Eltrombopag for the Treatment of Bone Marrow Failure Syndromes

艾曲波帕治疗骨髓衰竭综合征

• 批准号: 10699730
• 负责人: Andre LaRochelle
• 金额: $ 61.83万
• 依托单位: NATIONAL HEART, LUNG, AND BLOOD INSTITUTE
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10699730
• 关键词: AML/MDS; Adverse event; Affect; Affinity; Age; Allogenic; American Society of Hematology; Androgens; Anemia; Aplastic Anemia; Autologous; Blood; Blood Platelets; Bone Marrow; Bone Marrow Examination; Bone marrow failure; Bypass; CD34 gene; CRISPR/Cas technology; Cell division; Cells; Cellularity; Cessation of life; Chemotherapy and/or radiation; Chromosome abnormality; Clinical; Clinical Trials; Collection; Colony-Forming Units Assay; Common Terminology Criteria for Adverse Events; Cytogenetics; DNA Double Strand Break; DNA Repair; DNA replication fork; Disease; Disease Progression; Donor person; Dose; Double Strand Break Repair; Dysplasia; E. coli bacteremia; Enrollment; Ethnic Origin; Evaluable Disease; Exhibits; Extracellular Domain; Failure; Fanconi Anemia Complementation Group A Protein; Fanconi Anemia pathway; Fanconi Anemia-BRCA Pathway; Fanconi' s Anemia; Fibrosis; Frequencies; Funding; Genes; Genetic; Genome Stability; Germ-Line Mutation; Hematological Disease; Hematology; Hematopoiesis; Hematopoietic; Hemoglobin; Hemorrhage; Human; Hypersensitivity; Immune; Immune mediated destruction; Impairment; In Vitro; Ineffective Hematopoiesis; Infection; Inflammation; Inflammation Mediators; Inflammatory; Inherited; Interferons; Interruption; Investigation; Iron; Iron Chelating Agents; Iron Overload; Karyotype determination procedure; Lead; Life; Malignant - descriptor; Marrow; Maximum Tolerated Dose; Mediating; Metaphase; Modality; Molecular; Monosomy 7; Morphology; Mus; Natural regeneration; Nonhomologous DNA End Joining; Oral; Outcome; PF4 Gene; Pathogenicity; Pathway interactions; Patients; Phase; Phase I/II Clinical Trial; Property; Publishing; Refractory; Regimen; Research; Research Personnel; Residual state; Safety; Sepsis; Series; Signal Pathway; Signal Transduction; Signal Transduction Inhibition; Solid Neoplasm; Specimen; Stem cell transplant; TNF gene; Testing; Therapeutic; Therapeutic immunosuppression; Thrombopoietin; Time; Toxic effect; Transplant Recipients; Transplantation; Work; bone marrow failure syndrome; clinical efficacy; clinically significant; conditioning; crosslink; cytopenia; disorder risk; improved; indexing; insight; iron supplementation; knock-down; loss of function mutation; member; mimetics; myeloblast; neutrophil; novel; novel therapeutics; patient response; peripheral blood; preclinical study; progenitor; prospective; receptor; replication stress; response; side effect; small molecule; stem cells

Objective 1: Characterize the mechanisms by which Epag promotes trilineage hematopoiesis. 1.1 Epag evades IFN blockade of signal transduction from c-MPL in human HSPCs To determine whether EPAG can offer a new therapeutic modality for hematopoietic regeneration in patients with IBMFS, we first sought to gain insights into the molecular mechanisms by which EPAG could enhance trilineage hematopoiesis in subjects with AA. Paradoxically, TPO levels are already markedly elevated in patients with severe AA; how adjunct therapy with the TPO mimetic EPAG could improve the stem cell deficit was thus a conundrum. Because marrow failure in AA largely results from the suppressive effects of IFN, we hypothesized that EPAG might support HSPC survival by activating signaling pathways in these cells distinctly from endogenous TPO under inflammatory conditions. To test this possibility, we directly compared the effect of IFN on human HSPCs in the presence of TPO or EPAG in vitro. We made two observations. First, we found that IFN perturbed TPO-induced signaling pathways in human HSPCs and that EPAG could bypass this inhibition, resulting in enhanced progenitor activity and long-term HSPC repopulating potential in the presence of IFN. Second, we showed that IFN disrupted the low-affinity interaction between TPO and the extracellular domain of c-MPL by forming TPO-IFN heteromers, delineating a novel molecular mechanism by which IFN inhibits TPO signaling in HSPCs. EPAG may bypass the inflammatory inhibition of signal transduction by avoiding capture by IFN in the BM, thus providing an explanation for its clinical efficacy in AA, despite already elevated levels of TPO in these patients. This work was published Blood 133:2043-55 (2019). 