EMEA基因毒性杂质限度指南

1、20060628 EMEA/CHMP/QWP/251344/2006基因毒性杂质限度指南（中英文对照）London, 28 June 2006CPMP/SWP/5199/02EMEA/CHMP/QWP/251344/2006The European Agency for the Evaluation of Medicinal Products欧洲共同体药物评审委员会(EMEA)COMMITTEE FOR MEDICINAL PRODUCTS FOR HUMAN USE人用药品委员会(CHMP) GUIDLINE ON THE LIMITS OF GENOTOXIC IMPURITIES基因毒性

2、杂质限度指南 DESCUSSION IN THE SAFETY WORKING PARTY安全工作组之内的讨论June 2002-October 2002TRANSMISSION TO CPMPCPMP传递December 2002RELEASE FOR CONSULTATION专家讨论December 2002DEADLINE FOR COMMENTS建议收集最后期限March 2003DISCUSSION IN THE SAFETY WORKING PARTY AND QUALITY WORKING PARTY安全工作组和质量工作组之间的讨论June 2003-February 2004T

3、RANSMISSION TO CPMP转移给CPMPMarch 2004RE-RELEASE FOR CONSULTATION再次放行给顾问团June 2004DEADLINE FOR COMMENTS收集意见的最后期限December 2004DISCUSSION IN THE SAFETY WORKING PARTY AND QUALITY WORKING PARTY安全工作组和质量工作组之间的讨论February 2005-May 2006ADOPTION BY CHMP被CHMP采用28 June 2006DATE FOR COMING INTO EFFECT生效日期01January

4、 2007 KEYWORDS关键词Impurities; Genotoxicity; Threshold of toxicological concern (TTC); Structure activity relationship (SAR)GUIDLINE ON THE LIMITS OF GENOTOXIC IMPURITIES基因毒性杂质限度指南 TABLE OF CONTENTS 目录EXECUTIVE SUMMARY 内容摘要. 31. INTRODUCTION 介绍. 32. SCOPE 范围 . 33. LEGAL BASIS法 律依据. 34. TOXICOLOGICAL B

5、ACKGROUND 毒理学背景. 45. RECOMMENDATIONS 建议. 45.1 Genotoxic Compounds With Sufficient Evidence for a Threshold-Related Mechanism具有充分证据证明其阈值相关机理的基因毒性化合物. 45.2 Genotoxic Compounds Without Sufficient Evidence for a Threshold-Related Mechanism不具备充分证据支持其阈值相关机理的基因毒性化合物. 55.2.1 Pharmaceutical Assessment药学评价. 5

6、5.2.2 Toxicological Assessment毒理学评价. 55.2.3 Application of a Threshold of Toxicological Concern 毒理学担忧阈值应用. 55.3 Decision Tree for Assessment of Acceptability of Genotoxic Impurities基因毒性杂质可接受性评价决策树. 7REFERENCES. 参考文献. 8EXECUTIVE SUMMARY 内容摘要The toxicological assessment of genotoxic impurities and the

7、 determination of acceptable limits for such impurities in active substances is a difficult issue and not addressed in sufficient detail in the existing ICH Q3X guidances. The data set usually available for genotoxic impurities is quite variable and is the main factor that dictates the process used

8、for the assessment of acceptable limits. In the absence of data usually needed for the application of one of the established risk assessment methods, i.e. data from carcinogenicity long-term studies or data providing evidence for a threshold mechanism of genotoxicity, implementation of a generally a

9、pplicable approach as defined by the Threshold of Toxicological Concern (TTC) is proposed. A TTC value of 1.5 g/day intake of a genotoxic impurity is considered to be associated with an acceptable risk (excess cancer risk of <1 in 100,000 over a lifetime) for most pharmaceuticals. From this thres

10、hold value, a permitted level in the active substance can be calculated based on the expected daily dose. Higher limits may be justified under certain conditions such as short-term exposure periods.基因毒性杂质的毒理学评估和这些杂质在活性药物中的可接受标准的测定是一件困难的事情，并且在现有的ICH Q3X指南中也没有详细的规定。现有的关于基因毒性杂质的相关数据是容易变化的，也是对杂质可接受标准如何进

