国际上新药致癌性试验技术要求介绍

致癌性试验主要用于评价新药的潜在致癌性风险,是安全性评价的重要内容之一。新药人体致癌性风险目前主要依赖临床前试验结果来预测,以形成新药临床试验和上市后的风险控制计划。致癌性试验周期长,花费高,试验设计和结果评价比较复杂,需要研究者和管理机构加强交流沟通。     

FDA关于致癌性试验“特别方案评估”的流程和相关法规的介绍与探讨

目的：致癌性试验是药物非临床安全性评价和上市风险控制的重要组成部分,由于其试验周期长、费用高,且试验设计、实施以及结果评估和解释十分复杂,FDA要求申办方在致癌性试验正式开展前,预先向药品审评中心(CDER)提交“特别方案评估”(Special Protocol Assessment,SPA)的申请文件,针对拟开展的啮齿动物致癌性试验设计,征求FDA的审评意见。本文将详细介绍并探讨美国 FDA关于致癌性试验SPA的流程及相关法规的要点,以期为国内药物研发机构、临床前合同研究组织 (Contract Research Organization,CRO)、注册申报机构以及监管机构提供参考。方法：结合FDA致癌性试验“特别方案评估”指导原则的要求和相关工作经验,从致癌性试验方案提交FDA审评部门前的准备、提交程序、SPA审评文件材料内容的关注要点,以及FDA相关审评部门和致癌性评估执行委员会 (ECAC)内部审评流程等方面予以介绍。结果与结论：申办方应了解并熟悉致癌性试验SPA文件提交和评估的过程,并严格按照法规要求,加强与监管部门的沟通交流,从而获取科学性意见和建议,为顺利开展长期致癌性试验提供帮助。     

啮齿类动物致癌性试验统计学方法的使用现状

啮齿类动物致癌性试验是新药研发中非临床安全性评价的重要组成部分。致癌性试验周期较长、数据量大,其统计学方法选用的合理性、科学性将可能影响试验结果的结论。首先介绍了目前致癌性试验常用的生存分析和肿瘤发生率统计方法;其次,汇总了生存分析和肿瘤发生率统计方法的选用情况;最后,通过比较申报方、美国食品药品监督管理局审评方和美国国家毒理学项目中心在统计学方法选用的差异,分析和讨论了这些差异的来源和影响,并总结了致癌性试验统计分析设计思路。希望通过对以上内容的汇总和分析,能够为新药非临床致癌性试验提供参考。     

生物制品的致癌性评估及风险管理策略

大多数生物制品不会成为完全致癌物,但可以通过其药理学放大作用、免疫调节等成为肿瘤促长剂。在国际人用药品注册技术协调会（ICH）S1A和S6（R1）指导原则中对生物制品的致癌性评估有简单描述,但均缺少明确案例,且未考虑到新型技术药物的出现和监管思路的改变等情况。通过汇总2014—2021年美国食品药品监督管理局（FDA）批准的53项长期用药的生物制品的致癌性信息,并结合文献报道和实际工作经验,从生物制品的致癌性特点、致癌性评估策略、致癌性风险管理等几方面提出一些观点和建议,以期为国内同行、新药申报企业和审评机构提供有益的参考。     

药物中、短期致癌试验的研究进展

啮齿类致癌性试验是创新药物安全性评价和上市风险控制内容的重要组成部分。新药上市申请时通常需提供必要的整体动物致癌性试验结果。对于明显存在可能引起致癌风险的情况,药政管理部门均要求在早期提交该项试验结果以支持长期用药的临床试验。而愈来愈多的证据表明,利用2种啮齿类动物评价药物致癌风险的经典范例存在诸多的局限性     

啮齿类动物致癌性试验的关注要点

啮齿类动物致癌性试验的目的是确定候选药物在动物中是否具有致癌性,以及如果存在致癌性风险,这种风险是否会转化至人类。药物相关的致癌作用可能表现为肿瘤发生率增加、背景肿瘤发生潜伏期缩短或罕见肿瘤的发生。本文重点讨论啮齿类动物致癌性试验中的一些具体而关键的内容,包括试验设计、实施、报告和结果解释分析的考虑要点。本文重点阐述致癌性试验进行的时间、试验设计的关键方面(剂量选择、种属选择、如何处理早期死亡和试验组终止等)、试验报告的一般内容和注意事项、致癌性试验数据的统计分析和结果阐述分析等。使用综合证据权重(WoE)方法解释致癌性试验结果,尤其对啮齿类动物致癌试验发现是否与人体致癌风险相关的评价是至关重要的。     

