U.S. to phase out animal testing

From ANIMAL PEOPLE, March 2008:

BETHESDA, Maryland–Animal testing to meet U.S. federal
regulatory requirements is officially on the way out at last.
“The Environmental Protection Agency, the National Toxicology
Program and the National Institutes of Health have signed a
memorandum of understanding to begin developing the new methods,”
reported Elizabeth Weise of USA Today on February 14, 2008,
scooping most other media by about 24 hours. “The collaboration is
described in a paper in the February 15 edition of the journal
Science.”
“We propose a shift from primarily in vivo animal studies to
in vitro assays, in vivo assays with lower organisms, and
computational modeling for toxicity assessments,” wrote National
Humane Genome Research Institute director Francis S. Collins, EPA
research and development director George M. Gray, and National
Toxicology Program associate director John R. Bucher.

“Historically toxicity has always been determined by
injecting chemicals into laboratory animals, watching to see if the
animals get sick, and then looking at their tissues under the
microscope,” Collins explained to reporters at the annual meeting
of the American Association for the Advancement of Science in Boston.
“Although that approach has given us valuable information, it is
clearly quite expensive, it is time-consuming, it uses animals in
large numbers, and it doesn’t always predict which chemicals will be
harmful to humans.”
Besides, Collins added, “We are not rats and we are not
even other primates.”
Collins emphasized doing cellular level research, because
“After all, ultimately what you are looking for is, does this
compound do damage to cells? Can we, instead of looking at a whole
animal, look at cells from different organs?”
“We believe this is the beginning of the end for animal testing,”
Humane Society of the U.S. director of animal research issues Marty
Stephens told Weise. “We think the process will take about 10 years.”
Though a landmark in the often glacial pace of regulatory
evolution, the EPA/NTP/NIH memo of understanding only brings the
U.S. government to the same position accepted by Procter & Gamble,
the largest U.S. consumer chemical maker, in a 1984 agreement with
the late Henry Spira, founder of Animal Rights International. Since
then P&G has spent more than $200 million to develop and win
regulatory approval for more than 50 alternatives to animal tests.
The EPA, NTP, and NIH revealed their memo of understanding
nine days after the National Toxicology Program Interagency Center
for the Evaluation of Alternative Toxicological Methods (NICETAM) and
the Interagency Coordinating Committee on the Validation of
Alternative Methods (ICCVAM) published a five-year plan for helping
U.S. government agencies to phase out animal testing.
NICETAM and ICCVAM were created by Congress in increments as
a gradual endorsement of the “Three R’s” principle of pursuing
reduction, refinement, and replacement of animal use in biomedical
research, outlined by William Russell and Rex Burch in The
Principles of Humane Experimental Technique (1959). The “Three R’s”
were incorporated as a recommendation in the enforcement regulations
for amendments to the federal Animal Welfare Act adopted in 1985.
The U.S. National Institutes of Health Revitalization Act of
1993 directed the NIH to support research to reduce, refine, or
replace animal use. The ICCVAM Authorization Act of 2002 then formed
ICCVAM to expedite the process.
Fifteen agencies participate in ICCVAM, including the
Consumer Product Safety Commission, the USDA, the Department of
Defense, the Department of Energy, the Department of Health & Human
Services, the Centers for Disease Control & Prevention, the Agency
for Toxic Substances & Disease Registry, the National Institute for
Occupational Safety & Health, the Food & Drug Administration, the
National Institutes of Health, the National Cancer Institute, the
National Institute of Environmental Health Sciences, the National
Library of Medicine, the Department of the Interior, the Department
of Labor, the Occupational Safety & Health Administration, the
Department of Transportation, and the Environmental Protection
Agency.
“Priorities are test methods that may involve significant
pain and distress, use large numbers of animals, and have the
potential to provide improved prediction of adverse health or
environmental effects,” NICETAM director William S. Stokes and
ICCVAM chair Marilyn Wind wrote in a joint preface to the five-year
plan.

