20100923更新 EMA 关于基因毒性杂质限度指南的问答（转载中英文）

20100923更新 EMA 关于基因毒性杂质限度指南的问答（转载中英文）  

2012-10-16 11:39:00|  分类： EDQM|举报|字号 [url=]订阅[/url]

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原英文官网http://www.ema.europa.eu/docs/en_GB/document_library/Scientific_guideline/2009/09/WC500002907.pdf

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23 September 2010

EMA/CHMP/SWP/431994/2007 Rev. 3

Committee for Medicinal Products for Human Use (CHMP)

人用药品委员会

Safety Working Party (SWP)

安全工作组

Questions and answers on the 'Guideline on the limits of genotoxic impurities'

关于“基因毒性杂质限度指南”的问答

Agreed by Safety Working Party (SWP) 安全工作组（SWP）一致同意	September 2010
Adoption by CHMP 由CHMP采用	23 September 2010

Keywords 关键词

Impurities; Genotoxicity; Threshold of toxicological concern (TTC); Structure activity relationship (SAR)

Background 背景

The aim of this question-and-answer document is to provide clarification and harmonisation of the 'Guideline on the limits of genotoxic impurities' (EMEA/CHMP/QWP/251344/2006), published in 2006.

本问答文件的目的是对2006年出版的基因毒性杂质限度指南（EMEA/CHMP/QWP/251344/2006）进行相关内容统一和说明。

Questions and answers 问答

Question 1. The guideline does not need to be applied retrospectively to authorised products unless there is a specific cause for concern. What might constitute "a cause-for-concern" in terms of application to currently marketed products?

问题1：该指引并不要求对已批准销售的产品进行基因毒性杂质再评估，除非有一个特定的“重要原因”（cause-for-concern）。请问什么是“重要原因”？
If a manufacturing procedure for API remains essentially unchanged a re-evaluation with respect to the presence of potentially genotoxic impurities is generally not needed. However, new knowledge may indicate a previously unknown cause for concern. One example is the mesylate salt drug substances for which a few years ago, a concern regarding the potential for formation of genotoxic alkyl mesylates was raised. This concern resulted in the “Production Statement” requesting a specific evaluation of the potential for formation of these highly toxic products now included as part of the PhEur monographs for all the mesylates salts.

回答：如果原料药的生产过程基本上没有改变，就不需要对基因毒性杂质进行重新评价。但是，如果新知识表明有新原因时，例如几年前发现的甲磺酸盐药物可能形成甲磺酸烷基的基因毒性杂质，这需要进行基因毒性杂质的再评估，包括EP药典中收载的所有甲磺酸盐类产品，并出示“生产声明”。

Question 2. The guideline indicates that it is necessary to reduce a known or suspected mutagenic impurity to as low as reasonably practicable (ALARP) even if the level is below the threshold of toxicological concern (TTC), i.e. in the decision tree ALARP considerations precede TTC considerations. If the level is already known to be below the TTC (which is a very conservative value), why is it necessary to reduce it even further? On a practical basis this would often involve developing analytical methods that have limits of quantitation around or below 1ppm level. The effort and resource this can take, and the possibility that it is not actually achievable, does not seem commensurate with the perceived risk.

问题2：该指引指出：即使按决策树程序其水平低于毒理学关注阈值(threshold of toxicological concern,TTC)，也要尽可能地减少已知或未知的诱变杂质（mutagenic impurity）。如果已知其诱变杂质的水平低于TTC（TTC是一个非常保守的值），为什么要还进一步减少呢？实际上这还涉及定量限在1ppm左右的分析方法，可以这样做但可能没结果，这是否有必要呢？

If the level of a mutagenic impurity is below the threshold of toxicological concern (equivalent to a clinical dose ≤1.5 μg/day) it is not necessary to apply ALARP considerations unless it is a structure of very high concern, e.g. N-nitroso, aflatoxins-like and azoxy-compounds.

回答：如果一个诱变杂质的水平低于毒理学关注阈值（相当于临床剂量≤1.5微克/天），就没有必要这样做。除非它具有一个高度关注的风险结构：如N -亚硝基，黄曲霉毒素类和氧化偶氮物就需要这样做。
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Question 3. The guideline states: “When a potential impurity contains structural alerts, additional genotoxicity testing of the impurity, typically in a bacterial reverse mutation assay, should be considered.”

i) If an impurity triggers a mutagenic structural alert, will a negative result in an Ames test on the impurity (conducted to regulatory acceptable standards) be sufficient to conclude that the compound is of no concern with respect to genotoxicity and no further ‘qualification’ studies will be required?

ii) Is the absence of a structural alert sufficient to show that the impurity is of no concern?

iii) Is it acceptable to control impurities with a structural alert by assuming they will be positive (without resorting to any testing) and ensuring the level remains below the appropriate TTC value?

问题3：该指引规定：“当一个潜在的杂质包含“警示结构”（structural alerts）时，应考虑用细菌突变试验对其杂质进行的基因毒性分析”。
i）如果一个杂质能诱发“警示结构”，该杂质的致突变试验（Ames）结果为阴性时，是否就足以得出结论：该化合物不属于关注的遗传毒性杂质？是否还需要进一步的确认研究？
ii）“警示结构”不存在就足以说明不属于关注杂质呢？
' G7 @( g: E1 K* [iii）假设某杂质属于“警报结构”，但只要加以控制确保其杂质水平低于TTC，不进行常规检测是否可以接受？
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i) Yes, a negative Ames test (conducted to regulatory acceptable standards) will overrule a structural alert and no further studies would be required providing the level remains below ICH Q3A/B limits.

ii) Yes, the absence of a structural alert based on a well-performed assessment (e.g. through application of commonly used QSAR assessment software such as DEREK or MCASE) will be sufficient to conclude that the impurity is of no concern with respect to genotoxicity and no further ‘qualification’ studies or justification will be required.

iii) Yes, genotoxicity testing is not obligatory when a potential genotoxic impurity is controlled at the TTC level, unless it belongs to a class of very potent genotoxic carcinogens (N-nitroso and azoxy compounds, or a aflatoxin-like compound).

回答：
i）是的。只要按Q3A/B的要求做Ames试验显示阴性时，即可认定该杂质不属于“警报结构”，就不需要进一步确认研究。
ii）是的。通过仔细评估，如果“警报结构”不存在，即可认定“关注杂质”（concern impurity）不存在。通常这种评估常用构效关系的评估软件，如DEREK或MCASE软件。
iii）是的。当一个潜在的基因毒性杂质水平控制在TTC的水平时，就不强制要求进行基因毒性的常规检测，除非它具有非常强的基因毒性物质类（N -亚硝基化合物及偶氮化合物或黄曲霉毒类化合物）。
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Question 4. What would be an appropriate strategy to qualify a new impurity that arises during Phase III or with a commercial product? For example, would it be acceptable that a new unidentified impurity, discovered at the 0.05-0.09% range requires no action to be taken? Would an impurity discovered in the 0.10 to 0.15%, even if it triggers a structural alert, be fully qualified by testing the active ingredient containing this impurity in an Ames test?

