Base-Edited Hematopoietic Stem and Progenitor Cells To Enable Safe Use Of Highly Potent CD33-Targeted Radioimmunotherapy

碱基编辑造血干细胞和祖细胞可安全使用高效 CD33 靶向放射免疫疗法

基本信息

批准号：
10346735
负责人：
Roland Bruno Walter
金额：
$ 74.3万
依托单位：
FRED HUTCHINSON CANCER CENTER
依托单位国家：
美国
项目类别：
财政年份：
2022
资助国家：
美国
起止时间：
2022-07-01 至 2027-06-30
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10346735
关键词：
Actinium Acute Myelocytic Leukemia Address Adenine Adverse event Alpha Particle Emitter Animal Model Animals Antibodies Antibody-drug conjugates Antigens Astatine Autologous Blood Cells CD69 antigen CRISPR/Cas technology Caliber Cell Cycle Arrest Cell Surface Proteins Cell surface Cells Chromosomal Rearrangement Clinic Clinical Complex Coupled Cytidine DNA Damage DNA Double Strand Break Data Development Disease Dose Engineering Engraftment Focus Groups Gemtuzumab Ozogamicin Genes Glycoproteins Guide RNA Hematopoiesis Hematopoietic Hematopoietic stem cells Human Human Engineering In Vitro Infection Life Measures Mediating Messenger RNA Methods Modeling Modification Monitor Monoclonal Antibodies Mus Mutation Myeloid Cells Myelosuppression Neoplasms Normal Cell Nucleotides Patients Pharmaceutical Preparations Proteins Radiation Radioimmunoconjugate Radioimmunotherapy Radioisotopes Radiolabeled Radiopharmaceuticals Recurrence Research Personnel Resistance Risk Safety Stem cell transplant T-Lymphocyte TP53 gene Technology Testing Therapeutic Toxic effect Variant acute myeloid leukemia cell arm base base editing base editor cell killing clinical translation clinically relevant delivery vehicle early onset early phase clinical trial humanized mouse improved improved outcome in vivo interest leukemia leukemic stem cell mouse model multidisciplinary neoplastic cell next generation sequencing nonhuman primate novel nuclease pre-clinical preclinical study reconstitution response screening stem cells targeted treatment transplant model

项目摘要

ABSTRACT Antigen-specific therapies have long been pursued to improve outcomes in acute myeloid leukemia (AML). So far most exploited are monoclonal antibodies (mAbs) targeting CD33, a glycoprotein displayed on the cell surface of leukemic blasts in almost all cases and possibly leukemia stem cells in some. Longer survival of some patients treated with the CD33 antibody-drug conjugate gemtuzumab ozogamicin (GO) validates this approach, but GO is often ineffective, prompting efforts to develop improved, more potent CD33-directed therapeutics. Because AML cells are exquisitely sensitive to radiation in a dose-dependent fashion, radionuclides are ideal to arm anti- CD33 mAbs. Indeed, early phase clinical trials demonstrated substantial anti-AML efficacy of the anti-CD33 mAb lintuzumab (HuM195, SGN-33) when coupled with the a-emitter actinium-225 (225Ac). a-emitters deliver a very high amount of radiation over just a few cell diameters, thereby enabling precise and efficient target cell kill, rendering them particularly interesting for specific targeting of AML with radioimmunoconjugates (“RIT”). However, even with 225Ac-lintuzumab, an important shortcoming is CD33 expression on normal myeloid cells, which leads to “on-target, off-tumor cell” toxicities that manifest as severe and prolonged myelosuppression with life-threatening sequelae (e.g. infection). Thus, clinical use of CD33-directed RIT without immediate stem cell rescue is currently limited to suboptimal drug doses. We have recently demonstrated in mice and nonhuman primates that CRISPR/Cas9 nuclease-based editing of CD33 results in functionally normal hematopoiesis that expresses reduced levels of CD33 and is protected from GO and CD33-directed T cell-engaging therapeutics. We hypothesize CD33-edited normal hematopoietic stem and progenitor cells (HSPCs) will resist CD33-directed RIT with a-particle-emitting radionuclides and enable their safe use at maximally effective drug doses. However, the CRISPR/Cas9-based CD33 gene editing strategy suffers from significant off-target activity, and DNA double strand breaks (DSBs) can generate larger deletions and complex chromosomal rearrangements and cause TP53-dependent DNA damage response and cell cycle arrest. To address this limitation, we will optimize and characterize a novel gene-editing strategy to protect normal hematopoiesis from highly potent CD33-directed RIT by utilizing the recently described base editor (BE) technology. BEs induce precise nucleotide modifications without intentional introduction of DSBs, making them an attractive strategy to generate CD33null “normal” hematopoietic cells. We have assembled a multidisciplinary team of investigators with complementary expertise in CD33-directed therapies, preclinical optimization of RIT, and radiopharmaceutics to conduct well-controlled preclinical IND-enabling studies to develop BE-based CD33 engineering of normal human HSPCs for clinical use with a-emitter CD33-directed RIT for patients with AML and other CD33-expressing disorders.

