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发表于 2018-9-19 09:26:00
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来自 重庆
Ⅶ DEMONSTRATING BIOSIMILARITY生物相似性的论证
This section discusses scientific considerations in the stepwise approach to developing data and information needed to support a demonstration of biosimilarity. To demonstrate biosimilarity, a sponsor must provide sufficient data and information to show that the proposed product and the reference product are highly similar notwithstanding minor differences in clinically inactive components and that there are no clinically meaningful differences between the two products in terms of safety, purity, and potency. The type and amount of analyses and testing that will be sufficient to demonstrate biosimilarity will be determined on a product-specific basis.
本部分主要讨论采用阶梯式方法收集生物相似性的数据信息时应注意的科学问题。为了论证生物相似性,申请者必须提供有效的数据信息来说明尽管临床非活性成分存在微小差异,类似药和参比制剂仍然高度相似,且两种产品间的安全性、纯度和效能无临床有意义差别。应根据每个产品的特性,分别采用不同的分析试验类型和数量充分证明其生物相似性。
A.Structural Analyses结构分析
The PHS Act requires that a 351(k) application include information demonstrating biosimilarity based on data derived from, among other things, analytical studies that demonstrate that the biological product is highly similar to the reference product notwithstanding minor differences in clinically inactive components, unless FDA determines that an element is unnecessary in a 351(k) application. FDA expects that first, a sponsor will extensively characterize the proposed product and the reference product with state-of-the-art technology, because extensive characterization of both products serves as the foundation for a demonstration of biosimilarity. It is expected that the expression construct for a proposed product will encode the same primary amino acid sequence as its reference product. However, minor modifications such as N- or Cterminal truncations that are not expected to change the product performance may be justified and should be explained by the sponsor. Additionally, sponsors should consider all relevant characteristics of the protein product (e.g., the primary, secondary, tertiary, and quaternary structure; posttranslational modifications; and biological activities) to demonstrate that the proposed product is highly similar to the reference product notwithstanding minor differences in clinically inactive components. The more comprehensive and robust the comparative structural and functional characterization is, the stronger the scientific justification for a selective and targeted approach to animal and/or clinical testing.
除非FDA认为不需要,PHS Act要求 351(k) 申请提交的证明生物相似性性的信息,除了其他必需事项外,还应包括能够证明即使临床非活性成分存在微小差异,类似药和参比制剂仍然高度相似的分析试验研究。首先,FDA 希望申请者采用最先进的技术对类似药和参比制剂进行广泛研究,因为这些研究结果是论证生物相似性的基础。通常情况下,FDA 希望类似药和参比制剂的氨基酸序列表达构造相同,但是,像N-或C-端断裂等不会影响安全有效性的微小差异,申请者只要给出科学合理性的解释即可。另外,申请人还必须考虑到蛋白制品所有相关性质(包括一、二、三、四级结构、翻译后修饰、生物活性),以证明即使在临床非活性成分存在微小差异的情况下,其与参比制剂仍具有高度生物相似性。对结构功能比较得越全面,动物和/或临床试验的选择和针对性越科学合理。
Sponsors should use appropriate analytical methodologies with adequate sensitivity and specificity for structural characterization of the proteins. Generally, such tests include the following comparisons of the proposed product and the reference product:
• Primary structures, such as amino acid sequence
• Higher order structures, including secondary, tertiary, and quaternary structure (including aggregation)
• Enzymatic posttranslational modifications, such as glycosylation and phosphorylation
• Other potential variations, such as protein deamidation and oxidation
• Intentional chemical modifications, such as PEGylation sites and characteristics
申请人需要使用灵敏度高、专属性强的分析方法分析蛋白质的结构特性。一般而言,分析实验通常需要比较以下几个方面:
(1)一级结构,如氨基酸序列;
(2)高级结构,包括二级、三级和四级结构(包括聚合);
(3)酶转录后的修饰,如糖基化和磷酸化;
(4)其他可能的变化,如蛋白脱酰基化反应和氧化反应;
(5)意向化学修饰,如聚乙二醇化结合位点及其特征。
Sponsors should conduct extensive structural characterization of both the proposed product and the reference product in multiple representative lots to understand the lot-to-lot variability of both products in the manufacturing processes. Lots used for the analyses should support the biosimilarity of both the clinical material used in the clinical study(ies) intended to support a demonstration of biosimilarity, and the to-be-marketed proposed product, to the reference product. Characterization of lots manufactured during process development for the proposed product may also be useful. Sponsors should justify the selection of the representative lots, including the number of lots.
