Shares of Osiris Therapeutics Inc. rose 16 percent in heavy trading yesterday after the Baltimore biotech said one of its adult stem cell drugs, made from donor bone marrow, helps prevent adverse effects after a heart attack and also improves heart and lung function.
The data, from the six-month point of an early-stage clinical trial of 53 patients, were presented over the weekend at the American College of Cardiology conference in New Orleans. There, Boston company Mytogen Inc. also showed that its adult stem cells, taken from patients' leg muscles and injected into their hearts, were safe and may have repaired tissue.
"Heart disease is the No. 1 killer in the world," said Robin Young, a Pennsylvania-based medical technology analyst who has done some consulting work for Osiris. "To be able to treat damaged heart muscles ... is a bit of a game changer, frankly."
While such drugs have years of trials ahead before they're proven effective and marketable, Osiris' stock started moving on hints of the news late last week, rising 18 percent from Thursday to Friday.
Osiris stock closed up $2.87 to $20.77 yesterday, the fifth-most-advanced stock on the Nasdaq. Trading, at nearly 1.4 million shares, was more than five times normal volume.
As many as 8 million Americans have survived at least one heart attack, and another 650,000 have their first attack every year, according to the Centers for Disease Control. Each incident leaves patients with impaired organs and a greater risk of another attack.
Current therapies, such as surgery, can't do much to prevent the formation of scar tissue. Doctors have high hopes for experimental stem cell treatments that might do so.
"What we know about prognosis after heart attacks is that the bigger the scar, the worse the heart function and the worse the long-term prognosis," said Dr. Bartley P. Griffith, chief of cardiac surgery at the University of Maryland Medical Center, who does not work with Osiris. "If you could prevent scarring of significance from occurring, then you could have a hundred heart attacks and be fine."
Researchers around the country, including Griffith, are using adult stem cells to try to stop damage to the heart muscle. Scientists aren't quite certain how the cells work, though they're thought to migrate to damaged areas and send signals to stop inflammation, then perhaps even trigger tissue growth.
Some companies, such as Mytogen, first harvest cells from a patient, multiply them, make a minor incision and inject the cells into the damaged area.
Osiris' drug, called Provacel, works a little differently. It's harvested from healthy donors, rather than the patients, and given via intravenous injection, meaning most any medical professional can administer it. Like other adult stem cells, Provacel also won't cause negative immune system responses in recipients, so it could potentially be designed for ready-to-use distribution, rather than custom made.
Previous animal studies of Provacel conducted at Johns Hopkins showed it eradicated 75 percent of dead scar tissue on pig hearts. But investigators were unsure whether that would translate to humans.
This weekend's results, however, appear to show it does.
"This scar basically is smaller in the patients who've received the cells," Griffith said.
The early-stage clinical trial involved 34 patients who were given Provacel injections within 10 days of their heart attacks, and 19 others who received a placebo. They'll be followed over the next two years.
The data showed Provacel recipients were four times less likely to experience irregular or extra heart beats than their placebo counterparts and had a much higher improvement in their pulmonary function and overall condition.
'A first step'
"We were looking to see that the drug didn't cause a safety concern, and in fact, it actually prevented common effects that result from a heart attack," Osiris chief executive C. Randal Mills said last week.
Still, the study's lead author, Dr. Joshua Hare of the University of Miami, offered a word of caution via a statement from the American College of Cardiology.
"It's important to note that this study represents a first step," Hare said. "As in other disease categories, we must perform additional, larger trials to determine the real world application."
Osiris is in the midst of designing its next trial.
Results from an early-stage, 53-person trial testing adult stem cell drug Provacel, which is made by Baltimore's Osiris Therapeutics from donated bone marrow, show promise as a treatment for heart attack patients.
Nine percent of patients who received Provacel had an arrhythmic event, or irregular heartbeat, compared with 37 percent of those who received a placebo.
two months, 9 percent of the Provacel recipients experienced extra heartbeats, compared with 38 percent of placebo recipients.
Forty-two percent of Provacel patients had overall improvement in their conditions at six months compared with 11 percent of the patients who received a placebo.
[Source: Osiris Therapeutics Inc.]