问题4：什么是限定新杂质出现的适当战略（在三期临床阶段或商业批生产阶段）？，例如，下列战略是否可以接受？当发现一个新未知杂质在0.05-0.09％的范围就不需采取行动，在0.10至0.15％范围，即使它会诱导出“警示结构”，只要对含有这种杂质的成分进行Ames试验即可？

In line with the ICH guideline, no action is generally required for a new unidentified impurity found at levels below the ICH identification threshold. When an impurity is found above the ICH identification threshold, but below the qualification threshold, and the structure gives rise to a structural alert, this can be negated by carrying out an Ames test on the active ingredient containing the impurity as long as the impurity is present at a minimum concentration of 250 μg/plate (estimated detection limit for most relevant mutagens in Ames test, see Kenyon et al., Reg Tox & Pharm, 2007, 75-86). If the structure cannot be elucidated, then no action is generally required. Above the ICH qualification threshold, then the ICH guidance should be followed.

回答：出现新的低于鉴别阈值（identification threshold）的未知杂质时，ICH指南没有要求有任何行动；但是当高于鉴别阈值，低于确认阈（qualification threshold）并且可能成为“警示结构”时，并且该原料药中含该杂质的最小浓度为250μg/板（Ames方法的评估检测线，详见Kenyon et等,Reg Tox & Pharm, 2007, 75-86），就需要对含有这种杂质的活性成分进行Ames实验并成阴性。

Question 5. The guideline states that “A TTC value higher than 1.5 μg /day may be acceptable under certain conditions e.g. short-term exposure….”. Is the CHMP in agreement with the principles of “staged TTC” dependent on the duration of clinical exposure, i.e. higher levels allowed for marketed drugs used to treat acute conditions, e.g. antibiotics. If ‘yes’, what levels would be acceptable?

问题5：该指引指出，“毒理学关注阈（TTC）值高于1.5微克/天，在一定条件下是可以接受的，例如短期接触….”，阶段性TTC与临床接触的持续时间有关，例如抗生素。如果是这样的话，什么是短期接触的可接受水平？

TTC values for genotoxic impurities above 1.5 μg /day will be treated on a case-by-case basis. For short-duration treatments, the acceptability of higher levels will be in line with the principles outlined in the CHMP’s answer to question 6.

回答：高于1.5 μg /天微克以上的基因毒性杂质的要逐案处理。对于短期治疗，更高水平的接受能力原则见问题6的回答。

Question 6. The wording of the guideline implies that it is intended to cover an issue not covered specifically by ICH Q3A/B guidelines. The scope of the ICH guidelines does not include clinical development prior to NDA or MAA submission. However, experience across a range of pharmaceutical companies indicates that some regulatory authorities are applying the genotoxic impurity guideline during clinical development. In case the scope should include application to clinical development, can the CHMP advise on how genotoxic impurities should be controlled during the development stage?

问题6：该指引的措辞意味着它覆盖了ICH Q3A没有涉及的问题。ICH指南范围不包括NDA前的临床申请（或备忘录）。然而，实践表明，临床研发阶段涉及的基因毒性指南同样适合于注册法规要求。在研发阶段如何控制基因毒性杂质呢？

According to the scope of the guideline, it mainly applies to genotoxic impurities in “new active substances” which includes new active substances in both, MAA submissions as well as clinical trial applications. In fact, the CHMP Guideline on the Requirements to the Chemical and Pharmaceutical Quality Documentation Concerning Investigational Medicinal Products in clinical trials (CHMP/QWP/185401/2004) states that “For impurities in IMPs, a justification that the product is safe for its intended use, considering the anticipated exposure of volunteers and patients, respectively, will be required.”, and further on “a brief justification of the specifications and acceptance criteria for impurities …… should be provided based on safety and toxicity data.”

The CHMP agrees with the use of a staged TTC concept during clinical development.

The acceptable limits for daily intake of genotoxic impurities are 5, 10, 20, and 60μg/day for a duration of exposure of 6-12 months, 3-6 months, 1-3 months, and less than 1 month, respectively. For a single dose an intake of up to 120 μg is acceptable. Compared to the proposal of a staged TTC in the Mueller et al (Reg Tox & Pharm, 2006, 44, 198–211) paper these values incorporate a dose rate correction factor of 2 to account for deviations from the linear

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	Single dose	≤1 month	≤3 months	≤6 months	≤12 months
Allowable daily intake	120μg	60μg	20μg	10μg	5μg

回答：根据该指南的范围，它主要适用于“新的活性物质”中的基因毒性杂质，包括临床申请和备忘录中提到的新活性物质和临床试验申请中提到的新活性物质。事实上，临床试验的化学品和药品质量文件要求指（CHMP/QWP/185401/2004）已经对IMP中的杂质对志愿者和患者的安全性提出过要求。要基于安全和毒性数据提供杂质的规格与接受标准。

CHMP认可在临床研发阶段采用TTC分段概念。

在临床研发时段，短期的TTC应符合下列要求。允许的日吸入量与接触时间关系见下表。

下面这些值都是考虑了单次校正因子为2后通过线性外推的模式来计算偏差得来的。

	接触时间
	单剂量	≤1个月	≤3个月	≤6个月	≤12个月
允许的日吸入量	120μg	60μg	20μg	10μg	5μg

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Question 7. The guideline text implies that the indicated TTC value of 1.5 μg /day is a level that can be applied to each individual genotoxic impurity in a drug substance. Could this be confirmed?

问题7：按指引条款要求，意味着1.5微克/天的TTC值可适用于每一个原料药中的基因毒性杂质，请问这样的理解是否确切？

When more than one genotoxic impurity is present in the drug substance, the TTC value of 1.5 μg/day can be applied to each individual impurity only if the impurities are structurally unrelated.

In case of structural similarity, it can be assumed that the impurities act by the same genotoxic mode of action and have the same molecular target. and thus might exert effects in an additive manner. In such a situation, a limitation of the sum of the genotoxic impurities at 1.5 μg/day is recommended. This might be practically not achievable with reasonable efforts in particular when the maximum daily dose is very high and thus may demand application of lower group limits. Justifications should be made on a case-by-case basis taking into consideration issues such as:

回答：在原料药中存在一个以上的基因毒性杂质时，1.5微克/天TTC值对每一个结构不相关的杂质是适用的。在结构相似的情况下，基因毒性杂质的作用模式一致，并具有相同的分子靶向，在这种情况下，建议基因毒性杂质的总和为1.5微克/天。这可能不符合实际，特别是最大日剂量很高而且又要求按低限要求申报时。此时应根据下列因素逐案考虑：

l         Maximum daily dose of the active substance;

l         原料药的每日最高剂量；

l         Therapeutic indication;

l         治疗适应症;

l         Step of the synthesis at which the genotoxic impurity(ies) arise;

l         产生基因毒性杂质的合成步骤；

l         Capability of the manufacturing process (purification steps) to eliminate these impurities;

l         消除这些杂质生产纯化能力；

l         Capability of the analytical procedure to control these impurities.

