Die Grenzen der Wunderheiler ,ZDF 22.15

A total of 32 patients were enrolled in the trial with 31 available for evaluation. As previously reported, 29 of 31, or 94% responded after receiving two infusions of PROCHYMAL, with 23 patients, or 74% achieving a complete response, meaning the patients had experienced total clinical resolution of the disease. Six patients, or 19% had a partial response and 2 patients, or 6% did not respond. A study previously published in Biology of Blood and Marrow Transplantation (MacMillan et al, 2002) evaluated 443 patients with acute GVHD, grades II-IV, and found that only 35% of patients had a complete response to steroids by day 28.

There were a total of 8 patient deaths during the first 120 days following treatment. None of the deaths were attributed to PROCHYMAL. Patients experiencing a complete response rate by day 28 had a statistically significant improvement in survival as compared to patients experiencing a partial or non-response (91.3% survival vs. 25% survival, p less than 0.001). Overall survival for the study was 74% at day 120.

"In this trial, approximately twice the number of patients achieved a complete response when given PROCHYMAL as we would expect with steroids alone," Hans Klingemann, M.D., Ph.D., Director, Bone Marrow and Hematopoietic Cell Transplant Program, Tufts New England Medical Center. "But what is most important is that this improvement in response carried over into high survival rates."

In the study, 22 of the 31, or 71% of the patients received only PROCHYMAL and steroids for the treatment of GVHD. In this group there were only two deaths reported by day 120. One was the result of an accidental fall and the other was related to the relapse of the patient's underling disease. Importantly, there were no deaths from infection. Nine patients received 2nd line therapeutic agents for GVHD in addition to treatment with PROCHYMAL. Only 3 of the 9 patients in this group survived to day 120. Four patients in this group died from infection and 2 died from pulmonary complications. Patients spared additional second line treatments for GVHD had significantly improved rates of survival at 120 days (90.9% vs. 33%, p=0.001).

"In this study, many of the patients who received additional immunosuppressive therapies developed severe complications associated with these treatments, such as infection, said Rod Monroy, Ph.D., Sr. Director for PROCHYMAL. "We were pleased to see that we could achieve higher complete response rates with PROCHYMAL, without the mortality that often arises as a result of more aggressive immunosuppression."

"We are very optimistic about the survival data that continues to emerge from this study," said C. Randal Mills, Ph.D., President and CEO of Osiris. "The American Society for Hematology provides an excellent opportunity for us to share this exciting information with our physician investigators conducting the ongoing Phase III trial. We also wanted to make sure that interested parties who are not able to attend the conference had access to this additional data."

The information contained within this release will be the focus of the poster session being held Monday, December 11th. Due to the early filing deadline for the conference, the abstract published in the conference proceedings was compiled from an analysis of preliminary data. As a result, the abstract does not reflect the current status of the trial. An electronic version of the poster will be available for review on our website at www.Osiris.com starting Monday, December 11, 2006.

PROCHYMAL is a preparation of mesenchymal stem cells specially formulated for intravenous infusion. The stem cells are obtained from the bone marrow of healthy adult donors. PROCHYMAL is currently being evaluated in a double-blind, placebo controlled Phase III study for the treatment of GVHD. The ongoing Phase III study for GVHD is anticipated to be the final trial before the product is submitted to FDA, Canadian and European regulatory agencies for full approval. PROCHYMAL has been granted both Fast Track and Orphan Drug status by FDA for GHVD. FDA established the Fast Track program to accelerate the development of drugs that show promise for treating life-threatening conditions. Orphan Drug designation provides incentives to companies that develop drugs for underserved patient populations. PROCHYMAL is also being evaluated for the treatment of Crohn's Disease and has completed a Phase II trial, which demonstrated positive results, including a significant reduction in the Crohn's Disease Activity Index.

