Adoptive transfer of gene-modified autologous T-cells post-ASCT for myeloma

描述(申请人提供)：尽管进行了大剂量化疗、自体干细胞移植(ASCT)和靶向治疗，骨髓瘤仍在很大程度上无法治愈。回顾研究表明，较好的临床结果可能与移植后早期较快的淋巴细胞恢复有关。此外，在未经治疗的骨髓瘤患者的骨髓或血液中，肿瘤反应性T细胞的出现频率很低。因此，加强自体T细胞移植后的恢复和功能的策略可能在临床上是有益的。此外，它们有可能与目前的治疗方法协同作用，促进缓解并实现长期无病生存。我们已经对多发性骨髓瘤的过继转移T细胞治疗进行了多项试验，验证了通过静脉输注体外CD28共刺激T细胞来改善T细胞恢复可能为移植后免疫治疗提供平台和增强疫苗策略的假设。在促进中枢记忆细胞和Th1/Tc1功能的条件下，用人工抗原提呈细胞刺激自体T细胞。在第一项研究中，使用7价肺炎球菌结合疫苗(PCV)作为明确的抗原，使我们能够证明体内疫苗启动的自体T细胞和体外共刺激的自体T细胞在移植后早期的过继转移可以促进T细胞的恢复，并产生疫苗特异性的T和B细胞反应。在第二项研究中，这个联合疫苗和T细胞免疫治疗的平台也在相当大比例的患者中产生了对由人端粒酶(HTERT)多肽和Survivin组成的假定肿瘤抗原疫苗的免疫反应。目前，我们正在研究是否可以通过使用基于MAGE-A3的不同疫苗和一种名为Poly-ICLC(TLR-3受体激动剂)的新型疫苗佐剂来增强骨髓瘤导向的免疫反应的频率和幅度。然而，到目前为止，我们采取的方法至少有两个潜在的缺点：i)过继转移的T细胞是多克隆的，因此只有一小部分真正针对骨髓瘤肿瘤细胞；ii)骨髓瘤的特异性依赖于在收集和共刺激/扩增之前成功的自体T细胞的“启动”，这一过程效率低下，特别是在恶性活动的背景下。为了解决有效免疫治疗的这些障碍，我们将通过转导慢病毒构建体对自体T细胞进行基因修饰，慢病毒构建体编码来自肿瘤抗原MAGE-A3和NY-ESO-1的两个自然处理表位的高亲和力T细胞受体(TCR)。这些肿瘤/睾丸肿瘤抗原(CTAgs)在骨髓瘤细胞中频繁且特异地表达。我们将专门研究这些转导细胞在自体干细胞移植(ASCT)后是否能很快安全地转移，以及这些基因修饰的T细胞是否在患者体内持续存在、发挥作用和靶向骨髓瘤细胞。我们还将使用来那度胺作为骨髓瘤移植后的维持治疗和可能的免疫调节剂。最近的研究表明来那度胺可能具有重要的免疫刺激作用。如果这项研究表明TCR基因修饰的T细胞是安全和有功能的，那么ASCT和过继转移“重定向”的自体T细胞的组合策略可能是一个有效的骨髓瘤和其他血液肿瘤移植后免疫治疗的平台。

DESCRIPTION (provided by applicant): Myeloma remains largely incurable in spite of high-dose chemotherapy and autologous stem cell transplantation (ASCT) and targeted therapies. Retrospective studies suggest that better clinical outcomes may be associated with more rapid lymphocyte recovery during the early post-transplant period. In addition, tumor-reactive T-cells are present at low frequencies in the marrow or blood of untreated patients with myeloma. Thus, strategies to augment the recovery and function of autologous T-cells post-transplant may be clinically beneficial. Furthermore, they have the potential to synergize with current therapies to promote remissions and achieve long term disease free survival. We have conducted several trials of adoptive transfer T cell therapy for multiple myeloma, testing the hypothesis that improved T-cell recovery through intravenous infusion of ex-vivo CD28 costimulated T cells might provide a platform for post-transplant immunotherapy and enhance vaccine strategies. Autologous T-cells were stimulated by artificial antigen presenting cells under conditions that promote central memory cells and Th1/Tc1 function. In the first study, a 7-valent pneumococcal conjugate vaccine (PCV) was used as a well-defined antigen which allowed us to show that the adoptive transfer of in-vivo vaccine-primed and ex-vivo costimulated autologous T-cells early after transplant led to enhanced T-cell recovery and generated vaccine-specific T and B-cell responses. In the second study, this platform of combined vaccine and T-cell immunotherapy also generated immune responses in a significant proportion of patients against a putative tumor antigen vaccine composed of peptides derived from human telomerase (hTERT) and survivin. Currently, we are studying whether the frequency and magnitude of the myeloma-directed immune responses can be enhanced by using a different vaccine based on MAGE-A3 and a novel vaccine adjuvant called Poly-ICLC (a TLR-3 receptor agonist). However, there are at least two potential drawbacks of the approach that we have taken so far: i) the adoptively transferred T-cells are polyclonal and thus only a small proportion are truly directed against the myeloma tumor cells; and ii) the myeloma specificity depends on successful "priming" of the autologous T-cells prior to collection and costimulation/expansion, a process that is inefficient especially in the setting of active malignancy. To address these impediments to effective immunotherapy in this proposal, we will genetically modify autologous T-cells through transduction of lentiviral constructs which encode high-affinity T-cell receptors (TCRs) for two naturally processed epitopes that are derived from tumor antigens MAGE-A3 and NY-ESO-1. These cancer/testis tumor antigens (CTAgs) are frequently and specifically expressed in myeloma cells. We will specifically study whether these transduced cells can be safely transferred very soon after autologous stem cell transplantation (ASCT) and whether these gene-modified T-cells persist, function and target myeloma cells in patients. We will also use lenalidomide both as a post-transplant maintenance treatment for myeloma and as a possible immunomodulator. Recent work indicates that lenalidomide may have important immunostimulatory properties. If this study shows that TCR-gene modified T-cells are safe and functional then this combination strategy of ASCT followed by adoptive transfer of "redirected" autologous T-cells could be a platform for effective post-transplant immunotherapy of myeloma and perhaps other hematologic neoplasms.