Immunization with a poly (lactide co-glycolide) encapsulated plasmid DNA expressing antigenic regions of HPV 16 and 18 results in an increase in the precursor frequency of T cells that respond to epitopes from HPV 16, 18, 6 and 11.

A phase II trial was conducted in subjects with human papillomavirus (HPV) associated high-grade cervical dysplasia testing the safety and efficacy of a microparticle encapsulated pDNA vaccine. Amolimogene expresses T cell epitopes from E6 and E7 proteins of HPV types 16 and 18. An analysis was performed on a subset of HLA-A2+ subjects to test whether CD8+ T cells specific to HPV 16, 18, 6 and 11 were increased in response to amolimogene immunization. Of the 21 subjects receiving amolimogene, 11 had elevated CD8+ T cell responses to HPV 16 and/or 18 peptides and seven of these also had increases to corresponding HPV 6 and/or 11 peptides. In addition, T cells primed and expanded in vitro with an HPV 18 peptide demonstrated cross-reactivity to the corresponding HPV 11 peptide. These data demonstrate that treatment with amolimogene elicits T cell responses to HPV 16, 18, 6 and 11.

Unexpected association between induction of immunity to the universal tumor antigen CYP1B1 and response to next therapy.

PURPOSE: The carcinogen activator cytochrome P450 1B1 (CYP1B1) is expressed on almost all human tumors with rare expression on normal tissues. Anti-CYP1B1-specific T cells kill CYP1B1-expressing tumors, providing the rationale to examine CYP1B1 as a target for immunotherapy. EXPERIMENTAL DESIGN: ZYC300, a plasmid DNA of CYP1B1 encapsulated in biodegradable poly-DL-lactide-coglycolide microparticles, was used in a phase I clinical trial to treat 17 patients with advanced stage, progressive cancer. ZYC300 was administered i.m. at a fixed dose of 400 microg every other week for up to 12 doses. RESULTS: Thirteen patients received six vaccinations and five received all 12 doses. No significant adverse events were observed. Six patients developed immunity to CYP1B1, three of whom developed disease stabilization. All but 1 of 11 patients who did not develop immunity to CYP1B1 progressed and did not respond to salvage therapy. Five patients who developed immunity to CYP1B1 required salvage therapy for progressive metastatic disease and showed marked response to their next treatment regimen, most of which lasted longer than 1 year. CONCLUSIONS: The association between immunity to CYP1B1 and response to next salvage therapy was not expected. Because six of the seven patients who had clinical benefit regardless of the nature of salvage therapy had developed immunity to CYP1B1, it seems highly unlikely that this occurred by chance alone. Regardless of the mechanism(s) that induced tumor regression, these findings force us to rethink how the generation of antitumor immunity might be integrated into the treatment of cancer.

Use of interferon-gamma ELISPOT in monitoring immune responses in humans.

The interferon (IFN)-gamma enzyme-linked immunospot (ELISPOT) assay has become a useful tool for immunologists seeking to quantify immune responses on a per-cell basis. The assay is sensitive and allows for the enumeration of low-frequency T-cells. Many have applied this assay to clinical trials as a way to measure biological activity in a patient cohort. It is critical that each laboratory attempting to use the assay in their facility perform rigorous development and qualification work to establish an assay that suits their particular needs. This chapter serves as a demonstration of two practical and slightly different approaches to using the ELISPOT assay to monitor immune activity in the human periphery: (1) assays using whole samples of peripheral blood mononuclear cells with and without the use of additional antigen presenting cells and (2) assays using enriched T-cell populations. Detailed protocols and procedures will be covered, as well as a demonstration of results obtained from three separate applications.

Encapsulated plasmid DNA treatment for human papillomavirus 16-associated anal dysplasia: a Phase I study of ZYC101.

High-grade dysplasia induced by high-risk types of human papillomavirus (HPV) precedes invasive cancer in anal squamous epithelium just as it does in the cervix. A therapeutic HPV vaccine strategy as a potential treatment for anal dysplasia was tested in a standard Phase I dose escalation trial. The primary objective was to evaluate the safety of the agent; additional study aims were to evaluate the histological response, immune response, and effect on anal HPV-16 infection. Each subject was treated with four i.m. injections of 50-400 microg of ZYC101 at 3-week intervals. ZYC101 is composed of plasmid DNA encapsulated in biodegradable polymer microparticles. The plasmid DNA encodes for multiple HLA-A2-restricted epitopes derived from the HPV-16 E7 protein, one of two HPV oncoproteins consistently expressed in neoplastic cells. Fifty-six potential anal dysplasia subjects were screened to identify 12 eligible subjects with HPV-16 anal infection and a HLA-A2 haplotype. The investigational agent was well tolerated in all subjects at all dose levels tested. Three subjects experienced partial histological responses, including one of three subjects receiving the 200-microg dose and two subjects at the 400-microg dose level. Using a direct Elispot, 10 of 12 subjects demonstrated increased immune response to the peptide epitopes encoded within ZYC101; each continued to show elevated immune responses 6 months after the initiation of therapy. These results support the continued investigation of a therapeutic vaccination strategy for anal dysplasia.

