Sirtris Pharmaceuticals Added to Russell 3000(R) Index

  
    
  
  
    
      Sirtris Pharmaceuticals, Inc. (NASDAQ: SIRT), a biopharmaceutical 
      company focused on discovering and developing small molecule drugs to 
      treat diseases of aging such as Type 2 Diabetes, announced today that it 
      was added to the Russell 3000(R) Index as well as the Russell 
      Microcap(R) Index when Russell Investment Group reconstituted its family 
      of U.S. indexes on June 22, 2007.
    
    
      “Being included among the leading growth 
      companies in the U.S. in the Russell Indexes is an honor. We believe 
      that this achievement is a reflection of the scientific progress we have 
      made in developing new therapies to treat diseases of aging," said 
      Christoph Westphal, M.D., Ph.D., Chief Executive Officer of Sirtris 
      Pharmaceuticals, Inc.
    
    
      Membership in the Russell 3000(R), which remains in place for one year, 
      means Sirtris will automatically be included in the Russell Microcap 
      (R), as well as appropriate growth and value style indexes. Russell 
      determines membership for its equity indexes primarily by objective, 
      market-capitalization rankings and style attributes.
    
    
      According to Russell, Russell indexes are widely used by investment 
      managers and institutional investors for index funds and as benchmarks 
      for both passive and active investment strategies. $4 trillion in assets 
      currently are benchmarked to Russell indexes, and investment managers 
      who oversee these funds purchase shares of member stocks according to 
      that company's weighting in the particular index.
    
    
      About Sirtris Pharmaceuticals
    
    
      Sirtris Pharmaceuticals is a biopharmaceutical company focused on 
      discovering and developing proprietary, orally available, small molecule 
      drugs with the potential to treat diseases associated with aging, 
      including metabolic diseases such as Type 2 Diabetes. Our drug 
      candidates are designed to mimic certain beneficial health effects of 
      calorie restriction, without requiring a change in eating habits, by 
      activation of sirtuins, a recently discovered class of enzymes that 
      control the aging process. The company's headquarters are in Cambridge, 
      Massachusetts.
    
    
      This press release contains forward-looking statements within the 
      meaning of the Private Securities Litigation Reform Act of 1995 
      concerning Sirtris Pharmaceuticals, its product candidates, and those 
      candidates' clinical potential. These forward-looking statements about 
      future expectations, plans and prospects of Sirtris Pharmaceuticals 
      involve significant risks, uncertainties and assumptions, including 
      risks related to the lack of results that would provide a basis for 
      predicting whether any of the Company’s 
      product candidates will be safe or effective, or receive regulatory 
      approval, the Company's potential inability to initiate and complete 
      preclinical studies and clinical trials for its product candidates, the 
      fact that none of the Company's product candidates has received 
      regulatory approvals, the potential inability of the Company to gain 
      market acceptance of the Company's product candidates, and those other 
      risks factors that can be found in the Company's filings with the 
      Securities and Exchange Commission. Actual results may differ materially 
      from those Sirtris Pharmaceuticals contemplated by these forward-looking 
      statements. Sirtris Pharmaceuticals does not undertake to update any of 
      these forward-looking statements to reflect a change in its views or 
      events or circumstances that occur after the date of this release.