The Wikipedia page says says she has had default judgments entered against her in the United States for civil offenses. If I am not mistaken extradition requires criminal offenses, and usually only a limited number of offenses are deemed serious enough to be "extraditable". It also requires an extradition treaty. Does her country of residence have an extradition treaty with the United States?

A Nature article some years ago mentioned she has no assets in the United States. The plaintiffs are therefore unlikely to ever collect any of the $15 million in damages.