l         控制这些杂质的分析方法能力。

In cases where routine use of more powerful detection methods would be difficult, one could consider using such methods during development or testing of the first commercial batches, in order to demonstrate that the actual values are sufficiently below the TTC. In such a case, skip testing could be considered instead of routine testing, providing that the Competent Authorities, based on a risk assessment, consider the approach as acceptable. 在这种情况下将这种检测方法能力强的分析方法作为常规检测将是困难的，人们可以在开发过程或首次商业批生产中考虑使用这种分析方法，以充分证明其实际值低于TTC值。在这种情况下，使用风险评估的方法，定期检测而不是常规检测是可以接受的。
Question 8. The European Pharmacopoeia Commission Policy for dealing with potentially genotoxic impurities was issued in March 2008. This policy is to be applied during elaboration and revision of pharmacopoeial monographs. It provides very pragmatic guidance on how the CHMP guideline can be applied to active substances described in existing monographs. Can the same principles, as outlined within this policy, apply to established drug substances, which do not have pharmacopoeial monographs?

问题8：2008年3月欧洲药典委员会对具有潜在基因毒性杂质颁发过一个政策。这项政策将在制定和修订药典中得到应用。它提供了非常务实的一个政策来指导如何处理现行药典中收载的活性物质中存在的潜在基因毒性杂质。这些政策是否适用于没有收载到药典中的API吗？
" g$ }$ v" Y2 f/ @Yes. For active substances included in medicinal products authorized by the competent authorities before implementation of the CHMP guideline, the specifications as described in the dossier for marketing authorization should be followed. Action is needed only where there is study data demonstrating genotoxicity of the impurity. The existence of structural alerts alone is considered insufficient to trigger follow-up measures unless it is a structure of very high concern, e.g. N-nitroso, aflatoxins-like and azoxy-compounds. If a new synthetic route is used that may give rise to different potentially genotoxic impurities or to higher levels of previously recognized potentially genotoxic impurities then the situation should be discussed with the competent authority.

回答：是的。在这个指南执行前已批准的API是适用的。在注册申报文件中应递交相关的规格要求。只有当研究数据表明存在遗传毒性杂质时才需要采取行动，仅存在“警示结构”时不足以引发的后续措施，除非在出现一个高度关注的风险结构，例如：N -亚硝基，黄曲霉毒素类和氧化偶氮化合物。如果似使用新的合成路线，该合成路线可能引起潜在基因遗传毒性杂质出现或先前确认的潜在基因毒性杂质水平提高，这种情况应与主管机关进行讨论。

Question 9. What is a reasonable policy for setting specifications for potentially genotoxic impurities which are theoretical or actual impurities in a drug substance manufacturing process?

问题9：在原料药生产过程中，对于理论推测存在或实际存在的潜在基因毒性杂质质量标准的设定依据是什么？

Different possible scenarios can be identified and the applicable policies to be applied for each of them are described below:

回答：各种不同情形时的潜在基因毒性杂质质量标准可以依据下面的情况来进行设定：

Example 1 – A potential genotoxic impurity

例1：一个潜在基因毒性杂质

The definition for a potential genotoxic impurity is derived from the definition for “Potential impurity”: an impurity that theoretically can arise during manufacture or storage. It may or may not actually appear in the (new) drug substance (ICH Q3A, Glossary).

潜在基因毒性杂质的定义是基于“潜在杂质”的定义得来的。潜在杂质是指按照理论推测在生产或储存过程中可能产生的杂质。它可能在(新)原料药中存在，也可能不存在（ICH Q3A，术语）。
If a potential genotoxic impurity is just a theoretical impurity i.e. based on theoretical considerations but not found in practice as demonstrated by studies during development of the manufacture, the impurity does not need to be included in the drug substance specification.

如果一个潜在基因毒性杂质仅仅是理论上推测存在，也就是说基于理论推测存在但生产中并未实际检测到（由生产工艺开发阶段的研究证实），则不需要将其列入到原料药的质量标准中。

Example 2 – A (potentially) genotoxic impurity actually formed or introduced prior to the final step of the synthesis

例2：合成最后一步前，实际生成或引入了一个（潜在）基因毒性杂质
If a (potentially) genotoxic impurity is formed or introduced in a step before the final synthesis step, it is considered possible to not include this impurity in the drug substance specification if it is controlled by a suitable limit in a synthesis intermediate and if it is unambiguously demonstrated by analysis results (use of spiking experiments are encouraged) that presence of this impurity does not exceed 30 % of the limit, derived either from TTC or otherwise defined acceptable limit etc, in the drug substance. If these conditions are not fulfilled, this impurity has to be included in the drug substance specification and the test has to be carried out on a routine basis.

如果在最后一步合成前，实际生成或引入了一个（潜在）基因毒性杂质，可以不将其纳入原料药质量标准中，但是必须保证该杂质在合成中间体中有合理的控制限度并且在原料药检测结果中明确其含量不超过来源于TTC或其他认可标准的30%（推荐使用标准加入法检测原料药）。但是如果不能满足这些要求，就必须在原料药质量标准中进行日常检测。

Should a genotoxic impurity not be controlled at the intermediate stage, then the scenario of example 3 applies.

如果一个基因毒性杂质不可在中间阶段控制，那么适用例3情况。

Example 3 - A (potentially) genotoxic impurity is formed or introduced in the last synthesis step

例3：最后一步合成中，实际生成或引入了一个（潜在）基因毒性杂质

If a (potentially) genotoxic impurity is formed or introduced in the final synthesis step, it should be included in the specifications. However, it is considered possible to apply skip testing if the level of the impurity does not exceed 30 % of the limit, derived from either TTC or otherwise defined acceptable limit etc, in the drug substance. Data should be presented for at least 6 consecutive pilot scale or 3 consecutive production scale batches. If this condition is not fulfilled, a routine test in the drug substance specification is needed.

如果在最后一步合成中实际生成或引入了一个（潜在）基因毒性杂质，必须在原料药质量标准中控制该杂质。如果在原料药中该杂质的含量不超过TTC或其他认可标准的30%，可实行定期检测。至少要提交6批中试批或3批大生产的数据。如果不能满足这个要求，就必须在原料药质量标准中进行日常检测。

The following definitions apply: 以下为文件中涉及的定义

Genotoxic impurity: an impurity that has been demonstrated to be genotoxic in an appropriate genotoxicity test model, e.g. bacterial gene mutation (Ames) test.

基因毒性杂质：某种杂质在适当的基因毒性试验模式中表示为基因毒性，例如细菌基因诱变（Ames）试验

Potentially genotoxic impurity: an impurity that shows (a) structural alert(s) for genotoxicity but that has not been tested in an experimental test model. Here potentially relates to genotoxicity, not to the presence or absence of this impurity.