啮齿类动物致癌性试验的关注要点

啮齿类动物致癌性试验的目的是确定候选药物在动物中是否具有致癌性，以及如果存在致癌性风险，这种风险是否会转化至人类。药物相关的致癌作用可能表现为肿瘤发生率增加、背景肿瘤发生潜伏期缩短或罕见肿瘤的发生。本文重点讨论啮齿类动物致癌性试验中的一些具体而关键的内容，包括试验设计、实施、报告和结果解释分析的考虑要点。本文重点阐述致癌性试验进行的时间、试验设计的关键方面(剂量选择、种属选择、如何处理早期死亡和试验组终止等)、试验报告的一般内容和注意事项、致癌性试验数据的统计分析和结果阐述分析等。使用综合证据权重(WoE)方法解释致癌性试验结果，尤其对啮齿类动物致癌试验发现是否与人体致癌风险相关的评价是至关重要的。     

毒性试验中评估化学物致癌性的数学模型

<正> 毒性试验的主要目的之一是研究化学物的致癌性。作者曾应用有关概率方法和试验的灵敏度、特异度,求得化学物在结果群条件下是致癌物的概率。这就是比值评估法。现介绍比值评估法的两种应用:(1)由一系列观察指标不同的毒性试验在不同实验室所得的     

药物致癌性的机制研究

 动物致癌性试验是药物非临床安全性评价的重要内容之一,在我国起步相对较晚。随着我国新药创制及相关领域的不断发展,初步具备了进行致癌性评价的条件。机制研究是致癌性评价的重要内容,结合暴露量分析、适应症与患者人群特征、同类化合物致癌性特征等进行利弊权衡,综合评估对人体的潜在风险,并最终通过说明书等方式进行风险控制。目前国际上正在着力于致癌机制的探索,有些已经被药品评价机构接受。文中对一些常见的机制研究进行总结分析,包括遗传毒性机制、药理学作用相关机制、苯巴比妥样CYP450诱导作用、致癌组织的种属差异等,以期为我国药物致癌性评价提供一定参考。     

医疗器械监管中致癌性试验研究进展

目的：为完善我国医疗器械监管,提高医疗器械致癌性方面的研究水平提供一定参考。方法：通过查阅相关文献,介绍医疗器械的定义分类以及致癌性试验的有关模型,并且对现有医用材料致癌性试验进行论述。结果与结论：医疗器械监管中的致癌性试验是在对试验动物进行浸提液或植入物暴露试验后测定其致癌潜能的试验,根据试验结果初步估计产生不良影响的剂量指标,为建立人体暴露的安全标准提供参考依据。当前我国医疗器械相关的规范性文件有所欠缺,提高国产医疗器械的检测技术和相关标准,实现医疗器械风险性评价有助于完善监管体系,加快相关医疗器械产品进入市场。     

Human carcinogenic risk evaluation, Part III: Assessing cancer hazard and risk in human drug development.

Assessing cancer risk for human pharmaceuticals is important because drugs are taken at pharmacologically active doses and often on a chronic basis. Epidemiologic studies on patient populations have limited value because of the long latency period for most cancers and because these studies lack sensitivity. The Center for Drug Evaluation and Research (CDER) of the U.S. Food and Drug Administration relies on short-term surrogate assays (genetic toxicology studies) to assess risk to patients involved in clinical trials and on rodent carcinogenicity studies to assess cancer risk for drug approval. Unlike some other agencies that typically perform quantitative risk assessments on chemical pollutants or pesticide products, CDER does not perform such quantitative extrapolations. Rather, the evaluation of risk is the result of an integrated assessment of what is known about the drug, and risk is considered in the context of the clinical benefit. Mode of action of carcinogenesis and thresholds for effects are important considerations. The results of carcinogenicity studies of approved products are published in the drug labeling and individual clinicians balance risk and benefit in making prescribing decisions.     

致癌试验与人类风险评估无关的肿瘤概述

致癌试验的目的是考察药物在动物体内的潜在致癌作用,从而评价其可能对人类的相关风险,是非临床药物安全性评价的主要内容之一。啮齿动物致癌试验的结果与人类安全性评估的相关性经常引起争议,可能需要做进一步的研究来探讨其作用方式,以帮助确定是否存在对人类的潜在致癌性。当啮齿动物致癌试验出现阳性结果时,可能需要进行进一步的毒性病理学研究探讨其作用机制,来评估与人类的相关性。简要介绍动物致癌试验结果与人类相关性的必要性、致癌试验基于作用方式与人类风险评估无关的肿瘤、致癌试验基于作用方式与人类风险评估可能无关的肿瘤,以期为我国非临床药物致癌试验的结果分析和药物评价研究提供一定参考。     

