Therapeutic vaccination against genital HPV infection

描述（由申请人提供）：人乳头瘤病毒（HPV）感染的治疗是一个主要的未满足的医疗需求。重要的是，许可的HPV疫苗无法清除现有的感染，现在有多种FDA批准的检测方法来检测高危HPV DNA，特别是HPV 16。随着这些HPV DNA检测的广泛实施，大量感染患者正在被确定。目前持续性HPV 16+患者未接受治疗，但 被跟踪直到他们发展为癌前病变，然后经历手术或消融干预，这具有显著的成本和副作用。我们的总体目标是开发一种治疗性疫苗，以消除持续的HPV 16感染。治疗性HPV疫苗需要有效的细胞毒性T细胞免疫应答来控制慢性HPV感染和HPV相关疾病，而不是抗体。HPV早期蛋白E6和E7在所有HPV感染的细胞中特异性表达，在正常细胞中不存在，并且是“非自身”抗原。因此，虽然E6和E7是治疗性HPV疫苗接种的逻辑靶点，但它们的免疫原性较弱，需要Papivax的新型免疫刺激技术来产生有效的细胞毒性T细胞免疫。我们以前曾利用裸DNA疫苗显着增强HPV 16 E7的MHC I类呈递通过其融合结核分枝杆菌热休克蛋白70（HSP 70）。这种连接增强了E7特异性CD 8 + T细胞免疫应答至少50倍，并在接种疫苗的小鼠中产生了针对HPV 16 E7表达细胞的有效治疗效果。这些数据导致在HPV 16+患者中的I期临床试验，其证明用E7 HSP 70 DNA疫苗免疫在患者中诱导E7特异性CD 8 + T细胞应答。TA-HPV是经工程改造以表达来自HPV 16和HPV 18的E6和E7基因的牛痘病毒。对近100例HPV 16+宫颈癌和肛门生殖器肿瘤患者进行TA-HPV皮肤给药未能产生明确的临床反应。重要的是，虽然用E7 HSP 70 DNA疫苗引发小鼠，然后用表达HPV E7的重组牛痘进行皮肤加强，增强了E7特异性CD 8 + T细胞应答，但我们最近证明，用表达E7的牛痘进行病灶内加强比单独进行皮肤加强或病灶内E7牛痘更有效。我们假设，用E7 HSP 70 DNA疫苗引发，然后病灶内注射TA-HPV牛痘（也表达HPV 16 E7），通过结合优先牛痘复制和细胞杀伤， HPV抗原特异性CD 8 + T细胞介导的免疫应答被吸引到病变处。因此，我们将使用小鼠阴道中持续HPV 16感染的新模型来测试临床级HPV DNA疫苗和HPV重组牛痘的病灶内施用的组合是否触发免疫清除。这些临床前研究将推动未来Papivax驱动的治疗性疫苗临床试验，以消除持续性HPV感染。

DESCRIPTION (provided by applicant): Treatment of Human papillomavirus (HPV) infections is a major unmet medical need. Importantly, the licensed HPV vaccines are not able to clear existing infections, and there are now multiple FDA-approved tests to detect high risk HPV DNA, and specifically HPV16. As these HPV DNA tests are widely implemented, large numbers of infected patients are being identified. Currently persistently HPV16+ patients are not treated, but are followed until they develop pre-cancer and then undergo a surgical or ablative intervention with significant costs and side effects. Our overall goal is to develop a therapeutic vaccine to eliminate persistent HPV16 infections. Rather than antibodies, therapeutic HPV vaccines require a potent cytotoxic T cell immune response to control chronic HPV infections and HPV-associated disease. The HPV early proteins E6 and E7 are obligately expressed in all HPV infected cells, absent from normal cells and are 'non-self' antigens. Thus while E6 and E7 are the logical targets for therapeutic HPV vaccination, nevertheless they are weakly immunogenic and require Papivax's novel immunostimulatory technology to generate potent cytotoxic T cell immunity. We have previously utilized a naked DNA vaccine to significantly enhance MHC class I presentation of HPV16 E7 by its fusion to the Mycobacterium tuberculosis heat shock protein 70 (HSP70). This linkage augmented the E7-specific CD8+ T cell immune responses at least 50-fold and led to potent therapeutic effects against HPV16 E7-expressing cells in vaccinated mice. These data led to a phase I clinical trial in HPV16+ patients which demonstrated that immunization with E7HSP70 DNA vaccine induces an E7-specific CD8+ T cell response in patients. TA-HPV is vaccinia virus engineered to express the E6 and E7 genes from HPV16 and HPV18. Cutaneous administration of TA-HPV to nearly a hundred patients with HPV16+ cervical cancer and anogenital neoplasias failed to produce a clear clinical response. Importantly, while priming of mice with the E7HSP70 DNA vaccine followed by cutaneous boosting with recombinant vaccinia expressing HPV E7 enhanced E7-specific CD8+ T cell responses, we recently demonstrated that intralesional boosting with E7- expressing vaccinia was far more effective than either cutaneous boosting or intralesional E7-vaccinia alone. We hypothesize that priming with the E7HSP70 DNA vaccine followed by intralesional injection of TA-HPV vaccinia (which also expresses HPV16 E7) will generate potent therapeutic effects against persistent HPV infection by combining preferential vaccinia replication and cell killing in the lesion with boosting of HPV antigen-specific CD8+ T cell mediated immune responses attracted to the lesion. Thus, we will test whether combining clinical grade HPV DNA vaccine and intra-lesional administration of HPV recombinant vaccinia triggers immune clearance using a new model of persistent HPV16 infection in the mouse vagina. These preclinical studies will drive future Papivax-driven clinical trials of therapeutic vaccines to eliminate persistent HPV infections.