Claudia Trautwein

Multipeptide immune response to cancer vaccine IMA901 after single-dose cyclophosphamide associates with longer patient survival

IMA901 is the first therapeutic vaccine for renal cell cancer (RCC) consisting of multiple tumor-associated peptides (TUMAPs) confirmed to be naturally presented in human cancer tissue. We treated a total of 96 human leukocyte antigen A (HLA-A)*02+ subjects with advanced RCC with IMA901 in two consecutive studies. In the phase 1 study, the T cell responses of the patients to multiple TUMAPs were associated with better disease control and lower numbers of prevaccine forkhead box P3 (FOXP3)+ regulatory T (Treg) cells. The randomized phase 2 trial showed that a single dose of cyclophosphamide reduced the number of Treg cells and confirmed that immune responses to multiple TUMAPs were associated with longer overall survival. Furthermore, among six predefined populations of myeloid-derived suppressor cells, two were prognostic for overall survival, and among over 300 serum biomarkers, we identified apolipoprotein A-I (APOA1) and chemokine (C-C motif) ligand 17 (CCL17) as being predictive for both immune response to IMA901 and overall survival. A randomized phase 3 study to determine the clinical benefit of treatment with IMA901 is ongoing.

Natural HLA class I ligands from glioblastoma: extending the options for immunotherapy

Glioblastoma multiforme is the most frequent and most malignant primary brain tumor with poor prognosis despite surgical removal and radio-chemotherapy. In this setting, immunotherapeutical strategies have great potential, but the reported repertoire of tumor associated antigens is only for HLA-A*02 positive tumors. We describe the first analysis of HLA-peptide presentation patterns in HLA-A*02 negative glioma tissue combined with gene expression profiling of the tumor samples by oligonucleotide microarrays. We identified numerous candidate peptides for immunotherapy. These are peptides derived from proteins with a well-described role in glioma tumor biology and suitable gene expression profiles such as PTPRZ1, EGFR, SEC61G and TNC. Information obtained from complementary analyses of HLA-A*02 negative tumors not only contributes to the discovery of novel shared glioma antigens, but most importantly provides the opportunity to tailor a patient-individual cocktail of tumor-associated peptides for a personalized, targeted immunotherapeutic approach in HLA-A*02 negative patients.

Identification of naturally processed hepatitis C virus-derived major histocompatibility complex class I ligands.

Fine mapping of human cytotoxic T lymphocyte (CTL) responses against hepatitis C virus (HCV) is based on external loading of target cells with synthetic peptides which are either derived from prediction algorithms or from overlapping peptide libraries. These strategies do not address putative host and viral mechanisms which may alter processing as well as presentation of CTL epitopes. Therefore, the aim of this proof-of-concept study was to identify naturally processed HCV-derived major histocompatibility complex (MHC) class I ligands. To this end, continuous human cell lines were engineered to inducibly express HCV proteins and to constitutively express high levels of functional HLA-A2. These cell lines were recognized in an HLA-A2-restricted manner by HCV-specific CTLs. Ligands eluted from HLA-A2 molecules isolated from large-scale cultures of these cell lines were separated by high performance liquid chromatography and further analyzed by electrospray ionization quadrupole time of flight mass spectrometry (MS)/tandem MS. These analyses allowed the identification of two HLA-A2-restricted epitopes derived from HCV nonstructural proteins (NS) 3 and 5B (NS31406–1415 and NS5B2594–2602). In conclusion, we describe a general strategy that may be useful to investigate HCV pathogenesis and may contribute to the development of preventive and therapeutic vaccines in the future.

Abstract 2396: IMA950: A novel multi-peptide cancer vaccine for treatment of glioblastoma

