抗体偶联药物的技术现状和展望

抗体偶联药物（antibody drug conjugate,ADC）通常由抗体通过链接体与毒素小分子偶联而成,同时具备抗体的高靶向性和小分子药物的高活性,使之作为一种新兴的靶向治疗手段,在肿瘤治疗领域展现出了优秀的疗效和潜力,成为药物研发领域的新热点。目前全球已有14款ADC药物获批上市,处于临床研究阶段的ADC候选药物分子超过140个。为了进一步提高ADC药物的安全性和有效性,近年来涌现出了各种新颖的技术。本文对ADC药物分子的关键元素,包括抗体、链接体、毒素小分子以及偶联技术等方面的最新研究进展进行总结,并讨论其优缺点。期望这些讨论能够帮助增加对ADC药物研究和开发更加系统的理解,为研发出更加高效和安全的ADC药物带来一些思考。     

2014 年全球热门药物靶点分析—— IL-6 靶标药物

IL-6 是一种多效性前炎症细胞因子,具有多种生物学活性,包括介导炎症反应、免疫反应等。随着对 IL-6 及其受体信号通路研究的不断深入,IL-6 现已成为一个有效的治疗靶点,在炎症及自身免疫性疾病的治疗过程中发挥重要作用。采用文献调研、数据库检索、数据统计与分析等定性定量情报学研究方法,从研发阶段、适应证、临床及上市药物等方面对全球 IL-6 靶标药物的研发情况进行分析,旨在为我国免疫药物的研发提供参考。     

抗体药物的发展与应用

早期抗体药物是鼠源单克隆抗体,存在免疫原性强、半衰期短等问题。历经数十年的发展,抗体药物从最初的鼠源单抗,逐步发展为人鼠嵌合抗体、人源化抗体及全人源化抗体。通过片段重组、位点修饰、药物偶联等方法,科研人员研发了包括抗体融合蛋白、抗体偶联药物、双特异性抗体、小分子抗体片段等形式多样的抗体药物。抗体药物在恶性肿瘤、自身免疫病、感染性疾病的治疗上发挥重要作用。通过对抗体药物人源化历程,不同类型的抗体结构和特点,以及抗体药物在新型冠状病毒肺炎治疗中的应用进行综述,并对抗体药物的发展前景进行展望,以期为我国抗体药物的研发提供参考。     

抗肿瘤抗体-药物偶联物的临床研究进展

个体化靶向治疗已成为肿瘤临床治疗的新趋势.抗肿瘤靶向药物与传统的细胞毒性化疗药物相比具有特异性高、选择性强和非细胞毒性等优点,近年来发展迅速.抗体-药物偶联物(ADCs)属于抗肿瘤靶向药物,由抗体、“弹头”药物(细胞毒性药物)通过链分子连接而成.ADCs将抗体的靶向性与细胞毒性药物的抗肿瘤作用相结合,可以降低细胞毒性抗肿瘤药物的不良反应,提高肿瘤治疗的选择性,还能更好地应对靶向单抗的耐药性问题.目前,FDA已批准2种ADC药物上市,即Mylotarg和Adcetris,有多种ADCs处于Ⅰ～Ⅲ期临床试验阶段,取得了显著的临床效果.本文概述了以美登素,卡奇霉素、Auristantin等三种细胞毒性药物为“弹头”药物的ADCs药物的临床研究状况及临床试验结果,为ADCs的研究和应用提供参考.     

基于单克隆抗体的肿瘤免疫疗法研究进展

一百多年前,\"魔术子弹\"学说首次提出了具有靶向特异性的抗体可以用来治疗疾病。此后,随着单克隆抗体制备技术的成熟,以及癌症血清疗法的发展,靶向肿瘤抗原的治疗性抗体开始进入临床,至今已有20余种抗体药物用于癌症的治疗。近两年,以免疫检查点蛋白拮抗剂、双特异性抗体、抗体药物偶联药物等为代表的新一代抗体药物,不断在治疗恶性肿瘤上取得突破性进展。本文回顾了抗肿瘤抗体的发展历程,总结了新一代抗体药物的作用机制与构建策略,以及主要临床副作用。并对基于抗体的肿瘤免疫疗法未来发展趋势进行了展望。     

