一种人源化的 4-1BB 靶向激动性抗体在结直肠癌中发挥强大的抗肿瘤活性，而无全身毒性。

A humanized 4-1BB-targeting agonistic antibody exerts potent antitumor activity in colorectal cancer without systemic toxicity.

机构信息

Department of Geriatrics, The First Affiliated Hospital of University of Science and Technology of China, Gerontology Institute of Anhui Province, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230001, Anhui, China.

Hefei HankeMab Biotechnology Limited, Hefei, 230088, Anhui, China.

出版信息

J Transl Med. 2022 Sep 8;20(1):415. doi: 10.1186/s12967-022-03619-w.

DOI:10.1186/s12967-022-03619-w

PMID:36076251

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC9461191/

Abstract

BACKGROUND

Colorectal cancer (CRC) is one of the most common malignancies and the patient survival rate remains unacceptably low. The anti-programmed cell death-1 (PD-1)/programmed cell death ligand 1 (PD-L1) antibody-based immune checkpoint inhibitors have been added to CRC treatment regimens, however, only a fraction of patients benefits. As an important co-stimulatory molecule, 4-1BB/CD137 is mainly expressed on the surface of immune cells including T and natural killer (NK) cells. Several agonistic molecules targeting 4-1BB have been clinically unsuccessful due to systemic toxicity or weak antitumor effects. We generated a humanized anti-4-1BB IgG4 antibody, HuB6, directed against a unique epitope and hypothesized that it would promote antitumor immunity with high safety.

METHODS

The antigen binding specificity, affinity and activity of HuB6 were determined by enzyme-linked immunosorbent assay (ELISA), surface plasmon resonance (SPR), biolayer interferometry (BLI) and flow cytometry. The antitumor effects were evaluated in humanized mice bearing syngeneic tumors, and possible toxicity was evaluated in humanized mice and cynomolgus monkeys.

RESULTS

HuB6 showed high specificity and affinity for a binding epitope distinct from those of other known 4-1BB agonists, including utomilumab and urelumab, and induced CD8 + T, CD4 + T and NK cell stimulation dependent on Fcγ receptor (FcγR) crosslinking. HuB6 inhibited CRC tumor growth in a dose-dependent manner, and the antitumor effect was similar with urelumab and utomilumab in humanized mouse models of syngeneic CRC. Furthermore, HuB6 combined with an anti-PD-L1 antibody significantly inhibited CRC growth in vivo. Additionally, HuB6 induced antitumor immune memory in tumor model mice rechallenged with 4 × 10 tumor cells. Toxicology data for humanized 4-1BB mice and cynomolgus monkeys showed that HuB6 could be tolerated up to a 180 mg/kg dose without systemic toxicity.

CONCLUSIONS

This study demonstrated that HuB6 should be a suitable candidate for further clinical development and a potential agent for CRC immunotherapy.

摘要

背景

结直肠癌（CRC）是最常见的恶性肿瘤之一，患者的生存率仍然低得令人无法接受。抗程序性细胞死亡-1（PD-1）/程序性细胞死亡配体 1（PD-L1）抗体的免疫检查点抑制剂已被添加到 CRC 治疗方案中，但只有一部分患者受益。作为一个重要的共刺激分子，4-1BB/CD137 主要表达在包括 T 细胞和自然杀伤（NK）细胞在内的免疫细胞表面。几种针对 4-1BB 的激动性分子由于全身毒性或弱抗肿瘤作用而在临床上未能成功。我们生成了一种针对独特表位的人源化抗 4-1BB IgG4 抗体 HuB6，并假设它将以高安全性促进抗肿瘤免疫。

方法

通过酶联免疫吸附试验（ELISA）、表面等离子体共振（SPR）、生物层干涉（BLI）和流式细胞术测定 HuB6 的抗原结合特异性、亲和力和活性。在携带同源肿瘤的人源化小鼠中评估抗肿瘤作用，并在人源化小鼠和食蟹猴中评估可能的毒性。

结果

HuB6 与人源化 IgG1 相比，对不同于其他已知 4-1BB 激动剂（包括utomilumab 和 urelumab）的结合表位具有高特异性和亲和力，并且依赖于 Fcγ 受体（FcγR）交联诱导 CD8+T、CD4+T 和 NK 细胞刺激。HuB6 以剂量依赖性方式抑制 CRC 肿瘤生长，并且在同源 CRC 人源化小鼠模型中，其抗肿瘤作用与 utomilumab 和 urelumab 相似。此外，HuB6 与抗 PD-L1 抗体联合显著抑制体内 CRC 生长。此外，HuB6 在接受 4×10 个肿瘤细胞重挑战的肿瘤模型小鼠中诱导抗肿瘤免疫记忆。人源化 4-1BB 小鼠和食蟹猴的毒理学数据表明，HuB6 可耐受高达 180mg/kg 的剂量而无全身毒性。