Biologic Therapy for B-cell non-Hodgkin's Lymphoma

描述(申请人提供)：B细胞非霍奇金淋巴瘤(NHL)是美国癌症相关死亡的第六大常见原因。虽然许多侵袭性淋巴瘤患者可以用细胞毒疗法治愈，但大多数惰性淋巴瘤用目前的疗法是无法治愈的。因此，需要新的有效疗法来治疗这些患者。我们研究的目标是通过利用增强对恶性B细胞的免疫反应的策略来为B细胞NHL患者开发新的生物治疗方法。在之前的资助期间，我们评估了在B细胞淋巴瘤患者中加入免疫刺激细胞因子IL-12是否会增加利妥昔单抗的抗体依赖性细胞毒作用。在临床试验中，我们发现IL-12并没有显著提高应答率，而不是单用利妥昔单抗。在相关研究中，我们发现IL-12导致外周血细胞基因上调，但在肿瘤中没有类似的作用。在实验室研究中，我们发现对IL-12免疫刺激缺乏反应的效应细胞部分与肿瘤内具有抑制功能的T细胞的存在有关。最近的研究表明，CD4+CD25+调节性T细胞(Treg)通过诱导外周血对肿瘤特异性抗原的耐受参与抗肿瘤免疫的调节。然而，关于Treg细胞在B细胞NHL中对肿瘤特异性T细胞免疫的影响以及随后对恶性B细胞生长的影响的数据很少。在初步研究中，我们已经确定了B细胞NHL中存在的具有Treg细胞表型的CD4+CD25+T细胞亚群。此外，我们发现这些Treg细胞具有抑制B细胞NHL中肿瘤浸润性CD4+和CD8+T细胞的能力，并且它们在恶性B细胞产生的趋化因子(如CCL22)的作用下迁移。我们的中心假设是，肿瘤Treg细胞通过抑制肿瘤浸润性T细胞来促进恶性淋巴瘤B细胞的生长，而恶性B细胞通过选择性地将Treg细胞招募到B细胞NHL区域而发挥积极作用。因此，我们建议首先确定这些Treg细胞被招募到非霍奇金淋巴瘤的恶性B细胞微环境中的机制，并发现当它们存在于肿瘤微环境中时是否获得抑制活性(目标1)。其次，我们将评估恶性B细胞是否与肿瘤微环境中的Treg细胞直接相互作用，从而协调对其存在的耐受性(目标2)。第三，我们将确定清除肿瘤内的Treg细胞和抑制恶性B细胞以减少Treg细胞募集，是否会为B细胞NHL患者带来临床益处(AIM 3)。我们期望这项拟议的研究能更好地理解Treg细胞在B细胞恶性肿瘤中的调节作用。我们还预计，白介素2和白喉毒素融合蛋白Denileukin diftitox与抗CD20单抗美妥昔单抗的临床应用将抑制B细胞淋巴瘤患者的Treg细胞，并将耗尽恶性淋巴结中的淋巴瘤B细胞，从而防止Treg细胞进一步募集到B细胞淋巴瘤区域。这种治疗组合将导致一种新的治疗方法来调节Treg细胞，这将为B细胞NHL患者带来临床益处。

DESCRIPTION (provided by applicant): B-cell non-Hodgkin lymphomas (NHL) are the sixth most common cause of cancer-related deaths in the United States. While many patients with aggressive lymphomas may be cured with cytotoxic therapy, most indolent lymphomas are incurable with current therapy. Novel effective therapies are therefore needed to treat these patients. The goal of our research is to develop novel biologic therapies for patients with B-cell NHL by utilizing strategies that augment the immune response to the malignant B-cell. During the previously funded period we evaluated whether adding IL-12, an immunostimulatory cytokine, to rituximab in patients with B-cell lymphoma would increase the antibody dependent cytotoxicity of rituximab. In the clinical trial, we found that IL-12 did not significantly increase the response rate above what would be expected with rituximab alone. In correlative studies we found that IL-12 resulted in upregulation of genes in peripheral blood cells but did not have similar effects in the tumor. In laboratory studies, we found that the lack of effector cell response to immune stimulation with IL-12 was related in part to the presence of intratumoral T-cells with suppressive function. Recent studies have suggested that CD4+CD25+ regulatory T (Treg) cells are involved in the regulation of anti-tumor immunity by inducing peripheral tolerance to tumor specific antigens. However, there are little data regarding the effect of Treg cells on tumor-specific T cell immunity in B-cell NHL and subsequently on the malignant B-cell growth. In preliminary studies, we have identified a subset of CD4+CD25+ T cells with a Treg cell phenotype that are present in B-cell NHL. In addition, we find that these Treg cells have the ability to suppress tumor-infiltrating CD4+ and CD8+ T cells in B-cell NHL and that they migrate in response to chemokines such as CCL22 produced by the malignant B-cells. Our central hypothesis is that tumor Treg cells contribute to the growth of malignant lymphoma B cells by suppressing tumor-infiltrating T cells and that malignant B-cells play an active role by selectively recruiting Treg cells to the areas of B-cell NHL. We therefore propose to firstly determine the mechanism by which these Treg cells are recruited to the malignant B-cell microenvironment in non-Hodgkin lymphoma and to discover whether they gain suppressive activity when present in the tumor microenvironment (Aim 1). Secondly, we will assess whether malignant B-cells interact directly with Treg cells in the tumor microenvironment and thereby orchestrate tolerance to their presence (Aim 2). Thirdly, we will establish whether depletion of intratumoral Treg cells, and inhibition of malignant B-cells to decrease Treg cell recruitment, will result in clinical benefit for patients with B-cell NHL (Aim 3). We anticipate that the proposed research will provide a better understanding of the Treg cell-mediated effects in B-cell malignancies. We also anticipate that the clinical use of denileukin diftitox, an interleukin-2 and diphtheria toxin fusion protein, in combination with rituximab, an anti-CD20 monoclonal antibody, will inhibit Treg cells in B-cell lymphoma patients and will also deplete lymphoma B-cells in malignant lymph nodes thereby preventing further recruitment of Treg cells into areas of B-cell lymphoma. This treatment combination will lead to a novel therapeutic approach to modulating Treg cells that will result in clinical benefit for patients with B-cell NHL.