潜在基因毒性杂质：某种杂质其结构警示可能具有基因毒性，但未经过试验测试模式。这里潜在意指可能具有基因毒性，而不是指杂质的存在与否。

References 参考文献

M.O. Kenyon, J.R. Cheung, K.L. Dobo, W.W. Ku: An evaluation of the sensitivity of the Ames assay to discern low-level mutagenic impurities. Reg Tox & Pharm, 2007, 75-86.

http://zhuyujiao1972.blog.163.com/blog/static/98694727201291611295528/

版主好强大，谢谢分享

20080124 EMEA关于要求进行基因毒性杂质评估的函件（转载中英文）  

2012-10-16 15:22:40|  分类： EDQM|举报|字号 [url=]订阅[/url]

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London, 24 January 2008

2008 年1 月24 日，伦敦

Doc. Ref.: EMEA/44714/2008

文件号：EMEA/44714/2008

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THE FOLLOWING LETTER IS INTENDED FOR ALL MARKETING

AUTHORIZATION HOLDERS FOR MEDICINAL PRODUCTS

CONTAINING ACTIVE SUBSTANCES IN THE FORM OF MESILATES,

(DI)ISETIONATES, TOSILATES OR BESILATES.

以下函件内容针对所有药品中含以甲磺酸盐，羟乙基磺酸盐，对甲苯磺酸盐

或苯磺酸盐形式存在之药物活性成分之上市许可持有人

REQUEST TO ASSESS THE RISK OF OCCURRENCE OF CONTAMINATION WITH MESILATE ESTERS AND RELATED COMPOUNDS IN PHARMACEUTICALS.

对药品中出现甲磺酸酯和相关化合物的风险进行评估的要求

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Dear Sirs, 各有关单位：

Preclinical studies with certain mesilate esters have revealed that their DNA alkylation action can induce mutagenic, carcinogenic and teratogenic effects. This has been reported for methyl and ethyl mesilate and it is not unreasonable to suspect that similar toxic effects may exist in alkyl esters of other low molecular weight sulfonic acids, e.g. tosilates. Although there are no data showing the toxic effect of such esters in humans, there is nevertheless a potential risk that genotoxic substances as described above may be present as impurities in medicinal products containing active substances in the form of sulfonic acid esters.

一些甲磺酸酯的临床前研究发现这些甲磺酸酯的 DNA 烷基化作用会导致诱变效应，致癌效应和致畸效应。甲磺酸甲酯和甲磺酸乙酯已有这方面报导，因此有理由怀疑其它低分子量磺酸（如对甲苯磺酸）的烷基酯可能也存在着类似的毒性影响。尽管无数据表明这些酯对人的毒性影响，但依然有上述基因毒性物质以杂质的形式存在于含磺酸酯类药物活性成分的药品中的潜在风险。

For this reason and following the recent case of mesilate ester contamination of Viracept, Competent Authorities requests all Marketing authorization holders concerned to undertake a risk assessment on the occurrence of these impurities in their preparations and to inform Competent Authorities should any risk be detected that requires corrective measures in the manufacture and control of the medicinal product. This risk assessment should also include the procedure regarding the cleaning procedures and the used solvents etc.

由于这个原因及最近发生的维拉赛特（甲磺酸奈非那韦）事件，药政管理部门要求所有相关的上市许可持有人对在他们的药品中是否会出现这些杂质开展风险评估，并告知药政管理部门所发现的任何风险，这些风险需要在药品的生产和控制过程中采取整改措施。该风险评估也应包括关于清洗程序和所用溶剂等的程序。

Below you will find some information to help you in your risk assessment.

下列一些信息旨在帮助开展风险评估：

(1)    In which preparations can mesilate esters (or alkyl mesilates) occur as impurities?

（1） 在哪个药品中会出现甲磺酸酯（或甲磺酸烷基酯）？

Alkyl mesilates, e.g. methanesulfonic acid methyl esters (MMS) and methanesulfonic acid ethyl esters (EMS), are esters of methanesulfonic acid with methanol, ethanol, or other lower alcohols. Alkyl mesilates can therefore be found as potential impurities, in particular in active substances that occur as salts of methanesulfonic acid or mesilates or in active substances for which methanesulfonic acid is used in the synthesis.

甲磺酸烷基酯，如甲磺酸甲酯（MMS）和甲磺酸乙酯（EMS），是甲磺酸与甲醇，乙醇，或其它低级醇(lower alcohol)形成的酯。特别是在以甲磺酸盐或甲磺酸酯形式存在的药物活性成分中或其合成过程中用到了甲磺酸的药物活性成分中，甲磺酸烷基酯会被视为潜在杂质。

(2)    Are there any other potentially dangerous sulfonic acid ester impurities that can occur in medicines?

（2） 在药品中是否还会出现其它有潜在危险的磺酸酯杂质？

The similar alkyl or aryl sulfonic ester contaminations could be found in active substances that are in the form of (di)isetionates, besilates (benzenesulfonic acid esters) and tosilates (toluene-p-sulfonic acid esters). The risk of them occurring should therefore be clarified.

在以羟乙基磺酸盐，苯磺酸盐和对甲苯磺酸盐形式存在的药物活性成分中也会发现类似的磺酸烷基酯或芳基酯污染。因此，需说明出现这些污染的风险。

(3)    Is there a threshold value for these impurities, under which the risk is negligible? Which limits should be used?

（3） 这些杂质是否有阈值（在该阈值之下，风险是可以被忽略的）？应设定什么限度？

In the absence of other toxicological data the TTC (threshold of toxicological concern) for genotoxic impurities (cf. EMEA guidelines ‘Limits for Genotoxic Impurities’ EMEA/CHMP/QWP/251334/2006) should be used to set limits.

在没有其它毒性数据的情况下，应根据基因毒性杂质的毒理学关注阈值（TTC，threshold of toxicological concern）来设定限度。

(Calculating the limits to be applied: 1.5 micrograms divided by the maximum daily dose in grams gives the limit in ppm to be applied to the active substance).

（限度计算方法：1.5mg 除以以克为单位的最大日剂量得以ppm 为单位的该杂质在药物活性成分中的限度。）

(4) What legislative basis is there for restricting alkyl mesilates in pharmaceutical active substances?

（4） 限制药物活性成分中甲磺酸烷基酯的法律基础是什么？

In all monographs for active substances that are present in the form of mesilates and diisetionates the European Pharmacopoeia requires the following safety measures to be applied in the manufacturing process:

在所有以甲磺酸盐和羟乙基磺酸盐形式存在的药物活性成分的欧洲药典各论中，欧洲药典均要求在其生产过程中采取如下安全措施：

?The production method must be evaluated to determine the potential formation of alkyl mesilates (respectively alkyl diisetionates), which is particularly likely to occur if the reaction medium contains lower alcohols. Where necessary, the production method is validated to demonstrate that alkyl mesilates (respectively alkyl diisetionates) are not detectable in the final product.“

“必须对生产工艺进行评估以确定甲磺酸烷基酯（羟乙基磺酸烷基酯）的形成可能，特别是当反应溶媒含低级醇的时候，很可能会出现这些杂质。必要的话，需要对生产工艺进行验证以说明在成品中未检出甲磺酸烷基酯。”

(5) How can these requirements be put into practice?

