Thanks for the link ghmm. That made for a good read. I'd just add that LGND also has a very early stage BACE inhibitor in partnership with Schering-Plough thanks to the PCOP merger.
"Ligand Pharmaceuticals Inc. today announced that it has earned a $1 million milestone payment from Schering-Plough Corporation related to the progress of Schering-Plough’s inhibitor of β-site of APP cleaving enzyme (BACE) for the treatment of Alzheimer's disease, which resulted from a research collaboration with Pharmacopeia (acquired by Ligand). Alzheimer's disease is characterized by plaques of the toxic amyloid-beta protein within the brain. Amyloid-beta is formed when the larger amyloid precursor protein (APP) is cleaved by two enzymes, BACE and gamma-secretase, which releases the amyloid-beta fragment. A BACE inhibitor is expected to reduce amyloid-beta generation in Alzheimer's disease patients...."