Comparative Stock Performance Graph

The comparative stock performance graph below compares the cumulative stockholder return on our common stock for the period from December 31, 2001 through the year ended December 31, 2006 with the cumulative total return on (i) the Total Return Index for the NASDAQ Stock Market (U.S. Companies), which we refer to as the NASDAQ Composite Index, and (ii) the NASDAQ Pharmaceutical Index. This graph assumes the investment of $100 on December 31, 2001 in our common stock, the NASDAQ Composite Index and the NASDAQ Pharmaceutical Index and assumes all dividends are reinvested. Measurement points are the last trading days of each of the years ended December 31, 2001, 2002, 2003, 2004, 2005 and 2006.