Regulators on Friday gave the all-clear to a clinical trial that will test embryonic stem cells as a treatment for spinal cord injury, potentially the first time embryonic stem cells are tested on humans.
The developer of the treatment, Geron Corp., said the Food and Drug Administration removed a clinical hold on its GRNOPC1 therapy. The FDA accepted Geron's study application in January 2009, which gave the company clearance to test GRNOPC1 on humans. But the FDA placed any potential study on hold in August because some mice treated with GRNOPC1 developed microscopic spinal cysts.
Geron hopes to start testing GRNOPC1 on humans by year-end. The company plans to enroll eight to 10 patients in the study at sites nationwide. The trial will take about two years, with each patient being studied for one year. Early-stage clinical trials are primarily designed to test a therapy's safety, although Geron said it will also measure the effectiveness of GRNOPC1.
A successful test would lead to larger and longer studies that would focus on the effectiveness of GRNOPC1. The company plans to continue monitoring patients for a total of 15 years for safety.
In afternoon trading, Geron shares jumped 74 cents, or 15.4 percent, to $5.54.
Geron said many spinal cord injury patients develop much bigger cysts in spinal cord tissue. It also said it had found a new way to test GRNOPC1 and did not see any cysts in a separate animal study.
GRNOPC1 contains cells called oligodendrocyte progenitor cells. Those progenitor cells turn into oligodendrocytes, a type of cell that produces myelin, a coating that allows impulses to move along nerves. When those cells are lost due to injury, paralysis can follow. If GRNOPC1 works, the progenitor cells will produce new oligodendrocytes in the injured area of the patient's spine, potentially allowing for new movement.
The therapy will be injected into the patient's spine one to two weeks after the patients suffer an injury between their third and tenth thoracic vertebrae, or roughly the middle to upper back. Later trials would include patients with less severe spinal injuries and damage to other parts of the spine.
Geron, based in Menlo Park, Calif., is not the only company that hopes to start a trial of a stem cell therapy soon. Advanced Cell Technology Inc. is also seeking FDA clearance for an embryonic stem cell therapy called retinal pigment epithelium, or RPE. RPE is designed to treat Stargart disease, an inherited condition that affects children and can lead to blindness in adulthood.
Advanced Cell Technology filed an application with the FDA in November. After the agency asked it for additional information, the company submitted its application last week. Advanced Cell Technology expects a response from the FDA within 30 days.