11、行评价的主要影响因素。如果缺少风险评估方法所需要的数据，比如，致癌作用的长期研究数据，或为基因毒性的阀值提供证据的数据，一般建议使用一般通用的被定义为毒理学关注的阈值（TTC）的方法。一个“1.5g/day”的TTC值，即相当于每天摄入1.5g的基因毒性杂质，被认为对于大多数药品来说是可以接受的风险（一生中致癌的风险小于十万分之1）。按照这个阀值，可以根据这个预期的每日摄入量计算出活性药物中可接受的杂质水平。较高的临界值可以在特定的条件下，如短期暴露周期等，进行推算。1. INTRODUCTION 介绍A general concept of qualification of impuriti

12、es is described in the guidelines for active substances (Q3A, Impurities in New Active Substances) or medicinal products (Q3B, Impurities in New Medicinal Products), whereby qualification is defined as the process of acquiring and evaluating data that establishes the biological safety of an individu

13、al impurity or a given impurity profile at the level(s) specified. In the case of impurities with a genotoxic potential, determination of acceptable dose levels is generally considered as a particularly critical issue, which is not specifically covered by the existing guidelines.在原料药（Q3A）和药物制剂（Q3B）的

14、杂质指导原则中，杂质限度确定的依据包括各个杂质的生物安全性数据或杂质在某特定含量水平的研究概况。而对于遗传毒性杂质限度的确定，通常都认为是特别关键的问题，但目前尚无相关的指导原则。 2. SCOPE 范围This Guideline describes a general framework and practical approaches on how to deal with genotoxic impurities in new active substances. It also relates to new applications for existing active subst

15、ances, where assessment of the route of synthesis, process control and impurity profile does not provide reasonable assurance that no new or higher levels of genotoxic impurities are introduced as compared to products currently authorised in the EU containing the same active substance. The same also

16、 applies to variations to existing Marketing Authorisations pertaining to the synthesis. The guideline does, however, not need to be applied retrospectively to authorised products unless there is a specific cause for concern.本指导原则阐述了如何处理新原料药中遗传毒性杂质的一般框架和实际方法。该指导原则也适用于已有原料药的新申请，如果其合成路线、过程控制和杂质研究尚无法确保

17、不会产生新的或更高含量的遗传毒性杂质（与EU目前批准的相同原料药相比）。该指导原则同样适用于已上市原料药有关合成方面的补充申请。除非有特殊原因，本指导原则不适用于已上市的产品。In the current context the classification of a compound (impurity) as genotoxic in general means that there are positive findings in established in vitro or in vivo genotoxicity tests with the main focus on DNA r

18、eactive substances that have a potential for direct DNA damage. Isolated in vitro findings may be assessed for in vivo relevance in adequate follow-up testing. In the absence of such information in vitro genotoxicants are usually considered as presumptive in vivo mutagens and carcinogens.目前对于基因毒性杂质的

19、分类主要是指：在以DNA反应物质为主要研究对象的体内体外试验中，如果发现它们对DNA有潜在的破坏性，那可称之为基因毒性。如果有足够的后续试验，可由单独的体外试验结果，对它的体内关联性进行评估。在缺乏这样的信息时，体外基因毒性物质经常被考虑为假定的体内诱变剂和致癌剂。3. LEGAL BASIS 法规依据This guideline has to be read in conjunction with Directive 2001/83/EC (as amended) and all relevant CHMP Guidance documents with special emphasis o

20、n:在阅读该指南时有必要参考“Directive 2001/83/EC”以及相关的CHMP指南文件，特别是以下几个指南：Impurities Testing Guideline: Impurities in New Drug Substances (CPMP/ICH/2737/99, ICHQ3A(R)Note for Guidance on Impurities in New Drug Products (CPMP/ICH/2738/99, ICHQ3B (R)Note for Guidance on Impurities: Residual Solvents (CPMP/ICH/283/9

21、5)Note for Guidance on Genotoxicity: Guidance on Specific Aspects of Regulatory Genotoxicity Tests for Pharmaceuticals (CPMP/ICH/141/95, ICHS2A)Note for Guidance on Genotoxicity: A Standard Battery for Genotoxicity Testing of Pharmaceuticals (CPMP/ICH/174/95, ICHS2B)4. TOXICOLOGICAL BACKGROUND 毒理学背景