1.2 Epag promotes DNA DSB repair in human HSPCs. To further elucidate the mechanisms by which EPAG improves hematopoiesis and assess its therapeutic potential in FA, we investigated whether EPAG could promote DNA repair in human HSPCs. We demonstrated that EPAG specifically activated the classical non-homologous end joining (C-NHEJ) DNA DSB repair mechanism, a pathway known to support genomic stability, in both normal human HSPCs and donor HSPCs subjected to CRISPR/Cas9-mediated knockdown of FANCA. Importantly, EPAG-mediated DNA repair resulted in enhanced genomic stability, survival, and function of primary human HSPCs, as demonstrated in karyotyping analyses, colony-forming unit (CFU) assays and after transplantation into immunodeficient NSG mice. This work was published Exp Hematol 73:1-6 (2019). Objective 2: Evaluate the safety and efficacy of Epag in subjects with Fanconi anemia. The ability of EPAG to stimulate multipotent long-term repopulating HSPCs in patients with AA, to maintain HSPCs under inflammatory conditions and to promote DNA repair in these cells suggested potential therapeutic relevance in FA-associated BMF. We have initiated an investigator-sponsored prospective phase I/II clinical trial of EPAG in Fanconi anemia (NCT03204188) and enrolled 14 patients to date (FANCA, n=12 and FANCC, n=2). One subject withdrew early after identifying a suitable matched donor for transplant. All other subjects received EPAG at an oral daily dose adjusted for age and ethnicity. The primary efficacy endpoint was the proportion of subjects with at least 2-fold increase in marrow cellularity or CD34+ HSPC frequency (marrow response), or clinically significant improvement in peripheral blood (PB) counts at 6 months (blood response). The primary safety endpoint was the global toxicity profile assessed at 6 months using CTCAE criteria. Responders were invited to continue EPAG on an extension phase of the study for an additional 3 years. Ten of the 13 evaluable patients have reached the 6-month assessment endpoint. A marrow response was observed in 9 subjects at 6 months; the marrow specimens were of poor quality at baseline and 6 months for one patient and response assessment could not be performed. Mean marrow cellularity increased by a factor of 4.1, and CD34+ HSPC frequency improved 1.6-fold at 6 months relative to pre-treatment values. Primary PB response was observed in 7 of 10 patients in one (hemoglobin, n=4) or two lineages (hemoglobin and platelets, n=3) at 6 months of treatment. One patient who had a marrow but no PB response underwent an unrelated allogeneic HSPC transplantation and is clinically well. The other nine subjects received EPAG on the extension phase of the study (range, 12 to 40 months) with stable or improving blood counts. One patient who had stable but no increase in PB counts at 6 months displayed a unilineage response at 12 months and three subjects met criteria for trilineage response at 9, 21 and 24 months, respectively. All evaluable patients tolerated the maximum dose of EPAG and no interruption or dose reduction was required for adverse events attributable to EPAG. Patients without transfusional iron overload at study entry developed progressive depletion of iron stores attributable to the known potent iron chelating and mobilizing properties of EPAG. At a median of 3 months after initiating EPAG (range, 1 to 6 months), affected patients initiated daily oral iron supplementation with gradual amelioration of iron depletion. To date, there has been no occurrence of marrow fibrosis, solid tumors or overt clinical transformation to MDS/AML. However, we recently observed monosomy 7 on standard metaphase analysis in one subject treated with EPAG for 12 months. There was no associated morphologic dysplasia or increased myeloblasts. Several studies have recognized cytogenetic abnormalities on BM examination of untreated FA patients, many of them noting a high frequency of monosomy 7; thus, attribution of aberrant cytogenetics to EPAG cannot be confirmed in this patient. Nevertheless, given the well-documented association between monosomy 7 and increased risk for disease progression, EPAG was discontinued and he underwent an allogeneic stem cell transplantation. He is clinically well. One subject who had no improvement in neutrophil counts developed Escherichia coli bacteremia and sepsis-related death occurred after 13 months of treatment with eltrombopag. This work was presented at the American Society of Hematology (ASH 2019, ASH 2021) and the Fanconi Anemia Research Funds (FARF 2021, FARF 2022).

