The Straits Times, 18 Oct 2003
Medical breakthrough: New hope for sufferers of clogged arteries

By: Chang Ai-Lien, Science correspondent

Drug-coated polymer stents developed by Singapore biotech company being tested on humans in Germany and South America

A LOCAL company is breaking new ground with its work on heart stents, by coating them with special drugs to help the patient recover better.

Developed by biotech company Biosensors International, its latest model is being used on humans in clinical trials in Germany and South American.

This move takes the tests a step further as the stents were recently tested on pigs at the National Heart center.

A stent is a tiny metallic tube used to keep open an artery that has been cleared of its fat and cholesterol.

The company's special stents use biodegradable polymer. They reduce the risk of infection since they will disintegrate and be absorbed by the patient's body.

The latest stent, called Matrix, is coated with a drug called Biolimus, which is a type of immuno-suppressants.

Because it is fat-soluble, it could potentially stay in the blood vessel wall longer and work better. This in turn could reduce scarring which would narrow the artery again.

Before the clinical trail at Germany 's Siegberg Heart center, the stents were implanted in arteries in the hearts of pigs, to assess the short- and intermediate-term effects.

This was carried out under general anaesthetic, said Dr Mak Koon Hou, a senior consultant at the National Heart center and its director of clinical trials.

The pigs are doing well and the experiment should be completed next month, said Dr Mak, adding that pigs are ideal for heart studies because their organs are similar to humans.

Initial results in the animals have been promising.

The human study will take about one to two years and, if the results are promising, the new stent could be approved by the European authorities soon afterwards.

Another Biosensors stent that is closer to being marketed is coated with the drug Everolimus, which aims to stop renarrowing of the patients' arteries

This stent, now known as Champion, is being bought over by US-based Guidant Corporation.

It could be sold in Europe and Asia soon.

In Singapore, about 2,000 balloon/stent procedures are done yearly to help patients unblock their arteries.

About one-third of stent patients experience a re-narrowing of the arteries, probably from the build-up of scar tissue.

Drug-coated stents were developed to prevent this problem.

Those such as the Sirolimus stent, made by health-care giant Johnson & Johnson of US, and the Taxus stent, produced by medical device maker Boston Scientific, have been available here since last year.

To help it get ahead in this competitive market, Biosensors said recently it was teaming up with US company X-cell Medical to create a company to develop and sell such stents which administer drugs to the blood vessel.

THE MATRIX

What it does

• The tiny metallic tube is used to keep open an artery that has been cleared of its fat and cholesterol.

How it's special

• Coated with a drug that combines immuno-suppressants with antibiotics.
• Fat-soluble, so it can stay in the tissue longer and work better. This could reduce scarring which would otherwise narrow the artery again.
• Made of biodegradable polymer, so it will disintegrate and be absorbed by the patient's body. This reduces the risk of infection.