International Stem Cell Corp. has teamed up with North Carolina's prestigious Duke University to test a stem cell therapy for Parkinson's disease.
It aims to replace certain brain cells destroyed in Parkinson's, a neurodegenerative disease characterized by progressive loss of movement. These cells produce dopamine, a neurotransmitter enabling movement. No one knows why the cells are destroyed, and there is no cure.
The Carlsbad-based biotech says it can turn stem cells into new dopamine-making neurons, which doctors can transplant into the brain, restoring normal movement. Its therapy has already been successfully tested in a small trial in rats and African green monkeys.
The company could apply to begin a human trial by the middle of next year if all goes well, said Simon Craw, executive vice president of business development.
Patients might get relief for 10 to 15 years, said Mark Stacy, a Duke University neurologist and Parkinson's disease researcher who heads its clinical trial division. More animal tests will be performed before a human trial is conducted, he said.
There is scientific precedent for the trial from fetal brain cell transplants about 20 years ago, Craw said. Results were mixed. Some patients experienced improvement, while others did not. Craw said researchers have learned from those experiments, and now know how to grow cells of the right type, in the quantity needed.
The stem cell trial is one of two being prepared for Parkinson's by San Diego area scientists. The other comes from the lab of Jeanne Loring of The Scripps Research Institute. Both use stem cells that act like human embryonic stem cells. The teams are familiar with each other's work; they have collaborated on some studies.
Each approach is intended to improve on embryonic stem cells, which can turn into nearly any kind of cell in the body. This extreme plasticity makes them attractive to researchers, who hope to tame them to regenerate lost or damaged body parts, or use them as "disease in a dish" models. But embryos are killed to get them, which many people object to on moral grounds.
ISCO makes its stem cells from unfertilized, or parthenogenetic human egg cells. The egg cells are chemically treated to activate them, causing them to make the parthenogenetic stem cells, Craw said. Its technology steers the cells into becoming dopamine-producing neurons.
The cells will be transplanted in a precursor stage to the mature cell. Experiments have shown that slightly immature cells wire into the brain more effectively than completely mature cells, Stacy said.
Loring’s group starts with skin cells, treating them with chemicals and genes that regress them to the embryoniclike state. These “induced pluripotent stem cells” will be matured to the precursor state and implanted in eight Parkinson’s patients, providing that regulators give approval and the group can raise enough money.
Craw says ISCO’s approach has several advantages over the IPS cell technology. One is that no genes are added to the parthenogenetic cells. The genes used for IPS cells can cause unwanted side effects such as tumors. Moreover, parthenogenetic cells have their origin in a young cell, the egg, while IPS cells come from older cells, which may carry aging-related defects. And generating stem cells from parthenogenetic egg cells has a much higher success rate than that of IPS cells.
IPS cells have their own advantages. It’s far easier to collect skin cells than human eggs cells. Moreover, IPS cells can be produced from the patient to be treated, which Loring’s group proposes to do. This means they carry the same genes as the patient, which in theory virtually eliminates an immune mismatch. ISCO’s cells are produced from unrelated female donors, although the parthenogenetic process reduces any potential immune reaction, Craw said.
Both groups possess strong scientific credentials, having published their work in peer-reviewed journals. But they also share major financial obstacles in raising the millions that will be needed for clinical trials.
Publicly held International Stem Cell Corp. has a market value of less than $20 million, extremely small by the standards of public companies. Craw said the alliance with Duke helps validate ISCO’s approach.
Loring’s scientists and patients have no grants, so they are raising the money themselves. In October, a group of supporters and patients plan to climb to Base Camp at Mount Everest as a fundraising event.