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In an effort to present the FACTS to both the toxicology testing community and animal rights advocates regarding the formal ECVAM validation status of MatTek's EpiDerm™ in vitro human tissue equivalent as an alternative to animal testing for the determination of human skin irritation potential, MatTek has created this Skin Irritation Validation FACTS Web page.
Here are the FACTS:
FACT: In April, 2007, ECVAM formally validated MatTek's EpiDerm in vitro human skin tissue equivalent as a replacement for animal testing for the determination of skin irritation potential.*
FACT: The MTT reduction assay was the ONLY endpoint used to determine skin irritation in this validation.
FACT: In the validation announcement, ECVAM stated that, "At the present time, the IL-1α endpoint should be regarded as a useful adjunct to the MTT assay".
FACT: EpiDerm’s SPECIFICITY (correct prediction of non-irritants) for determination of skin irritation in multi-lab testing of 58 chemicals was 83.8%, the best result obtained in the validation testing.
FACT: EpiDerm’s SENSITIVITY (correct prediction of irritants) was 57.3%. However, as stated in the report, since almost all of the misclassified chemicals were lying at the threshold between irritant and non-irritant, the predictive capacity of EpiDerm was sufficient.**
These FACTS were excerpted from the ECVAM statement on the validity of EpiDerm as an in vitro test for skin irritation. It is public record and is available on the ECVAM Web site or by clicking on the link at the bottom of this page.***
What do these FACTS mean?
FIRST, it means that you can use EpiDerm in vitro human skin tissue equivalents to perform your skin irritation testing and that the results will be accepted throughout the European Union as validated skin irritation test results.
SECOND, you only have to determine ONE endpoint in your skin irritation testing, the MTT reduction assay, saving you both TIME and MONEY.
And FINALLY, the results of a comprehensive EpiDerm skin irritation follow-up study are with ECVAM regulators and this revised EpiDerm skin irritation protocol that eliminates the need for additional testing for negative (no irritation) results will be accepted by ECVAM as soon as November 2008.
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Notes
* The validation process used historical rabbit skin test results as the in vivo standard. Because EpiDerm’s barrier function is more like that of human skin, and is therefore less sensitive than rabbit skin, negative EpiDerm test results (no irritation detected) require an additional (one animal) test for confirmation when using the validated protocol.
** A comprehensive EpiDerm skin irritation follow-up study using a protocol with a longer sample exposure time has been completed and the results submitted to ECVAM. Formal validation of this revised protocol is expected before the end of 2008. Once this portocol is validated, it will eliminate the need for additional testing for negative test results.
*** See ECVAM's “STATEMENT ON THE VALIDITY OF IN-VITRO TESTS FOR SKIN IRRITATION” issued on 27 April 2007.
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