Age-related macular degeneration as well as some forms of Retinitis Pigmentosa (RP) are characterized by a retinal degeneration involving the retinal pigment epithelium (RPE). Various strategies were proposed to cure these disorders including the replacement of RPE cells using human pluripotent stem cells (hPSCs), an unlimited source material to generate in vitro RPE cells. The formulation strategy of the cell therapy (either a reconstructed sheet or a cell suspension) is crucial to achieve an efficient and long lasting therapeutic effect. We previously developed a hPSC-RPE sheet disposed on human amniotic membrane that sustained the vision of rodents with retinal degeneration compared to the same cells injected as a suspension. However, the transplantation strategy was difficult to implement in large animals. Herein we developed two medical devices for the preparation, conservation and implantation of the hPSC-RPE sheet in nonhuman primates. The surgery was safe and well tolerated during the 7-week follow up. The graft integrity was preserved in primates. Moreover, the hPSC-RPE sheet did not induce teratoma or grafted cell dispersion to other organs in rodent models. This work clears the way for the first cell therapy for RP patients carrying RPE gene mutations (LRAT, RPE65 and MERTK).

Human T-cell Lymphotrophic Virus 1 (HTLV-1) is the etiologic agent of Adult-T cell Leukemia/Lymphoma (ATL). Therapeutic options for ATL patients are very limited and in aggressive forms of the disease survival rate is only 10% to 30% with conventional chemotherapies and bone marrow transplantation. Although some clinical trials gave encouraging results regarding the efficacy of new treatments, most of them are lifelong, aggressive and failed to achieve a significant impact on long-term survival. Consequently, new treatments for ATL patients are needed to limit relapses and side effects. Specific HTLV-1 cellular immune response is dramatically impaired in ATL patients, which could favor the initiation and the progression of the disease. Hence, stimulating immune responses against HTLV-1 can be an appropriate therapeutic option to treat ATL. THERAVECTYS has developed an anti-HTLV-1 vaccine, based on its lentiviral vector technology inducing a broad, intense and long-lasting cellular immune response after intra-muscular injection. THERAVECTYS was the first company to have launched a clinical trial based on lentiviral vectors technology with the THV01 vaccine for the treatment of HIV (NCT02054286). Results obtained demonstrated both safety and immunogenicity of THV01 in human, with polyfunctional and multi-specific CD4 and CD8 T-cells responses. The anti-HTLV-1 lentiviral vector, THV02 vaccine, encodes for a unique polypeptide derived from Tax, HBZ, p12I and p30II proteins, involved in HTLV-1 pathogenicity and known to be recognized by the immune system of HTLV-1 infected patients. Our preclinical results have demonstrated that THV02 can induce a cellular immune response in C57Bl/6j and BalbC mice and in Sprague Dawley rats, as demonstrated by IFN-γ Elispot. Safety of the THV02 vaccine has been demonstrated during carcinogenicity and regulatory GLP preclinical toxicity studies. Biodistribution and shedding studies demonstrated the very limited diffusion of THV02 after injection, its fast clearance and a non-dissemination in body fluids. As no relevant ATL immunocompetent animal model is available to assess the anti-tumor effect of THV02, THERAVECYTS is developing an ex-vivo efficacy model using blood samples of ATL patients. Briefly, monocyte-derived dendritic cells (MDDC) from blood of ATL patients are purified by isolation of CD14 positive cells from PBMC and differentiation in the presence of IL4 and GM-CSF. MDDC are then transduced with lentiviral vectors encoding for the anti-HTLV-1 antigen and maturation is induced upon TNFa and PGE2 exposure before the co-culture with autologous CD8+ T-cells for stimulation of the cellular immune response. Then, stimulated CD8+ are co-cultured with autologous CD4+ CD25+ ATL cells and the cytotoxic activity is monitored by flow cytometry. Preliminary results demonstrated that MDDC from a chronic ATL patient can be efficiently transduced and matured as attested by the CD40, CD86, HLA-DR, -A, -B and C markers on their surface. In addition, we have observed a specific stimulation of the CD8+, ie an increase of IFNg, TNFa, IL2 and perforin in the media of the co-culture of CD8+ with MDDC expressing anti-HTLV-1 antigen. These data are very encouraging and demonstrate for the first time the feasibility to develop an ex vivo model to assess vaccine efficacy using ATL blood sample. The development of this model is ongoing using several ATL donors representing the different subtypes of the disease and will be presented at the meeting. Regarding the indication and the safety profile of THV02, THERAVECTYS plans to begin a clinical trial in Q4 2015. This assay will be an open-label, dose escalation phase I/II study to assess the safety and the immunogenicity (cellular immune response) of the THV02 vaccination as a treatment of ATL patients. All ATL subtypes will be considered since THV02 vaccine can be combined with conventional ATL treatments. In addition, as the THV02 antigen contains peptides derived from Tax but also HBZ, p12I and p30II viral proteins, all ATL patients can be treated whatever the status of Tax expression. As secondary objectives, both humoral immune response and clinical effect will be assessed. HTLV-1 RNA expression and clonality of HTLV-1 infected cells will be studied as exploratory objectives. Finally, up to 16 patients will be enrolled in France, UK, French Guiana, Martinique and Guadeloupe before doing a phase of extension cohort in US. Disclosures No relevant conflicts of interest to declare.

No abstract

Chronic wounds, such as leg ulcers associated with sickle cell disease, occur as a consequence of a prolonged inflammatory phase during the healing process. They are extremely hard to heal and persist as a significant health care problem due to the absence of effective treatment and the uprising number of patients. Indeed, there is a critical need to develop novel cell- and tissue-based therapies to treat these chronic wounds. Development in skin engineering leads to a small catalogue of available substitutes manufactured in Good Manufacturing Practices compliant (GMPc) conditions. Those substitutes are produced using primary cells that could limit their use due to restricted sourcing. Here, we propose GMPc protocols to produce functional populations of keratinocytes and fibroblasts derived from pluripotent stem cells to reconstruct the associated dermo-epidermal substitute with plasma-based fibrin matrix. In addition, this manufactured composite skin is biologically active and enhances in vitro wounding of keratinocytes. The proposed composite skin opens new perspectives for skin replacement using allogeneic substitute.

No abstract

No abstract

Bauche et al.: Lentiviral-based anti-HIV therapeutic vaccine: design, preclinical studies and phaseI/II clinical trial preliminary results. BMC Infectious Diseases 2014 14(Suppl 2):P81.

No abstract