A new Alzheimer's drug from Eli Lilly failed in a large medical trial, tanking shares of the company. The drug - called solanezumab - failed to slow loss of cognitive ability in patients with mild Alzheimer's disease. That was a major setback for patients, investors, and the U.S. drugmaker. Based on the trial failure, Lilly said it would not seek U.S. approval of the drug for mild dementia. But it is being tested in patients who have not yet developed Alzheimer's symptoms, but who are prone to develop the disease in the future.