申请人应该对类似药和参比制剂多个有代表性批次进行广泛的结构确认,以了解生产过程中不同批次间的变化。用于进行生物相似性分析的批次应能够代表临床试验、待上市的产品和参比制剂。类似药产品工艺开发期间批次的性质也是有用信息,申请者应能够说明批次及批数选择的合理性。
In addition, FDA recommends that sponsors analyze the finished dosage form of multiple lots of the proposed product and the reference product, assessing excipients and any formulation effect on purity, product- and process-related impurities, and stability. Differences in formulation between the proposed product and the reference product are among the factors that may affect the extent and nature of subsequent animal or clinical testing. A sponsor considering manufacturing changes after completing the initial analytical similarity assessment or after completing clinical testing intended to support a 351(k) application should perform an additional analytical similarity assessment with lots manufactured by the new process and the reference product and establish comparability of the proposed product manufactured by the old and new manufacturing processes. The nature and extent of the changes may determine the extent of the analytical similarity and comparability studies and any necessary additional studies.
此外,FDA 建议申请人分析多个批次的成品来评价辅料和处方对纯度、产品和工艺相关杂质和稳定性的影响。类似药和参比制剂处方不同可能是后续动物或临床试验的影响因素之一。在完成初始相似性评估或临床试验后,申请人为支持其351(K)申请考虑到生产工艺变化,应对新工艺和参比制剂生产的批次进行额外的相似性分析评估,并对由新旧生产工艺生产的产品进行相似性分析。生产工艺的变化可能决定相似性分析的程度,是否需要对比及其他附加试验。
If the reference product or the proposed product cannot be adequately characterized with stateof-the-art technology, the application for the proposed product may not be appropriate for submission under section 351(k) of the PHS Act; and the sponsor should consult FDA for guidance on the appropriate submission pathway.
如果利用最先进的技术仍不能全面描述类似药和参比制剂的特征,则PHS Act351(k) 可能不适用于该产品的申请,申请人应咨询FDA,请FDA指导PHS Act 351(k)是否适用于这种蛋白产品的申请。
B.Functional Assays功能性实验
The pharmacologic activity of protein products should be evaluated by in vitro and/or in vivo functional assays. In vitro assays may include, but are not limited to, biological assays, binding assays, and enzyme kinetics. In vivo assays may include the use of animal models of disease (e.g., models that exhibit a disease state or symptom) to evaluate functional effects on pharmacodynamic markers or efficacy measures. A functional evaluation comparing a proposed product to the reference product using these types of assays is also an important part of the foundation that supports a demonstration of biosimilarity and may be used to scientifically justify a selective and targeted approach to animal and/or clinical testing.
蛋白产品的药理学活性应当通过体内和/或体外功能性实验评估。体外分析包括但不仅限于生物分析、结合分析和酶动力学。体内分析包括应用动物病理模型(例如表现出疾病状态或病症的模型)来评价对药效学标志物或疗效测定的影响。功能性试验不仅是论证生物相似性的基础,还可用于合理和有针对性的选择动物和/或临床试验。
Sponsors can use functional assays to provide additional evidence that the biologic activity and potency of the proposed product are highly similar to those of the reference product and/or to support a conclusion that there are no clinically meaningful differences between the proposed product and the reference product. Such assays also may be used to provide additional evidence that the MOA of the two products is the same to the extent the MOA of the reference product is known. Functional assays can be used to provide additional data to support results from structural analyses, investigate the consequences of observed structural differences, and explore structure-activity relationships. These assays are expected to be comparative so they can provide evidence of similarity or reveal differences in the performance of the proposed product compared to the reference product, especially differences resulting from variations in structure that cannot be detected using current analytical methods. FDA also recommends that sponsors discuss limitations of the assays they used when interpreting results in their submissions to FDA. Such discussions would be useful for the evaluation of analytical data and may guide whether additional analytical testing would be necessary to support a demonstration of biosimilarity.
申请人可以利用功能性实验进一步说明类似药的生物活性和效力与参比制剂高度相似,证明两者没有临床有意义差异;亦可用于证明两者作用机制相同。功能性试验也可以用于结构分析的结果分析,研究结构差异的影响和结构-活性之间关系。功能性试验应该是比较性的,从而能够证明类似药和参比制剂之间的相似性或揭示其差异,尤其是在现有分析方法不能检测到结构变化导致的结果差异的情况下。此外,FDA 建议申请人在提交的结果中应当讨论功能性实验的限制条件。此类讨论将有助于评估分析数据,并可以用来判断是否需要进行额外的分析测试以支持其生物相似性。
Functional assays can also provide information that complements the animal and clinical data in assessing the potential clinical effects of minor differences in structure between the proposed product and the reference product. For example, cell-based bioactivity assays may be used to detect the potential for inducing cytokine release syndrome in vivo. The available information about these assays, including sensitivity, specificity, and extent of validation, can affect the amount and type of additional animal or clinical data that may be needed to establish biosimilarity. As is the case for the structural evaluation, sponsors should justify the selection of the representative lots, including the number of lots.
