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Clinical translation of peptide-based vaccine trials: the HER-2/neu model
M L Disis1, K L Knutson, D G McNeel
1Division of Oncology, University of Washington, Seattle 98195-6527, USA. ndisis@u.washington.edu
Abstract:
In the development of targeted cancer immunotherapies, the choice of antigen is obviously critical to the design of any therapeutic strategy, but particularly so for tumor vaccines, which must distinguish malignant cells from normal cells. Investigations a decade ago focused on mutated tumor antigens, or viral tumor antigens, with the belief that these foreign or abnormal proteins would be best recognized by the host immune system. Within the last 10 years, however, several tumor antigens have been identified on the basis of recognition by infiltrating T cells in tumor samples. Studies on melanoma, in particular, have revealed that in addition to some mutated tumor antigens, several aberrantly expressed normal proteins, as well as tissue-specific differentiation factors, are recognized by the host immune system. Similar studies in other solid tumors have revealed that certain oncogenes overexpressed in malignant cells, such as p53 and HER-2/neu, are also recognized by host T cells. Our group has been investigating the HER-2/neu oncogenic protein as a vaccine target in patients with HER-2/neu-overexpressing cancers. However, several issues unique to the design of human clinical trials of cancer vaccines must be addressed when translating preclinical experiments to human clinical trials. First, HER-2/neu protein expression can vary depending on the tumor type. How would expression differences impact clinical trial design? Secondly, what are the issues in clinical trial design that are critical to the successful execution of a phase I study of a peptide-based vaccine? Thirdly, what types and amounts of clinical material are readily available for immunologic analysis and can be obtained with little distress and risk to the patients enrolled in the study? Finally, what steps must be implemented for a laboratory assay to evolve to meet the validation criteria needed for application as an immunologic monitoring tool?
Insights
Identifying optimal tumor antigens is crucial for effective cancer immunotherapy vaccines. This study investigates the HER-2/neu oncogene as a vaccine target, addressing key clinical trial design challenges for HER-2/neu-overexpressing cancers.
Area of Science:
- Oncology
- Immunology
- Vaccine Development
Background:
- Targeted cancer immunotherapies rely on selecting appropriate antigens for therapeutic strategies, especially for tumor vaccines distinguishing malignant from normal cells.
- Historically, research focused on mutated or viral tumor antigens, but recent studies identify aberrantly expressed normal proteins and tissue-specific differentiation factors recognized by T cells.
- Oncogenes like p53 and HER-2/neu, overexpressed in malignant cells, are also recognized by host T cells, presenting potential vaccine targets.
Purpose of the Study:
- To investigate the HER-2/neu oncogenic protein as a vaccine target in patients with HER-2/neu-overexpressing cancers.
- To address critical issues in designing human clinical trials for cancer vaccines, particularly peptide-based vaccines targeting HER-2/neu.
- To explore how variations in HER-2/neu expression impact clinical trial design and to define requirements for immunologic monitoring assays.
Main Methods:
- Investigating HER-2/neu as a vaccine target in preclinical models and patient populations.
- Analyzing the impact of tumor type-specific HER-2/neu expression on clinical trial design.
- Evaluating critical factors for Phase I peptide-based vaccine trials, including clinical material availability and patient risk.
- Defining criteria for validating laboratory assays for immunologic monitoring.
Main Results:
- HER-2/neu is a recognized target in HER-2/neu-overexpressing cancers, indicating its potential for vaccine development.
- Tumor-specific variations in HER-2/neu expression necessitate careful consideration in clinical trial design.
- Availability of clinical material and patient safety are paramount for successful Phase I studies.
- Standardized and validated immunologic assays are essential for monitoring vaccine efficacy.
Conclusions:
- The HER-2/neu oncogene represents a promising target for cancer vaccine development in relevant patient populations.
- Successful translation of preclinical findings to human trials requires addressing logistical and biological complexities, including antigen expression variability.
- Rigorous clinical trial design, focusing on patient safety and robust immunologic monitoring, is essential for advancing cancer immunotherapy.