Arena: 2nd weight loss trial shows cardiac benefit

* FDA filing on track for late 2009

* Partnership talks still under way

By Deena Beasley

LOS ANGELES, Oct 27 (Reuters) - Arena Pharmaceuticals (ARNA.O: Quote, Profile, Research) said on Tuesday detailed results from a second pivotal trial of its experimental obesity drug, lorcaserin, show that it improves cardiovascular risk factors.

The company reported in August that the 4,000-patient trial found that 47.2 percent of subjects taking lorcaserin, an oral drug, lost 5 percent or more of their weight after a year, compared with 25 percent of placebo patients.

At a meeting of the Obesity Society in Washington, Arena reported over the weekend similar secondary findings from its first pivotal trial of the drug, triggering a nearly 4 percent rise in its share price.

Arena, along with rivals Vivus Inc (VVUS.O: Quote, Profile, Research) and Orexigen Therapeutics Inc (OREX.O: Quote, Profile, Research), is working to develop the first new prescription weight loss drug in a decade.

Lorcaserin works in a way similar to fenfluramine, which was part of the fen-phen diet cocktail before it was withdrawn in 1997 after being linked to heart valve damage.

Arena's drug is designed to block appetite signals in the brain, but by being much more selective than fenfluramine in the receptors it affects. Fenfluramine also binds to a separate cell receptor in the heart.