General Information About NICEATM-ICCVAM Test Method Evaluation Areas
View a summary of test methods evaluated by ICCVAM as of April 2008
Please scroll down to read an overview on each area
To reduce the risk for accidental poisonings, U.S. Federal regulatory agencies require
the testing of marketed products for acute oral toxicity in rodents. Acute oral toxicity test results are
used to determine the hazard classification and labeling of products, which alert handlers
and consumers to potential toxicity hazards. The LD50 values (dose that produces lethality in 50% of the
animals tested) determined from acute oral toxicity tests are used to place substances in various toxicity
categories that determine the hazard phrases that are used on product labels.
In addition to classification and labeling, acute oral toxicity test results may also be used for:
- Establishing dosing levels for repeated dose toxicity studies or other toxicity studies
- Identifying potential target organs
- Providing information related to the mode of toxic action
- Aiding in the diagnosis and treatment of toxic reactions
- Providing information for comparison of toxicity and dose response among substances in a specific chemical or product class
- Aiding in the standardization of biological products
- Aiding in judging the consequences of single, high accidental exposures in the workplace, home, or from accidental release
- Serving as a standard for evaluating alternatives to animal tests
NICEATM and ICCVAM have evaluated alternatives to the LD50 for assessment of
acute oral toxicity. The Up-And-Down Procedure (UDP)
is an in vivo acute oral toxicity test that reduces and refines animal
use. ICCVAM has recommended that the UDP be used instead of the conventional LD50
test to determine the acute oral toxicity hazard of chemicals.
A Validation Study of In Vitro Cytotoxicity Test Methods generated in vitro
toxicity data to predict rodent in vivo LD50
values and starting doses for acute oral toxicity test methods. ICCVAM has
recommended that these test methods be considered before
using animals for acute oral toxicity testing, and that the methods should be used where determined appropriate
for estimating starting doses for acute oral systemic toxicity tests with rodents.
Further explorations of alternative methods for acute chemical safety testing took place at a
joint NICEATM-ICCVAM/ECVAM/JaCVAM Workshop entitled “Acute Chemical Safety Testing: Advancing
In Vitro Approaches and Humane Endpoints for Systemic Toxicity Evaluations”. International
experts in the fields of toxicology and
human and veterinary medicine considered the identification of key toxicity pathways in order to apply
mechanistically-based in vitro approaches and humane endpoints for systemic toxicity evaluations.
The workshop took place in February 2008 at the NIH.
Biological products, commonly referred to as biologics, are products intended for therapeutic use that are
derived from biological sources. They include viruses, therapeutic sera, toxins, antitoxins and vaccines, and
a variety of other substances that have therapeutic use in humans or animals (e.g., insulin, alpha1 proteinase
inhibitor, anti-hemophillic factor). Current regulatory requirements include testing in animals for identity or
potency for labeling and lot release purposes. ICCVAM welcomes nominations and submissions of alternative test
methods that will refine, reduce, or replace animal testing for these products.
In October 2005, the Humane Society of the United States (HSUS) submitted a test method nomination requesting
that ICCVAM consider alternative tests methods for the determination of the potency of botulinum toxin, and
that ICCVAM convene a workshop to review the state of the science of such test methods.
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Skin corrosion is defined as the production of irreversible damage to the skin, namely, visible necrosis through
the epidermis and into the dermis, following the application of a test substance. Skin irritation is the production
of reversible damage to the skin following the application of a test substance. Dermal corrosivity and irritation
testing is conducted to identify corrosive chemicals that may cause burns and permanent scarring to the skin, or
identify chemicals that cause skin irritation. Test results are used to classify and label corrosive or irritant
chemicals so that consumers and workers can take appropriate precautions to prevent injury. Test results are also
used to determine appropriate packaging that will minimize hazardous spills during transport.
ICCVAM has conducted independent scientific peer reviews of the usefulness and limitations of four in vitro
corrosivity test methods for use as an alternative to the in vivo rabbit skin test. Based on these reviews,
ICCVAM recommended that all four methods (Corrositex®,
EPISKIN™, EpiDerm™,
and the Rat Skin Transcutaneous Electrical Resistance [TER] assay)
could be used as part of weight-of-evidence approach in an integrated testing scheme for dermal corrosion/irritation.
In this approach, positive in vitro corrosivity responses do not generally require further testing and can be used
for classification and labeling without the need for animal testing.
