** Shares of Australian biotech giant CSL CSL.AX fall 3.7% to A$171.25; hit lowest since May 2018
** Stock extends losses from its 15.9% slump on Tuesday; on track for fifth straight day of decline
** On Tuesday, CSL cut profit forecast and delayed plans to spin off its vaccine division
** Company blamed an unprecedented fall in U.S. flu immunization rates
** Investors, frustrated with company's tanking share price, rejected executive pay packages for the second year in a row in AGM on Tuesday
** Shares down 39% YTD
(Reporting by Rishav Chatterjee in Bengaluru)
((Rishav.Chatterjee@thomsonreuters.com))