I can't resist passing on this argument, made unsuccessfully by Schering-Plough. It's a tactic that's been tried before, and has never worked. But desperate times demand such measures, I suppose, although - well, you be the judge.
SGP's Clarinex is, as I've mentioned, extremely similar to their Claritin. It's an active metabolite, so if you've taken Claritin, you've taken Clarinex. That's the whole point, according to Schering. If you allow other companies to sell Claritin as a generic, then when people take it, their bodies will turn that into Clarinex.
Which is, of course, a patented, proprietary substance. Which these patients are breaking the law by producing - led into this illegal act by the actions of a generic drug maker. Shocking!
This didn't fly. For this and other reasons I'll go into next week, Schering ended up on the losing side (by a summary judgment) and generic Claritin (loratadine) moved much closer to the market.
[Disclosure added on 8/16: notwithstanding the tone of the above, I actually own some SGP stock, back from the days when it was a good performer.]