我国临床前药物致癌试验转基因动物模型研究进展

目的：综述我国临床前药物致癌试验转基因动物模型研究进展。方法：介绍致癌试验常用转基因动物模型的构建、利用转基因动物模型开展致癌试验的优势、国际认可及国际监管机构新药申报中的应用、国内外致癌试验相关指导原则、我国开展基于转基因动物致癌试验面临的困境以及转基因动物模型构建的最新进展。结果与结论：基于转基因动物模型的致癌试验具有诸多优势也是目前国际趋势,在我国建立临床前药物致癌试验转基因动物模型非常必要。     

Integrated approach to testing and assessment for predicting rodent genotoxic carcinogenicity

We investigated the performance of an integrated approach to testing and assessment (IATA), designed to cover different genotoxic mechanisms causing cancer and to replicate measured carcinogenicity data included in a new consolidated database. Genotoxic carcinogenicity was predicted based on positive results from at least two genotoxicity tests: one in vitro and one in vivo (which were associated with mutagenicity categories according to the Globally Harmonized System classification). Substances belonging to double positives mutagenicity categories were assigned to be genotoxic carcinogens. In turn, substances that were positive only in a single mutagenicity test were assigned to be mutagens. Chemicals not classified by the selected genotoxicity endpoints were assigned to be negative genotoxic carcinogens and subsequently evaluated for their capability to elicit non‐genotoxic carcinogenicity. However, non‐genotoxic carcinogenicity mechanisms were not currently included in the developed IATA. The IATA is docked to the OECD Toolbox and uses measured data for different genotoxicity endpoints when available. Alternatively, the system automatically provides predictions by SAR genotoxicity models using the OASIS Tissue Metabolism Simulator platform. When the developed IATA was tested against the consolidated database, its performance was found to be high, with sensitivity of 74% and specificity of 83%, when measured carcinogenicity data were used along with predictions falling within the models' applicability domains. Performance of the IATA would be slightly changed to a sensitivity of 80% and specificity of 72% when the evaluation by non‐genotoxic carcinogenicity mechanisms was taken into account. Copyright © 2016 John Wiley & Sons, Ltd.     

Covalent binding of drug metabolites to DNA — a tool of predictive value?

The presently available data suggest at least some correlation between covalent binding of drug metabolites to DNA and carcinogenicity of that drug. More data, however, are needed to establish the predictability of covalent DNA binding assays for extrahepatic cancer. A covalent binding assay requires administration of radioactively labelled compound to the experimental animals; the availability of labelled compound and requirements as to radiochemical purity, chemical and biochemical stability are limiting the applicability of this procedure. Many technical pitfalls accompany covalent DNA binding assays. It is concluded that at the present time DNA binding assays do not represent routine procedures within a standard test battery for carcinogenicity, but are invaluable for more in-depth research which probably follows routine testing.     

非临床毒性试验和致癌性试验动物死亡原因分析方法简介

本文简要介绍了美国国家毒理研究中心动物死亡原因分类、美国毒性病理学会颁布的判定毒性试验死亡原因的建议、英国亨廷顿生命科学公司病理部致癌性试验幼龄SD大鼠的死亡原因分析、美国华盛顿大学比较医学和比较病理学系啮齿类动物试验死亡原因分析推荐方法等内容,目的是为我国药物非临床安全性评价领域毒性病理学家更好地分析动物死亡原因及解释毒性试验和致癌性试验结果提供参考。     

Histamine Food Poisoning: Toxicology and Clinical Aspects

The 2-year rodent carcinogenicity bioassay evolved more than 40 years ago, and although it is complex, long lasting, expensive, and animal consuming, it is still the only generally accepted test for assessing the carcinogenicity of chemicals. Over time, different alternative approaches have been developed with the final goal to replace the bioassay. Unfortunately, at present, none of these strategies alone provides sufficient assurance of accurate prediction. In this review paper, we discuss the major advantages and pitfalls of the existing alternative methodologies to the carcinogenicity bioassay. Finally, based on the available scientific data in the public domain, we propose what we would like to call a “feasible integrated testing strategy” which incorporates some promising alternatives, providing at the same time information on the mechanism of action and the toxic nature of the compounds tested. It is, however, clear that the adoption of whatever “new” testing scheme should be considered with caution and its effectiveness should be experimentally demonstrated in advance by addressing a reasonable number of chemical carcinogens and non-carcinogens from a variety of structural and functional classes.