（5） 如何能落实这些要求？

The production and storage of the active substances and preparations concerned should be subjected to a risk analysis taking account of the following points (not an exhaustive list) .

对相关药物活性成分和药品的生产和储存进行风险分析应考虑如下几点（非完全列表）：

l         Does the production of the active ingredient involve the use of lower aliphatic alcohols, such as methanol, ethanol, n-propanol, or isopropanol, in the presence of methanesulfonic acid (or isetionic acid, benzolsulfonic acid, paratoluolsulfonic acid) or the corresponding acid chlorides? If so, is the formation of alkyl mesilates or the analogous alkyl besilates and alkyl tosilates minimized and is followed by an efficient purification stage?

l         药物活性成分的生产是否涉及到在甲磺酸（或羟乙基磺酸，苯磺酸，对甲苯磺酸）或相应的酰氯存在的情况下，使用了低级脂肪酯，如甲醇，乙醇，正丙醇或异丙醇的情况？如果是这种情况的话，甲磺酸烷基酯或类似苯磺酯烷基酯和对甲苯磺酸烷基酯的形成可能性是否已被降至最低？是否存在有效的精制步骤？

l         Does the cleaning procedures for equipments, particularly those in contact of sulfonic acid reagents involve the use of lower aliphatic alcohols?

l         设备（特别是接触到磺酸试剂的设备）的清洗程序是否涉及到低级脂肪醇的使用？

l         Are appropriate specifications and validated testing methods available to verify the alkyl- or arylsulfonic acid ester impurities in the active substance (at theTTC)?

l         是否有适宜的质量标准和已验证的分析方法可以证实药物活性成分中的磺酸烷基酯或磺酸芳基酯杂质处于毒理学关注阈值？

l         Is the quality of the starting materials methanesulfonic acid (benzolsulfonic acid, paratoluolsulfonic acid, isetionic acid) checked for alkyl- or arylsulfonic acid ester impurities (e.g. EMS and MMS in methanesulfonic acid) and the corresponding acid chlorides? Are appropriate specifications and validated testing methods available for this?

l         是否检查了起始物料，如甲磺酸盐（苯磺酸盐，对甲苯磺酸盐，羟乙基磺酸），中的烷基磺酸酯或芳基磺酸酯杂质（如甲磺酸中的EMS 和MMS）及相应的酰氯？是否有这些杂质的适宜标准和验证过的方法？

l         Is it ensured that when using sulfonic acids contaminated with sulfonic acid esters or related compounds as the starting materials for producing the active ingredient the TTC for the potential genotoxic impurities in the active substance is not exceeded? The cumulative risk of various alkyl- or aryl-substituted sulfonic acid ester impurities should be taken into account.

l         当被磺酸酯或相关物质所污染了的磺酸作为起始物料用于药物活性成分时，是否能保证药物活性成分中潜在基因毒性杂质不超过其毒理学关注阈值（TTC）？应当要考虑各种烷基或芳基取代磺酸酯杂质的累加风险。

l         If a sulfonic acid derivative is used in one of the last stages of synthesis during production of the active substance, this should be included in the risk analysis.

l         如在药物活性成分生产的最后一步合成步骤用到了磺酸衍生物，应将其纳入风险分析。

l         Is the quality of recycled solvents controlled for the enrichment and carry-over of sulfonic acid ester impurities (e.g. EMS in ethanol, MMS in methanol, IMS in isopropanol)?

l         是否对回收溶剂中磺酸酯类杂质（如，乙醇中的EMS，甲醇中的MMS，异丙醇中的IMS） 的富集和残留进行了控制？

l         Can the formation of alkyl- or aryl-sulfonic acid esters be excluded during the storage of an active substance that exists in the form of a mesilate, besilate, tosilate or isetionate/diisetionate, or in the related preparation?

l         是否能排除以甲磺酸盐，羟乙基磺酸盐，对甲苯磺酸盐或苯磺酸盐形式存在的药物活性成分，或其相关制剂，在储存过程中形成烷基或芳基磺酸酯？

l         Can the formation of alkyl- or aryl-sulfonic acid esters be excluded during the processing of mesilate, disetionate, besilate or tosilate active substances to make the finished preparation, e.g. when using alcohols for granulation? Is a sufficiently sensitive method available to detect these impurities in the pharmaceutical dosage form (at the TTC)?

l         是否能排除以甲磺酸盐，羟乙基磺酸盐，对甲苯磺酸盐或苯磺酸盐形式存在的药物活性成分在制成最终制剂的过程中形成烷基或芳基磺酸酯，如在制粒过程中使用了醇？是否有足够灵敏的的方法可以检测到制剂中的（处于TTC水平的）这些杂质？

(6) In which cases should the results of the risk analysis carried out under (5) and the related investigations be reported to Competent Authorities ?

（6） 在什么情况下应将如（5）项所开展的风险分析结果和相关的调查报告给药政管理部门？

The Marketing Authorization Holder for the finished product is responsible for carrying out the risk analysis. The information necessary for risk assessment should be made available to the Marketing Authorization Holder by the manufacturers involved in the galenic production and in particular by the manufacturers of the active substance.

制剂的上市许可持有人负责进行风险分析。药品生产过程中所涉及到的生产厂家，特别是原料药的生产厂家，应向上市许可持有人提供风险评估所需的信息。

If there is a related risk that must be controlled by making changes to the production process or by means of specifications, any changes to the marketing authorization that require amendment to the method of manufacture or control of the active substance and/or finished product must be submitted to Competent Authorities using the relevant procedure for assessment..

如果存在着必须通过变更生产工艺或变更质量标准才能得到控制的风险，则任何需要对药物活性成分和/或制剂的生产工艺或质量控制进行改进的上市许可变更均必须根据相关的评估程序递交至药政管理部门。

We hereby request that you provide us by 30 April 2008 a statement that the risk analysis has been carried out and specifying its outcome:

特此通知，请有关单位于2008 年4 月30 日前提交声明说明已进行了风险分析，并指明风险分析的结果：

a. no safety risk identified

a) 未发现安全风险

b. amendment to the manufacturing process/control of active substance and/or finished product has been provided to the Competent Authority by variation to the marketing authorisation.

b) 已通过上市许可变更程序向药政管理部门递交了药物活性成分和/或制剂的生产工艺/质量控制方面的改进

In the latter case the Marketing Authorization Holder should provide a justified timetable for the submission of the variations(s) needed.

如属于后种情况，上市许可持有人应提供递交所需的变更文件的合理时间表。

The statement should include a commitment to make the risk analysis available upon request from any Competent Authority.

