Introduction

1. monocytes iDC GM-CSF + IL-4 # Leukaferesis § § § TNFa + IL-1b Semi-mature, WT1 electroporated DC Injection in Aldara-treated skin (groins) WT1 mRNA Wilms’ tumor gene 1 (WT1) Dendritic Cell Immunotherapy in Patients with Uterine Tumors: a Phase I/II Clinical Trial 1Department of Gynecologic Oncology, 2Neuroscience, 3Imaging and Pathology and 4Microbiology and Immunology, KU Leuven, Belgium; 5Gynecology and Obstetrics, 6Pathology and 7Pediatrics, University Hospital Leuven, Belgium; 8Laboratory of Experimental Hematology, Vaccine and Infectious Disease Institute, University of Antwerp, Belgium A. Coosemans1,5, A. Vanderstraeten1, S. Tuyaerts1, T. Verschuere2, Ph. Moerman3,6, V. Van Tendeloo8, Z. Berneman8, I. Vergote1,5, F. Amant1,5, S.W. Van Gool4,7 Results HLA-A2 negative patients Results HLA-A2 positive patients • Introduction • Uterine tumors can be subdivided in endometrial carcinoma and uterine sarcoma. With the standard treatments, prognosis remains poor with 5-year survival ranging from 5 to 40% in carcinomas (depending on the subtype) and 10% in sarcomas. Wilms’ tumor gene 1 (WT1) has recently been ranked as the most important tumor antigen. It is overexpressed in both uterine carcinoma and sarcoma. For sarcomas, we were able to correlate its overexpression to a deterioration of the prognosis. Since 2004, clinical case reports and studies were published about WT1 immunotherapy. Most commonly, a modified WT1 peptide is injected to elicit a WT1-specific T cell response. Vaccination with autologous dendritic cells (DCs) loaded with WT1 peptides is another mean to establish such a response. One of the obstacles for the use of synthetic peptides is that patient accrual is limited to patients with the specific HLA-type, for which the peptide is restricted. One way that would allow to apply WT1-targeted immunotherapy for patients regardless of their HLA-type, is transfection of WT1 mRNA into DCs to achieve transient expression and subsequent presentation of antigenic epitopes. The in vitro work of several laboratories has suggested that mRNA transfection is an effective, if not superior, method to generate immunostimulatory DCs. Our research groups developed the technique of DC immunotherapy in the context of high grade glioma patients patients, acute myeloid leukemia and endometrial carcinoma. • Clinical Trial set up • Six patients with uterine cancer received 4 intradermal vaccinations with DCm-WT1-RNA, once every week. Patients with disease stabilization or regression received further monthly vaccinations with DCm-WT1-RNA until disease progression. The skin of the injection sit was pretreated with Imiquimod cream during 3 days. * on a scale ranging from 1 (very poor) to 7 (excellent); ° all values below detection levels; # measured by flow cytometry (tetramer staining); § PBMC were incubated with an overlapping peptide mixture covering WT1. After 24 h incubation, cells were analyzed by flow cytometry using anti-CD4, anti-CD137 and anti-CD8. The culture supernatant was used for cytokine quantification HQLE: Health and Quality of Life Estimation, PFS: progression-free survival, OS: overall survival, V3/4: vaccination 3/4, PD: progressive disease, CT: computed tomography, NA: not applicable Conclusions We present the first series of six patients with uterine cancer treated with autologous dendritic cells loaded with WT1 RNA. This approach was feasible and well supported by the patients. The only side-effect was the allergic reaction to the Imiquimod cream in one patient. A transient oncological (patient 1, 2, 4) and immunological (patient 1, 3, 4) reaction was seen in three patients after 4 vaccinations, all HLA-A2 positive. In two of them, oncological and immunological response matched. When receiving boosting vaccines, the immune response was not maintained, correlating with progressive disease on CT scan. HLA-A2 negative patients did not show an oncologic nor immunologic response.