Eyes, biologics, & skin

“Evaluation of alternative methods for eye safety testing is
one of ICCVAM’s four highest priorities because it is required by
multiple agencies, as one of the four most commonly required product
safety tests,” the five-year plan explains. “Two critically
important goals are replacement of the rabbit eye test and
implementation of procedures to avoid pain and distress where animals
must still be used. NICEATM and ICCVAM recently evaluated and
recommended two in vitro test methods,” the five-year plan says,
“that do not use animals. In collaboration with the European Centre
for the Validation of Alternative Methods, NICEATM and ICCVAM will
evaluate the use of these and other in vitro test methods.”
Alternative biologics test methods are under development,
according to the five-year plan, “that target reduction and
replacement of animal testing with in vitro test methods, as well as
refinement of animal testing through modifications to the current
animal tests.”
“Evaluation and development of alternatives for dermal (skin)
safety testing is also one of ICCVAM’s four highest priorities,” the
five-year plan continues, “because rabbits used in tests to identify
dermal hazards can experience significant pain and distress. In
vitro alternatives have been developed, and several of these test
methods have been recommended and accepted for regulatory use as
screening methods.
“NICEATM and ICCVAM will evaluate alternative dermal
irritation test methods for their usefulness and limitations in U.S.
regulatory testing,” the five-year plan pledges. “NICEATM and
ICCVAM will also evaluate non-animal methods and approaches for
determining the skin irritation potential of antimicrobial cleaning
products.”

Toxicity testing

Acute toxicity testing, traditionally based on the LD-50 and
LD-10 tests, causing the deaths of half of the test subjects, “is
the most commonly conducted product safety test worldwide,” says the
five-year-plan. “ICCVAM evaluated and recommended an alternative
animal test method,” called the up-and-down procedure, “that has
now been accepted by regulatory agencies as a replacement for the
traditional acute oral toxicity test. This can reduce the use of
animals for this purpose by up to 70%. NICEATM and ICCVAM were also
involved in the development of international guidance for humane
endpoints that can be used as criteria to euthanize animals rather
than allowing them to die during the study.
“The ultimate goal is to find ways to conduct acute oral
toxicity testing without animals,” states the five-year plan. In
support of this goal, ICCVAM evaluated and recommended two cell
culture test methods that, while not sufficiently accurate to
replace animals, can be used to estimate the starting doses for
animal studies, and thereby further reduce the number of animals
needed for each test.”
Immunotoxicity testing presently relies upon skin
sensitization tests. “The Murine Local Lymph Node Assay reduces the
number of animals needed, reduces the time required for testing,
and can substantially reduce or minimize the pain and distress
associated with traditional testing,” says the five-year plan. “The
Local Lymph Node Assay was the first alternative test method
evaluated and recommended by ICCVAM, and has been accepted by
regulatory agencies. NICEATM and ICCVAM will evaluate whether the
Local Lymph Node Assay can be used as a stand-alone method, and will
also evaluate modifications that may further reduce the number of
animals used.”
Hormones & fever
“Laws passed in 1996 mandate the development of screening for
endocrine disruptors,” explains the five-year plan. “Programs are
being developed throughout the world to screen for chemicals that
might interfere with the endocrine systems of humans or wildlife.
These programs could result in the use of large numbers of animals if
valid alternatives are not identified. NICEATM and ICCVAM recently
reviewed a number of in vitro tests designed to detect chemicals that
might act as, or interfere with, male and/or female hormones. Based
on this review, ICCVAM provided recommendations for future test
method development and validation that are being implemented by the
EPA.”
In addition, the five-year plan says, NICEATM will lead a
joint effort with the European Centre for the Validation of
Alternative Methods and the Japanese Center for the Validation of
Alternative Methods “to evaluate the usefulness and limitations of an
in vitro test method to identify estrogen-like chemicals that does
not require the use of animals.”
Pyrogen testing, to identify substances that could cause
fever, is chiefly under the purview of the Food & Drug
Administration. Although other agencies are seldom involved,
pyrogen testing is an ICCVAM priority because it involves large
numbers of animals.
“Alternative pyrogenicity test methods,” using cultured
human blood cells, “take advantage of the role of these cells in the
fever response,” summarizes the five-year-plan. “ICCVAM recently
evaluated five such in vitro test methods proposed as potential
replacements for the current rabbit test. ICCVAM will issue
recommendations on the current usefulness of these test methods.”

Reproduction & cancer

Seeking to reduce animal use in reproductive and
developmental toxicity testing, ICCVAM recently evaluated the
usefulness and limitations of a test called the Frog Embryo
Teratogenesis Assay-Xenopus. Although this test “was not considered
sufficiently reproducible for regulatory use,” the five-year plan
reported, “ICCVAM endorsed the recommendations of an independent
expert peer review panel that further studies should be conducted to
improve performance.”
“Two-year studies approximating lifetime exposure in rats and
mice remain the primary method by which chemicals are tested for
their potential to cause cancer and chronic disease in humans,” the
five-year plan explains. “The National Institute of Environmental
Health Sciences and the FDA are involved in the research and
development of alternative models that could reduce the number of
animals used and shorten the duration of these tests,” says the
five-year plan, but this “will likely take longer” than a five-year
time frame.
“Federal regulatory agencies also typically require the use
of tests that evaluate genetic toxicity, the ability of chemical or
physical agents to damage the DNA and/or chromosomes of cells,”
notes the five-year plan. “Genetic toxicity can potentially
contribute to the cancer-causing or developmental toxicity potential
of a chemical. Although genetic toxicity testing is not currently
considered a substitute for carcinogenicity testing, the FDA is
studying the usefulness and limitations of various human primary
cells and cell lines” for this purpose.