急性髓系白血病的免疫疗法

急性髓系白血病(acute myeloid leukemia, AML)是一种高度异质性的恶性血液病,复发率较高。尽管化疗在治疗AML中取得了一定的疗效,但部分AML患者无法耐受化疗或化疗后仍有复发。复发是影响患者生存的最重要因素。与化疗相比,免疫疗法能够直接杀伤或者激活免疫系统进而杀伤肿瘤细胞。为了改善患者的远期预后,免疫治疗将成为这部分患者的最佳选择。本文总结了国内外急性髓系白血病免疫治疗的主要方法,包括抗体-偶联药物、双特异性T细胞单链抗体、抗原特异性过继免疫疗法、非抗原特异性过继免疫疗法、免疫检查点抑制剂。本文就免疫疗法在急性髓系白血病中的最新研究进展进行了总结和讨论。     

以Ⅳ型胶原酶为靶点的小型化单抗免疫偶联物的抗肿瘤作用

Ⅳ型胶原酶与肿瘤的侵袭、转移以及新血管生成等过程密切相关. 以Ⅳ型胶原酶为分子靶点, 利用小鼠抗Ⅳ型胶原酶单抗构建了小型化的Fab'片段与高效抗肿瘤抗生素力达霉素(LDM)的免疫偶联物 (Fab'-LDM). 偶联物的分子量约为65 kD, 偶联分子比为1︰1. 以ELISA方法检测, Fab'-LDM偶联物保留了单抗Fab′片段对肝癌22(H22)细胞的免疫结合活性; 以MTT法测定, Fab'-LDM偶联物对肝癌22细胞显示出更强的细胞毒性. 动物体内试验观察对小鼠移植性肝癌22的疗效, 小鼠皮下接种肿瘤, 24 h后开始给药(静脉注射2次, 分别在接种后1和8天), Fab'-LDM偶联物0.025, 0.05和0.10 mg/kg剂量组的抑瘤率分别为76.7%, 93.3%和94.8%, 而游离LDM 0.05 mg/kg的抑瘤率为76.1%; 另一批实验于接种肿瘤96 h后开始给药(静脉注射2次, 分别在接种后4和11天), Fab'-LDM偶联物0.025和0.05 mg/kg组的抑瘤率分别为74.2%和80.9%, 而LDM 0.05 mg/kg组的抑瘤率为60.5%. Fab'-LDM偶联物0.05 mg/kg可显著延长荷瘤小鼠的生存时间, 与同等剂量的游离LDM相比, 延长生存时间的效果更强(P < 0.05). 以上结果表明, 以Ⅳ型胶原酶为靶点的小型化单抗免疫偶联物在肿瘤的实验治疗中有显著的疗效.     

抗体偶联小分子药物T-DM1的ELISA检测方法的建立

目的:建立一种灵敏、特异、快速的ELISA方法,用于检测猕猴血清中T-DM1的含量。方法:采用双抗夹心ELISA法对T-DM1进行定量。以DM1单抗作为一抗包被到96孔板中,加入待检样品,之后再加入稀释好的猴血清吸附的羊抗人IgG-HRP(二抗),使之与结合到一抗上的T-DM1特异性结合,加底物显色,在酶标仪上读取D450nm值。结果:建立了检测T-DM1的ELISA方法并得到确证,方法的线性范围为0.625~80 ng/mL,定量下限为0.625 ng/mL,板内及板间精密度和准确度均在±15%以内,室温、冻融、稀释效应稳定性良好。结论:方法学验证表明ELISA法测定猴血清中T-DM1浓度的特异性、精密度和准确度均满足新生物制药临床前药代动力学研究指导原则要求,可用于T-DM1的检测。     

我国生物技术快速发展的十年

我国生物技术快速发展的十年徐新耒（中国生物工程开发中心,北京１０００８１）现代生物技术是直接操作有机体细胞和基因的一种全新技术,已从７０年代纯学术研究的分子生物学领域,发展为一种关键的工艺性技术,成为解决农业、医疗保健、环境保护诸多问题的重要手段。我国发展生物技术旨在更好地满足人民营养需求和提高人民健康保障水平。     

