DDW: Stem Cells Can Cure Perianal Fistulas

WASHINGTON, May 22 -- Stem cells derived from a patient's own fat can cure a perianal fistula, a Spanish researcher said here.

In a phase II clinical trial, patients treated with a combination of fibrin glue and stem cells derived from their own adipose tissue saw their fistulas cured 71% of the time, according to Damian Garca-Olmo, Ph.D., of La Paz Hospital in Madrid.

In contrast, patients treated with fibrin glue alone -- a standard therapy -- were cured 16% of the time, Dr. Garca-Olmo said during Digestive Disease Week sessions.

"We defined a cure as complete rehabilitation" of the region of the fistula, both internally and externally, he said.

Perianal fistulas are a common problem in Crohn's disease, he said, although they occur in other conditions as well. For this study, the researchers enrolled 49 patients with fistulas from either cryptoglandular or Crohn's disease.

Those in the stem cell arm had fat extracted with liposuction and stem cells were grown up in the lab for re-injection three months later.

The researchers injected 20 million cells, plus fibrin glue, into the internal opening of the fistula. Control patients were treated with fibrin glue alone.

At eight weeks, if the fistula was not healed, controls were given a second dose of fibrin glue, while those in the treatment arm got another 40 million cells plus glue, Dr. Garca-Olmo said.

The stem cell treatment was effective in both Crohn's and non-Crohn's patients, he said, and the difference from the control arm was significant at P=0.0001.

The main problem in healing fistulas is the internal opening, Dr. Garca-Olmo said, which is exposed to the contents of the bowel, with a resulting low quality of life for the patient.

"We need a new treatment for these patients, because we have a low rate of healing and high rate of recurrence," he said.

There are "two reasons why this is special," said Maria Abreu, M.D., of Mount Sinai in New York, who moderated the press conference during which the Spanish study was discussed.

"One is the morbidity of fistulas and how conventional medicine has not been effective and surgery can leave a defect in the anus that leaves a person incontinent," said Dr. Abreu, who was not involved in the research.

"And the second is that it uses stem cells."

"The glue alone is only slightly better than doing nothing at all," she said. "What is not clear is whether you need the stem cells plus the glue to get this great effect."

She noted that the study is only a phase II, but added that Dr. Garca-Olmo and colleagues used an endpoint -- complete response -- that is "a very high bar to meet."

In the field, a partial response is defined as having less than half of a patient's fistulas draining to the outside and a complete response is defined no drainage from any fistula, she said.