National Toxicology Program

National Toxicology Program

Evaluation of In Vitro Cytotoxicity Test Methods

International initiatives to use in vitro cytotoxicity test methods to reduce animal use in acute toxicity testing were evaluated at the International Workshop on In Vitro Methods for Assessing Acute Systemic Toxicity in October 2000. Pursuant to this workshop, ICCVAM recommended further evaluation of the use of in vitro cytotoxicity data as one of the approaches that could be used to estimate the starting doses for rodent acute oral systemic toxicity studies. To assist in the adoption and implementation of this approach, the Guidance Document on Using In Vitro Data to Estimate In Vivo Starting Doses for Acute Toxicity was prepared by ICCVAM with the assistance of the workshop participants.

ICCVAM recommended that near-term validation studies should focus on two standard basal cytotoxicity assays: one using a human cell system and one using a rodent cell system. ICCVAM also recommended that long-term research focus on the development of in vitro test methods to assess biokinetics, metabolism, and organ-specific toxicity so as to improve in vitro predictions of acute oral systemic toxicity. NICEATM and the European Centre for the Validation of Alternative Methods subsequently designed an international multi-laboratory validation study to evaluate the usefulness of two in vitro basal cytotoxicity test methods (one using a rodent cell type and the other using a human cell type) using a neutral red uptake endpoint for predicting starting doses for acute oral systemic toxicity tests.

ICCVAM Test Method Recommendations: Appendix I of Workshop Report
View Workshop Report (NIH 01-4499 - August 2001)

Transmittal of ICCVAM Recommendations and Agency Responses

Transmittal Letter on Acute Systemic Toxicity from Dr. Kenneth Olden to the Agency Heads (March 21, 2003) 

Agency Responses:

Background Information

View relevant references

NIEHS Press Release #01-22, Oct. 3, 2001:
Drop of 30 Percent in use of Animals in Some Tests Could Be Quickly Achieved Through Use of Cells, U.S. Says

NTP is located at the National Institute of Environmental Health Sciences, part of the National Institutes of Health.