-defective poxvirus vectors (modified vaccinia Ankara [MVA] and fowlpox [FPV]) in a homologous and heterologous vector prime-boost vaccination regimen containing matching HIV inserts (MVA-HIV and FPV-HIV) given at months 0, 1, 3, 5 and 7 in 150 healthy HIV-negative vaccinia-naïve participants. FPV-HIV alone was poorly immunogenic, while the high dose (10(9)pfu/2 ml) of MVA-HIV alone elicited maximal responses after two injections: CD4+ and CD8+ T-cell responses in 26/55 (47.3%) and 5/60 (8.

Overall survival analysis of a phase II randomized controlled trial of a Poxviral-based PSA-targeted immunotherapy in metastatic castration-resistant prostate cancer.

Purpose: Therapeutic prostate-specific antigen (PSA) -targeted poxviral vaccines for prostate cancer have been well tolerated. PROSTVAC-VF treatment was evaluated for safety and for prolongation of progression-free survival (PFS) and overall survival (OS) in a randomized, controlled, and blinded phase II study.

Patients And Methods: In total, 125 patients were randomly assigned in a multicenter trial of vaccination series.

A Phase 1 study to evaluate the safety and immunogenicity of a recombinant HIV type 1 subtype C-modified vaccinia Ankara virus vaccine candidate in Indian volunteers.

A recombinant modified vaccinia Ankara virus vaccine candidate (TBC-M4) expressing HIV-1 subtype C env, gag, tat-rev, and nef-RT genes was tested in a randomized, double-blind, dose escalation Phase I trial in 32 HIV-uninfected healthy volunteers who received three intramuscular injections of TBC-M4 at 0, 1, and 6 months of 5 x 10(7) plaque-forming units (pfu) (low dosage, LD) (n = 12) or 2.5 x 10(8) pfu (high dosage, HD) (n = 12) or placebo (n = 8). Local and systemic reactogenicity was experienced by approximately 67% and 83% of vaccine recipients, respectively.

Safety and immunogenicity of recombinant poxvirus HIV-1 vaccines in young adults on highly active antiretroviral therapy.

A trial to evaluate the safety and immunogenicity of recombinant modified vaccinia Ankara (MVA) and fowlpox (FP) vectors expressing multiple HIV-1 proteins was conducted in twenty HIV-1 infected youth with suppressed viral replication on HAART. The MVA and FP-based multigene HIV-1 vaccines were safe and well tolerated. Increased frequencies of HIV-1 specific CD4+ proliferative responses and cytokine secreting cells were detected following immunization.

Therapeutic vaccination against murine lymphoma by intratumoral injection of recombinant fowlpox virus encoding CD40 ligand.

The interaction between CD40 ligand (CD40L, CD154) and its receptor CD40 on antigen-presenting cells is essential for the initiation of cell-mediated and humoral immune responses. Malignant B cells also express CD40 and respond to CD40L by enhancing expression of costimulatory molecules. In this study, we investigated the therapeutic antitumor effect of intratumoral administration of recombinant fowlpox virus encoding murine CD40L (rF-mCD40L) in a murine B-cell lymphoma model.

Heterologous prime/boost immunization of rhesus monkeys by using diverse poxvirus vectors.

As the diversity of potential immunogens increases within certain classes of vectors, the possibility has arisen of employing heterologous prime/boost immunizations using diverse members of the same family of vectors. The present study was initiated to explore the use of divergent pox vectors in a prime/boost regimen to elicit high-frequency cellular immune responses to human immunodeficiency virus type 1 envelope and simian immunodeficiency virus gag in rhesus monkeys. We demonstrated that monkeys vaccinated with a recombinant modified vaccinia virus Ankara (rMVA) prime/recombinant fowlpox virus (rFPV) boost regimen and monkeys vaccinated with a recombinant vaccinia virus prime/rFPV boost regimen developed comparable cellular immune responses that were greater in magnitude than those elicited by a homologous prime/boost with rMVA.

Recombinant vaccinia/fowlpox NY-ESO-1 vaccines induce both humoral and cellular NY-ESO-1-specific immune responses in cancer patients.

NY-ESO-1 is a cancer/testis antigen expressed in a range of human malignancies, and a number of vaccine strategies targeting NY-ESO-1 are being developed. In the present study, the safety and immunogenicity of recombinant vaccinia-NY-ESO-1 and recombinant fowlpox-NY-ESO-1 were analyzed in a series of 36 patients with a range of different tumor types. Each construct was first tested individually at two different dose levels and then in a prime-boost setting with recombinant vaccinia-NY-ESO-1 followed by recombinant fowlpox-NY-ESO-1.

Evaluation of prime/boost regimens using recombinant poxvirus/tyrosinase vaccines for the treatment of patients with metastatic melanoma.

Purpose: Two clinical trials were conducted to evaluate the clinical efficacy and immunologic impact of vaccination against the tyrosinase protein plus systemic interleukin 2 (IL-2) administration in patients with advanced metastatic melanoma.

