FOSTER CITY, Calif.--(BUSINESS WIRE)--Feb. 8, 2013--
      Gilead Sciences, Inc. (Nasdaq: GILD) today announced that it has
      completed its acquisition of YM BioSciences Inc. (NYSE MKT: YMI, TSX:
      YM).
    
      On February 8, 2013, a subsidiary of Gilead acquired all of the
      outstanding common shares of YM pursuant to the terms of a plan of
      arrangement. As a result, YM has become a wholly-owned subsidiary of
      Gilead and it is anticipated that the common shares of YM will no longer
      be listed for trading on the NYSE MKT LLC or the Toronto Stock Exchange,
      on or about February 12, 2013. Shareholders of YM on this date will be
      entitled to receive U.S. $2.95 per common share in cash, and holders of
      warrants and stock options will be entitled to receive a cash payment
      equal to the difference between U.S. $2.95 and the exercise price of
      such warrant or stock option.
    
About Gilead Sciences
Gilead Sciences is a biopharmaceutical company that discovers, develops
      and commercializes innovative therapeutics in areas of unmet medical
      need. Gilead’s mission is to advance the care of patients suffering from
      life-threatening diseases worldwide. Headquartered in Foster City,
      California, Gilead has operations in North America, Europe and Asia
      Pacific.
    
Forward-Looking Statements
      This press release includes forward-looking statements within the
      meaning of the Private Securities Litigation Reform Act of 1995 that are
      subject to risks, uncertainties and other factors, including risks
      related to the ability of Gilead to advance YM's product pipeline,
      including CYT387, and the possibility of unfavorable results of clinical
      trials of CYT387. These risks, uncertainties and other factors could
      cause actual results to differ materially from those referred to in the
      forward-looking statements. The reader is cautioned not to rely on these
      forward-looking statements. These and other risks are described in
      detail in Gilead’s Quarterly Report on Form 10-Q for the quarter ended
      September 30, 2012, as filed with the U.S. Securities and Exchange
      Commission. All forward-looking statements are based on information
      currently available to Gilead, and Gilead assumes no obligation to
      update any such forward-looking statements.
    
For more information on Gilead Sciences, please visit the company’s
      website at www.gilead.com,
      follow Gilead on Twitter (@GileadSciences) or call Gilead Public Affairs
      at 1-800-GILEAD-5 or 1-650-574-3000.
Source: Gilead Sciences, Inc.
      Gilead Sciences, Inc.Patrick O’Brien, 650-522-1936 (Investors)Nathan
      Kaiser, 650-522-1853 (Media)