BRUSSELS—The European Union has signed a contract with GlaxoSmithKline (GSK) for the supply of up to 220,000 treatments of its investigational monoclonal antibody therapy sotrovimab against COVID-19, it said on Wednesday. The drug, which is developed together with U.S. firm Vir Biotechnology, can be used for the treatment of high-risk coronavirus patients with mild symptoms who do not require supplemental oxygen, according to the Commission. The deal is a boost to GSK work on potential treatments for COVID-19 after the company played a limited role in the development of vaccines. Rather than making its own coronavirus shot, GSK has focused on supplying its booster to other developers and has partnered with Sanofi to develop a jab. GSK confirmed the deal in a statement on Wednesday, saying it represented “a crucial step forward for treating cases of COVID-19” in Europe. The drug is currently being assessed by the European Medicines Agency …