UPDATE 2-Lexicon Pharma's tumor drug shows positive results

* Says drug well-tolerated in patients

* Says to discuss late-stage study plan with FDA (Adds details on trial)

Aug 9 (Reuters) - Lexicon Pharmaceuticals Inc said on Tuesday its experimental drug reduced symptoms related with tumors in small intestine, colon, appendix and lungs in a mid-stage study.

The drug, LX1032 or telotristat etiprate, is designed to treat carcinoid syndrome -- a group of symptoms associated with tumors that usually originate from the gastrointestinal tract.

The primary endpoint of the study was safety and tolerability. Efficacy measures included change in bowel movement frequency, relief of symptoms, and reduction in serotonin synthesis.

"The Phase 2 data clearly shows a reduction in bowel movements and symptom relief in a population that has exhausted all standard-of-care treatment options," Chief Medical Officer Pablo Lapuerta said.

Excess production of serotonin -- a compound found in the pineal gland, blood platelets, the digestive tract and the brain -- may lead to carcinoid syndrome.

It is characterized by severe diarrhea and flushing episodes with long-term consequences including malnutrition, heart disease and death.

Lexicon's drug is designed to reduce excess serotonin production.

The company said the drug was well tolerated in 23 patients with carcinoid syndrome who did not respond to currently available therapy.

Adverse events in the study were usually mild to moderate with similar frequencies between the treatment and placebo groups, the company said.

Lexicon said it intends to discuss a late-stage study development plan for the drug with the U.S. Food and Drug Administration.

Separately, preliminary data from an ongoing study of the drug in Europe showed that 5 out of 6 patients with carcinoid syndrome experienced 30 percent reductions in bowel movement frequency.

Shares of the Woodlands, Texas-based company closed at $1.40 on Monday on Nasdaq. (Reporting by Kavyanjali Kaushik in Bangalore; Editing by Roshni Menon)