Lexicon Pharmaceuticals has posted top-line results from an initial Phase II study exploring the use of LX1033 in diarrhea-predominant irritable bowel syndrome (IBS-d). LX1033 is an investigational drug that inhibits serotonin synthesis in the gastrointestinal tract. Serotonin has been shown to play a role in the symptoms of IBS. The primary endpoint of this study was the change in stool consistency averaged from baseline to day 28. All treatment groups, including placebo, showed significant im...