抽象的长期以来，人们一直在寻求抗原特异性疗法来改善急性髓系白血病（AML）的预后。目前最常用的是针对 CD33 的单克隆抗体 (mAb)，CD33 是一种细胞表面的糖蛋白几乎所有病例中都存在白血病原始细胞，某些患者的生存期可能更长。用 CD33 抗体-药物缀合物 gemtuzumab ozogamicin (GO) 治疗验证了这种方法，但是 GO 通常无效，促使人们努力开发改进的、更有效的 CD33 导向疗法。 AML 细胞对辐射极其敏感，且呈剂量依赖性，放射性核素是武装抗-AML 细胞的理想选择。事实上，早期临床试验证明了抗 CD33 mAb 具有显着的抗 AML 功效。林妥珠单抗 (HuM195、SGN-33) 与 α 发射极 Actinium-225 (225Ac) 结合使用时可提供非常好的效果。仅在几个细胞直径上产生大量辐射，从而能够精确有效地杀死目标细胞，这使得它们对于用放射免疫结合物（“RIT”）特异性靶向 AML 非常有意义。然而，即使使用 225Ac-lintuzumab，一个重要的缺点是正常骨髓细胞上的 CD33 表达，这会导致“靶向、脱肿瘤细胞”毒性，表现为严重且长期的骨髓抑制危及生命的后遗症（例如感染）因此，临床上使用CD33定向的RIT无需立即使用干细胞。我们最近在小鼠和非人类身上证明了救援目前仅限于次优药物剂量。灵长类动物基于 CRISPR/Cas9 核酸酶的 CD33 编辑导致功能正常的造血功能 CD33 表达水平降低，并免受 GO 和 CD33 导向的 T 细胞参与疗法的影响。我们接受 CD33 编辑的正常造血干细胞和祖细胞 (HSPC) 将抵抗 CD33 定向 RIT 具有发射α粒子的放射性核素，并使其能够在最大有效药物剂量下安全使用。基于 CRISPR/Cas9 的 CD33 基因编辑策略存在显着的脱靶活性和 DNA 双倍链断裂 (DSB) 会产生更大的缺失和复杂的染色体重排，并导致为了解决这一限制，我们将优化和优化 TP53 依赖性 DNA 损伤反应和细胞周期停滞。描述了一种新的基因编辑策略，以保护正常造血免受高效 CD33 导向的影响 RIT 利用最近描述的碱基编辑器 (BE) 技术诱导精确的核苷酸修饰。无需有意引入 DSB，使其成为生成 CD33null“正常”的有吸引力的策略我们组建了一支具有互补专业知识的多学科研究团队。 CD33定向疗法、RIT临床前优化和放射性药物以进行良好的控制临床前 IND 支持研究，开发正常人类 HSPC 的基于 BE 的 CD33 工程，用于临床与 a 发射体 CD33 定向 RIT 一起用于治疗 AML 和其他表达 CD33 的疾病患者。