Experimental Design: Full-length tyrosinase was employed as an immunogen to induce diverse immunologic responses against a commonly expressed melanoma antigen. Heterologous prime/boost vaccination with recombinant vaccinia and fowlpox vectors encoding tyrosinase was first explored in a randomized three-arm phase II trial, in which vaccines were administered alone or concurrently with low-dose or high-dose IL-2.

Preservation of functional virus-specific memory CD8+ T lymphocytes in vaccinated, simian human immunodeficiency virus-infected rhesus monkeys.

Functional impairment of virus-specific memory CD8(+) T lymphocytes has been associated with clinical disease progression following HIV, SIV, and simian human immunodeficiency virus infection. These lymphocytes have a reduced capacity to produce antiviral cytokines and mediators involved in the lysis of virally infected cells. In the present study, we used polychromatic flow cytometry to assess the frequency and functional capacity of central memory (CD28(+)CD95(+)) and effector memory (CD28(-)CD95(+)) subpopulations of Gag-specific CD8(+) T cells in SIV/simian human immunodeficiency virus-infected rhesus monkeys.

A randomized phase II study of concurrent docetaxel plus vaccine versus vaccine alone in metastatic androgen-independent prostate cancer.

Purpose: Docetaxel has activity against androgen-independent prostate cancer and preclinical studies have shown that taxane-based chemotherapy can enhance antitumor response of vaccines. The primary objective of this study was to determine if concurrent docetaxel (with dexamethasone) had any effect on generating an immune response to the vaccine. Secondary end points were whether vaccine could be given safely with docetaxel and the clinical outcome of the treatment regimen.

Costimulatory molecules as adjuvants for immunotherapy.

Tumor-associated antigens (TAAs) are by definition either weakly immunogenic or functionally nonimmunogenic. Therefore, efforts have concentrated on the development of vaccine strategies in which the presentation of TAAs to the immune system results in far greater activation of T cells than that occurring naturally in the host. Several strategies are being explored in our laboratory and others to enhance the immunogenicity of TAAs.

Potential approach to immunotherapy of chronic lymphocytic leukemia (CLL): enhanced immunogenicity of CLL cells via infection with vectors encoding for multiple costimulatory molecules.

Chronic lymphocytic leukemia (CLL) is a disease of CD5(+) B lymphocytes (designated as CLL cells) that are inefficient antigen-presenting cells. Their poor ability to present antigens to the T cells, largely due to an inadequate costimulatory capacity, is manifested as a failure to stimulate proliferation of both allogeneic and autologous T cells. We have investigated the ability of in vitro manipulated CLL cells, via hyperexpression of a triad of costimulatory molecules (B7-1, intercellular adhesion molecule 1 [ICAM-1], and leukocyte-function-associated antigen 3 [LFA-3], designated TRICOM), to stimulate effective antitumor T-cell responses.

Role of genes that modulate host immune responses in the immunogenicity and pathogenicity of vaccinia virus.

Poxvirus vaccine vectors, although capable of eliciting potent immune responses, pose serious health risks in immunosuppressed individuals. We therefore constructed five novel recombinant vaccinia virus vectors which contained overlapping deletions of coding regions for the B5R, B8R, B12R, B13R, B14R, B16R, B18R, and B19R immunomodulatory gene products and assessed them for both immunogenicity and pathogenicity. All five of these novel vectors elicited both cellular and humoral immunity to the inserted HIV-BH10 env comparable to that induced by the parental Wyeth strain vaccinia virus.

Phase I study of immunization with dendritic cells modified with fowlpox encoding carcinoembryonic antigen and costimulatory molecules.

Purpose: To determine the safety and immunologic and clinical efficacy of a dendritic cell vaccine modified to hyperexpress costimulatory molecules and tumor antigen.

Experimental Design: In this phase I study, we administered one or two cycles of four triweekly s.c.

Dysfunction of simian immunodeficiency virus/simian human immunodeficiency virus-induced IL-2 expression by central memory CD4+ T lymphocytes.

Production of IL-2 and IFN-gamma by CD4+ T lymphocytes is important for the maintenance of a functional immune system in infected individuals. In the present study, we assessed the cytokine production profiles of functionally distinct subsets of CD4+ T lymphocytes in rhesus monkeys infected with pathogenic or attenuated SIV/simian human immunodeficiency virus (SHIV) isolates, and these responses were compared with those in vaccinated monkeys that were protected from immunodeficiency following pathogenic SHIV challenge. We observed that preserved central memory CD4+ T lymphocyte production of SIV/SHIV-induced IL-2 was associated with disease protection following primate lentivirus infection.

Vaccine-elicited memory cytotoxic T lymphocytes contribute to Mamu-A*01-associated control of simian/human immunodeficiency virus 89.6P replication in rhesus monkeys.

The expression of particular major histocompatibility complex (MHC) class I alleles can influence the rate of disease progression following lentiviral infections. This effect is a presumed consequence of potent cytotoxic T-lymphocyte (CTL) responses that are restricted by these MHC class I molecules. The present studies have examined the impact of the MHC class I allele Mamu-A*01 on simian/human immunodeficiency virus 89.

Analyses of recombinant vaccinia and fowlpox vaccine vectors expressing transgenes for two human tumor antigens and three human costimulatory molecules.

