Osiris Therapeutics Achieves $15M Milestone Payment

COLUMBIA, Md. -- Osiris Therapeutics, Inc. (NASDAQ: OSIR), today announced that the company has achieved a $15 million milestone payment from NuVasive (NASDAQ: NUVA) related to the sale of the Osteocel business. Triggering the payment, NuVasive recently reached $35 million in cumulative sales of Osteocel. With this final payment, Osiris has realized the full $85 million value from the sale of its Osteocel business to Nuvasive.

"This significant commercial milestone underscores Osiris' position as a world leader in the development and commercialization of stem cell technology," said Philip R. Jacoby, Jr., Chief Financial Officer of Osiris Therapeutics. "The fact that NuVasive achieved $35 million in cumulative sales of Osteocel ahead of projections demonstrates the unique position of this product in facilitating spine fusion. It is the goal of both our therapeutic and biosurgery divisions is to develop high-quality cell therapy products that fill unmet medical needs. Osteocel is a great example of this type of innovation, having become the clear leader in market share, with sales more than double its closest competitors."

About Osiris Therapeutics

Osiris Therapeutics, Inc. is the leading stem cell therapeutic company focused on developing products to treat serious medical conditions in the inflammatory, orthopedic and cardiovascular areas. The Company's pipeline of internally developed biologic drug candidates under evaluation includes Prochymal for inflammatory, autoimmune, and cardiovascular indications, as well as Chondrogen for arthritis in the knee. Osiris is a fully integrated company, with capabilities in research, development, manufacturing, and distribution of stem cell products. Osiris has developed an extensive intellectual property portfolio to protect the company's technology including 49 U.S. patents each having one or more foreign counterparts. Osiris, Prochymal and Chondrogen are registered trademarks of Osiris Therapeutics, Inc. More information can be found on the company's website, www.Osiris.com. (OSIR-G)

In November 2008, Osiris and Genzyme announced a strategic alliance for the development and commercialization of Prochymal and Chondrogen. Under the terms of the agreement, Osiris retains commercialization rights to Prochymal and Chondrogen in the United States and Canada, with Genzyme having these rights in all other countries.