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One of the diabetics given a trial transplant of New Zealand pig cells has been able to stop her insulin injections, far exceeding the researchers' expectations.
Stopping the injections was the ultimate aim of the pig-cell transplants into people with type 1 diabetes. But it was not expected to result from the comparatively small doses given at the start of the clinical trial in Russia.
"These early-stage results have exceeded our expectations, with one patient no longer dependent on insulin therapy following the smallest dose of DiabeCell [the processed cells]," said Professor Bob Elliott, the Auckland scientist who pioneered the therapy.
It involves transplanting more than a billion insulin-producing cells from the pancreases of piglets into the abdominal cavity of a type 1 diabetes patient.
Clusters of the cells are encapsulated in a seaweed-based gel. This protects them from the human immune system, yet allows them to release insulin in response to the person's fluctuating blood-glucose level, freeing patients from endless blood testing and insulin injections.
The 40-year-old Russian woman received her first transplant of DiabeCell last month. The amount of insulin she needed to inject each day gradually reduced and by a month after the implant, she needed none.
She was the second patient treated. The first, a 26-year-old, had his first dose in June. His insulin requirement has reduced by 39 per cent. Each will have a second dose of the therapy.
The company which produces the therapy, Living Cell Technologies, has approval from regulatory agencies for a clinical trial at Middlemore Hospital in South Auckland, but is still awaiting Health Minister Pete Hodgson's consent.
Living Cell's chief executive, Paul Tan, said both Russian patients were treated with the same number of cell clusters per kilogram of body weight.
It was too soon to be certain, he said, but the differences in the patients' present injected insulin needs might be related to the amounts they needed daily before the trial. The first patient treated had required much more than the second.
In the trial at the Sklifasovsky Institute in Moscow, each of six patients is scheduled to receive two transplants of the smallest dose, which is one-third of the maximum dose planned for the New Zealand study.
Dr Tan said enrolment for the New Zealand trial could still start this year if approval was granted this week.
The company's trials follow one in Auckland using an earlier version of the therapy. That trial was halted in 1996 over concerns that transplants from pigs could infect humans with pig retroviruses.