22、According to current regulatory practice it is assumed that (in vivo) genotoxic compounds have the potential to damage DNA at any level of exposure and that such damage may lead/contribute to tumour development. Thus for genotoxic carcinogens it is prudent to assume that there is no discernible thre

23、shold and that any level of exposure carries a risk.根据目前的研究实践，具有（体内）遗传毒性的化合物在任何暴露量下都有可能对DNA产生损伤，而这种损伤可能会引发肿瘤。因此，对于遗传毒性致癌物质，应谨慎认为不存在明确的阈值，任何暴露量下都存在风险。However, the existence of mechanisms leading to biologically meaningful threshold effects is increasingly acknowledged also for genotoxic events. This

24、holds true in particular for compounds interacting with non-DNA targets and also for potential mutagens, which are rapidly detoxified before coming into contact with critical targets. The regulatory approach to such chemicals can be based on the identification of a critical no-observed-effect level

25、(NOEL) and use of uncertainty factors.然而，对于一些遗传毒性事件，其产生生物学意义的阈值效应的机理正越来越为人所了解。对于非DNA靶点的化合物和潜在致突变剂更是如此，因为它们在与关键靶点接触前就已经去毒化了。对于这些化合物，研究的基础可以是确定关键的未观察到影响的剂量（NOEL）和采用不确定因子。Even for compounds which are able to react with the DNA molecule, extrapolation in a linear manner from effects in high-dose studies

26、 to very low level (human) exposure may not be justified due to several protective mechanisms operating effectively at low doses. However, at present it is extremely difficult to experimentally prove the existence of threshold for the genotoxicity of a given mutagen. Thus, in the absence of appropri

27、ate evidence supporting the existence of a threshold for a genotoxic compound making it difficult to define a safe dose it is necessary to adopt a concept of a level of exposure that carries an acceptable risk.即使对能与DNA分子发生反应的化合物，由于低剂量时有多种有效的保护机制存在，而不能将高剂量下的影响以线性方式外推到很低的（人）暴露水平。不过，目前要用实验方法证明某诱变剂的遗传毒性

28、阈值仍然非常困难。所以，在缺乏恰当的证据支持遗传毒性阈值存在的情况下，确定安全剂量很困难，因此非常有必要采用一个可接受风险的暴露水平概念。5. RECOMMENDATIONS 建议As stated in the Q3A guideline, actual and potential impurities most likely to arise during synthesis, purification and storage of the new drug substance should be identified, based on a sound scientific apprai

29、sal of the chemical reactions involved in the synthesis, impurities associated with raw materials that could contribute to the impurity profile of the new drug substance, and possible degradation products. This discussion can be limited to those impurities that might reasonably be expected based on

30、knowledge of the chemical reactions and conditions involved. Guided by existing genotoxicity data or the presence of structural alerts, potential genotoxic impurities should be identified. When a potential impurity contains structural alerts, additional genotoxicity testing of the impurity, typicall

31、y in a bacterial reverse mutation assay, should be considered (Dobo et al. 2006, Müller et al. 2006). While according to the Q3A guideline such studies can usually be conducted on the drug substance containing the impurity to be controlled, studies using isolated impurities are much more approp

32、riate for this purpose and highly recommended.正如Q3A指导原则所述，根据合理的化学反应机理分析，在新的原料药合成、纯化和贮存过程中很有可能产生实际的和潜在的杂质。依据现有的“可能引起遗传毒性的结构”数据库，潜在的遗传毒性杂质应能被确认。如果潜在的杂质含有可引起遗传毒性的结构单元，该杂质应考虑进行遗传毒性试验（一般是细菌回复突变试验）（Dobo等，2006）。虽然Q3A指导原则认为这些研究采用含有那些需控制杂质的原料药进行是可行的，但用分离出来的杂质进行这些研究更恰当，也是高度推荐的方法。For determination of acceptabl

