EN ISO 10993-3

EN ISO 10993-3

EN ISO 10993-3, a standard published by the International Organisation for Standardisation (ISO) and adopted by the European Committee for Standardisation (CEN), entitled ‘Biological evaluation of medical devices – Part 3: Tests for genotoxicity, carcinogenicity and reproductive toxicity’, i.e. ‘Biological evaluation of medical devices – Part 3: Tests for genotoxicity, carcinogenicity and reproductive toxicity’.

Regulatory status and version note: The current base text of the standard is ISO 10993-3:2014 (third edition) and has been adopted at European level as EN ISO 10993-3:2014. The standard has been recognised as a harmonised standard under the EU Medical Devices Regulation (MDR 2017/745). The status and scope of its recognition by the FDA must be verified prior to submitting an application.

The main feature of the standard is that, rather than defining specific test methods in detail, it provides a framework and a strategy for determining the circumstances under which an assessment of genotoxicity, carcinogenicity and reproductive toxicity is required, and to refer to the OECD test guidelines for the test methods. The assessment is carried out within the framework of the multi-tiered, weight-of-evidence approach; the necessary tests are selected following an evaluation of the chemical characterisation (ISO 10993-18), the material history, the literature and the available data.

1. Genotoxicity

This is the most comprehensive and most frequently applied section of the standard. The genotoxicity assessment is designed to cover the three basic types of genetic damage:

• Gene mutations: Bacterial reverse mutation assay (OECD TG 471) and gene mutation assays in mammalian cells (e.g. OECD TG 476 – HPRT, OECD TG 490 – tk)
• Structural and numerical chromosomal changes: In vitro chromosomal aberration test on mammalian cells (OECD TG 473), in vitro micronucleus test (OECD TG 487), in vivo micronucleus test on mammalian erythrocytes (OECD TG 474) and in vivo chromosome aberration test on mammalian bone marrow (OECD TG 475)
• DNA damage: Indicator tests where appropriate (e.g. comet assay, OECD TG 489)

The standard stipulates that in vitro tests are generally used as a first step, but are supplemented by in vivo tests in cases where the in vitro results are insufficient or positive/suspicious. When testing extracts from medical devices, the extract must be prepared in accordance with ISO 10993-12, and the suitability of the extract for the test system (e.g. sterility, cytotoxicity, pH) must be verified. The applicability of in vitro tests to extracts from medical devices must be carefully assessed due to matrix effects.

2. Carcinogenicity

The assessment of carcinogenicity is based on a weighted evidence approach, drawing on genotoxicity and other biocompatibility data, chemical characterisation, the literature and the material’s history. Routine long-term carcinogenicity studies in animals are generally not required; such studies are only considered under specific conditions (e.g. genotoxic potential, long-term implantation, unknown material history) and upon a reasoned request from the regulatory authority. The standard emphasises the central role of genotoxicity data and chemical characterisation in the assessment of carcinogenicity risk.

3. Reproductive toxicity

The assessment of reproductive toxicity takes into account the product’s contact with the reproductive organs, the potential for systemic exposure and the origin of the material. Comprehensive reproductive toxicity studies are not usually required as a matter of routine; this assessment is also carried out using the weighted evidence approach. Where necessary, suitable studies may be planned with reference to the OECD test guidelines (e.g. OECD TG 414 – prenatal developmental toxicity, OECD TG 421/422 – screening studies, OECD TG 443 – extended one-generation study).

The key parameters reported in the study are:

• Definition of the scope of the assessment and the rationale (genotoxicity/carcinogenicity/reproductive toxicity)
• Chemical characterisation and summary of the available data
• Selected test methods and corresponding OECD Technical Guidelines (TG) references
• Conditions for extract preparation (in accordance with ISO 10993-12)
• Test system (bacteria, mammalian cells, animal species) and test conditions
• Doses/concentrations used and excipient (vehicle)
• Status of metabolic activation (+S9 / −S9)
• Results (mutation frequency, aberration rate, micronucleus rate, etc.) and comparison with the control groups
• Validity of the positive and negative controls
• Result: genotoxic / non-genotoxic – assessment and justification
• Data on measurement uncertainty and repeatability

What is the purpose of the examination?

EN ISO 10993-3 is carried out for the following scientific and regulatory purposes:

• Assessment of patient safety: Evaluation of the potential of material components or extracts of the medical device with regard to genotoxicity, carcinogenicity and reproductive toxicity
• MDR compliance: Provision of the necessary data for the biological safety assessment under the EU Medical Devices Regulation (2017/745)
• Risk management: Assessment and mitigation of long-term toxicological risks associated with the parts of the medical device that come into contact with patients and users
• Material selection and development: Early identification of substances with potential genotoxic, carcinogenic or reproductive toxic effects as part of the product development process, and evaluation of alternatives
• A step-by-step and weighting-based evidence approach: avoiding unnecessary testing; making sensible use of existing chemical characterisation data and literature references
• Animal welfare (3Rs): Priority should be given to in vitro genotoxicity tests; animal testing should only be carried out where absolutely necessary
• Support for regulatory documentation: Use as part of the biocompatibility dossier for applications submitted to the FDA, in accordance with the EU MDR and other regulatory authorities
• Evidence-weighting approach: Chemical characterisation (ISO 10993-18), cytotoxicity (ISO 10993-5), sensitisation (ISO 10993-10), irritation (ISO 10993-23), haemocompatibility (ISO 10993-4) and other biocompatibility data contributing to the holistic assessment of the product

EN ISO 10993-3 alone does not cover the product’s entire biocompatibility profile. In particular, assessments of carcinogenicity and reproductive toxicity are usually carried out using a weight-of-evidence approach and on the basis of other data; routine animal testing is generally not required. The results should be interpreted in the context of the chemical characterisation, other biological tests, the product design and clinical data.

As part of our nano-testing services, we carry out assessments of genotoxicity, carcinogenicity and reproductive toxicity in accordance with EN ISO 10993-3, using scientific rigour within the framework of our accredited laboratory infrastructure and our quality management system. Our scope of services includes the following:

Development of test strategies and protocols

• Determination of the scope of the assessment in accordance with the nature and duration of contact with the medical device, its material composition and the regulatory requirements
• Chemical characterisation (ISO 10993-18), evaluation of the material history and literature data (weighted evidence approach)
• Selection and justification of a suitable battery of genotoxicity tests (OECD TG 471, 476, 490, 473, 487 and, where applicable, 474, 475, 489)
• Carrying out a weighted assessment of the evidence regarding carcinogenicity and reproductive toxicity; where appropriate, justifying the need for further studies
• Establishment of an extraction strategy in accordance with ISO 10993-12 (polar/non-polar solvents, temperature, duration, concentration)
• Assessment of the extract’s suitability for the test system (sterility, cytotoxicity, pH)
• Planning of positive and negative controls; compliance with ethical and regulatory requirements

For information on test strategies, the selection of test batteries, extract preparation, sample acceptance criteria, the test schedule and reporting procedures as part of your genotoxicity, carcinogenicity and reproductive toxicity assessments in accordance with EN ISO 10993-3, please feel free to contact Nano-Test.