GVHD is a T-cell mediated inflammatory process that results in high levels of pro-inflammatory chemical signals called cytokines. These cytokines cause the unbalanced activation of certain immune cells that results in tissue damage. Delivered intravenously, PROCHYMAL is able to target areas of active inflammation. Laboratory data indicates that PROCHYMAL is able to down-regulate the production of pro-inflammatory cytokines, including tumor necrosis factor-alpha or TNF-alpha and interferon-gamma. Additional data indicates that PROCHYMAL up-regulates the production of beneficial anti-inflammatory cytokines, specifically interleukin-10 and interleukin-4. When the stem cells found in PROCHYMAL are delivered into an inflammatory environment, they appear to change the course of the disease by altering the cytokine secretion profile of the dendritic and T cell subsets, thereby resulting in a shift from a pro-inflammatory to an anti-inflammatory state and arresting disease progression. Furthermore, it is believed that PROCHYMAL facilitates the repair of previously damaged tissue through the secretion of growth factors that promote tissue regeneration.

About Osiris Therapeutics

Osiris Therapeutics, Inc. is a leading stem cell therapeutic company focused on developing and marketing products to treat medical conditions in the inflammatory, orthopedic and cardiovascular areas. Osiris currently markets and sells Osteocel(R) for regenerating bone in orthopedic indications. Prochymal(TM) is in Phase 3 clinical trials and is the only stem cell therapeutic currently designated by FDA as both an Orphan Drug and Fast Track product. The Company's pipeline of internally developed biologic drug candidates under evaluation also includes Chondrogen(TM) for regenerating cartilage in the knee, and Provacel(TM), for repairing heart tissue following a heart attack. Osiris is a fully integrated company, having developed stem cell capabilities in research and development, manufacturing, marketing and distribution. Osiris has developed an extensive intellectual property portfolio to protect the company's technology in the United States and a number of foreign countries including 46 U.S. and 164 foreign patents owned or licensed. More information can be found on the company's website, www.Osiris.com. (OSIR-G)

Crohn's Disease is the second indication for which Osiris has obtained Fast Track status and has advanced into Phase III trials. Osiris was the first company to receive Fast Track status for a ready to use stem cell treatment, when in 2005, FDA granted PROCHYMAL Fast Track status for the treatment of GVHD. Since receiving Fast Track, Osiris has advanced the product through Phase II testing and is currently enrolling patients in a Phase III trial for resistant GVHD.

"PROCHYMAL's unique mechanism of action may represent a new class of anti-inflammatory agent," said Jane Onken, M.D., Director of the Inflammatory Bowel Disease Clinic and Associate Professor of Medicine at the Duke University School of Medicine. "Laboratory data indicate that the stem cells in PROCHYMAL respond according to the level of inflammation present. When there are higher concentrations of inflammatory signals, the cells produce a stronger anti-inflammatory effect. When there is no inflammation, the anti-inflammatory effect is turned off. It is our hope that this proportional response will lead to a treatment that avoids many of the dangerous side effects associated with systemic immunosuppressive therapy and provide us with a safer alternative for treating patients with serious inflammatory diseases."

FDA established Fast Track to facilitate the development and accelerate the pre-market review of treatments for serious and life-threatening conditions, so that these products can reach approval more rapidly. To receive Fast Track designation, the product must address a serious unmet medical condition, and be supported by strong results from preclinical or clinical testing demonstrating the product potential. FDA reached their decision to grant Osiris Fast Track for treatment resistant Crohn's Disease after reviewing the accumulation of clinical trial data submitted by the Company, along with a detailed plan for the Phase III evaluation of the drug.

"We are very pleased with the tremendous progress that the entire PROCHYMAL team has made over the past two years," said C. Randal Mills, Ph.D., President and CEO. "Moving the program into Phase III and receiving Fast Track status are key components in our plan to expand the market applicability of this exciting stem cell technology as quickly as possible. Our vision is to leverage the unique properties of stem cells and create a new treatment paradigm, applicable to a broad spectrum of inflammatory disease."