In 2006, the European Centre for the Validation of Alternative Methods (ECVAM) completed a multi-laboratory validation
study designed to assess the usefulness and limitations of irritation protocols for EPISKIN™ and EpiDerm™ as replacements
for the in vivo rabbit test. Results from this study are anticipated in 2007.
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Current Federal regulations require determination of the developmental toxicity
(i.e., toxicity to the developing fetus) potential of many chemicals and products
(including pesticides, food additives, industrial chemicals, and pharmaceuticals)
marketed in the United States. Most developmental toxicity test protocols use rats,
rabbits, or other mammalian species. ICCVAM sponsored an evaluation of the utility
of the Frog Embryo Teratogenesis Assay -Xenopus
(FETAX) to determine the developmental
toxicity potential of chemicals.
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An endocrine disruptor is a synthetic substance that, when absorbed into the body,
either mimics or blocks hormones resulting in a disruption of normal hormonal function.
A variety of substances have been classified as endocrine disruptors based on laboratory
studies, and compelling evidence suggests that endocrine systems of certain fish and
wildlife have been affected by environmental contaminants, resulting in developmental
and reproductive problems. In response to such findings, the U.S. Congress passed the
Food Quality Protection Act in 1996, mandating the U.S. Environmental Protection Agency (EPA) to initiate an endocrine disruptor
testing program to screen pesticides and environmental contaminants for their potential
to affect the endocrine systems of humans and wildlife. The EPA subsequently initiated
an Endocrine Disruptor Screening Program (EDSP) and began efforts to standardize and
validate test methods for inclusion in the EDSP. As part of this effort, the EPA asked
ICCVAM to evaluate the validation status of in vitro estrogen receptor (ER) and androgen
receptor (AR) binding and transcriptional activation (TA) assays.
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Genetic toxicology is the study of compounds or physical agents that have the ability to damage the
DNA and/or chromosomes of cells. Such damage can lead to mutations that increase the likelihood of certain
diseases, such as cancer and birth defects. The EPA, the U.S. Food and
Drug Administration (FDA), and the U.S. Consumer Product Safety Commission (CPSC) have testing requirements and
guidelines in place for assessing the genotoxicity of regulated products. ICCVAM and
its Genetic Toxicity Working Group review and provide comments to sponsors on proposed validation
studies, provide recommendations on test method nominations and submissions for alternative test
methods related to genetic toxicity, and evaluate proposed test guidelines and activities relevant
to genetic toxicity from the Organization for Economic Co-Operation and Development (OECD).
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Skin sensitization (allergic contact dermatitis) is an immunologically mediated cutaneous reaction to a
substance. ICCVAM previously conducted an independent scientific peer review of the usefulness and limitations
of the Murine Local Lymph Node Assay (LLNA) as an alternative test method
for assessing the skin sensitizing potential of chemicals. Based on the recommendations of ICCVAM and the
peer review panel, the LLNA has been accepted as an alternative to the guinea pig maximization test for
assessing skin sensitization. ICCVAM, and its Immunotoxicity Working Group (IWG) organized an implementation
workshop on the LLNA in 1999, and drafted an OECD test guideline (TG 429) for the LLNA that was adopted by
the OECD in 2002.
More recently, the IWG has begun to assist ICCVAM with the technical evaluation of several issues
that are relevant to the LLNA. One activity will be the development of performance standards that can be
used as the basis for determining the acceptability of new test methods similar to any of the test methods
eventually recommended by ICCVAM. In addition, the CPSC has recently
requested that ICCVAM assess the validation status of the LLNA as a stand-alone assay for potency
determinations (including severity) for classification purposes, the validation status of non-radioactive
LLNA protocols, the LLNA limit test, the use of the LLNA to test mixtures, aqueous solutions and metals,
and the applicability domain for which the LLNA has been validated.
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Accidental eye injury is a leading cause of visual impairment in the U.S., and many of these
injuries occur due to contact with workplace or household chemicals.
According to the National Institute of
Occupational Safety and Health (NIOSH), each day
about 2000 U.S. workers have a job-related eye injury that requires medical treatment. Even more eye injuries
occur in the home, with about 125,000 eye injuries a year caused by accidents involving common household products
such as oven cleaner and bleach (source, American Academy of Ophthalmology).
