Roche has announced that they're halting trials of aleglitazar, a long-running investigational drug in their diabetes portfolio. I'm noting this because I think that this might be the absolute last of the PPAR ligands to fail in the clinic. And boy howdy, has it been a long list. Merck, Lilly, Kyorin, Bristol-Myers Squibb, Novo Nordisk, GlaxoSmithKline, and Bayer are just the companies I know right off the top of my head that have had clinical failures in this area, and I'm sure that there are plenty more. Some of those companies (GSK, for sure) have had multiple clinical candidates go down, so the damage is even worse than it appears.
That why I nominated this class in the Clinical Futility Awards earlier this summer. Three PPAR compounds actually made it to market, but the record has not been happy there, either. Troglitazone was pulled early, Avandia (rosiglitazone) has (after a strong start) been famously troubled, and Actos (pioglitazone) has its problems, too.
The thing is, no one knows about all this, unless they follow biomedical research in some detail. Uncounted billions have been washed through the grates; years and years of work involving thousands of people has come to nothing. The opportunity costs, in retrospect, are staggering. So much time, effort, and money could have been spent on something else, but there was no way to know that without spending it all. There never really is.
I return to this theme around here every so often, because I think it's an important one. The general public hears about the drugs that we get approved, because we make a big deal out of them. But the failures, for the most part, are no louder than the leaves falling from the trees. They pass unnoticed. Most people never knew about them at all, and the people who did know would rather move on to something else. But if you don't realize how many of these failures there are, and how much they cost, you can get a completely mistaken view of drug discovery. Sure, look at the fruit on the branches, on those rare occasions when some appears. But spare a glance at that expensive layer of leaves on the ground.