Here's a posting about the difficulty of developing neuroprotective drugs from an interesting blog called "In the Pipeline"...
October 26, 2006
It Should Work. It Just Doesn't.
Posted by Derek
The late-stage clinical failure of a small company/big company drug partnership story gets told over and over, and today it was the turn of Renovis and AstraZeneca. Renovis had come up with a candidate (NXY-059) for post-stroke therapy that targeted free-radical oxidative damage. Initial clinical trials were fairly positive, but this latest one, a larger and more rigorous effort, totally failed to demonstrate any benefits for the drug.
They've got plenty of company. I've lost count of the number of neuroprotective drug candidate failures I've heard about during my time in industry. It's humbling, like much of drug discovery is when you look at it closely. I mean, if you get your information from the newspapers or (God help you) television news segments, you'd think that we know just how tissues are damaged after an event like a stroke, which means we know just how to block the process, so all it takes it just sending in some drug to keep it from happening. The folks in the lab coats should be whipping one right out any day now.
Nope. Hasn't worked out. Excitatory glutamate toxicity for example, was all the rage about ten years ago, but a number of Phase II and III wipeouts showed that even if these drugs could work (a big if), they would have to be given very, very quickly, which isn't clinically realistic. Since that run of failures, a new set of standards were developed to try to improve the quality of clinical candidates and trials in the field. The Renovis drug is one of the first to come in under those criteria, but little good did they do in this case. Neuroprotection is hard.