The chimeric antigen receptor (CAR) derived from the CD30 specific murine antibody, HRS-3, has produced promising clinical efficacy with a favorable safety profile in the treatment of relapsed or refractory CD30-positive lymphomas. However, persistence of the autologous CAR-T cells was brief, and many patients relapsed a year after treatment. The lack of persistence may be attributed to the use of a wild-type immunoglobulin (Ig)G1 spacer that can associate with Fc receptors. We first identified the cysteine-rich domain (CRD) 5 of CD30 as the primary binding epitope of HRS-3 and armed with this insight, attempted to improve the HRS-3 CAR functionality with a panel of novel spacer designs. We demonstrate that HRS-3 CARs with OX40 and 4-1BB derived spacers exhibited similar anti-tumor efficacy, circumvented interactions with Fc receptors, and secreted lower levels of cytokines than a CAR employing the IgG1 spacer. Humanization of the HRS-3 scFv coupled with the 4-1BB spacer preserved potent on-target, on-tumor efficacy, and on-target, off-tumor safety. In a lymphoma mouse model of high tumor burden, T cells expressing humanized HRS-3 CD30.CARs with the 4-1BB spacer potently killed tumors with low levels of circulating inflammatory cytokines, providing a promising candidate for future clinical development in the treatment of CD30-positive malignancies.

中文翻译：

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新型 OX40 和 4-1BB 衍生间隔物增强 CD30 阳性淋巴瘤模型中的 CD30 CAR 活性和安全性


源自 CD30 特异性鼠抗体 HRS-3 的嵌合抗原受体 (CAR) 在治疗复发或难治性 CD30 阳性淋巴瘤方面产生了良好的临床疗效和良好的安全性。然而，自体 CAR-T 细胞的持续时间很短，许多患者在治疗一年后复发。缺乏持久性可能是由于使用了可与 Fc 受体结合的野生型免疫球蛋白 (Ig)G1 间隔区。我们首先确定了 CD30 的富含半胱氨酸结构域 (CRD) 5 作为 HRS-3 的主要结合表位，并利用这一见解，尝试通过一组新颖的间隔区设计来改善 HRS-3 CAR 功能。我们证明，与使用 IgG1 间隔基的 CAR 相比，具有 OX40 和 4-1BB 衍生间隔基的 HRS-3 CAR 表现出相似的抗肿瘤功效，避免了与 Fc 受体的相互作用，并且分泌的细胞因子水平较低。 HRS-3 scFv 人源化与 4-1BB 间隔区结合保留了有效的在靶、在肿瘤功效以及在靶、脱肿瘤安全性。在高肿瘤负荷的淋巴瘤小鼠模型中，表达带有 4-1BB 间隔区的人源化 HRS-3 CD30.CAR 的 T 细胞可有效杀死循环炎症细胞因子水平较低的肿瘤，为未来 CD30 治疗的临床开发提供了有希望的候选者- 阳性恶性肿瘤。