蛋白药物涂层支架的制备表征与体外释放研究

目的:探讨将蛋白大分子药物以较高的担载量涂层于心脏支架,并在不发生蛋白聚集的前提下实现数周之久缓释的方法.方法:将牛血清白蛋白通过稳定的水相-水相乳液技术制备成多糖玻璃体颗粒,并将多糖玻璃体颗粒分散于聚乳酸溶液中喷涂于支架表面制成蛋白涂层支架,在37°CPBs中进行体外释放动力学研究,用SEC-HPLC比较了蛋白涂层支架制备前后蛋白的聚集情况,并用扫描电镜等对蛋白涂层支架表面进行了表征.结果:蛋白涂层支架在电镜观察下外观圆整,表面光滑,制剂过程中未产生蛋白聚集,且能从涂层中缓慢释放达50天以上.结论:稳定的水相-水相乳液技术及其基础上制备的蛋白多糖玻璃体颗粒应用于心脏支架涂层上,能在有效保护蛋白构象的同时实现蛋白的缓释,为具有抗再狭窄活性蛋白应用于心脏支架提供了技术平台.     

先天性非结合性高胆红素血症的分子诊断、治疗进展

先天性非结合性高胆红素血症是临床常见的胆红素代谢异常,由于缺乏特异性的体征和病理改变,很难得到临床明确诊断。基因水平的检测可以为因葡萄糖醛酸转移酶基因缺陷造成该酶活性下降或缺失而导致的先天性非结合性高胆红素血症提供确诊依据,而在基因水平治疗先天性非结合性高胆红素血症也已取得很大进展。对目前先天性胆红素代谢异常的分子遗传学基础、分子生物学检测方法、常用治疗手段以及基因治疗进展进行了综述。     

针对CD33分子的抗体偶联药物的研究进展

单克隆抗体因具有分子量小、毒副作用低、靶向性好等优点,近年来已成为肿瘤治疗用药的主要方式。CD33分子是免疫球蛋白超家族成员,同时也是唾液酸依赖的免疫球蛋白样凝集素家族的成员,在免疫调节过程中具有重要作用。CD33分子特异表达于白血病细胞表面而在造血干细胞中不表达,因而成为白血病免疫治疗的理想靶点。以CD33为靶点的抗体药物主要有CMA676、HUMl95、AVE9633、WM537LHIM3-4等,目前大多处于临床试验阶段。该实验室也在进行抗CD33全人源抗体的研究,利用噬菌体展示技术筛选与CD33胞外区特异性结合的单链抗体,并构建免疫毒素和抗体偶联药物以研究其体内外抗肿瘤作用。该文针对CD33分子及其抗体偶联药物的现状及趋势作一综述。     

Lorvotuzumab mertansine,a CD56-targeting antibody-drug conjugate with potent antitumor activity against small cell lung cancer in human xenograft models

Lorvotuzumab mertansine (LM) is an antibody-drug conjugate composed of a humanized anti-CD56 antibody, lorvotuzumab, linked via a cleavable disulfide linker to the tubulin-binding maytansinoid DM1. CD56 is expressed on most small cell lung cancers (SCLC), providing a promising therapeutic target for treatment of this aggressive cancer, which has a poor five-year survival rate of only 5–10%. We performed immunohistochemical staining on SCLC tumor microarrays, which confirmed that CD56 is expressed at high levels on most (~74%) SCLC tumors. Conjugation of lorvotuzumab with DM1 did not alter its specific binding to cells and LM demonstrated potent target-dependent cytotoxicity against CD56-positive SCLC cells in vitro. The anti-tumor activity of LM was evaluated against SCLC xenograft models in mice, both as monotherapy and in combination with platinum/etoposide and paclitaxel/carboplatin. Dose-dependent and antigen-specific anti-tumor activity of LM monotherapy was demonstrated at doses as low as 3 mg/kg. LM was highly active in combination with standard-of-care platinum/etoposide therapies, even in relatively resistant xenograft models. LM demonstrated outstanding anti-tumor activity in combination with carboplatin/etoposide, with superior activity over chemotherapy alone when LM was used in combinations at significantly reduced doses (6-fold below the minimally efficacious dose for LM monotherapy). The combination of LM with carboplatin/paclitaxel was also highly active. This study provides the rationale for clinical evaluation of LM as a promising novel targeted therapy for SCLC, both as monotherapy and in combination with chemotherapy.     