声明中应承诺在任一药政管理部门要求提供风险分析（报告）的情况下，均应提供。

http://zhuyujiao1972.blog.163.com/blog/static/98694727201291632240311/

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Yours faithfully,

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200601 FDA指南《推荐的遗传毒性试验结果综合分析法指导原则》中英文  

2012-10-16 12:24:01|  分类： FDA|举报|字号 [url=]订阅[/url]

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英文官网FDAhttp://www.fda.gov/downloads/Drugs/GuidanceComplianceRegulatoryInformation/Guidances/ucm079257.pdf

中文官网CDE http://www.cde.org.cn/dzkw.do?method=largePage&id=220

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Guidance for Industry and Review Staff

Recommended Approaches to Integration of Genetic Toxicology Study Results

推荐的遗传毒性试验结果综合分析法指导原则

Additional copies are available from:

Office of Training and Communications

Division of Drug Information, HFD-240

Center for Drug Evaluation and Research

Food and Drug Administration

5600 Fishers Lane

Rockville, MD 20857

(Tel) 301-827-4573

http://www.fda.gov/cder/guidance/index.htm

U.S. Department of Health and Human Services

Food and Drug Administration

Center for Drug Evaluation and Research (CDER)

January 2006

Pharmacology and Toxicology

药理和毒理

TABLE OF CONTENTS 目录

I. INTRODUCTION 介绍........................................1

II. BACKGROUND 背景...........................................1

III. INTEGRATION OF GENETIC TOXICOLOGY STUDY RESULTS 基因毒性研究结果整合..............2

A. Weight-of-Evidence Approach 重量-证据法..............................................................3

B. Mechanism of Action 行为机理..............................................3

C. Additional Supportive Studies 额外的支持性研究......................................................3

REFERENCES 参考文献........................................................5

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Guidance for Industry and Review Staff[1]

Recommended Approaches to Integration of Genetic Toxicology Study Results

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This guidance represents the Food and Drug Administration’s (FDA’s) current thinking on this topic. It does not create or confer any rights for or on any person and does not operate to bind FDA or the public. You can use an alternative approach if the approach satisfies the requirements of the applicable statutes and regulations. If you want to discuss an alternative approach, contact the FDA staff responsible for implementing this guidance. If you cannot identify the appropriate FDA staff, call the appropriate number listed on the title page of this guidance.

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I. INTRODUCTION 简介

The purpose of this guidance is to inform industry and the review staff in the Center for Drug Evaluation and Research (CDER) on how CDER views positive findings in genetic toxicology assays during drug development. The guidance provides recommendations on how to proceed with clinical studies while ensuring the safety of study participants when results in genotoxicity studies suggest a potential cancer or genetic hazard. This guidance pertains to pharmaceuticals administered through oral, intravenous, topical, and other routes, as appropriate.

本指导原则的目的是为了向企业和CDER的审评人员说明，CDER如何看待药物开发过程中出现的遗传毒性试验阳性结果。当遗传毒性试验结果提示药物具有潜在的致癌性或遗传危害时，本指导原则为如何继续进行临床试验并保证受试者的安全性提供建议。本指导原则中讨论了单次给药和多次给药临床试验相关的管理决策。本指导原则适用于经口、静脉、局部和其他途径给药的药物。

FDA’s guidance documents, including this guidance, do not establish legally enforceable responsibilities. Instead, guidances describe the Agency’s current thinking on a topic and should be viewed only as recommendations, unless specific regulatory or statutory requirements are cited. The use of the word should in Agency guidances means that something is suggested or recommended, but not required.

FDA的指导原则，包括本指导原则在内，并不具有法律上的强制性，而是描述了当前FDA对某一问题的想法，应该被认为仅是一种建议，除非是援引了特殊的管理性的或法令性的要求。FDA指导原则中的“应该”一词是指建议的或推荐某些东西，而不是要求某些东西。

II. BACKGROUND 背景

The timing and conduct of genetic toxicology studies have been described in the ICH guidelines M3, S2A, and S2B.[2] We recommend that these guidances be consulted and that this document be considered an adjunct guidance.

遗传毒性试验的时间安排和如何进行在ICH指导原则M3、S2A和S2B中已有描述。我们建议参考这些指导原则，而本指导原则可认为是仅作为附件性指导原则。

Risk for carcinogenesis is usually determined in rodent assays, either 2-year studies or shorter-term studies using alternative models.[3] A core battery of genetic toxicology studies has been accepted by industry and regulators through the International Conference on Harmonisation (ICH) consultative process. These studies, which are designed to identify genotoxic hazard, include:   

通常是在啮齿类动物试验中评估致癌性风险，包括周期为2年的试验或采用替代模型而周期较短的试验。通过ICH程序，企业和管理者接受了遗传毒性核心组合试验方案。这些试验是用于确定化合物的遗传毒性，包括：

? A test for gene mutation in bacteria;

    ■ 一项细菌基因突变试验

? An in vitro assessment of chromosomal damage using mammalian cells or an in vitro mouse lymphoma tk+/- assay; and

    ■ 一项采用哺乳动物细胞进行的体外染色体损伤评估试验，或体外小鼠淋巴瘤tk+/- 试验

? An in vivo test for chromosomal damage using rodent hematopoietic cells.

    ■ 一项采用啮齿类动物造血细胞进行的体内染色体损伤试验。
) }7 x9 p! j4 x4 ^( z5 p+ LThe following discussion is based on current guidance documents.[4] We recommend that results from in vitro genetic toxicology studies be available before the initiation of phase 1 trials.   

以下讨论是根据当前的指导原则文件进行的。我们建议在进行I期临床试验前完成体外遗传毒性试验。

III. INTEGRATION OF GENETIC TOXICOLOGY STUDY RESULTS遗传毒性试验结果的综合分析

The Agency takes into account the totality of safety data when considering whether it is safe to proceed with a clinical trial when there are positive genetic toxicology study results. This consideration includes a thorough evaluation of all the genetic toxicology data and the nature of the proposed trial. If the results of the genetic toxicology tests indicate a lack of genotoxic potential, then clinical trials can generally be undertaken in healthy subjects or patient populations with the proposed medical indication.   

当遗传毒性结果为阳性结果时，对进入临床试验是否安全，FDA会考虑所有的安全性资料。这些考虑包括对所有遗传毒性资料的全面彻底的评价和拟进行的临床试验的性质。如果这些遗传毒性试验的结果提示无潜在的遗传毒性，临床研究一般可在健康受试者和拟用临床适应症的病人中进行。

Pharmaceuticals that give positive results in genetic toxicology assays but do not directly interact with DNA do not always present a significant in vivo risk. In such cases, we recommend providing evidence of the mechanism of genotoxicity and relevance of the mechanism to anticipated in vivo exposure. Alternatively, it is also appropriate to rule out mechanisms involving direct interaction with DNA (e.g., demonstration that a drug does not cause DNA alkylation or DNA strand breakage).

