Unleashing the Promise - Pharmaceutical Executive


Unleashing the Promise
An up-close look at some companies that may soon bring stem cell-based therapies to market.

Pharmaceutical Executive

MacroPore BioSurgery The stem cell-based research efforts of MacroPore BioSurgery, a San Diego-based life science company that discovers and develops regenerative medicines that depend on fat. The company has two platforms, regenerative cell technology and bioresorbable polymer implants for orthopedics and spinal applications (distributed through Medtronic Sofamor Danek). MacroPore's development efforts are aimed at harnessing the potential of adipose derived adult stem cells (ADCs) to develop applications for heart disease, bone and disc regeneration, and fat tissue for cosmetic and reconstructive purposes.

Cell quantity "There is a fundamental difference in our approach," says CEO Chris Calhoun. "It all comes down to the amount of available cells. Stem cells are very rare and the older we get the rarer they become. So we need to isolate them and regenerate them. Cell culturing is hard on cells and bad for cells. The FDA is working on how to regulate cell cultures. So, for example, if you extract one hundred cubic centimeters [ccs] of bone marrow, you get about five thousand stem cells. But in adipose tissue there is a substantial reservoir of stem cells. In one hundred ccs of ADC we get about five hundred thousand stem cells. We avoid all the culturing, while saving money and time. We can provide a significant number of ADCs in real-time."

Cell cocktail Adipose-derived cells are really an agglomeration of various cell types, including stem cells, angiogenic cells (cells that promote blood vessel growth), and cells useful for combating apoptosis (programmed cell death). Calhoun suggests that this cell cocktail could benefit patients who have heart attacks. After the fat is separated from the stem cells using MacoPore's proprietary filtration system, the leftover cells would function as cardiomyocytes (heart muscle cells), which do not normally regenerate in adults, and also promote angiogenesis as a way to promote blood flow to the region. Normally when heart muscle is damaged during a heart attack, the functional heart muscle is replaced with nonfunctional scar tissue, and even if the patient recovers, heart functionality and overall well-being decrease.

Healing from a heart attack Statistics indicate that 1.2 million people had heart attacks in 2004. Based on the MacroPore model, individuals who have heart attacks could potentially benefit from a process called Cellect, which Calhoun says, "fits into the current clinical paradigm." Traditionally, when a patient comes to the emergency room after having a heart attack, the patient is catheterized to undergo a dye injection process so the doctors can find the blockages. Then the patient is stented and de-catheterized. Calhoun suggests that Cellect can help the patient heal better.

"During the catheterization process, we would take one to two hundred ccs of fat and filter it through the MacroPore system," he says. "Then we would inject the cell cocktail right into the catheter, allowing the healing cells to migrate to the defect site. Animal studies in pigs provide evidence that when you can regenerate the heart cells immediately, healing is permanent. After damage to the heart, there is a race between regeneration and scarring. Heart attacks begin the process of degenerative heart disease. We want to stop it at the source and salvage the muscle."

So far, all of the early efficacy, safety, and tolerability data are positive. In fact, this model was validated in a recent study using bone marrow-derived stem cells. In a double-blind study (BOOST) published in the Lancet in 2004, 60 patients who had been treated for heart attacks were randomized to standard-of-care treatment or injected with bone marrow-derived stem and progenitor cells. After six months, patients who received stem and progenitor cells had significantly better heart function than the standard-treatment patients.

Financial status Calhoun characterizes MacroPore's intellectual property portfolio as "very aggressive." The company derives income from its bioresorbable spine and orthopedic devices as well as its complementary bioresorbable thin-film products. Its products and relationships in this niche are so strong that the company has been able to shore up cash reserves through strategic sales of non-core assets. As of March 2004, MacroPore had $15.13 million in cash. In May 2004, it announced the sale of part of its bioresorbable thin-film product line for a $7 million payment in 2004, followed by a $2 million payment in 2005.


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