Although the drug underwent grossly deficient testing, it did endure some testing, on mice. They didn't display phocomelia, however, and so the ill-fated drug was promptly unleashed upon the world. Last year, scientists discovered why this discrepancy exists.
"... when chicken and human embryos are exposed to thalidomide they produce superoxide, a powerful oxidising agent that causes cell death and birth defects. Mice are apparently protected from superoxide because they also make glutathione, an antioxidant that mops up the superoxide before it can damage cells. Human and chicken embryonic cells treated with glutathione had reduced levels of superoxide and less cell death."
The good news about this discovery is that thalidomide is actually otherwise quite a useful drug. Amongst other things, it has shown much promise in the treatment of multiple myeloma. Knowing the mechanism by which it produces its deleterious effects therefore opens up the possibility of modifying the drug to avoid them, whilst still retaining its beneficial properties.
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