I've never understood the ire against me-too drugs. Consumer choice is usually thought of as a good thing: competition reduces prices somewhat, therapeutic side-benefits may be discovered, and often different drugs work well on different sub-classes of patients. If you don't think the world would be a better place with only one kind of coffee, I fail to see why you think it will be better off with only one kind of anti-depressant.
But for a large number of people, me-too drugs seem like a waste of effort, a way for soulless pharmaceutical companies to get rich copying their competitors by doing "real" innovation rather than this piddling incrementalism. Of course, as Derek Lowe points out, me-too drugs often don't make their creators rich:
If this drug had been found ten or fifteen years ago, it might have made it though. But the trial data showed that while it made its primary endpoints (reducing vertebral fractures, for example), it missed several secondary ones (such as, well, non-vertebral fractures). And the side effect profile wasn't good, either. That combination meant that the drug was going to face at hard time at the FDA for starters, and even if it somehow got through, it would face a hard time competing with generic Fosamax (and Lilly's own Evista).
So down it went, and it sound like the right decision to make. Unfortunately, given the complexities of estrogen receptor signaling, the clinic is the only place that you can find out about such things. And there are no short, inexpensive clinical trials in osteoporosis, so the company had to run one of the big, expensive ones only to find out that arzoxifene didn't quite measure up. That's why this is a territory for the deep-pocketed, or (at the very least) for those who hope to do a deal with them at the first opportunity.
One more point is worth emphasizing. Take a look at the structures of the two compounds (from those Wikipedia links in the first paragraph). Pretty darn similar, aren't they? Arzoxifene is clearly a follow-up drug in every way - modified a bit here and there, but absolutely in the same family. A "me-too" drug, in other words, an attempt to come up with something that works similarly but sands off some of the rough edges of the previous compound. But anyone who thinks that development of a follow-up compound is easy - and a lot of people outside the industry do - should consider what happened to this one.
Those sanded-off edges can make a big difference--just ask someone who's had to take a drug every six hours, and then gets to switch to a once- or twice-a-day formulation. But there are no more guarantees in a me-too than in the "real" new drugs.