Crohn's Disease is a life-long, chronic inflammatory disease of the intestines, often leading to abdominal pain, disability, and surgical removal of the affected portion of the bowel in more than half of patients with the disease. Crohn's Disease affects over 500,000 patients in the US, with more than 20,000 new cases diagnosed each year. It most often begins between ages 15 and 35, although it can start at any age.

The Phase III program for Crohn's Disease will consist of two double-blind, placebo-controlled trials. As was the case with Phase II, the new trials will evaluate patients with Crohn's Disease who are intolerant or unresponsive to standard treatments including steroids, immunosuppressants, and anti-TNF treatments like Remicade(R). The primary endpoint is the induction of disease remission 28 days after treatment. Patients will have an equal chance of receiving either a high dose of PROCHYMAL, a low dose of PROCHYMAL, or a placebo. Initially, up to 258 subjects are scheduled to be enrolled in each trial. Patients that respond to treatment will be eligible for re-treatment under a separate study protocol.

PROCHYMAL is a preparation of mesenchymal stem cells specially formulated for intravenous infusion. The stem cells are obtained from the bone marrow of healthy adult donors. PROCHYMAL is currently being evaluated in a double-blind, placebo controlled Phase III study for the treatment of GVHD. The ongoing Phase III study for GVHD is anticipated to be the final trial before the product is submitted to FDA, Canadian and European regulatory agencies for full approval. PROCHYMAL has been granted both Fast Track and Orphan Drug status by FDA for GVHD. Orphan Drug designation provides incentives to companies that develop drugs for underserved patient populations.

GVHD and Crohn's Disease are cell-mediated inflammatory processes that result in high levels of pro-inflammatory chemical signals called cytokines. These cytokines cause the unbalanced activation of certain immune cells that result in tissue damage. Delivered intravenously, PROCHYMAL is able to target areas of active inflammation. Laboratory data indicate that PROCHYMAL is able to down-regulate the production of pro-inflammatory cytokines, including tumor necrosis factor-alpha or TNF-alpha and interferon-gamma. It is believed that the way PROCHYMAL is able to change the course of inflammatory disease is by altering the cytokine secretion profile of the dendritic and T-cell subsets, thereby resulting in a shift from a pro-inflammatory to an anti-inflammatory state and arresting disease progression. Furthermore, it is believed that PROCHYMAL facilitates the repair of previously damaged tissue through the secretion of growth factors that promote tissue regeneration and block programmed cell death or apoptosis.

About Osiris Therapeutics

Osiris Therapeutics, Inc. is a leading stem cell therapeutic company focused on developing and marketing products to treat medical conditions in the inflammatory, orthopedic and cardiovascular areas. Osiris currently markets and sells Osteocel(R) for regenerating bone in orthopedic indications. Prochymal(TM) is in Phase III clinical trials and is the only stem cell therapeutic currently designated by FDA as both an Orphan Drug and Fast Track product. The Company's pipeline of internally developed biologic drug candidates under evaluation also includes Chondrogen(TM) for regenerating cartilage in the knee, and Provacel(TM), for repairing heart tissue following a heart attack. Osiris is a fully integrated company, having developed stem cell capabilities in research and development, manufacturing, marketing and distribution. Osiris has developed an extensive intellectual property portfolio to protect the company's technology in the United States and a number of foreign countries including 46 U.S. and 165 foreign patents owned or licensed. More information can be found on the company's website, www.Osiris.com. (OSIR-G)

