An experimental drug from pig intestinal tissue could reduce the number of deaths following stem cell transplants, Harvard Medical School (HMS) researchers at the Dana Farber Cancer Institute announced in a recent study.

The new drug, defibrotide, works to reverse the symptoms of severe veno-occlusive disease (VOD) in transplant patients.

VOD is a liver disease common in patients who undergo high doses of chemotherapy prior to transplantation.

Chemotherapy can damage the small blood vessels lining the liver, thereby disrupting the liver’s circulation and leading to swelling, discomfort and the possible failure of other associated organs.

In many cases, VOD is fatal.

While the current drugs available to treat VOD can cause severe bleeding, defibrotide—a single-stranded piece of DNA—can repair blood vessel damage on the surface of the liver without harsh side effects, according to the research team.

Paul G. Richardson, the lead researcher in the study and an HMS instructor of medicine first recognized that defibrotide, which is currently used in Europe for other medical problems, had the right properties to reverse VOD.

Researchers then put together a research protocol study that allowed for the use of defibrotide on an emergency-only basis.

Defibrotide was given to 88 transplant patients with severe VOD and completely reversed VOD in 36 percent of these cases.

The drug also allowed 35 percent of transplant patients to survive for more than 100 days—a significant improvement over the less than 10 percent expected to survive for this period.

The drug has also proven to be remarkably effective in pediatric cases of VOD, according to the new research, which will be published in the Dec. 15 issue of the journal Blood.

Richardson and Eva C. Guinan, associate professor of pediatrics at the medical school, are currently in the middle of an additional study to investigate the most effective dosage of the drug, which is manufactured by an Italian pharmaceutical company, Gentium SpA.

“The second study will serve as a pivotal approval trial,” Guinan said. “The pharmaceutical company can then take our results to the FDA.”

Guinan also said that if defibrotide is federally approved, it can then be made more broadly available to patients who suffer from VOD.

Defibrotide could also be used as a preventive measure in patients at high risk for developing VOD.

“In the future this may allow us to treat patients who otherwise would be denied transplants because of their high risk of VOD,” Richardson said in a press release.