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[IP] Weizmann scientists develop first diabetes vaccine


Weizmann scientists develop first diabetes vaccine

By Judy Siegel November, 23 2001


REHOVOT (November 23) - Scientists at the Weizmann Institute in Rehovot have 
developed the first successful vaccine for Type I diabetes.

The vaccine blocks the immune system's destruction of pancreatic beta cells 
in humans.

The drug, DiaPep277, offers the possibility both of preventing the onset of 
the disease in those with a genetic risk and of halting its progression in 
those whose cells have already begun to die.

With Phase II trials on DiaPep 277 successfully completed, Phase III trials 
are to begin in various centers around the world next year. Peptor Ltd. - 
the Rehovot biopharmaceutical company that purchased the rights - is 
planning to present an application to the US Food and Drug Administration in 

A team of researchers, led by Weizmann's Irun Cohen, has worked more than 10 
years on a small peptide fragment known as p277, despite skepticism among 
others in the field about its possible efficacy.

Results on a mouse model were dramatic, and the team proceeded to show its 
efficacy on patients, 200 of whom have been treated successfully so far here 
and in England, Hungary, Bulgaria, and Germany. Based on the results of 
their research, Peptor developed DiaPep 277.

Cohen, Dr. Dana Elias (then a postdoctoral fellow at Weizmann and now vice 
president for research and development at Peptor), and colleagues will 
report on the clinical study performed at Hadassah-University Hospital in 
Jerusalem's Ein Kerem by Itamar Raz, president of the Israel Diabetes 
Association and head of the hospital's diabetes unit, in tomorrow's issue of 
the British journal The Lancet.

The researchers proved three injections in six months of DiaPep277 were 
successful in arresting the progression of Type l diabetes in newly 
diagnosed patients - without displaying any harmful or significant side 
effects and without participants leaving the study.

Recent data show 120 million-140 million people suffer from one of the two 
types of diabetes.

Type I (insulin-dependent) usually results from an autoimmune disorder in 
which the immune system mistakenly attacks the body's insulin-producing 
pancreatic cells, reducing and ultimately stopping all insulin production. 
Sufferers need to test their blood sugar levels and inject insulin several 
times daily.

Type II is a metabolic disorder resulting from the body's inability to 
properly use insulin. Patients with the more severe cases of Type II 
diabetes must supplement their natural insulin production with insulin 

The Phase II study was of 35 male patients 16-55 who were newly diagnosed 
with Type I. Eighteen received injections of DiaPep277 at the beginning of 
the study, at one month, and at six months; 17 received three injections of 
a placebo. Those who received DiaPep277 showed a halt or delay in the attack 
upon, or destruction of, their beta cells when examined at a follow-up 10 
months after the first injection. These results were evident in the level of 
the body's own insulin production and thus a decreased need for insulin 
injections. The researchers were able to trace the mechanism of this 
improvement to changes in the patients' immune lymphocytes, called T-cells. 
Those receiving the placebo showed a significant decline in their natural 
insulin production and a persistent rise in the need for insulin injections.

"The older you are, the slower the progression of beta-cell destruction," 
Cohen said

In children, the destruction of pancreatic cells is very rapid, taking place 
even in a few months, Raz said. People at genetic risk for the disease who 
are exposed to a specific virus, toxic material, or food are likely to 
develop Type I diabetes. Phase II trials on children seven to 16 showed an 
improvement, but it was not statistically significant.

Younger children are now being tested using this strategy, Elias said.

For the past several years, Cohen and his team have been studying the 
mechanism by which the immune system destroys the insulin-producing 
pancreatic cells. Working with mice, they discovered a particular protein is 
closely linked to this destructive process. It acts like an antigen, 
prompting the immune cells to attack. Further investigation revealed 
injecting diabetic mice with p277 - a small peptide fragment of the protein 
- shut down the immune response, preventing the progression of Type I 

The peptide essentially acts to "re-educate" the immune cells, switching off 
their destructive activity, Cohen said.

The idea for using p277 stemmed from the discovery the immune system has 
different options to choose from in responding to an antigen. It can act to 
destroy the antigen or protect it from destruction. In this case, it 
indirectly prevents the pancreatic cells from being destroyed.

About 15 agents have been found to halt destruction of beta cells in mice, 
but none of them worked in humans, Raz said.

"No one believed it would work in people," he said.

Peptor, which was established in 1993, now has 51 employees here and in 
Germany. It will soon start preliminary testing on two other peptides, 
including one for kidney damage due to diabetes.

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