Apparently when the negotiations broke down (Brazil wanted the same rate as Thailand but Merck wanted to charge them more), Brazil declared sovereign property rights in the good of it's citizens.
This was for Cipro for Anthrax. Bayer, at the last minute, gave in to some pricing concessions. There's also been talks about it happening during some H1N1 and avian flu scares.
A $100k pill that cures cancer? I'm not saying it would be taken by the gov't, but I think you'd have to seriously consider it.
Is there precedent for such a thing?