Inhibition of CD38 NADase by anti-CD38 antibody: a novel therapy for systemic scleroderma

摘要 Teneobio的抗体（Ab）开发专家将与西北大学的系统性硬化症 (SSc)，肌成纤维细胞和烟酰胺腺嘌呤二核苷酸（NAD）代谢专家， 新的发现将CD 38抑制作为纤维化的治疗范例推进临床;最终目标是 开发选择性阻断CD 38 NAD酶的仅全人重链多价/双互补位Ab 活性，同时保持CD 38+细胞完整。SSc是一种与炎症相关的慢性孤儿病， 皮肤、肺和其他器官的纤维化，导致它们的衰竭。SSc关键效应子是肌成纤维细胞，但它们的 来源和持久性因素尚不清楚。SSc患者表现出细胞衰老的标志，包括细胞衰老的减少。 皮肤和肺中长寿相关SIRT赖氨酸脱乙酰酶的活性。SIRT活性抑制肌成纤维细胞 激活并受到NAD+生物利用度的严格调节，NAD+生物利用度的缺乏是年龄相关功能和 代谢下降CD 38是导致衰老中NAD+生物利用度降低的主要NMNase/NAD ase。 类似地，在SSc模型中，组织和血清中的NAD+水平降低，并且CD 38显著上调， 威尔斯，如SSc皮肤活检。在基质细胞中，CD 38具有直接的促纤维化作用，导致持续的肌纤维化。 成纤维细胞活化和纤维化;而选择性CD 38 NAD酶抑制，显示出体外抗纤维化作用， in vivo.因此，我们假设CD 38 NAD酶活性抑制可以预防和逆转组织NAD+， 因此，在SSc纤维化治疗中具有很高的前景。当前小 复合抑制剂和抗CD 38单克隆抗体不适合SSc，需要新的方法。 Teneobio开发了一个平台，该平台基于（i）全人重链单克隆抗体（UniAb）;（ii）高通量 NGS生物信息学管道;和（iii）专有的UniAb生产大鼠。UniAb的结构有利于多价 结合性、稳定性、上级安全性以及它们的小结合位点特别适合于酶阻断。 Teneobio鉴定了抑制人CD 38的UniAb组合和替代抗鼠CD 38 UniAb， 提高体内组织和血清中的烟酰胺单核苷酸（NMN）和NAD+。具体目标#1 该项目将侧重于使用靶向CD 38酶活性的UniAb进行体内小鼠概念验证研究， 测试其水解酶抑制剂在老年和年轻博莱霉素-纤维化模型小鼠中是否可以增加组织 NMN和NAD，并减少多个器官的纤维化和炎症;以及 CD 38在老年小鼠纤维化器官中的表达将导致有效的治疗反应。这将有助于阶段 II IND使SA#2中确定的临床候选药物的动物研究成为可能。具体目标#2将侧重于识别 和使用先前鉴定的序列表征人CD 38的高亲和力酶阻断剂 结合并部分中和细胞上的CD 38的家族和部分阻断的UniAb，以组合成一个 单一可行的候选药物这些研究将提供新的和临床相关的纤维化知识， 关于SSc和其他无法治疗的疾病的关键临床前数据，这些疾病的特征是未消退的纤维化。

ABSTRACT Teneobio’s antibody (Ab) development experts will join forces with Northwestern University’s systemic sclerosis (SSc), myofibroblasts and nicotinamide adenine dinucleotide (NAD) metabolism experts, to capitalize on recent novel findings to advance CD38 inhibition as a therapeutic paradigm in fibrosis into the clinic; with the end goal of developing a fully human heavy chain only multivalent/biparatopic Ab that selectively blocks CD38 NADase activity while leaving CD38+ cells intact. SSc is a chronic orphan disease associated with inflammation and fibrosis of skin, lungs and other organs, resulting in their failure. SSc key effectors are myofibroblasts but their origin and persistence factors are unknown. SSc patients display hallmarks of cellular aging, including diminished activity of longevity-associated SIRT lysine deacetylases in skin and lung. SIRT activity inhibits myofibroblasts activation and is tightly regulated by NAD+ bioavailability, shortage of which underlies age-related functional and metabolic decline. CD38 is the principal NMNase/NADase responsible for reduced NAD+ bioavailability in aging. Similarly, NAD+ levels in tissue and serum are reduced and CD38 is significantly upregulated in SSc models, as wells as in SSc skin biopsies. In stromal cells, CD38 had a direct profibrotic effect, leading to persistent myofi- broblast activation and fibrosis; while selective CD38 NADase inhibition, showed anti-fibrotic effects in vitro and in vivo. Therefore, we hypothesize that CD38 NADase activity inhibition can prevent and reverse tissue NAD+ depletion and attenuate multiorgan fibrosis, thus holding high promise for SSc fibrosis treatment. Current small compound inhibitors and anti-CD38 monoclonal Abs are unsuitable for SSc, necessitating a novel approach. Teneobio developed a platform based on (i) fully human heavy chain only Abs (UniAbs); (ii) high-throughput NGS bioinformatics pipeline; and (iii) proprietary UniAb-producing rats. UniAbs’ structure facilitates multivalent binding, stability, superior safety profiles, and their small binding sites are uniquely suited for enzyme blockade. Teneobio identified UniAbs combinations inhibiting human CD38, and a surrogate anti-murineCD38 UniAb able to raise nicotinamide mononucleotide (NMN) and NAD+ in tissues and serum in vivo. Specific Aim #1 of this project will focus on in vivo murine proof-of-concept studies using UniAbs targeting CD38 enzymatic activity, to test whether its hydrolase inhibition in both old and young bleomycin-fibrosis model mice can augment tissue NMN and NAD and reduce fibrosis and inflammation in multiple organs; and whether the age-dependent rise in CD38 expression in fibrotic organs of old mice will lead to potent therapeutic response. This will facilitate Phase II IND enabling animal studies for clinical candidates identified in SA#2. Specific Aim #2 will focus on identification and characterization of high-affinity enzymatic blockers of human CD38, using previously identified sequence families that bound and partially neutralized CD38 on cells and partial-blocking UniAbs, to be combined into a single viable drug candidate. These studies will provide novel and clinically relevant knowledge of fibrosis and critical pre-clinical data regarding SSc and other untreatable diseases characterized by unresolving fibrosis.