    遗传毒性试验出现阳性结果、但不直接与DNA发生作用的药物，可能不总是带来明显的体内给药的风险。在这种情况下，我们建议要提供有关遗传毒性机制的证据以及这种机制与预期体内暴露的相关性。或者，排除直接与DNA作用的机制也是可行的（如证明药物不产生烷化或DNA链断裂）。

Drugs known to directly damage DNA may be permitted to be used in patients with debilitating or life-threatening diseases, such as cancer, but should not be administered to healthy subjects.[5]

已知直接损伤DNA的药物可能会允许用于极其虚弱（debilitating）的患者或危及生命的疾病，如癌症，但不应在健康受试者中使用。

If any of the three assays in the ICH genotoxicity standard battery are positive, then we recommend completing the fourth test in the ICH battery. Equivocal studies should be repeated to determine the reproducibility of the results. If a positive response is seen in one or more assays, sponsors should consider choosing from one or more of the following options.

    如果ICH推荐的标准三项试验组合中任何一项结果为阳性，我们建议完成ICH试验组合中的第四项试验。若结果模棱两可时需重复试验以确定结果的可重现性。如果一项或多项试验结果为阳性，申办人应考虑以下选择中一项或更多项。

A. Weight-of-Evidence Approach   

A. 证据权衡法（Weight-of-evidence approach）

In some instances, after evaluation of all available data, the weight of evidence (WOE) suggests a lack of genotoxic hazard. For example, a positive response is observed in one exposure regimen of an in vitro cytogenetics assay. The positive result is seen only at the high dose, and the increase is within or just outside the range for historical control values for the solvent and cell line employed. The WOE approach could indicate that although a small increase in the frequency of chromosomal aberrations is statistically significant, it lacks biological relevance. Contributing considerations could include (1) the level of cytotoxicity at which the response was seen, and (2) corroborating data from the same or complementary assays. For example, a positive response seen with a short-term exposure without metabolic activation but not corroborated with the longer exposure at comparable levels of cytotoxicities would argue against the biological significance of the positive result. Similarly, such a positive finding in an in vitro chromosomal aberration assay that is not corroborated by the matching exposure regimen of the mouse lymphoma assay could also call into question the significance of the positive finding. If the WOE approach indicates a lack of genotoxic hazard, clinical studies could proceed provided the positive response is described in the investigator’s brochure and the informed consent form.

    在某些情况下，在对所有现有资料进行评估后，证据权衡提示无遗传毒性危害。例如，在体外细胞遗传学试验的一种暴露方案下出现了阳性反应，这个阳性结果仅在高剂量时出现，而发生率升高的程度在所用溶剂和细胞系的历史对照数据范围内或刚刚超出该范围。证据权衡后可能提示，虽然染色体异常频率的轻微升高有统计学意义，但无生物学相关性。有帮助的考虑因素包括（1）在出现阳性结果的剂量时细胞毒性的水平，（2）相同试验或补充试验的确证性数据。例如，在无代谢活化下短期暴露时出现阳性结果，但在相当细胞毒性水平的长期暴露中未得到确证，这时阳性结果可能不具有生物学意义。相似地，在体外染色体异常试验得到阳性结果，而在相当暴露方案下小鼠淋巴瘤试验未得到确证，也可对该阳性结果的意义产生疑问。如果证据权衡法提示无遗传毒性危害，可进行重复给药的临床试验，该阳性结果应写入研究者手册和知情同意书。
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B. Mechanism of Action   

B. 作用机制

Positive results are sometimes satisfactorily explained by knowledge of the mechanism of action. For example, it has been demonstrated that in vitro clastogenic effects can result from excessively high osmolarity or low pH. Positive responses elicited under such nonphysiologic exposure conditions are not relevant to human risk. In addition, certain genotoxic responses are thought to have thresholds below which a hazard does not exist. Agents that induce effects by indirect mechanisms (e.g., interference with metabolism of nucleotides and their precursors, damage to spindle proteins, inhibition of DNA synthesis, or inhibition of topoisomerase) can have thresholds for genotoxic effects. In such cases, we recommend presenting evidence of the existence of a threshold that would not be attained during the proposed clinical exposure or presenting evidence of a mechanism not expected to be operative in vivo. Positive responses that are satisfactorily explained by an MOA may allow clinical studies in normal volunteers or in patients to proceed without additional studies.

有些情况下作用机制的相关信息可以满意地解释阳性结果出现的原因。例如，资料显示，过高的克分子渗透压浓度或较低的pH可导致体外诱裂作用。在这种非生理性暴露条件下出现的阳性反应与人体风险无相关性。此外，一些遗传毒性反应被认为产生风险存在阈值。有些药物通过非直接机制产生影响，例如干扰核苷及其前体的代谢、损伤纺锤体蛋白、抑制DNA合成或抑制拓扑异构酶，这些药物的遗传毒性可能具有阈值。在这种情况下，我们建议提供阈值存在的证据，而该阈值在拟进行的临床暴露过程中可能达不到，或者存在的机制证据在体内预期是无效的。如果阳性反应能被MOA合理解释时，可能会允许在正常志愿者或病人上进行临床试验而不需要附加试验。

C. Additional Supportive Studies

C. 附加的支持性试验

On occasion, results from in vitro studies demonstrate a reproducible positive dose-response. Results from bone marrow cytogenetic studies are frequently negative, even for those compounds giving positive results in in vitro genetic toxicology assays. This discrepancy can result from a number of differences between cultured cells and intact animals: differing metabolic pathways occurring in vitro and in vivo, metabolic inactivation in the intact animal, failure of the parent compound or active metabolite to reach the target cell, or simply, an inability to achieve plasma levels in vivo comparable to concentrations that generated positive responses in the in vitro assays.   

    有些情况下，体外试验的结果显示出了可重复性的阳性的剂量反应关系。骨髓细胞遗传学试验的结果经常为阴性，即使是体外遗传毒性试验结果为阳性的药物。这种差异可能来源于培养细胞和整体动物间的多种差异：体外和体内不同的代谢途径，整体动物的代谢灭活作用，母体化合物或活性代谢产物不能到达靶细胞，或者很简单，体内血浆药物浓度不能达到在体外试验中产生阳性反应的药物浓度。
, R* A, C. P! Y' S  R0 MAdditional in vivo assays can be useful in clarifying in vitro positive results. For example, peripheral blood smears from repeat-dose toxicity studies in mice can be evaluated for micronucleus induction, and peripheral blood lymphocytes from repeat-dose studies in rats or monkeys can be cultured and assessed for chromosome damage in metaphase spreads. DNA damage can be assessed in potential target tissues (e.g., DNA adducts or DNA strand breakage using the Comet or alkaline elution assay), or transgenic rats or mice can be used to assess mutagenicity in potential target tissues.[6]

