LONDON -(Dow Jones)- GlaxoSmithKline PLC (GSK.LN) Thursday said the European Commission, or EC, has granted marketing authorization for Benlysta, or belimumab, 10 mg/kg as an add-on therapy in adult patients with active autoantibody-positive systemic lupus erythematosus, or SLE, with a high degree of disease activity, despite standard therapy. MAIN FACTS: -European summary of product characteristics, or SmPC, lists patient groups which have not been studied with belimumab, including severe active CNS lupus or severe active lupus nephritis; Use of belimumab is therefore not recommended to treat these conditions. -GlaxoSmithKline and Human Genome Sciences (HGSI) are developing belimumab under a definitive co-development and co-commercialisation agreement entered into in 2006. -Shares of GlaxoSmithKline at 1038 GMT down 13 pence or 0.9% at GBP13.47. -By Tapan Panchal, Dow Jones Newswires. Tel +44(0)207-842 9448, tapan.panchal@dowjones.com