Osiris Therapeutics net income increases to $4.0 million for first quarter 2011

Osiris Therapeutics, Inc. (NASDAQ: OSIR), the leading stem cell company focused on developing and marketing products to treat medical conditions in the inflammatory, autoimmune, cardiovascular, wound care and orthopedic areas, announced today its results for the first quarter ended March 31, 2011.

Highlights and Recent Developments

• Won top score on one of three abstracts presented describing the science and initial clinical results of Grafix®, a living skin substitute, at the 24^th Annual Symposium on Advanced Wound Care.
• Completed enrollment in a 220-patient Phase 2 trial for patients experiencing their first heart attack.
• Fully filed a complete response to inquiries from the Biologics and Genetic Therapies Directorate of Health Canada about Prochymal New Drug Submission (NDS).
• Received International Organization for Standardization (ISO) medical device certification, an internationally recognized quality standard.
• Strengthened the senior management team with the addition of Stephen W. Potter as Senior Vice President of Operations and Corporate Development.
• Reported net income of $4.0 million for the quarter; $0.12 per diluted common share.
• Reported cash, receivables and short-term investments of $63.2 million as of March 31, 2011.

"Osiris is off to a strong start in 2011," stated C. Randal Mills, Ph.D., President and Chief Executive Officer of Osiris Therapeutics. "We continue to make good progress with Prochymal in GvHD and our other larger, late stage indications. We are particularly pleased with the clinical performance of our new, sophisticated Biosurgery products. Our expectations are that 2011 will be a transformative year for the company."

First Quarter Financial Results

Net income for the first quarter of 2011 was $4.0 million compared to $2.4 million in the first quarter of 2010. Revenues were $10.4 million in the first quarter of 2011, consisting primarily of the amortization of license fees from our collaboration agreements. Revenues in the first quarter of 2010 were $11.4 million. As of March 31, 2011, Osiris had $63.2 million of cash, receivables and short-term investments.

Research and development expenses for the first quarter of 2011 were $4.7 million, compared to $6.6 million incurred in the first quarter of 2010. General and administrative expenses were $1.7 million for the first quarter of 2011 compared to $1.8 million for the same period of the prior year. Net cash used in continuing operations for the three months ended March 31, 2011 was $6.0 million.