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得到满足的医疗需求。重要的是，获得许可的HPV疫苗不能清除现有的感染，现在有多个FDA批准的测试来检测高危HPV DNA，特别是HPV16。随着这些HPV DNA检测的广泛实施，大量受感染的患者正在被确认。目前HPV16+患者不接受治疗，但 被跟踪，直到他们发展为癌症前期，然后接受手术或消融干预，费用和副作用很大。我们的总体目标是开发一种治疗性疫苗，以消除持续的HPV16感染。治疗性HPV疫苗需要强大的细胞毒性T细胞免疫反应，而不是抗体，以控制慢性HPV感染和HPV相关疾病。HPV早期蛋白E6和E7在所有HPV感染细胞中都有表达，在正常细胞中不表达，是“非自身”抗原。因此，虽然E6和E7是治疗性HPV疫苗的合理靶点，但它们的免疫原性较弱，需要Papivax的新免疫刺激技术来产生强大的细胞毒性T细胞免疫。我们之前已经利用裸DNA疫苗通过与结核分枝杆菌热休克蛋白70(HSP70)的融合，显著增强了HPV16E7的MHC I类递呈。这种连锁使E7特异的CD8+T细胞免疫反应增加至少50倍，并导致对免疫小鼠中表达HPV16E7的细胞产生强大的治疗效果。这些数据导致了对HPV16+患者的I期临床试验，证明了E7HSP70 DNA疫苗免疫在患者中诱导了E7特异性CD8+T细胞反应。TA-HPV是一种表达HPV16和HPV18 E6和E7基因的痘苗病毒。近百例HPV16阳性的宫颈癌和肛门肿瘤患者经皮注射TA-HPV未能产生明显的临床反应。重要的是，虽然用E7HSP70 DNA疫苗接种小鼠，然后用表达HPVE7的重组疫苗进行皮肤免疫增强了E7特异性CD8+T细胞反应，但我们最近证明，用表达E7的疫苗进行皮内免疫比单独皮下接种或皮内接种E7疫苗要有效得多。我们推测，用E7HSP70 DNA疫苗接种，然后瘤内注射TA-HPV疫苗(也表达HPV16E7)将通过结合优先复制疫苗和细胞杀伤来产生有效的治疗效果。 HPV抗原特异性CD8+T细胞介导的免疫反应增强的病变吸引病变。因此，我们将使用一种新的小鼠阴道持续HPV16感染模型来测试临床级别的HPV DNA疫苗和皮内注射HPV重组疫苗是否会触发免疫清除。这些临床前研究将推动未来由Papivax驱动的治疗性疫苗的临床试验，以消除持续的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.