ZYC101a for treatment of high-grade cervical intraepithelial neoplasia: a randomized controlled trial.

OBJECTIVE: The objective of this study was to assess the safety and efficacy of a novel therapeutic, ZYC101a, for the treatment of women with histologically confirmed cervical intraepithelial neoplasia (CIN) 2/3. ZYC101a contains plasmid-DNA-encoding fragments derived from the E6 and E7 proteins of human papillomavirus (HPV) 16 and 18, and is formulated within small biodegradable microparticles. METHODS: A multicenter, double-blind, randomized, placebo-controlled trial was conducted in a group of women with biopsy-confirmed CIN 2/3. Subjects were randomized to 3 intramuscular doses of either placebo or ZYC101a (100 or 200 microg). Six months after the first injection, subjects underwent cervical conization. The primary endpoint for this study was histologically confirmed resolution of CIN 2/3. A total of 161 subjects were randomized, dosed, and evaluated for safety. After central pathology review, 127 subjects were evaluable for efficacy. RESULTS: The most common adverse events were related to the injection site, were mild to moderate, and did not worsen at later treatments. The proportion of subjects who resolved was higher in the ZYC101a groups compared to placebo (43% versus 27%), but the difference was not statistically significant (P =.12). In a prospectively defined population of women younger than 25 years (n = 43), resolution was significantly higher in the combined ZYC101a groups compared to placebo (70% versus 23%; P =.007). ZYC101a activity was not restricted to HPV-16-or HPV-18-positive lesions. CONCLUSIONS: ZYC101a was shown to be well tolerated in all patients and to promote the resolution of CIN 2/3 in women younger than 25 years. LEVEL OF EVIDENCE: I

Dynamics of human papillomavirus infection between biopsy and excision of cervical intraepithelial neoplasia: results from the ZYC101a protocol.

BACKGROUND: Little is known about the dynamics of human papillomavirus (HPV) during the follow-up of cervical intraepithelial neoplasia (CIN) 2/3 after biopsy. METHODS: A total of 127 women with biopsy-confirmed CIN2/3 were enrolled in a phase 2 double-blinded, randomized, placebo-controlled clinical trial of ZYC101a. Colposcopic, cytologic, and HPV testing were performed over the course of 6 months, before a loop electrical surgical excision procedure was performed at study exit. RESULTS: Of the women tested, 99% were found to be HPV positive at study entry, 50% were found to be HPV type 16 positive at study entry, 22% were found to be positive for multiple HPV types at study entry, and 37% were found to be positive for additional HPV types during follow-up. Of those with a histologic outcome of CIN1 at study exit, 78% were found to be positive for additional HPV types; in 39%, the original type was replaced with a new HPV type. Virus load at study entry did not predict outcome, but pre-study-exit virus load correlated with a histologic outcome of any CIN, and changes in virus load correlated with risk for an outcome of CIN2/3 at study exit. CONCLUSIONS: The type and number of HPVs at study entry, detection of additional viral types, and virus load changes during follow-up influence histologic outcome at study exit. An outcome of CIN1 at study exit is most likely due to additional HPV infections, rather than morphologic reversion of CIN2/3 to CIN1. Knowledge of the dynamics of HPV infection during the biopsy-to-excision period is critical to understanding the natural history of HPV infection, its contribution to disease outcome, and interpretations of drug efficacy.

Immunotherapy of human cervical high-grade cervical intraepithelial neoplasia with microparticle-delivered human papillomavirus 16 E7 plasmid DNA.

OBJECTIVE: The purpose of this study was to evaluate the safety of the administration of a bacterial expression plasmid encoding a 13 amino acid sequence that is highly homologous with human papillomavirus E7 within poly (lactide-co-glycolide) microparticles (ZYC101) in women with HLA A2+ antigen and persistent cervical intraepithelial neoplasia grade 2/3 and human papillomavirus 16. STUDY DESIGN: Fifteen women entered an institutional review board-approved dose-escalating phase I study with the use of three levels of blood monitoring and urine studies, Papanicolaou tests, and colposcopy. Escalation required no serious adverse events. Immunologic responses were evaluated in peripheral blood with the use of human papillomavirus peptide-stimulated interferon gamma enzyme-linked immunosorbent assay for T-cell reactivity. In cervical secretions, immunoglobulin A anti-human papillomavirus 16 E2 concentrations were measured. Three doses every 3 weeks were followed 4 weeks later by surgical excision. RESULTS: No serious adverse events occurred. Five women had complete histologic responses; 11 women had human papillomavirus-specific T-cell responses. Four of five complete histologic responses developed immunoglobulin A anti-E2-specific antibody. CONCLUSION: ZYC101 warrants further investigation because of a 33% complete histologic responses, a 73% immunologic response, and no serious adverse events.