Despite promising results of various therapeutic approaches currently under investigation, including active immunotherapy, glioblastoma (GBM) remains one of the most fatal tumor types. IMA950 is a novel peptide vaccine aiming at the induction of a broad T-cell response against a variety of tumor-relevant antigens expressed by GBM cells. IMA950 consists of 11 synthetic tumor-associated peptides (TUMAPs) isolated from more than 30 primary human GBM specimens. Nine of the TUMAPs bind to the human leukocyte antigen (HLA) class I allele A*02 expressed by ∼ 45% of the Caucasian population and two TUMAPs bind to various HLA class II (DR) alleles expressed by the majority of patients. Therefore, cytotoxic T-lymphocyte (CTL) as well as T helper (Th) responses are expected to arise from vaccination with IMA950. TUMAPs were identified by isolating HLA-peptide complexes from primary tumors and determining the peptide sequences by mass spectrometry. This analysis resulted in the identification of more than 3,000 different HLA-A*02 peptides expressed by one or more GBM samples. TUMAPs were ranked according to a variety of criteria, including mRNA over-expression of the source antigens in GBM compared with normal tissues, known relevance of the source antigens in oncogenic processes, frequency of expression in GBM samples, in vitro immunogenicity in healthy donors, and feasibility of pharmaceutical development. Based on this approach IMA950 has been composed of 11 TUMAPs derived from 10 different source antigens ranking high in these categories. “Over-presentation” of finally selected TUMAPs was confirmed directly at the peptide level using a novel approach allowing label-free HLA-peptide quantitation directly by mass spectrometry. Moreover, T-cell reactivity in glioma patients was analyzed for all HLA-A*02 peptides in vitro with all patients tested responding to several IMA950 TUMAPs. Furthermore, peptide-specific functions of the observed T cells were investigated in more detail. In conclusion, the strong GBM association of IMA950 TUMAPs indicated by over-presentation together with pre-clinical immunogenicity results suggest that this multi-peptide vaccine may benefit the majority of HLA-A*02-positive patients. Clinical development is planned to start within 2010 with several phase I trials investigating the safety and immunogenicity of the vaccine in different patient populations and using various immunomodulatory regimens in order to explore the most promising strategy for further development. Note: This abstract was not presented at the AACR 101st Annual Meeting 2010 because the presenter was unable to attend. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2396.

Abstract 5365: Prolonged survival of patients with advanced renal cancer responding to multi-peptide vaccine IMA901 after single-dose cyclophosphamide

Proceedings: AACR 103rd Annual Meeting 2012‐‐ Mar 31‐Apr 4, 2012; Chicago, IL Translational research and the clinical development of therapeutic cancer vaccines requires stronger scientific rationalization. Here we demonstrate how immune response markers as well as biomarkers defining the immune regulatory environment were utilized as guiding tools from discovery to advanced clinical trials of IMA901, a novel therapeutic vaccine for the treatment of renal cell carcinoma (RCC). IMA901 consists of multiple tumor-associated peptides (TUMAPs) confirmed to be naturally presented in human RCC tissue by mass spectrometry, selected using differential transcriptomics and preclinically validated by systematic analysis of immunogenicity with artificial antigen-presenting cells. Two consecutive independent clinical studies in a total of 96 HLA-A*02+ advanced/metastatic RCC patients were conducted. The phase I study revealed that T-cell responses to multiple IMA901 antigens were significantly associated with disease control and negatively associated with the presence of FoxP3+ regulatory T cells (Tregs). The subsequent randomized phase II study demonstrated that pre-treatment with a single low dose of cyclophosphamide (Cy) reduced Treg frequencies and prolonged overall survival (OS) in patients who mounted an immune response to the IMA901 vaccine. Additionally, T-cell responses to multiple IMA901 antigens were again associated with clinical benefit. Furthermore, a comprehensive prognostic and predictive biomarker program was conducted. Among cellular biomarkers, highly significantly elevated levels of myeloid-derived suppressor cells (MDSC), IL-17-/IL-10-secreting T cells and dysfunctional T cells in RCC patients vs. healthy individuals were found. Two MDSC populations (CD14+ HLA-DR- and CD14- CD11b+ CD15+) were significantly negatively associated with survival in vaccinated RCC patients. Interestingly, both MDSC populations were also found to be negatively associated with OS in an independent trial in colorectal cancer patients (N=79) implying a broader role for these MDSC species. Additionally, among over 300 serum biomarkers tested, apolipoprotein A-I (ApoA1) and the chemokine CCL17 were found to be predictive for both immune responses to IMA901 and survival of the RCC patients. The knowledge acquired in these trials was used to design a randomized phase III study. In this ongoing study, IMA901 is combined with the tyrosine kinase inhibitor sunitinib based on the findings that sunitinib downmodulates the two MDSC populations described above. Furthermore, in this phase III study, the relevance of ApoA1/CCL17 will be explored by prospectively defined subgroup analyses. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 5365. doi:1538-7445.AM2012-5365