In a setback for Menlo Park-based Geron, the company announced Tuesday that federal authorities have put on hold its groundbreaking test on people of a spinal-cord injury treatment it developed from human embryonic stem cells.
Officials at Geron, which has yet to give its treatment to humans, were vague about the reason for the hold, saying only that it involved the U.S. Food and Drug Administration’s pending review of new animal study data the company had submitted.
Because human embryonic stem cells can grow into any type of tissue, one major concern about injecting them into people is that the cells might produce tumors. Consequently, before Geron could get FDA permission for the human study, it first had to extensively test the treatment on other animals.
Geron officials previously have said that none of those 24 animal studies turned up any safety issues. In announcing the FDA’s action Tuesday, company spokeswoman Anna Krassowska declined to comment on the reason for the hold and whether the latest animal data had raised safety concerns, calling the data confidential. She also declined to speculate on how long the FDA might hold up the study.
A prepared statement issued by the company said, “Geron will work closely with the FDA to facilitate their review of the new data and to release the clinical hold.”
The FDA also declined to comment.
Geron’s stock price fell 74 cents — more than 10 percent —
to $6.49 at the close of trading after the company disclosed the FDA’s action.
When Geron announced in January that it had won FDA permission to study the treatment in people suffering debilitating spinal injuries, it was a major victory for the biotechnology company and advocates of research with the cells, which are controversial because they are derived from discarded human embryos.
Geron had worked for 13 years and spent more than $150 million developing the medication. For its application requesting FDA approval to start the study, the company submitted 21,000 pages of data — far more than normal for such requests.
Geron’s revolutionary spinal treatment, which it began researching in 1995 with investors’ funding, has sparked the hopes of many people suffering from spinal injuries because the company has reported that the treatment helped paralyzed rats walk.
When a spine is damaged, myelin — a fatty substance that provides insulation — often is stripped off. That can disrupt the body’s ability to transmit sensory signals, similar to the way an electrical cord shorts out when its insulation is peeled away, resulting in paralysis. Geron coaxed embryonic cells into becoming oligodendrocytes, cells that help nerve fibers replace myelin.
Because scar tissue can form on damaged spines over time, making it hard to regenerate myelin, Geron plans to treat patients whose injuries are no older than two weeks.
Geron, which was incorporated in 1990, has no products on the market. In addition to its stem-cell spinal treatment, it is developing therapeutic agents for a variety of ailments, including cancer, heart failure and diabetes.
Contact Steve Johnson at 408-920-5043.
WHY GERON”S PROPOSED STUDY IS UNIQUE
The company plans to conduct the world”s first test on people of a treatment made from human embryonic stem cells, which are controversial because they are derived from discarded embryos.
PATIENTS TARGETED FOR THE STUDY
People who recently have suffered severe spinal injuries. The treatment is designed to help the patients regrow a spinal insulating material, called myelin. That material often gets stripped away during injuries, disrupting the body”s ability to transmit sensory signals and resulting in paralysis.
WHAT THE STUDY IS DESIGNED TO LEARN
It is primarily to determine if the treatment is safe for humans. Geron also hopes the study indicates whether the treatment improves neuromuscular control and sensation. Later studies in people would be needed to fully assess the treatment”s effectiveness in alleviating spinal damage.