Regeneron Pharmaceuticals Inc said on Tuesday initial data from an ongoing study of its experimental antibody cocktail for use in some hospitalized COVID-19 patients show the therapy was sufficiently effective to warrant continuing the trial.The company is testing the therapy, a combination of two antibodies casirivimab and imdevimab, in hospitalized patients requiring low-flow oxygen.The drugmaker said in September the cocktail reduced viral levels and improved symptoms in non-hospitalized COVID-19 patients.Also Read | Ten books from 2020 you must not missStudy participants included those who produced an effective immune response on their own (seropositive), and those whose immune response was not yet adequate (seronegative).Seronegative.