High Throughput

The National Toxicology Program “is working to identify and
develop rapid biochemical or cell-based tests that can be used to
screen large numbers of substances for their potential biological
activity,” the five-year plan summarizes. This approach is called
“high throughput screening.”
High throughput screening is believed to have much potential
for reducing or replacing animal tests. The leading high throughput
screening method uses roundworms in place of more neurologically
developed species.
“Because the genes involved in many biological processes,
for example, the stress response, have remained essentially
unchanged throughout evolution,” explains the five-year plan,
“responses elicited in roundworms may be applicable to understanding
similar processes in higher organisms, including humans. NICEATM
and ICCVAM will evaluate the validation status of future tests with
this model system that have utility for regulatory testing.”
ICCVAM is also monitoring a collaboration between the EPA and
European agencies “to develop assays to evaluate various toxicity
endpoints in fish and amphibians,” which might be used in high
throughput screening.
NIH Chemical Genomics Center director Christopher Austin
described to Weise of USA Today a high throughput test “done in a
3-by-5-inch glass tray with 1,536 tiny wells, each a fraction of a
millimeter across. A few hundred human cells grown in a test tube go
into each well,” Weise wrote. “The testing machine drips a
different chemical into each well. After some time has passed, the
machine shines a laser through each well to see how many cells
remain. A computer analyzes the toxicity of each compound based on
how the cells react.”
National Institutes of Health director Elias Zernouni
indicated to Weise that this relatively quick and simple test might
replace animal-based methods that have rigorously tested only about
2,500 potentially toxic compounds in 30 years.
National Institutes of Environmental Health Sciences head
Samuel Wilson told Reuters that automated laboratoriess can now use
non-animal methods to test 100,000 compounds at up to 15 different
concentrations in only two days.
But a complicating factor, warned National Human Genome
Research Institute director Collins, is that “We need to exactly
figure out what the correlations will be between animal testing and
this high-throughput approach.”
“We cannot abandon animal testing overnight,” cautioned Zerhouni.

Computer models

Increased use of computerized modeling is among the
approaches to reducing animal testing most often recommended by
animal advocates–but usually the models are based on information
gathered in real-life experiments.
“Using data generated from high throughput bioassays that
measure interactions with proteins or genes,” the five-year plan
mentions, “the EPA is developing computer models for prioritizing
chemicals for toxicology testing.”
National Center for Computational Toxicology director Robert Kavlock
told Weise of USA Today that the EPA program is currently looking at
about 300 chemical substances.
Also, the Department of Energy “is developing computer
models” to “help estimate the minimum number of animals that are
needed in experiments dealing with low-dose radiation exposure,”
says the five-year plan. These models “may also help make decisions
regarding the possible use of in vitro models instead of live
animals.”

Biomarkers & Nanomaterials

The National Institutes of Environmental Health Sciences and
the FDA “are evaluating biomarkers that could be used in current
toxicology tests to predict damage to a specific organ. Such
biomarkers may be used as the basis for early humane euthanasia to
reduce or relieve the pain and distress experienced by animals with
tumors or chronic disease,” suggests the five-year plan.
Identifying the biomarkers “will also support the development of
predictive in vitro screening tests.”
The rapid development of nanotechnology is of growing concern
among toxicologists, the five-year plan notes, defining
nanotechnology as “the control of matter at dimensions of roughly 1
to 100 nanometers,” explaining that “a sheet of paper is about
100,000 nanometers thick.”
Nanotechnology “is being applied in many fields in the
physical and biological sciences. Because hazards associated with
these types of materials have yet to be characterized,” the
five-year plan says, “the applicability of current toxicity tests
to nanomaterials will have to be evaluated. The number of tests
needed to characterize potential hazards of nanomaterials could be
very large, as could the number of animals required for such
testing. NICEATM and ICCVAM will work with regulators and
stakeholders to identify tests that might be useful,” the five-year
plan promises, within the context of trying to reduce, refine, and
replace animal use.