Recommendations for TestSmart--A Humane and Efficient Approach to Screening Information Data Sets (SIDS) Data

Recommendations from the January Meeting on TestSmart

The Johns Hopkins Center for Alternatives to Animal Testing (CAAT) is coordinating an effort to examine the current status of alternative methods for Screening Information Data Sets (SIDS) endpoints and to make recommendations about the use of these methods in the HPV Challenge Program. This effort, dubbed "TestSmart," began with funding provided by a Heinz Foundation grant awarded to the Environmental Defense Fund, the University of Pittsburgh, Carnegie-Mellon University, and CAAT.

On Jan. 26, CAAT sponsored a two-day workshop attended by 50 invited participants from government, industry, academia, and animal welfare/animal rights organizations. The goals of this workshop were to review the HPV Challenge Program from the perspective of the Environmental Defense Fund and the U.S. Environmental Protection Agency (EPA) and to clarify current requirements to meet SIDS endpoints. The EPA presenters emphasized the agency's commitment to the incorporation of alternative methods where possible. In a letter, Susan Hazen, Director of the Environmental Assistance Division, Office for Pollution Prevention and Toxics at EPA, stated, "EPA will make every effort to avoid unnecessary testing where scientifically valid data exist." She also stated that "if relevant non-animal test methods become validated and achieve regulatory acceptance during the implementation of the HPV Challenge Program, we will consider immediate implementation."

With this information as a background, the participants were sequestered in small groups and charged with:

identifying in vitro and other alternative tests that can be used immediately to provide SIDS endpoints;
naming promising tests that need validation, but that could be incorporated into the Challenge Program in the future; and,
summarizing areas where research is still needed for test development.

Following three hours of small group discussions, the participants reconvened to report to the entire group. A series of recommendations was delineated based upon the small group summaries. These recommendations are as follows:

Utilize all available data, including those held by industry and by EPA.
Employ "thoughtful science," i.e. combine studies as much as possible to maximize the available data and minimize the number of animals that will need to be used.
Employ SAR to the maximum extent and continue to add information to existing databases.
Incorporate in vitro assays as soon as possible.
Identify batteries of in vitro tests for specific SIDS endpoints.
Incorporate identified humane endpoints as outlined in the Organization for Economic Cooperation and Development (OECD) document and by the Humane Society of the United States, and establish others where none are identified.
Evaluate progress in the HPV Challenge Program at regular and frequent intervals so that new tests can be incorporated as they become validated.

A time frame for implementation of these recommendations also was established. In the short-term:

Reduction and refinement alternatives for acute toxicity testing should be incorporated, including the fixed-dose procedure, the up-and-down procedure, the acute toxic class method and the limit test.
Existing in vitro tests for genetic toxicity also should be employed immediately. These include the Ames-Salmonella and mouse lymphoma assays for bacterial and mammalian point mutations, respectively, and the Chinese Hamster Ovary cell assay for chromosomal aberrations.
In vitro tests evaluating sperm motility and sperm morphology should be used to screen for reproductive toxicity and SAR to establish chemical categories and to select specific chemicals within categories.
Finally, it was emphasized that protocols should be combined as much as possible to reduce animal numbers. It was suggested that perhaps the required repeat dose study should be a 90-day rather than a 28-day study in order to maximize the number of endpoints that could be satisfied from a given number of animals. For example, reproductive and developmental endpoints could be obtained from the repeat dose animals.

In the longer-term, other promising in vitro tests could be validated and, if done so successfully, could be incorporated into the testing process. Such tests include:

the in vitro micronucleus assay for genetic toxicity;
the FETAX, limb bud, and whole embryo culture assays for developmental toxicity; and
the basal cytotoxicity and neutral red uptake assays for acute toxicity.

Finally, areas requiring additional research were identified. Among those mentioned:

Development of organ cell cultures for determining organ-specific acute and repeat dose toxicity;
A general need for the identification of mechanistic endpoints for toxicity screening;
Further development of high throughput screening methods for identifying specific genes and/or proteins involved in toxicologic pathways;
More support for culturing human cells and tissues;
Development of whole animal refinement approaches, such as non-invasive imaging.

TestSmart HPV

Recommendations for TestSmart--A Humane and Efficient Approach to Screening Information Data Sets (SIDS) Data

Recommendations from the January Meeting on TestSmart