GlaxoSmithKline Plc’s Relenza may be as effective as Roche Holding AG’s Tamiflu in the treatment of bird flu, and should be included in government stockpiles against the potentially fatal illness, researchers said in this week’s Lancet medical journal. Relenza, also known as zanamivir, causes fewer adverse reactions than Tamiflu and has a favorable resistance profile, according to Kenneth Tsang, a researcher at Queen Mary Hospital in Hong Kong. Tsang’s study showed both drugs have similar efficacy.