Shares of Eli Lilly and Co. topped $50 for the first time in more than four years Monday after the drugmaker released more details behind late-stage studies of its potential Alzheimer's disease treatment.

The Indianapolis company said combined results from two studies of the drug, labeled solanezumab, found 34 percent less mental decline in patients with mild cases of the mind-robbing disease compared to those taking a dummy treatment for 18 months.