Purpose: The poor immunogenicity of tumor antigens and the antigenic heterogeneity of tumors call for vaccine strategies to enhance T-cell responses to multiple antigens. Two antigens expressed noncoordinately on most human carcinomas are carcinoembryonic antigen (CEA) and MUC-1. We report here the construction and characterization of two viral vector vaccines to address these issues.

Phase I study of sequential vaccinations with fowlpox-CEA(6D)-TRICOM alone and sequentially with vaccinia-CEA(6D)-TRICOM, with and without granulocyte-macrophage colony-stimulating factor, in patients with carcinoembryonic antigen-expressing carcinomas.

Purpose: Our previous clinical experience with vaccinia and replication-defective avipox recombinant carcinoembryonic antigen (CEA) vaccines has demonstrated safety and clinical activity with a correlation between CEA-specific immune response and survival. Preclinical evidence demonstrated that the addition of the transgenes for three T-cell costimulatory molecules (B7-1, ICAM-1, LFA-3, designated TRICOM) results in a significant improvement in antigen-specific T-cell responses and antitumor activity. We describe here the first trial in humans of the CEA-TRICOM vaccines (also including an enhancer agonist epitope within the CEA gene).

Recombinant poxvirus boosting of DNA-primed rhesus monkeys augments peak but not memory T lymphocyte responses.

Although a consensus has emerged that an HIV vaccine should elicit a cytotoxic T lymphocyte (CTL) response, the characteristics of an effective vaccine-induced T lymphocyte response remain unclear. We explored this issue in the simian human immunodeficiency virus/rhesus monkey model in the course of assessing the relative immunogenicity of vaccine regimens that included a cytokine-augmented plasmid DNA prime and a boost with DNA or recombinant pox vectors. Recombinant vaccinia virus, recombinant modified vaccinia Ankara (MVA), and recombinant fowlpox were comparable in their immunogenicity.

Immunogenicity of recombinant adenovirus serotype 35 vaccine in the presence of pre-existing anti-Ad5 immunity.

The high prevalence of pre-existing immunity to adenovirus serotype 5 (Ad5) in human populations may substantially limit the immunogenicity and clinical utility of recombinant Ad5 vector-based vaccines for HIV-1 and other pathogens. A potential solution to this problem is to use vaccine vectors derived from adenovirus (Ad) serotypes that are rare in humans, such as Ad35. However, cross-reactive immune responses between heterologous Ad serotypes have been described and could prove a major limitation of this strategy.

Avipox-based simian immunodeficiency virus (SIV) vaccines elicit a high frequency of SIV-specific CD4+ and CD8+ T-cell responses in vaccinia-experienced SIVmac251-infected macaques.

The ability of ALVAC- or fowlpox-based simian immunodeficiency virus (SIV) vaccines to boost SIV-specific CD4+ and CD8+ T-cell responses was tested in 10 vaccinia-experienced macaques infected with SIVmac251. The CD8+ T-cell response to the dominant Gag(181-189) CM9 was quantitated in seven Mamu-A*01-positive macaques by tetramer staining, by ex vivo cytotoxic T-lymphocyte (CTL) activity, and by intracellular cytokine staining (ICS) with the specific Gag(181-189) CM9 peptide. The overall CD8+ T-cell response to Gag was assessed using a peptide pool encompassing the entire Gag protein followed by measurement of TNF-alpha production in ICS assay.

Recombinant fowlpox viruses encoding the anchor-modified gp100 melanoma antigen can generate antitumor immune responses in patients with metastatic melanoma.

Purpose: The purpose of this study was to evaluate the immunological responses and therapeutic effectiveness of immunization with fowlpox vaccines encoding the gp100 melanoma antigen in patients with metastatic melanoma.

Experimental Design: In three consecutive clinical trials, patients were immunized with recombinant fowlpox viruses encoding three different forms of the melanoma/melanocyte-associated antigen gp100: (a) the native, full-length gp100 molecule; (b) the gp100 molecule with two amino acids modified to increase binding to HLA-A*0201 molecules; and (c) a "minigene" construct encoding a single, modified epitope gp100:209-217(210M) targeted to the endoplasmic reticulum. The immunogenicity of these constructs was studied using peripheral blood mononuclear cells to measure epitope-specific release of IFN-gamma.

Prior DNA immunization enhances immune response to dominant and subdominant viral epitopes induced by a fowlpox-based SIVmac vaccine in long-term slow-progressor macaques infected with SIVmac251.

A therapeutic vaccine for individuals infected with HIV-1 and treated with antiretroviral therapy (ART) should be able to replenish virus-specific CD4+ T-cells and broaden the virus-specific CD8+ T-cell response in order to maintain CD8+ T-cell function and minimize viral immune escape after ART cessation. Because a combination of DNA and recombinant poxvirus vaccine modalities induces high levels of virus-specific CD4+ T-cell response and broadens the cytolytic activity in naive macaques, we investigated whether the same results could be obtained in SIVmac251-infected macaques. The macaques studied here were long-term nonprogressors that naturally contained viremia but were nevertheless treated with a combination of antiviral drugs to assess more carefully the effect of vaccination in the context of ART.