Osiris Stem Cells Safe for Heart Injury

"Going into this study, there was a lot of consternation about the approach we were taking and concerns about safety," said Hare. "I think these results prove that Provacel is safe."

From an efficacy perspective, 42% of Provacel-treated patients reported an improvement in their overall condition compared with 11% of placebo patients. This global assessment of patient well-being was determined by treating physicians in the study. The results were statistically significant.

On more objectively measured tests of efficacy, Provacel also performed better than placebo, but not enough to reach the level of statistical significance.

Provacel patients had an 18% improvement in left ventricular ejection fraction (LVEF), a measurement of strength in the heart's main pumping chamber. But placebo patients showed an 11% improvement in LVEF, and the difference between the two groups was not statistically significant.

One big surprise in the study, says Hare, was that Provacel seemed to cause improved lung function, which suggests the drug might be used to treat pulmonary diseases such as chronic obstructive pulmonary disease and idiopathic pulmonary fibrosis.

Overall, Hare believes these Provacel data justify more advanced and larger studies to determine better whether adult stem cells do have a future as a heart-repairing therapy. Such studies would ultimately enroll large numbers of patients and require Provacel to show that it can reduce mortality, prevent or delay further heart attacks or stroke, or help patients avoid further re-vascularization procedures.

Osiris CEO Randy Mills says the company's next steps will be further analyze these results and consult with partner Boston Scientific on phase II Provacel studies. Independent of Boston Scientific, Osiris will also begin looking at stating Provacel studies in lung diseases.

Osiris shares closed Friday up 3.4%, or 59 cents, to $17.90.