Stem Cells Improve Outlook for Severe PAD

Stem cells reduce amputation in severe peripheral artery disease patients

(RxWiki News) Scientists have increasingly been experimenting with therapies tied to a patient's own stem cells, and peripheral artery disease (PAD) is no exception.

Injecting a patient's own stem cells appears to reduce the chance of leg amputation, worsening or death in those with severe cases of PAD, also referred to as "no option" patients because the disease is so advanced that amputation is the only available treatment.

"Talk to your cardiologist about treatment options for PAD."

PAD results from blocked arteries in the legs. It can usually be treated with stents or bypass surgery, but that is not an option for those suffering from a type of PAD called critical limb ischemia (CLI.)

Richard J. Powell, MD, chief of vascular surgery at Dartmouth-Hitchcock Medical Center and principal investigator of the study, noted that bone marrow stem cells can be used to repair other parts of the body.

By injecting a patient's own stem cells into the ischemic leg, the hope is that it will improve blood flow in that part of the leg, Dr. Powell said.

The three-year RESTORE-CLI clinical trial is now in its third stage clinical trial following findings that showed success at treating CLI patients in the previous two phases. During the three phases of the study a total of 550 severe PAD patients from more than 80 U.S. medical centers were treated.

During the study's second phase, the most recent final data available, 58 patients with CLI from 18 U.S. medical centers had bone marrow removed from their hips between June 2007 and March 2010. It was then sent to a lab where the stem cells were separated from the marrow and incubated for two weeks, which allowed additional stem cells to grow.

The stem cells were then injected into about 20 locations on the patient's affected leg.

An additional 28 CLI patients were randomly assigned to receive traditional treatment, which did not include stem cell injections. The patients were followed for six months.

After six months, investigators found that patients treated with stem cells had a significantly lower incidence of amputation. About half of the patients who did not receive stem cells died, needed an amputation or saw their legs worsen compared to only 25 percent of patients who were injected with stem cells.

Many of the patients that received stem cells also had significantly improved blood flow in the ischemic leg.

"What was truly remarkable was that it was a relatively small number of patients, but that we saw clinically significant improvement in the stem cell-treated patients," Dr. Powell said.

"It's compelling enough that there's no question that the pivotal trial needs to be done as quickly as possible."

During the ongoing third phase of the trial, half of the patients will receive stem cells and patients will be followed for one year after treatment.

The results of the second-stage clinical trial were published in the April issue of journal Molecular Therapy. Results of the phase three trial have not yet been published since it is still underway.

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Review Date: 
May 2, 2012