Combination immunotherapy for neuroblastoma: model of innate tumor immunity

描述（申请人提供）：神经母细胞瘤（Neuroblastoma， NB）是儿童最常见的颅外实体瘤。虽然强化诱导化疗和积极手术改善了年轻患者的缓解率，但在老年患者和40%的耐药NB患者中，结果却不那么令人印象深刻。在诊断时年龄为18个月的儿童中，转移性NB的长期无复发生存率仅为~20%。这些令人失望的结果是寻求新的治疗方法的有力理由。一种成功的替代方法是使用3F8进行免疫治疗，3F8是一种针对普遍存在于NB细胞上的GD2糖脂抗原的小鼠IgG3单克隆抗体。虽然3F8给药对缓解期NB患者有明显的生存益处，但对耐药软组织NB患者或疾病进展的患者无效。这可能部分是由于它依赖于抗体依赖性细胞介导的细胞毒性（ADCC），后者主要由自然杀伤（NK）细胞介导，在大量预处理的患者中，NK细胞被耗尽。来自健康同种异体来源的NK细胞过继转移可能恢复并增强这些低风险患者的3F8效应。自然杀伤细胞（NK）是通过多种途径具有抗肿瘤活性的淋巴细胞，包括通过与CD16 Fc受体结合而产生的ADCC。然而，NK细胞的细胞毒性反应能力是由其细胞表面受体决定的，特别是对自身mhc I类分子特异性的抑制和激活杀伤因子样受体（KIR）。为了最大限度地发挥过继性NK细胞转移的作用，应该选择最有可能产生NK同种异体反应并获得最高功能性NK反应的供体。这可以通过根据供体和患者的HLA和KIR基因型选择供体，并通过使用可能反映体内肿瘤MHC环境的体外系统评估NK功能来实现。在该提案的第一个目标中，我们提出肿瘤上MHC I类分子的上调选择性地抑制正常应答的NK群体，使正常功能低下的“未经许可的”NK群体介导患者的ADCC。抗体治疗过程中产生的炎性细胞因子也可能增强未经许可的NK活性。未经许可的NK人群的活动可能是显著的，在选择NK供体进行过性转移时应予以考虑。本文提出了一种新的免疫治疗方法来治疗高危神经母细胞瘤。3F8单克隆抗体与适当选择的供者过继转移的NK细胞联合使用，可提高ADCC、抗体疗效和肿瘤根除。由于这些免疫方法从未在实体肿瘤或儿童人群中进行过联合研究，因此有必要进行一期研究，以检查3F8与不断增加剂量的NK细胞联合使用的安全性，这代表了该提案的第二个目标。介绍了NK和3F8治疗的潜在毒性、毒性监测计划、剂量递增计划、预期结果和停药规则。在体外研究中，供体-受体KIR/HLA免疫遗传学和供体FcR多态性与NK激活和对NB靶细胞的细胞毒功能相关。的安全性和可行性论证

DESCRIPTION (provided by applicant): Neuroblastoma (NB) is the most common extracranial solid tumor of childhood. While intensive induction chemotherapy and aggressive surgery have improved remission rates in young patients, results have been less impressive in older patients and in the 40% of patients with chemo resistant NB. Metastatic NB in children > 18 months of age at diagnosis carries a long-term relapse-free survival of only ~20%. These disappointing results are compelling reasons for pursuing novel therapeutic approaches. One successful alternative approach has been immunotherapy with 3F8, a murine IgG3 monoclonal antibody to the GD2 glycolipid antigen ubiquitously present on NB cells. While 3F8 administration confers a clear survival benefit to NB patients in remission, it is not effective for patients with resistantsoft tissue NB or patients with progressive disease. This may be due in part to its dependence on antibody- dependent cell-mediated cytotoxicity (ADCC), the latter mediated largely by natural killer (NK) cells, which are depleted in heavily pre-treated patients. Adoptive transfer of NK cell from a healthy allogeneic source may restore and enhance 3F8 effects in these poor-risk patients. Natural killer (NK) cells are lymphocytes that have the capacity for antitumor activity via multiple pathways, including ADCC through engagement of the CD16 Fc receptor. The capacity of an NK cell for cytotoxic response, however, is dictated by its cell surface receptors, specifically the inhibitory and activating killer-Ig like receptors (KIR) that are specific for sel-MHC class I molecules. To maximize the effects of adoptively transferred NK cells, one should select donors from whom there is the greatest likelihood of engendering NK alloreactivity and of achieving highest functional NK response. This can be accomplished by selecting donors based on the HLA and KIR genotypes of the donor and the patient and by evaluating NK function using an in vitro system that may reflect the tumor MHC environment in vivo. In the first aim of the proposal, we propose that up regulation of MHC class I molecules on the tumor selectively inhibits normally responsive NK populations, leaving the normally hypofunctional, "unlicensed" NK population to mediate ADCC in patients. Inflammatory cytokines elaborated during antibody therapy may also enhance unlicensed NK activity. The activity of the unlicensed NK population can be significant and should be considered when selecting an NK donor for adoptive transfer. This proposal presents a novel immunotherapeutic approach for the treatment of high-risk neuroblastoma. Combination of 3F8 monoclonal antibody with adoptively transferred NK cells from appropriately selected donors should increase ADCC, antibody efficacy, and tumor eradication. Because these immunologic approaches have never been studied in combination for a solid tumor or in the pediatric population, a phase I study to examine the safety of 3F8 combined with escalating doses of NK cells is necessary and represents the second aim of the proposal. Potential toxicities of NK and 3F8 therapies, a toxicity monitoring plan, dose escalation plan, the expected outcome and stopping rules are presented. Donor-recipient KIR/HLA immunogenetics and donor FcR polymorphism will be correlated with NK activation and cytotoxic function against NB target cells in vitro. Demonstration of safety and feasibility of combining adoptively transferred NK cells with monoclonal antibody will not only result in a more potent therapeutic approach for poor-prognosis NB patients, but will be broadly applicable to other cancer populations such as lymphoma and breast carcinoma currently treated with monoclonal antibodies. Correlating donor-recipient KIR/HLA effects with outcome will clarify donor prioritization algorithms and provide prognostic value for future NK immunotherapy studies. PUBLIC HEALTH RELEVANCE: Natural killer (NK) cells are a vital component of the body's immune system, protecting the individual from developing cancer. This proposal is designed to help physicians use NK cells and the immune system as treatment for children with neuroblastoma, a childhood cancer. Findings from this study will be informative for other cancers that may also be killed by NK cells.