功能性实验也可以为用于评价类似药和参比制剂存在微小结构差异时可能会有的临床反应的动物、临床试验提供补充数据。例如,基于细胞的生物活性测定实验可用于检测诱发体内细胞因子释放综合能力的潜能。这些功能性实验分析信息,包括灵敏性、特异性和有效范围,均能够影响下一步所需的动物或临床数据的数量和类型。对于结构评价,申请人应选择有代表性的批次和批次数量。
C.Animal Data动物试验数据
The PHS Act also requires that a 351(k) application include information demonstrating biosimilarity based on data derived from animal studies (including the assessment of toxicity), unless FDA determines that such studies are not necessary in a 351(k) application. Results from animal studies may be used to support the safety evaluation of the proposed product and more generally to support the demonstration of biosimilarity between the proposed product and the reference product.
除非FDA认为不需要,PHS Act要求351(k)申请还应包括动物试验数据(包括毒性评价)。动物试验数据不仅可以用于类似药的安全性评价,更常用于支持类似药和参比制剂之间的生物相似性评价。
1.Animal Toxicity Studies动物毒理学研究
As a scientific matter, animal toxicity data are considered useful when, based on the results of extensive structural and functional characterization, uncertainties remain about the safety of the proposed product that need to be addressed before initiation of clinical studies in humans (assuming results from animal studies can meaningfully address the remaining uncertainties).
在产品结果和功能特性结果研究、临床试验之前某些需要确证的不确定性安全问题中,动物毒理学数据十分重要(假定动物试验研究结果对这些不确定性产生有益效果)。
The scope and extent of any animal toxicity studies will depend on information about the reference product, information about the proposed product, and the extent of known similarities or differences between the two. As described further in section IX, FDA encourages sponsors to initiate early discussions with the Agency with regard to their biosimilar development plans, including identifying appropriate scientific justifications for not conducting an animal toxicity study or for the scope and extent of such a study.
动物毒理学研究的内容需要根据已知的参比制剂信息、类似药的信息、以及两者相似和差异的程度决定。正如IX部分所述,FDA建议申请人提前和审批机构就生物类似药研究计划进行讨论,讨论不进行动物毒理学研究的原因,或者确定动物毒理学研究的内容。
If comparative structural and functional data using the proposed product provide strong support for analytical similarity to a reference product, then limited animal toxicity data may be sufficient to support initial clinical use of the proposed product. Such a study may be non-sacrificial and include endpoints that measure in-life parameters, PD, and PK (with an assessment of immunogenicity).
若所申请产品的比较结构和功能数据与参比制剂相比有较高相似性,则特定的动物毒性数据可能足以支持所产品的初始临床研究。此类研究是无死亡的,且包括测量寿命参数,PD和PK研究(具有免疫原性评估)。
If the structural and functional data are limited in scope or there are concerns about the proposed product quality, a general toxicology study may be needed that includes full animal pathology, histopathology, PD, PK, and immunogenicity assessments. When animal toxicology studies are conducted, it will be useful to perform a comparative study with the proposed product and the reference product (i.e., comparative bridging toxicology studies). The selection of dose, regimen, duration, and test species for these studies should provide a meaningful toxicological comparison between the two products. It is important to understand the limitations of such animal studies (e.g., small sample size, intra-species variations) when interpreting results comparing the proposed product and the reference product. For a detailed discussion on the design of animal toxicology studies relevant to biological products, see the ICH guidance for industry S6(R1) Preclinical Safety Evaluation of Biotechnology-Derived Pharmaceuticals (ICH S6(R1)).
