* High-dose AMR101 cut triglyceride levels by 33 percent
* Amarin brings forward U.S. filing date for drug to 2011
* AMR101 a competitor for GSK's best-selling Lovaza
LONDON, Nov 29 Amarin Corp Plc's (AMRN.O) closely watched heart pill AMR101 hit its targets in a pivotal clinical study on Monday, giving the Nasdaq-listed Irish firm ammunition to take on GlaxoSmithKline's (GSK.L) popular Lovaza.
Both drugs contain omega-3 fatty acids, the heart-protecting chemicals found in fish oil, and are designed to treat patients with very high levels of triglycerides, a blood fat that contributes to heart disease alongside cholesterol.
In the Phase III study, involving 229 patients, those on a 4-gram dose of AMR101 experienced a 33 percent decrease in blood triglyceride levels after 12 weeks compared to patients given a placebo, Amarin said.
Those on 2 grams saw a 20 percent decrease in the trial, which studied patients with greater than 500mg of triglycerides per decilitre of blood.
Importantly, taking AMR101 did not increase levels of low-density lipoprotein, or "bad cholesterol". Increased bad cholesterol is a side effect of Lovaza, which is less highly purified than AMR101.
Lovaza -- supplied to GSK by Norway's Pronova BioPharma ASA PRON.OL -- is currently the only omega-3 derived prescription drug approved in Europe and the United States.
GSK's sales of Lovaza sales jumped 31 percent to 450 million pounds ($702 million) in 2009 and the drug is expected to sell around $1 billion by 2011, according to consensus forecasts compiled by Thomson Reuters Pharma.
In future, Amarin hopes to take a chunk of that business with its new competitor and the group has brought forward plans to file AMR101 for U.S. regulatory approval to 2011. Previously, it had indicated a filing in 2012.
Amarin aims to seek a marketing partner for AMR101 and is currently in talks with a number of potential companies. (Reporting by Ben Hirschler; Editing by Jon Loades-Carter)