- Expands biologics platform for robust growth -

- Includes proprietary adult stem cell bone graft product and processing facility -

- Expects Osteocel(R) revenues of $15 million in 2008 and $25 million in 2009; no dilution to earnings per share in 2008 or 2009, excluding in-process R&D charge -

SAN DIEGO, May 8 /PRNewswire-FirstCall/ -- NuVasive, Inc. (Nasdaq: NUVA),a medical device company focused on developing products for minimallydisruptive surgical treatments for the spine, announced today that it hassigned a definitive agreement to acquire the Osteocel biologics business fromOsiris Therapeutics, Inc. (Nasdaq: OSIR). The Osteocel business includes aproprietary adult stem cell bone graft product containing beneficialproperties similar to autograft, as well as a processing facility withsignificant supply stream capacity.

Under the terms of the agreement, NuVasive will acquire the Osteocelbiologics business from Osiris for $35 million in cash at closing, plusadditional milestone-based contingent payments not to exceed $50 million ineither cash or a combination of cash and stock, at the Company's election.The purchase price will be funded out of available cash and the transaction isnot subject to financing conditions. The Company presently anticipates thatthe closing will occur in the third quarter of 2008, subject to Osirisstockholder approval and customary regulatory approvals.

    Strategic benefits of the transaction to NuVasive:    -- Provides comprehensive stem cell biologic platform with benefits       similar to autograft;    -- Proprietary production process with significant capacity;    -- Strengthens biologics platform for robust growth;    -- Provides opportunity for additional revenue per procedure of $2,000 to       $3,000;    -- Complements current Formagraft(R) biologic product line;    -- Allows for participation in all segments of the $1.5 billion U.S.       biologics market;    -- Leverages current market adoption of an established biologic used in       over 15,000 procedures to date; and    -- Includes rights to acquire next generation cultured version of product.

Osteocel is the only viable bone matrix product on the market thatprovides the three beneficial properties similar to autograft: osteoconduction(provides a scaffold for bone growth), osteoinduction (bone formationstimulation) and osteogenesis (production bone). Osteocel allows surgeons tooffer the benefits of these properties to patients without the discomfort andpotential complications of autograft harvesting, in addition to eliminatingthe time spent on a secondary surgical procedure. Osteocel is produced foruse in spinal applications through a proprietary processing method thatpreserves the native stem cell population that resides in marrow rich bone.

The three main components that comprise Osteocel are cancellous bone,demineralized bone matrix (DBM) and viable MSCs native to the marrow richbone. Found in human bone marrow, MSCs are fundamental regenerative cells inthe body and promote tissue repair by modulating immune responses andprotecting damaged tissue. MSCs are believed to help regulate the behavior ofother bone marrow cells.

Alex Lukianov, Chairman and Chief Executive Officer, said, 'Thisacquisition directly supports our strategy of complementing our product suitewith innovative technologies.