Therapeutic Vaccine for HIV/HPV-associated Oropharyngeal and Tonsillar Malignanci

描述(申请人提供)：该项目的目标是基于HPV在发病机制中的作用，进一步开发一种针对HIV相关恶性肿瘤的免疫治疗策略，并用一种新药进行临床前实验，使我们能够进入临床试验，以测试其安全性和有效性。HPV相关肿瘤表达HPV的E6/E7癌蛋白，是免疫诱导疫苗的理想靶点。我们开发了一种基于新型5型腺病毒载体(Ad5)平台的疫苗，该载体具有独特的和额外的病毒DNA聚合酶和早期基因2b(E2b)区前末端蛋白(Ad5[E1-，E2b-])的缺失。在利用传染病和癌症抗原的研究中，我们报道了新的Ad5[E1-，E2b-]载体疫苗在诱导多重同源免疫方案中的CMI反应时优于现有的Ad5[E1-]载体疫苗(包含早期基因1(E1)区的缺失)。我们已经证明，尽管存在预先存在的Ad5免疫，但在小鼠和猴子中仍能诱导显著的抗原特异性CMI反应。我们的数据表明，新的Ad5[E1-，E2b-]载体能够诱导针对肿瘤相关抗原(TAA)的强大CMI反应，从而产生抗肿瘤活性，即使在存在Ad5免疫的情况下也是如此。我们构建并生产了表达非致癌早期基因6(E6)和早期基因7(E7)HPV蛋白的HPV-E6/E7基因。我们已经将这个修饰的HPV-E6/E7基因整合到新的重组Ad5[E1-，E2b-]载体平台(Ad5[E1-，E2b-]-HPV-E6/E7)中，用于治疗HPV-E6/E7表达的肿瘤患者。该重组平台通过注射直接转染抗原提呈细胞，表达修饰后的HPV-E6/E7抗原，从而诱导免疫应答。我们评估了这种药物与Toll样受体激动剂(TLRa)平台的结合，该平台旨在增强载体诱导的免疫反应。在采用修饰的HPV-E6/E7基因插入的Ad5免疫小鼠肿瘤模型中，比较了Ad5[E1-，E2b-]-HPV-E6/E7与Ad5[E1-，E2b-]-TLRa重复免疫的免疫原性和体内抗肿瘤效果。与单独免疫Ad5[E1-，E2b-]-HPV-E6/E6/E7相比，Ad5[E1-，E2b-]-HPV-E6/E7+Ad5[E1-，E2b-]-TLRa免疫小鼠诱导的HPV-E6/E7诱导的CMI活性显著升高。重要的是，与注射Ad5[E1-，E2b-]空载体(空载体)的对照组相比，接受Ad5[E1-，E2b-]-HPV-E6/E7免疫治疗并添加或不添加Ad5[E1-，E2b-]-TLRa的小鼠肿瘤生长显著减少。这些结果表明，用新型Ad5[E1-，E2b-]-HPV-E6/E7免疫治疗表达HPV-E6/E7的肿瘤具有很强的抗肿瘤活性。我们以前的研究数据也表明，这种新的免疫治疗药物可能与化疗/放射治疗联合使用，以诱导有效的抗肿瘤活性。目前临床前计划中的研究将使我们能够推进生产方法，并获得数据，使我们能够推进FDA批准的临床试验

DESCRIPTION (provided by applicant): The objective of this project is to further develop an immunotherapeutic strategy for HIV-associated malignancy based on the role of HPV in the pathogenesis and perform the pre-clinical experiments with a new drug which allow us to enter clinical trials to test its safety and effectiveness. HPV related cancers express the E6/E7 oncoproteins of HPV that are ideal targets for immune inducing vaccines. We developed a vaccine based upon a novel adenovirus serotype-5 vector (Ad5) platform with unique and additional deletions of the viral DNA polymerase and the pre-terminal protein in the early gene 2b (E2b) region (Ad5 [E1-, E2b-]). In studies employing infectious disease and cancer antigens, we reported that new Ad5 [E1-, E2b-] vector vaccines are superior to current Ad5 [E1-] vector vaccines (containing deletion in the early gene 1 (E1) region) when used to induce CMI responses in a multiple homologous immunization regimen. We have demonstrated that significant antigen specific CMI responses are induced in mice and monkeys despite the presence of pre- existing Ad5 immunity. Our data indicates that the new Ad5 [E1-, E2b-] vectors induces robust CMI responses against tumor associated antigens (TAA) resulting in anti-tumor activity, even in the presence of pre-existing Ad5 immunity. We have constructed and produced a modified HPV-E6/E7 gene that expresses non-oncogenic early gene 6 (E6) and early gene 7 (E7) HPV proteins. We have incorporated this modified HPV-E6/E7 gene into the new recombinant Ad5 [E1-, E2b-] vector platform (Ad5 [E1-, E2b-]-HPV-E6/E7) to be used as an immunotherapeutic for the treatment of patients with HPV-E6/E7 expressing cancers. This recombinant platform induces immune responses by expressing the modified HPV-E6/E7 antigens after direct transfection of antigen presenting cells via injection. We evaluated this dru combination with a toll-like receptor agonist (TLRa) platform designed to enhance immune responses induced by the vector. In an Ad5 immune murine cancer model employing the modified HPV-E6/E7 gene insert, the immunogenicity and in vivo anti-tumor effects of repeated immunizations with the Ad5 [E1-, E2b-]-HPV-E6/E7 with or without the addition of Ad5 [E1-, E2b-]-TLRa were compared. Significantly higher levels of HPV-E6/E7 directed CMI activity was induced in mice immunized with Ad5 [E1-, E2b-]-HPV-E6/E7 plus Ad5 [E1-, E2b-]-TLRa as compared with mice immunized with Ad5 [E1-, E2b-]-HPV-E6/E7 alone. Importantly, mice treated by immunotherapy with Ad5 [E1-, E2b-]-HPV-E6/E7 with or without the addition of Ad5 [E1-, E2b-]-TLRa experienced large reductions in tumor growth as compared with control mice injected with Ad5 [E1-, E2b-]-null (empty vector). These results indicate that immunotherapy of HPV-E6/E7 expressing tumors using the new Ad5 [E1-, E2b-]-HPV-E6/E7 induces potent anti-tumor activity. Our previous research data also indicates that this new immunotherapeutic drug may be used in conjunction with chemotherapy/irradiation treatment to induce effective anti-tumor activity. The studies in the present pre-clinical program will allow us to advance manufacturing approaches and acquire data that will allow us to advance to FDA approved clinical trials