The results are in: Eli Lilly's (NYSE: LLY) experimental insulin, peglispro, is superior to Sanofi's (NYSE: SNY) flagship Lantus franchise.

Three late stage studies showed that Lilly's new drug controlled blood sugar and weight gain better than the current market leader. However, despite these tremendous results, Eli Lilly's victory may prove hollow. The specter of liver toxicity may hamper the peglispro's ability to get approved and depress consumer demand if and when it hits the market. 

In this video, Motley Fool health care analyst David Williamson discusses the positive and negatives of Eli Lilly's trial results, why sales could be tough to come by, and when investors can expect further action around this drug.