若结构和功能数据的范围有限,或怀疑产品质量,则需要进行一般毒理学研究,包括完整的动物病理学、组织病理学、 PD、PK和免疫原性评估。当进行动物毒理学研究时,将类似药和参比制剂进行比较研究是很有必要的(例如交叉毒理学比较研究)。剂量、给药途径、给药频率和测试对象的选择应使两种产品之间的毒理学比较有意义。当对类似药和参比制剂之间的结果进行对比分析时,了解动物研究的限制是十分重要的,例如小样本量、种内变异等。关于生物制品动物毒理学研究设计的讨论,详见ICH工业指导原则:《S6(R1)对生物技术来源药物的临床前安全性评价指南》。
Safety data derived from animal toxicity studies generally are not expected if clinical data (e.g., from studies or marketing experience outside the United States) using the proposed product are available (with the same proposed route of administration and formulation) that provide sufficient evidence for its safe use, unless animal toxicity studies are otherwise needed to address a specific product quality concern.
除非特殊制品需要额外的毒理研究,若生物类似药的临床数据(如来自美国境外的研究或市场销售数据)是可用的(相同的给药途径和剂型),且为其安全性提供了足够的支持,则通常不要求进行动物毒理实验。
Animal toxicity studies are generally not useful if there is no animal species that can provide pharmacologically relevant data for the product (i.e., no species in which the biologic activity of the product mimics the human response). For a detailed discussion about demonstrating species relevance, see the criteria described in ICH S6(R1). However, there may be some instances when animal data from a pharmacologically nonresponsive species (including rodents) may be useful to support clinical studies with a proposed product that has not been previously tested in human subjects, for example, comparative PK and systemic tolerability studies. If animal toxicity studies are not warranted based on an acceptable scientific justification, additional comparative in vitro testing (using human cells or tissues when appropriate) is encouraged. Data derived using human cells can provide important comparative information between the proposed product and the reference product regarding potential clinical effects (section VII.B), particularly in situations where there are no animal species available for safety testing.
若没有合适的动物能为生物类似药提供药理学相关数据(如在某种产品的生物活性反应中没有物种可以模拟人类的反应),则该动物毒理实验是无用的。关于物种相关性的详细讨论参见ICH S6(R1)。然而,在某些情况下,药理学非应答物种的动物(包括啮齿类)实验数据也可用于未进行临床试验的生物类似药的研究中,例如,比较性PK试验或全身耐受性研究。若动物毒理研究不够科学充分,需要进行额外的体外(适当的人细胞或组织)比较研究。在临床效用(第VII.B节)方面,人细胞试验数据可以提供生物类似药和参比制剂对比的重要信息,尤其是在没有安全性研究、没有合适动物物种的情况下。
In general, nonclinical safety pharmacology, reproductive and developmental toxicity, and carcinogenicity studies are not warranted when the proposed product and the reference product have been demonstrated to be highly similar through extensive structural and functional characterization and animal toxicity studies (if such studies were conducted).
通常情况下,若通过结构功能分析和动物毒理学研究已证实类似药和参比制剂高度相似,就不必再进行非临床安全性研究、生殖发育毒性研究、和致癌性研究。
2. Inclusion of Animal PK and PD Measures动物PK/PD研究
Under certain circumstances, a single-dose study in animals comparing the proposed product and the reference product using PK and PD measures may contribute to the totality of evidence that supports a demonstration of biosimilarity. Specifically, sponsors can use results from animal studies to support the degree of similarity based on the PK and PD profiles of the proposed product and the reference product. PK and PD measures also can be incorporated into a single animal toxicity study, where appropriate. Animal PK and PD assessment will not negate the need for human PK and PD studies.
某些情况下,类似药和参比制剂采用PK/PD方法进行动物单一剂量研究有助于论证生物相似性。特别指出,申请人可以依据动物PK/PD 研究结果论证两药相似的程度。如适用,PK/PD试验也可用于单次动物毒性研究。动物PK/PD研究并不意味着无需进行人体PK/PD研究。
3. Interpreting Animal Immunogenicity Results动物免疫学研究
Animal immunogenicity assessments are conducted to assist in the interpretation of the animal study results and generally do not predict potential immune responses to protein products in humans. However, when differences in manufacturing (e.g., impurities or excipients) between the proposed product and the reference product may result in differences in immunogenicity, measurement of anti-therapeutic protein antibody responses in animals may provide useful information. Additionally, differences observed in animal immunogenicity assessments may reflect potential structural or functional differences between the two products not captured by other analytical methods.
动物免疫学研究可以用来帮助解释动物研究的结果,但并不能预测蛋白制品在人体内的免疫反应。但是,若类似药和参比制剂生产工艺不同(包括杂质或辅料)导致免疫原性反应不同,测试动物的抗体反应可能会能提供某些有用信息。此外,在动物免疫原性研究观察到的差异可能反应出没有被其他分析方法检测到的类似药和参比制剂潜在的结构或功能差异。
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