目标1：表征EPAG促进三利属造血的机制。 1.1 EPAG逃避人类HSPC中C-MPL的信号转导的IFN阻塞 为了确定EPAG是否可以为IBMF患者的造血再生提供一种新的治疗方式，我们首先寻求深入了解EPAG可以增强AA受试者的三立碱造血的分子机制。矛盾的是，严重AA患者的TPO水平已经显着升高。因此，使用TPO模拟EPAG的辅助疗法如何改善干细胞不足是一个难题。由于AA的骨髓衰竭很大程度上是由于IFN的抑制作用而引起的，因此我们假设EPAG可以通过在炎症条件下从内源性TPO中明显激活这些细胞中的信号通路来支持HSPC存活。为了测试这种可能性，我们直接比较了在体外TPO或EPAG存在下IFN对人HSPC的影响。我们进行了两个观察。首先，我们发现IFN扰动TPO诱导的人类HSPC中的信号通路，并且EPAG可以绕过这种抑制作用，从而导致祖细胞活性增强，并在IFN存在下长期HSPC重新启动潜力。其次，我们表明IFN通过形成TPO-IFN异构体，破坏了TPO与C-MPL的细胞外域之间的低亲和力相互作用，从而描绘了一种新型的分子机制，IFN抑制了HSPC中的TPO信号传导。 EPAG可以通过避免在BM中捕获IFN来绕过对信号转导的炎症抑制，从而为AA的临床疗效提供了解释，尽管这些患者的TPO水平已经升高。这项工作是出版了血液133：2043-55（2019）。 1.2 EPAG促进人类HSPC中的DNA DSB修复。 为了进一步阐明EPAG改善造血并评估其在FA中的治疗潜力的机制，我们研究了EPAG是否可以促进人类HSPC中的DNA修复。我们证明，EPAG专门激活了经典的非同源末端连接（C-NHEJ）DNA DSB修复机制，这是一种已知支持基因组稳定性的途径，在正常的人类HSPC和供体HSPC中，受到FANCA的CRIS/CAS9介导的FANCAD的供体HSPC。重要的是，EPAG介导的DNA修复导致原代人HSPC的基因组稳定性，存活和功能增强，如在核分析分析，菌落形成单元（CFU）测定以及移植到免疫缺陷型NSG小鼠中后所证明的。这项工作发表了Exp Hematol 73：1-6（2019）。 目标2：评估EPAG在Fanconi贫血受试者中的安全性和功效。 EPAG在AA患者中刺激多能量重塑HSPC，在炎症条件下维持HSPC并促进这些细胞中DNA修复的能力表明在FA相关的BMF中具有潜在的治疗性相关性。我们已经启动了Fanconi贫血（NCT03204188）的EPAG的研究者发起的前瞻性I/II期临床试验，并招募了14名患者（Fanca，n = 12和FANCC，FANCC，n = 2）。一名受试者在识别出适当的匹配供体进行移植后提早退出。所有其他受试者都接受了针对年龄和种族调整的口服剂量的EPAG。主要疗效终点是受试者的比例至少增加了骨髓细胞或CD34+ HSPC频率（骨髓反应）的比例，或者在6个月时外周血（PB）计数的临床显着改善（血液反应）（血液反应）。主要的安全终点是使用CTCAE标准在6个月时评估的全球毒性特征。邀请响应者在研究的扩展阶段继续进行EPAG，再进行3年。 在13名可评估患者中，有10名已达到6个月的评估终点。在6个月时，在9名受试者中观察到骨髓反应；基线时骨髓标本的质量较差，一名患者的骨髓标本质量较差，无法进行反应评估。平均骨髓细胞度增加了4.1倍，相对于治疗预处理值，CD34+ HSPC频率在6个月时提高了1.6倍。在治疗6个月后，在10例（血红蛋白，n = 4）或两个谱系（血红蛋白和血小板，n = 3）的10例患者中，有7例中有7例PB反应。一名患有骨髓但没有PB反应的患者接受了无关的同种异体HSPC移植，并且在临床上很好。其他九名受试者在研究的扩展阶段（范围为12至40个月）接受了EPAG，并具有稳定或改善的血液计数。一名患有稳定但PB计数增加的患者在12个月时表现出单英寸的反应，三名受试者分别符合9、21和24个月的三利反应标准。 所有可评估的患者均能耐受EPAG的最大剂量，并且不需要造成EPAG的不良事件中断或减少剂量。研究进入时没有递交铁超负荷的患者发展了归因于已知的有效铁螯合和动员EPAG特性的铁储存的逐渐消耗。在发起EPAG（范围为1至6个月）后3个月的中位数，影响患者每天恢复口服铁，并逐渐改善铁耗尽。迄今为止，还没有发生骨髓纤维化，实体瘤或向MDS/AML的明显临床转化。然而，我们最近在用EPAG治疗的一名受试者中观察到了第7个中期分析中的单肌。没有相关的形态发育不良或骨髓细胞增加。几项研究已经识别出对未治疗的FA患者的BM检查的细胞遗传学异常，其中许多人注意到了7个单肌的高频。因此，在该患者中无法确认异常的细胞遗传学对EPAG的归因。然而，鉴于单根系7和疾病进展的风险增加了有据可查的关联，EPAG被停用，他接受了同种异体干细胞的移植。他在临床上很好。在用Eltrombopag治疗13个月后，一名没有改善中性粒细胞计数的受试者发生大肠杆菌菌血症和败血症相关死亡。这项工作是在美国血液学学会（Ash 2019，Ash 2021）和Fanconi贫血研究基金（Farf 2021，Farf 2022）中介绍的。