GlaxoSmithKline won an interesting patent fight in Canada the other day. This has been going for quite a while, as you'll be able to tell when I mention that involves AZT. Canadian generic companies Aponex and Novopharm had been trying to show that Glaxo's patent was invalid - and Glaxo had been trying to recover the money that they claimed they didn't make because of low-priced competition from those two.

The two generic companies argued that Glaxo's patent shouldn't have been issued for human treatment of AIDS, because at the time the compound had been tested only in mice. I'm relieved to say that this argument was rejected. Unless you've read the patent literature, you have no idea how many patents claim human therapy on the basis of even less data than that.

The generic companies claimed that Glaxo "had no way of reasonably foreseeing at that stage that its drug would ultimately work for humans." Well, fine - but who has such a way? I mean, what other sorts of data would you have by the time you file for a patent? There's always a timing decision to make on when you file, but I've never heard of anyone hesitating when they have proof of principle in an animal model. Would you wait until the compound had already gone into man? That takes years, of course, and you'd be working without a net the whole time - just one publication or patent filing and your work would be pulled out from under you. I think not.

At the same time, the judge in the case held that claims had to be in accord with the knowledge available at the time the patent was written. You can't just write all sorts of speculation in and hope to hit on a lucky chance. The fighting will come when two sides disagree over whether something was a reasonably sure extrapolation or sheer guesswork.

As an aside, Glaxo and Novopharm are no strangers in court - they fought a protracted battle (through most of the 1990s) over some Xantac (ranitidine) patents, which I'll post about some time. It's a very interesting one, and is a key case to study regarding the issue of disclosing the best mode of an invention (versus keeping it as a trade secret.) Actually, generic drug makers aren't strangers to anyone in court; they basically live there.