33、e levels of exposure to genotoxic carcinogens considerations of possible mechanisms of action and of the dose-response relationship are important components. Based on the above considerations genotoxic impurities may be distinguished into the following two classes:根据以上论述，遗传毒性杂质可以归纳成以下两类：- Genotoxic

34、compounds with sufficient (experimental) evidence for a threshold-related mechanism有充分阈值相关机理证据（实验）的遗传毒性化合物- Genotoxic compounds without sufficient (experimental) evidence for a threshold-related mechanism无充分阈值相关机理证据（实验）的遗传毒性化合物5.1 Genotoxic Compounds With Sufficient Evidence for a Threshold-Related

35、Mechanism 具有充分证据证明其阈值相关机理的基因毒性化合物Examples of mechanisms of genotoxicity that may be demonstrated to lead to non-linear or thresholded dose-response relationships include interaction with the spindle apparatus of cell division leading to aneuploidy, topoisomerase inhibition, inhibition of DNA synthes

36、is, overloading of defence mechanisms, metabolic overload and physiological perturbations (e.g. induction of erythropoeisis, hyper- or hypothermia).非线性或阈值明确的剂量效应关系的遗传毒性机理包括：与细胞分化过程中纺锤体相互作用；拓扑异构酶抑制；DNA合成抑制；过度的防御机制；代谢过度和生理性干扰（如诱导红血球生成，高体温和低体温）。For (classes of) compounds with clear evidence for a thres

37、holded genotoxicity, exposure levels which are without appreciable risk of genotoxicity can be established according to the procedure as outlined for class 2 solvents in the Q3C Note for Guidance on Impurities: Residual Solvents. This approach calculates a “Permitted Daily Exposure” (PDE), which is

38、derived from the NOEL, or the lowestobserved effect level (LOEL) in the most relevant (animal) study using “uncertainty factors” (UF).有明确遗传毒性阈值的化合物，不产生遗传毒性风险的暴露水平可以被确定，方法可参照Q3C“杂质指导原则”中二类溶剂的限度确定方法。该方法可计算 “每日最大允许暴露量”（PDE），数据来源于 “不确定因数”动物研究中的NOEL（未观察到效果的最低水平）或观察到效果的最低水平（LOEL）。5.2 Genotoxic Compounds W

39、ithout Sufficient Evidence for a Threshold-Related Mechanism 不具备充分证据支持其阈值相关机理的基因毒性化合物The assessment of acceptability of genotoxic impurities for which no threshold mechanisms are identified should include both pharmaceutical and toxicological evaluations. In general, pharmaceutical measurements shou

40、ld be guided by a policy of controlling levels to “as low as reasonably practicable” (ALARP principle), where avoiding is not possible. Levels considered being consistent with the ALARP principle following pharmaceutical assessment should be assessed for acceptability from a toxicological point of v

41、iew (see decision tree & following sections).对于此类遗传毒性杂质，研究应包括药学和毒理学评估。总之，如果杂质无法避免，药学方面的控制应遵循“合理可行的最低限量”原则（ALARP原则）。符合ALARP原则的杂质水平再经毒理学方面的进一步评估，以验证其合理性（见决策树和以下章节）。5.2.1 Pharmaceutical Assessment 药学评价A specific discussion as part of the overall discussion on impurities (see Q3A(R) should be provid

42、ed in the application with regard to impurities with potential genotoxicity.申请材料应提供关于潜在遗传毒性杂质的特别讨论资料（见Q3A（R）。 A rationale of the proposed formulation/manufacturing strategy should be provided based on available formulation options and technologies. The applicant should highlight, within the chemical

43、 process and impurity profile of active substance, all chemical substances, used as reagents or present as intermediates, or side-products, known as genotoxic and/or carcinogenic (e.g. alkylating agents).需要根据现在的配方选择和技术，提供证明所选的配方/生产策略合理性的证据。申请人应在合成工艺和杂质研究部分重点指出所有的化学物质，包括用到的试剂、中间体、副产物，哪些是已知遗传毒性和/或致癌性物

44、质（如烷化剂）。More generally, reacting substances and substances which show “alerting structure” in terms of genotoxicity which are not shared with the active substance should be considered (see e.g. Dobo et al. 2006). Potential alternatives which do not lead to genotoxic residues in the final product, sh