    对于确证体外试验的阳性结果，附加的体内试验可能很有用。例如，小鼠重复给药毒性试验中进行外周血涂片，可以用来评估诱导微核的作用，大鼠或猴重复给药毒性试验进行外周血淋巴细胞培养，可用于评估细胞分裂中期的染色体损伤。在潜在的靶组织中应评估DNA损伤（如通过彗星或碱基洗脱试验来评估DNA加合物或DNA链断裂），或用转基因大鼠或小鼠来评估在可能的靶组织中的诱变性。

The Syrian hamster embryo cell (SHE) transformation assay has been suggested as a follow-up assay in the face of positive in vitro genotoxicity results. Data in the literature suggest that the SHE assay correlates well with rodent carcinogenicity results for chemicals in general (Isfort et al. 1996). Results from an International Life Sciences Institute (ILSI) validation effort on human pharmaceuticals, although smaller in scope, suggest that the SHE assay is less predictive for human carcinogenic risk (Mauthe et al. 2001). With respect to human pharmaceuticals, the ILSI study found that the SHE assay had high sensitivity (83 percent) for detection of human carcinogens. However, its low specificity (15 percent) for prediction of putative human noncarcinogens led to a poor overall concordance of 37 percent. Although transformation assays measure endpoints more akin to the health effect of concern (cancer) and can be useful in making a WOE judgment, they also have inherent limitations. Many pharmaceuticals that give positive responses in 2-year rodent carcinogenicity studies do so through exaggerated pharmacological effects, immune suppression, or hormonal disequilibrium. It is unclear how an in vitro assay could be responsive to these mechanisms.

    当体外遗传毒性试验结果为阳性时，叙利亚仓鼠胚胎细胞（Syrian hamster embryo，SHE）转化试验可用作附加试验。文献资料显示，通常化学物质的SHE试验与啮齿类动物致癌性试验结果具有良好的相关性(Isfort et al. 1996)。国际生命科学会（International Life Sciences Institute，ILSI)对人用药物进行确证性研究，虽然是较小范围进行，但结果提示SHE试验对人体致癌性风险的预测能力较差(Mauthe et al. 2001)。对于人用药物，ILSI研究发现SHE对于检测人类致癌性具有高敏感性（83%）；但是，对于假定的人体非致癌剂（putative human noncarcinogens）预测的特异性较低（15%），这导致总体一致性仅为37%。虽然，转化试验检测的终点与所担忧的健康影响（癌症）更为接近，可能在进行证据权衡判断时有用，他们也有其固有的局限性。在两年啮齿类致癌性试验中表现出阳性结果的很多药物，是通过扩大的药理学作用、免疫抑制或激素失衡出现的。体外试验如何能反映出这些机制尚不明确。

In the last several years, a number of transgenic mouse strains have become available for use in short-term carcinogenicity studies. The p53 haplo insufficient mouse has been found to be useful in the identification of mutagenic carcinogens (MacDonald et al. 2004). Negative results in a p53 carcinogenicity study are considered evidence that a genotoxic agent does not present a carcinogenic hazard to humans through a p53-mediated mechanism.

    在最近几年中，已经有一些转基因小鼠可以在短期致癌性试验中应用。研究显示p53单一缺陷小鼠在致突变性致癌剂的鉴定方面有用(MacDonald et al. 2004)。当p53致癌性试验结果阴性时，可认为一种遗传毒性药物不会通过p53介导的机制对人类产生致癌性危害。

Supportive studies contribute to the WOE determination as to whether a drug giving a positive response in one of the ICH-specified assays presents a risk of genetic damage to subjects involved in clinical trials. The decision as to whether early assessment of oncogenic potential will be needed will, out of necessity, be on a case-by-case basis. Factors influencing the decision include target population, disease indication, duration of exposure, and safety profile of other drugs in the class or other drugs serving the same medical need.

    一个药物的一项ICH指定的试验结果为阳性时，支持性试验有助于证据权衡，以判断是否可为参加临床试验的受试者带来产生遗传损伤的风险。确定是否需进行潜在致瘤性的早期评价，可能是必要的，这将基于在具体情况具体分析基础上。影响这个决定的因素包括目标人群、适应症、暴露时间、同系的其他药物或相同用途的其他药物的安全特性。

REFERENCES     参考文献

ICH guidance for industry S1A The Need for Long-Term Rodent Carcinogenicity Studies of Pharmaceuticals. (http://www.fda.gov/cder/guidance/index.htm)

Isfort, RJ, GA Kerckaert, and RA LeBoeuf, 1996, Comparison of the Standard and Reduced pH Syrian Hamster Embryo (SHE) Cell Transformation Assays in Predicting the Carcinogenic Potential of Chemicals, Mutat. Res. 356:11-63.

MacDonald, J, JE French, RJ Gerson, J Goodman, T Inoue et al., 2004, The Utility of Transgenic Mouse Assays for Identifying Human Carcinogens — A Basic Understanding and Path Forward, Toxicol. Sci. 77(2):188-194.

Mauthe, RJ, DP Gibson, RT Bunch, and L Custer, 2001, The Syrian Hamster Embryo (SHE) Cell Transformation Assay: Review of Methods and Results, Toxicologic Pathology 29 (Supplement): 138-146.

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[1] This guidance has been prepared by the Pharmacology Toxicology Coordinating Committee (PTCC) in the Office of New Drugs (OND) in the Center for Drug Evaluation and Research (CDER) of the Food and Drug Administration.

本指南由FDA药审中心（CDER）新药办公室（OND）药理毒性协调委员会（PTCC）起草。

[2] ICH guidance for industry M3 Nonclinical Safety Studies for the Conduct of Human Clinical Trials for Pharmaceuticals, ICH guidance for industry S2A Specific Aspects of Regulatory Genotoxicity Tests for Pharmaceuticals, and ICH guidance for industry S2B Genotoxicity: A Standard Battery for Genotoxicity Testing of Pharmaceuticals. (http://www.fda.gov/cder/guidance/index.htm)

ICH行业指南M3：药物人类临床实施过程中的非临床安全性研究，ICH行业指南S2A 药物基因法定毒性检测的特定方面，和ICH行业指南2B基因毒性药物中基因毒性测试的标准电池

[3] ICH guidance for industry S1B Testing for Carcinogenicity of Pharmaceuticals(http://www.fda.gov/cder/guidance/index.htm)

ICH行业指南S1B：药物致癌性的测试

[4] We update guidances periodically. To make sure you have the most recent version of a guidance, check the CDER guidance Web page at http://www.fda.gov/cder/guidance/index.htm.

我们会定期更新指南。为保证你持有的指南为最新版本，请与CDER指南网址进行核对。

[5] ICH guidance for industry S2A Specific Aspects of Regulatory Genotoxicity Tests for Pharmaceuticals. (http://www.fda.gov/cder/guidance/index.htm)

ICH行业指南S2A：药物基因法定毒性检测的特定方面

[6] ICH guidance for industry S2B Genotoxicity: A Standard Battery for Genotoxicity Testing of Pharmaceuticals. (http://www.fda.gov/cder/guidance/index.htm)

ICH行业指南S2B基因毒性：药物中基因毒性测试的标准电池

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