Semi-Annual Changes to the NASDAQ Biotechnology Index

The Nasdaq Stock Market, Inc. ("NASDAQ") (Nasdaq:NDAQ) announced today the results of the semi-annual re-ranking of the NASDAQ Biotechnology Index(r) (Nasdaq:NBI), which will become effective with the market open on Monday, May 21, 2007.

The re-ranking will result in 13 securities being added to the Index. All securities are classified according to the Industry Classification Benchmark (ICB) as either biotechnology or pharmaceutical. The securities that meet the classification criteria then must meet other Index eligibility criteria including listing on the NASDAQ Global Market or the NASDAQ Global Select Market and meeting minimum requirements for market value, average daily share volume and seasoning as a public company. The Index is ranked on a semi-annual basis in May and November. For more information about the NASDAQ Biotechnology Index, including eligibility criteria, visit www.NASDAQ.com.

As a result of the re-ranking, Curis, Inc. (Nasdaq:CRIS), Gene Logic Inc. (Nasdaq:GLGC), Inhibitex, Inc. (Nasdaq:INHX) and Threshold Pharmaceuticals, Inc. (Nasdaq:THLD), will be removed from the Index.

The NASDAQ Biotechnology Index is the basis for the iShares Nasdaq Biotechnology Index(sm) Fund (Amex:IBB), which seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the NASDAQ Biotechnology Index. In addition, options based on the NASDAQ Biotechnology Index and the iShares Nasdaq Biotechnology Index Fund trade on various exchanges.

NASDAQ is the largest U.S. electronic equities exchange. With approximately 3,200 companies, it lists more companies and, on average, trades more shares per day than any other U.S. electronic market. It is home to companies that are leaders across all areas of business including technology, retail, communications, financial services, transportation, media and biotechnology. NASDAQ is the primary market for trading NASDAQ-listed stocks as well as a leading liquidity pool for trading NYSE-listed stocks. For more information about NASDAQ, visit the NASDAQ Web site at www.nasdaq.com or the NASDAQ Newsroom at www.nasdaq.com/newsroom/.

The Industry Classification Benchmark ("ICB") is jointly owned by FTSE International Limited ("FTSE") and Dow Jones & Company, Inc.

FTSE(sm) is a trademark of the London Stock Exchange Plc and The Financial Times Limited and is used by FTSE International Limited under license.

"Dow Jones" and "DJ" are trademarks of Dow Jones & Company Inc.

iShares are distributed by SEI Investments Distribution Co.Barclays Global Fund Advisors serves as an advisor to iShares and is a subsidiary of Barclays Global Investors, N.A., neither of which is affiliated with SEI. For a prospectus, call 1-800-iSHARES (1-800-474-2737).

IShares are not FDIC Insured. Have No Bank Guarantee. May Lose Value. Company Briefs

Akorn, Inc. (Nasdaq:AKRX) develops, manufactures, and markets ophthalmic and injectable pharmaceutical products. The Company sells various diagnostic and therapeutic pharmaceutical products focused primarily on ophthalmology, anesthesia, antidotes, and rheumatology. Akorn also markets ophthalmic surgical instruments and other supplies, and provides contract manufacturing for third parties.

Alexza Pharmaceuticals, Inc. (Nasdaq:ALXA) is a pharmaceutical company focused on the development and commercialization of proprietary products for the treatment of acute and intermittent conditions.

BioMimetic Therapeutics, Inc. (Nasdaq:BMTI) develops and markets drug-device combination products for the repair of injuries or defects in bones, cartilage, ligaments, and tendons. The company combines protein therapeutics with tissue specific scaffolds to stimulate tissue healing and regeneration.

CombinatoRx Incorporated (Nasdaq:CRXX) is a biopharmaceutical company focused on developing new medicines built from synergistic combinations of approved drugs. The company has discovered and advanced into clinical trials a portfolio of product candidates targeting multiple immuno-inflammatory diseases and cancer.

DRAXIS Health Inc. (Nasdaq:DRAX) is a specialty pharmaceutical company providing products in three categories: sterile products, non-sterile products and radiopharmaceuticals. Sterile products include liquid and freeze-dried (lyophilized) injectables and sterile ointments. Non-sterile products are produced as solid oral, liquid and semi-solid dosage forms. Radiopharmaceuticals are used for both therapeutic and diagnostic molecular imaging applications.

Dynavax Technologies Corporation (Nasdaq:DVAX) discovers, develops, and is seeking to commercialize products based on immunostimulatory sequences. The company is developing products to treat and prevent allergies, infectious diseases, and chronic inflammatory diseases using approaches that alter immune system responses in specific ways.

GenVec, Inc. (Nasdaq:GNVC) is a biopharmaceutical company developing novel gene-based therapeutic drugs and vaccines. The company's product candidates use patent-protected technology to deliver genes that produce beneficial proteins. GenVec is developing a therapeutic product for the treatment of locally advanced pancreatic cancer and other solid tumor cancers. GenVec also uses its proprietary adenovector technology to develop vaccines for infectious diseases.

Maxygen, Inc. (Nasdaq:MAXY) is a biopharmaceutical company which researches and develops protein drugs. The Company's products now in clinical trials include an interferon-alpha for treating Hepatitis C, and a G-CSF for treating neutropenia.

Medivation, Inc. (Nasdaq:MDVN) acquires, develops, and sells or partners biomedical technologies in the early development stage of the research and development process. The company's current portfolio consists of small molecule drugs in development to treat three large, unmet medical needs -- Alzheimer's disease, Huntington's disease and hormone-refractory prostate cancer.

Osiris Therapeutics, Inc. (Nasdaq:OSIR) utilizes adult stem cell technology to treat inflammatory and connective tissue disorders. Osiris markets a stem cell product for the regeneration of bone, and is developing follow-on products to treat Crohn's Disease, arthritis, and heart failure.

Sangamo BioSciences, Inc. (Nasdaq:SGMO) researches and develops transcription factors in the regulation of genes. These transcription factors are the proteins that turn genes on and off and regulate gene expression by recognizing specific DNA sequences.

Vanda Pharmaceuticals Inc. (Nasdaq:VNDA) is a biopharmaceutical company. The Company is focused on the development and commercialization of a portfolio of clinical-stage, small molecule product candidates for central nervous system disorders.

Warner Chilcott Limited (Nasdaq:WCRX) is a pharmaceutical company. The Company is focused on marketing, selling, developing and manufacturing branded prescription pharmaceutical products in women's healthcare and dermatology in the United States.