Lorvotuzumab mertansine,a CD56-targeting antibody-drug conjugate with potent antitumor activity against small cell lung cancer in human xenograft models

Lorvotuzumab mertansine (LM) is an antibody-drug conjugate composed of a humanized anti-CD56 antibody, lorvotuzumab, linked via a cleavable disulfide linker to the tubulin-binding maytansinoid DM1. CD56 is expressed on most small cell lung cancers (SCLC), providing a promising therapeutic target for treatment of this aggressive cancer, which has a poor five-year survival rate of only 5–10%. We performed immunohistochemical staining on SCLC tumor microarrays, which confirmed that CD56 is expressed at high levels on most (~74%) SCLC tumors. Conjugation of lorvotuzumab with DM1 did not alter its specific binding to cells and LM demonstrated potent target-dependent cytotoxicity against CD56-positive SCLC cells in vitro. The anti-tumor activity of LM was evaluated against SCLC xenograft models in mice, both as monotherapy and in combination with platinum/etoposide and paclitaxel/carboplatin. Dose-dependent and antigen-specific anti-tumor activity of LM monotherapy was demonstrated at doses as low as 3 mg/kg. LM was highly active in combination with standard-of-care platinum/etoposide therapies, even in relatively resistant xenograft models. LM demonstrated outstanding anti-tumor activity in combination with carboplatin/etoposide, with superior activity over chemotherapy alone when LM was used in combinations at significantly reduced doses (6-fold below the minimally efficacious dose for LM monotherapy). The combination of LM with carboplatin/paclitaxel was also highly active. This study provides the rationale for clinical evaluation of LM as a promising novel targeted therapy for SCLC, both as monotherapy and in combination with chemotherapy.     

Efficient chondrogenic differentiation of mesenchymal cells in micromass culture by retroviral gene transfer of BMP-2

The multipotential murine embryonic C3H10T1/2 mesenchymal cell line is able to undergo chondrogenesis in vitro, in a high density micromass environment, following treatment with soluble human bone morphogenetic protein-2 (BMP-2). To enhance this process, the human BMP-2 cDNA was cloned into a retroviral expression vector and a high titer, infectious retrovirus (replication defective) was generated. Infection of C3HIOT1/2 cells with this retroviral construct resulted in an infection efficiency of 90-95% and was highly effective in converting cells in micromass culture to a chondrocyte phenotype, as assessed by positive Alcian blue staining for extracellular matrix proteoglycans, increased sulfate incorporation, increased expression of the cartilage marker genes collagen type II and aggrecan, and decreased expression of collagen type I. Interestingly, BMP-2 expression in the micromass cultures also induced the expression of the cell cycle inhibitory protein/differentiation factor p21/WAF1, suggesting its functional involvement in chondrogenesis. The chondrogenic effect of retrovirally expressed BMP-2 in these high-density cultures was limited to the infected cells, since uninfected cells did not chondrify when co-cultured as a nonoverlapping micromass adjacent to BMP-2 expressing cells. These data indicate that retrovirally expressed BMP-2 is highly effective at inducing a chondrocyte phenotype in a multipotential mesenchymal cell line in vitro, and its action is restricted to the infected cell population. These findings should provide a framework for the optimization of chondrogenesis in culture using mesenchymal stem cells and retroviral gene transfer.     

体外诊断试剂防腐剂的选择策略

对体外诊断试剂中防腐剂的作用机理及选择原则进行了阐述,并对目前常用的防腐剂如叠氮钠、庆大霉素、硫柳汞、异噻唑啉酮类等的性能进行了比较,为体外诊断试剂的研究开发及生产中防腐剂的使用提供有益指导。     

News from the Biological Stain Commission,No. 17

In the 17^th issue of News from the Biological Stain Commission (BSC) under the heading of Regulatory affairs, the Biological Stain Commission’s International Affairs Committee presents information from the 20^th meeting of ISO/TC 212 Clinical laboratory testing and in vitro diagnostic test systems held on October 15 ? 17, 2014 in Toronto, Canada, and from the 29^th meeting of CEN/TC 140 In vitro diagnostic medical devices held on February 3, 2015 in Berlin, Germany.