The U.S. CPSC, EPA, FDA, and OSHA (Occupational Safety and
Health Administration) have regulatory testing requirements for assessing the hazard
potential of substances that may come in contact with human eyes. While these testing
requirements have effectively protected consumers and workers, the primary method
currently accepted by U.S. and international regulatory agencies for assessing ocular
toxicity requires the use of animals (i.e., the Draize rabbit eye test). Although
modifications to this test have reduced both the numbers of animals used and the
potential pain and distress associated with the procedure, more recent efforts have
focused on the development of nonanimal alternatives that would reduce or replace the
need for animals for the assessment of ocular toxicity.
Because there were no accepted alternative test methods for
the assessment of ocular irritancy and corrosion in the United States, ICCVAM gave
a high priority to the evaluation of alternative methods for this purpose. In October 2007,
ICCVAM forwarded its first recommendations for the use of in vitro methods for
ocular safety testing to Federal agencies. ICCVAM recommended that two methods (the Bovine
Corneal Opacity and Permeability test, and the Isolated Chicken Eye test) be used
in a tiered testing strategy to determine ocular hazards, with specific limitations for
certain chemical classes and/or physical properties. These recommendations have been
accepted by Federal agencies and should reduce the number of animals
used for safety testing to determine corrosive or severely irritating damage to the eye.
Other ICCVAM activities in the area of ocular toxicity include:
- Evaluation of the recommended test methods (described above) for use in assessing the
potential of test substances to cause mild-to-moderate irritation or reversible injury to the eye
- Evaluation of a nonanimal approach to assessing the eye irritation potential for
antimicrobial cleaning products
- Collection of data and information on the use of topical anesthetics and systemic
analgesics to alleviate pain and distress during in vivo ocular toxicity testing
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Pyrogens are substances (such as Gram-negative and Gram-positive bacteria, fungi, and viruses)
that can produce a rise in body temperature (in other words, fever). Pyrogenic substances increase body
temperature by inducing leukocytes to release pro-inflammatory cytokines (such as interleukin
[IL]-1, IL-6, and tumor necrosis factor-α) that can act as endogenous pyrogens. Pharmaceutical products (such as fluids for
injection, medical devices, and human biological products) intended for parenteral administration
must be properly and accurately evaluated for the presence of pyrogenic substances and shown to be
free of contamination prior to their clinical or veterinary use.
The U.S., European, and Japanese Pharmacopoeias
currently recognize two test methods for pyrogen testing. The rabbit pyrogen test
(USP28[151]) involves measuring the rise in temperature of
rabbits following intravenous injection of a test solution. The bacterial endotoxin test
(BET, USP28[85]) is an in vitro assay based on the coagulation of Limulus amoebocyte
lysate following exposure to endotoxin. An important distinction between these two tests is
that the BET detects only endotoxin pyrogens, whereas the rabbit pyrogen test is capable of
also detecting non-endotoxin pyrogens.
Recently, alternative test systems based on the activation of human monocytes or
monocytoid cell lines in vitro have been developed that take advantage of
the role of these cells in the fever response. ICCVAM is currently evaluating the
usefulness and limitations of five in vitro pyrogen test
methods.
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Additional Information
Scientific Advisory Committee on Alternative Toxicological Methods (SACATM)
Chartered on December 18, 2001, the Scientific Advisory Committee on Alternative Toxicological Methods
(SACATM) was established as a replacement
for the NTP Federal Advisory Committee on Alternative Toxicological
Methods (ACATM). This committee provides advice on the activities and
priorities of NICEATM and ICCVAM, and recommends ways to foster
partnership activities and productive interactions among all
stakeholders. SACATM will typically meet twice yearly, and meeting
materials and minutes will be posted.
Partnership Opportunities
Opportunities for organizations and
agencies to partner with NICEATM to support the development, validation,
and review of new alternative testing methods are available. Interested
individuals should contact Dr. William S. Stokes, NICEATM Director, for
further information (see below).
Additional Information
Additional information can be found
elsewhere in this website and in the
publication: Validation and Regulatory Acceptance of Toxicological
Test Methods, a Report of the ad hoc Interagency Coordinating Committee
on the Validation of Alternative Methods (NIH Publication 97-3981)
or you may contact NICEATM at 919-541-3398 (telephone), or at
iccvam@niehs.nih.gov (e-mail).
Specific questions about ICCVAM and NICEATM can be directed to the
ICCVAM Executive Director:
Dr. William S. Stokes,
NIEHS, EC-17, P.O. Box 12233
Research Triangle Park, NC, 27709
919-541-7997
stokes@niehs.nih.gov
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