Remicade(R) is a registered trademark of Centocor, Inc., Malvern, PA

Forward-Looking Statements

This press release contains forward-looking statements. Forward-looking statements provide our current expectations or forecasts of future events. Forward-looking statements include statements about our expectations, beliefs, plans, objectives, intentions, assumptions and other statements that are not historical facts. Words or phrases such as "anticipate," "believe," "continue," "ongoing," "estimate," "expect," "intend," "may," "plan," "potential," "predict," "project" or similar words or phrases, or the negatives of those words or phrases, may identify forward-looking statements, but the absence of these words does not necessarily mean that a statement is not forward-looking. Examples of forward-looking statements include, but are not limited to, statements regarding the following: our product development efforts; our clinical trials and anticipated regulatory requirements; the success of our product candidates in development; status of the regulatory process for our biologic drug candidates; implementation of our corporate strategy; our financial performance; our product research and development activities and projected expenditures, including our anticipated timeline and clinical strategy for MSCs and biologic drug candidates; our cash needs; patents and proprietary rights; ability of our potential products to treat disease; our plans for sales and marketing; our plans regarding our facilities; types of regulatory frameworks we expect will be applicable to our potential products; and results of our scientific research. Forward-looking statements are subject to known and unknown risks and uncertainties and are based on potentially inaccurate assumptions that could cause actual results to differ materially from those expected or implied by the forward-looking statements. Our actual results could differ materially from those anticipated in forward-looking statements for many reasons, including the factors described in the section entitled "Risk Factors" in our Registration Statement on Form S-1, File No: 333-134037, as filed with the United States Securities and Exchange Commission and declared effective on August 3, 2006. Accordingly, you should not unduly rely on these forward-looking statements. We undertake no obligation to publicly revise any forward-looking statement to reflect circumstances or events after the date of this press release or to reflect the occurrence of unanticipated events.

C. Randal Mills Ph.D., President and CEO of Osiris Therapeutics, said: "We were confident in the safety profile given our previous experience using the intravenous form of these stem cells to treat other diseases in later stage clinical trials. However, the magnitude of the across-the-board improvement was surprising. These data further validate the broad clinical applicability of our stem cell technology. Based on these encouraging results, we have started working on the design of the next stage of clinical trials."

Trial Highlights

-- Administration of PROVACEL was found to be well tolerated at all dose levels.

-- Patients in the PROVACEL group were four times less likely to experience an arrhythmic event compared to those receiving placebo (9% vs. 37%, p=0.025).

-- Fewer patients experienced clinically significant premature ventricular contractions after receiving PROVACEL as compared to placebo across all time points (11% vs. 24%, p less than 0.001).

-- PROVACEL patients with major "anterior wall" heart attacks had a statistically significant 7.0 point (24%) improvement in ejection fraction at three months and a 7.3 point (25%) improvement at six months over baseline (p less than 0.05), while similar patients receiving placebo did not have significant improvement.

-- Patients receiving PROVACEL had significantly improved lung function as measured by improvement in FEV1 % predicted values (17 point PROVACEL vs. 6 point placebo, p less than 0.05).

-- Significantly more patients who received PROVACEL experienced improvement in their overall condition at six months as compared to those receiving placebo (42% vs. 11%, p=0.027).

"The data speak for themselves," said Timothy Henry M.D., Director of Research at the Minneapolis Heart Institute Foundation at Abbott Northwestern. "This was a carefully executed, double-blind, placebo-controlled trial where patients who received the stem cells simply did better. The results are fascinating, particularly given the route of administration, and lead us to challenge our basic assumptions about cell therapy for heart disease."

Safety Data

Administration of PROVACEL was found to be well tolerated at all dose levels evaluated. There were no patient deaths, and no toxicity was observed with the administration of PROVACEL. Importantly, there were fewer adverse events in patients receiving PROVACEL as compared to placebo (5.3 vs. 7.0 adverse events per patient). Patients receiving placebo required repeat hospitalization sooner and more often than those treated with PROVACEL (31.5% at an average of 66 days vs. 23.5% at an average of 120 days). There were no serious adverse events attributed to the drug.

"Unlike other cell therapies that have been used in the heart, these cells are readily available when we need them and are administered through a standard IV line like many of the other drugs we give our patients," Jay Traverse M.D., principal investigator and Assistant Professor of Medicine at the University of Minnesota. "If the safety and efficacy profile remains strong, the practicality of the treatment model clearly supports wide-scale use."

