UPDATE 1-GSK files for U.S. approval of new diabetes drug

(Adds details on albiglutide, forecast sales and competitors) LONDON, Jan 14 (Reuters) - GlaxoSmithKline said onMonday it had filed for U.S. approval of its new once-weeklydiabetes drug albiglutide and would make a similar submissionshortly in Europe as it vies for a share of a crowded market. Albiglutide belongs to the same class of injectable GLP-1medicines as Victoza, from Novo Nordisk, and Byettaand Bydureon, from Bristol-Myers Squibb andAstraZeneca's Amylin unit. The submission by GSK, Britain's biggest drugmaker, was inline with its plan to seek regulatory approval for the newproduct in 2013. As a latecomer to the GLP-1 market, however,analysts believe albiglutide may struggle to generate majorsales. Consensus forecasts for albiglutide currently point tomodest annual sales of around $367 million by 2017, according toThomson Reuters Pharma. Albiglutide is one of a number of new drugs GSK hopes willrevive its product portfolio. It is also hoping for approval ofthe two lung drugs, Relvar and Anoro; an HIV medicine calleddolutegravir; and two melanoma drugs dabrafenib and trametinib. Further ahead, GSK expects to have pivotal clinical trialresults on up to 14 medicines in the next two years, includingtwo potentially ground-breaking experimental drugs for heartdisease and cancer - darapladib and MAGE-A3. (Reporting by Ben Hirschler)