Diacrin's experimental treatment for stroke victims Maribeth Cook
and Amanda Davis was an initial Phase 1 trial, in essence, a safety trial.
There are two more phases to go.
Of the five patients involved in this Phase 1 trial, four appeared to have
improved. One patient did not improve, and Amanda was one of two patients who had seizures.
Diacrin and the FDA called an immediate halt to the trial after Amanda's
seizure. Further trials cannot proceed until the FDA finds out what caused
the seizure and whether it had anything to do with the pig neural cell
Jim Finn was part of Diacrin/Genzyme's Phase 1 safety trial. Twelve
patients participated in this phase which was "open label," meaning everyone
receives the treatment and the patients and doctors all know they got the
treatment. The twelve were divided into two groups of six. One group was given
cyclosporine to suppress their immune systems. In order to suppress their immune response, the other group was treated with a proprietory
technology Diacrin has licensed from
Massachusetts General. The technology coats the cells prior to transplantation
with an antibody to protect against a molecule on the surface of the cell that
tends to trigger the immune response. This Phase 1 trial showed indications of
efficacy and no safety problems.
Eighteen patients with severe Parkinson's disease participated in Phase 2 clinical
trials at three U.S. medical centers. Nine were injected with pig cells and nine were not.
The FDA mandated the trial be "double-blinded" with surgical control so neither Diacrin nor the patients knew which ones were treated with
the pig cells. The
treated patients went into the operating room, a hole was drilled in their skulls
and the cells were injected with a long needle that is targeted by using MRI and
The nine patients in the control group, who didn't get the cells, went into
the operating room for six hours under a general anesthesia, had the skin
opened and had a divit put on the skull. The idea is when the patient woke up
from anesthesia they would feel they had surgery and they could feel the dent
in their head.
The only people that knew whether these patients got cells were the OR staff;
the OR windows were covered. The patients were rated by a neurologist who had
no idea who got the cells. The cells used were from a non-transgenic, but
Diacrin/Genzyme announced on March 16, 2001 that preliminary data indicates
that 18 months after the procedure was done, both the treated and the control
group seemed to improve, indicating a strong placebo effect.
Diacrin/Genzyme has postponed Phase 3 trials for Parkinson's patients until
further studies are done on the Phase 2 data. The company hopes to report on
this in July 2001.
If these proceed, they will be a "confirmatory trials." 32 new patients will be
divided into two groups. One group will get the pig cell treatment and the other will receive more
traditional medical care. All the patients will be monitored using the same measurement
scales and the progress between those who get the cells and those who get the
medical care will be compared. Patients and doctors will know who got the
cells and who didn't.
Diacrin's treatment of epilepsy and Huntington's disease using pig cells are
in Phase 1 trials using 6-12 patients with the disease, depending on the
In Phase 1 clinical trials during the late 1990s, approximately six patients
facing acute liver failure were hooked up to a pig liver outside their body
which filtered their blood while the patient waited for a human liver
transplant. Robert Pennington was one of the people who had his life
saved by this procedure. The pig liver used in his case came from a transgenic pig
developed by Nextran.
Nextran has no plans to further develop this procedure. Essentially, the
clinical trial was designed to see how the pig liver would perform pumping
human blood through it, thus indicating how it would work if it were
transplanted into a human.
Nextran says it is interested in filing for Phase 1 trials that would involve
transplanting kidneys and hearts into humans. Kidney and hearts are less
complicated than the liver in terms of the functions they have to perform.
Here's a summary of human clinical trials and studies on
xenotransplantation done in both Europe and the U.S. , prepared by the Council
of Europe. It includes statistics and a general summary on what has been
shown in clinical trials done in the 1990s. A large majority of these trials
involved pig neural cell transplants.
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