Arrhythmia Data

Patients enrolled in the trial were monitored for the occurrence of cardiac arrhythmia. Patients in the PROVACEL group were four times less likely to experience an arrhythmic event compared to those receiving placebo (9% vs. 37%, p=0.025). Of particular interest, half of the arrhythmias noted in the placebo group involved the ventricle, or blood pumping part of the heart, while only 14% of the arrhythmias in the PROVACEL group involved the ventricle. Ventricular arrhythmias are associated with scar formation in the affected portion of the heart following a heart attack and can be a sign of poorer prognosis.

The anti-arrhythmic effects of PROVACEL were also seen in the number of premature ventricular contractions (PVCs) observed. Patients treated with PROVACEL had fewer PVCs at all time points after day 10, despite having more PVCs at baseline. The percentage of patients who experienced clinically significant PVCs (greater than 10 PVCs per hour) was also significantly less in those patients receiving PROVACEL as compared to placebo (11% vs. 24%, p less than 0.001) and was most pronounced at the one-month (6% vs. 32%, p less than 0.05) and two-month (9% vs. 38%, p less than 0.05) time points. Patients often experience an increase in the number of PVCs following a heart attack, corresponding with the formation of scar tissue in the heart.

Performance Data

Preliminary echocardiogram data demonstrated that patients with clinically significant heart attacks involving the anterior wall had pronounced improvement in left ventricular ejection fraction (LVEF) not seen in patients receiving placebo. Patients treated with PROVACEL had a statistically significant 7.0 point (24%) improvement in LVEF at three months and a 7.3 point (25%) improvement at six months over baseline (p less than 0.05). This compared favorably to the 2.9 point (6%) and 3.4 point (8%) improvement found in patients receiving placebo, neither of which was significant over baseline.

Overall, patients treated with PROVACEL had an 18% improvement in LVEF at three months compared to an 11% improvement for the placebo group. The improvement observed in the PROVACEL patients was statistically significant over baseline (p less than 0.005), and the effect was maintained through six months, at which time LVEF was 19% higher than baseline.

The positive differences observed in arrhythmias and the echocardiogram were consistent with the more practical assessments used in the study. A greater proportion of patients had prompt heart rate recovery (less than 15 minutes) following a six-minute walk test when treated with PROVACEL as compared to placebo at the six month time point (55% vs. 26%, p=0.08).

Finally, the patients' overall condition was assessed by the treating physician for signs of improvement or deterioration. In this global assessment, significantly more patients in the PROVACEL group experienced improvement in their overall condition at six months as compared to those receiving placebo (42% vs. 11%, p=0.027).

Pulmonary Data

Lung function tests were performed to monitor subjects for potential adverse changes related to the treatment. Surprisingly, patients who received PROVACEL had significantly improved pulmonary function following treatment compared to placebo as measured by improvement in FEV1 % predicted values (17 point PROVACEL vs. 6 point placebo, p less than 0.05). Preclinical studies performed at Osiris Therapeutics had previously demonstrated that the anti-inflammatory and anti-fibrotic (anti-scarring) effects of the stem cells may be of benefit to patients with conditions such as Chronic Obstructive Pulmonary Disease (COPD) and Idiopathic Pulmonary Fibrosis (IPF). However, this finding is the first placebo-controlled evidence in humans that indicates MSCs may play a beneficial role in the treatment of certain lung disorders.

The PROVACEL trial is one of five ongoing clinical trials at Osiris, including two Phase III trials using the cells in the treatment of steroid refractory Graft vs. Host Disease and Crohn's Disease, both of which have been granted fast track status by FDA. Osiris is developing PROVACEL as part of a strategic alliance with Boston Scientific Corporation (NYSE:BSX) for commercialization of Osiris' mesenchymal stem cell technology in the cardiac field.

Evaluation of patients in the PROVACEL trial will continue for a total of two years following treatment.