Semagacestat - Top 10 Phase III Failures

The drug: Semagacestat
The disease: Alzheimer's
The company: Eli Lilly

Alzheimer's presents one of the most complex disease challenges in medical science, as Eli Lilly learned earlier this year when it poured over the results of its Phase III Identity and Identity-2 trials for semagacestat.

Just when it most needed to prove that it had what it takes to pursue in-house drug development, Lilly found that the drug not only failed its endpoints on slowing progression, it appears to have worsened the condition of the patients taking the drug. In August, Lilly halted further development of the drug.

One of the problems with developing drugs for Alzheimer's is that researchers are relying on some informed hunches about what causes the memory-wasting disease. Semagacestat targets amyloid-β proteins, which are found in abundance in the brains of Alzheimer's patients. But there is still no universal agreement that attacking the plaque is the right way to slow or stop disease progression.

Eli Lilly isn't done with Alzheimer's, though. The reward for any pharma company that can bring a drug to that market is enormous, and it's pushing ahead with late-stage work on solanezumab, which relies on a different mechanism of action.

Jan M. Lundberg, PhD, Lilly's executive vice president, science and technology, called the trials a "setback," but vowed to push ahead. This is not a field for the weak of heart.

Semagacestat - Top 10 Phase III Failures
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