45、ould be used if available.值得关注的是，虽然有些含有“可能引起遗传毒性的结构” （alerting structure）的反应试剂与最终活性物质并没有共同结构，但也要考虑它们的遗传毒性(see e.g. Dobo et al. 2006).。如果有可能，应该对它们进行一些替代研究，以使最终产品中不会引入基因毒性残留。A justification needs to be provided that no viable alternative exists, including alternative routes of synthesis or formulation

46、s, different starting materials. This might for instance include cases where the structure, which is responsible for the genotoxic and/or carcinogenic potential is equivalent to that needed in chemical synthesis (e.g. alkylation reactions).需要提供充分的论证来说明没有可行的替代方法存在，包括可替代的合成路线或配方，不同的起始物料等。比如，应证明具有遗传毒性和

47、/或致癌性的结构在化学合成中（如烷化反应）是必需的。 If a genotoxic impurity is considered to be unavoidable in a drug substance, technical efforts (e.g. purification steps) should be undertaken to reduce the content of the genotoxic residues in the final product in compliance with safety needs or to a level as low as reason

48、ably practicable (see safety assessment). Data on chemical stability of reactive intermediates, reactants, and other components should be included in this assessment.如果遗传毒性杂质在原料中不可避免，则应该采取适当的技术（如纯化步骤）降低该杂质的含量，以满足安全性要求，或符合“合理可行的最低限量”原则（见安全评估）。药学评估还应包括反应中间体、反应物和其它组件等的化学稳定性研究。Detection and/or quantific

49、ation of these residues should be done by state-of-the-art analytical techniques.应该使用比较先进的分析检测技术来检测和量化这些残留的杂质。5.2.2 Toxicological Assessment 毒理学评价The impossibility of defining a safe exposure level (zero risk concept) for genotoxic carcinogens without a threshold and the realization that complete el

50、imination of genotoxic impurities from drug substances is often unachievable, requires implementation of a concept of an acceptable risk level, i.e. an estimate of daily human exposure at and below which there is a negligible risk to human health.鉴于在没有明确阈值的前提下定义安全暴露水平（零风险）是不可能的，且从原料药中完全除去遗传毒性杂质经常是很难

51、做到的，所以有必要提出一个“可接受风险水平”（acceptable risk level）的概念，比如估算一个“每日最大暴露量”值，低于该暴露量时就可以忽略其对人体健康的风险。Procedures for the derivation of acceptable risk levels are considered in the Appendix 3 of the Q3C Note for Guidance on Impurities: Residual Solvents for Class 1 solvents. However, these approaches require avail

52、ability of adequate data from long-term carcinogenicity studies.对于可接受风险水平的推导过程请参见Q3C（杂质指南注释: 一类溶液残留）中的附件三。然而，应用这些方法必须有足够多的长期致癌性研究数据。In most cases of toxicological assessment of genotoxic impurities only limited data from in vitro studies with the impurity (e.g. Ames test, chromosomal aberration test

53、) are available and thus established approaches to determine acceptable intake levels cannot be applied. Calculation of “safety multiples” from in vitro data (e.g. Ames test) are considered inappropriate for justification of acceptable limits. Moreover, negative carcinogenicity and genotoxicity data

54、 with the drug substance containing the impurity at low ppm levels do not provide sufficient assurance for setting acceptable limits for the impurity due to the lack of sensitivity of this testing approach. Even potent mutagens and carcinogens are most likely to remain undetected when tested as part

55、 of the drug substance, i.e. at very low exposure levels. A pragmatic approach is therefore needed which recognises that the presence of very low levels of genotoxic impurities is not associated with an unacceptable risk.大多数情况下，遗传毒性杂质的毒理学评估只是局限于杂质的体外研究（如Ames试验，染色体畸变试验），但这些方法并不适用于确定杂质可接受的摄入水平。也就是说，根据体外数据（如Ames试验）计算杂质的“安全倍数（safety multiples）”、进而确定可接受的限度，是不合适的。此外，用含有较低（ppm级）杂质水平的原料药研究其致癌性和遗传毒性，即使得出阴性结果也不足以确保该杂质限度的合理