Pluristem stem cell treatment shows early promise

Tue Apr 27, 2010 6:30am EDT

* No serious adverse events among 21 patients tested

* 6 of 12 patients improved in 2 of 3 efficacy measures

* CEO says expects to start Phase II in Q3 2011

By Bill Berkrot

NEW YORK, April 27 (Reuters) - Pluristem Therapeutics Inc (PSTI.O) said on Tuesday its experimental stem cell treatment appeared to be safe and showed promise in treating a serious arterial blood flow condition called critical limb ischemia, according to interim data from a tiny Phase I study.

The treatment, PLX-PAD, met the primary safety goal of the 21-patient study with no serious adverse events reported, the company said.

In addition, the injected cells did not trigger an immune, or rejection, response in any of the tested patients, demonstrating that PLX-PAD is well tolerated, the Israel-based company said.

Pluristem said it was encouraged enough by the results that it will move into larger Phase II studies of PLX-PAD for critical limb ischemia -- the final stage of peripheral artery disease that often leads to amputations. It expects to be able to begin Phase II testing by the third quarter of 2011.

While this was a safety study, 12 of the patients had completed a three month follow-up at the time of the interim analysis and were available to measure the potential efficacy of the treatment, which is derived from placental stem cells taken from the maternal, rather than fetal, end of the placenta.

Measurements of blood flow in the ankle and toe and of oxygen below the skin were used to determine efficacy, with 6 of the 12 patients showing improvement in two -- 4 of them in all three -- of the measures.

Ten of the 12 patients also reported improvements in quality of life, such as diminished pain and improvements in walking ability, the company said.

"We did not expect to see any real or significant efficacy results and we have seen the results," Pluristem Chief Executive Zami Aberman said in a telephone interview.

Stem cells are a hot area of medical research because they are believed to be able to transform into many other types of cells that could one day help treat a wide variety of injuries and illnesses.

By using placental cells, Pluristem will likely avoid the controversy over embryonic stem cells, which are vehemently opposed by some religious and anti-abortion groups.

The cells are harvested from the placenta and purified and treated using Pluristem's unique culture technology, Aberman explained. They are then given to the patient via 30 to 50 localized intramuscular injections in the leg, rather than by an infusion process used in many stem cell treatments under development.

Critical limb ischemia (CLI) can cause terrible pain, difficulty walking, wounds that will not heal and gangrene.

"We believe if you inject them (with PLX-PAD) at an early stage we can eliminate the need for amputations," Aberman said.

While the company plans to concentrate initially on PLX-PAD as a treatment for CLI, it believes PLX-PAD has the potential to treat a variety of conditions, such as nerve pain, ischemic stroke, inflammatory bowel diseases and wound healing.

"When we look at the initial data ... this gives us a lot of hope that we've chosen the right way to become a leader in the space," Aberman said.

(Reporting by Bill Berkrot; Editing by Phil Berlowitz)