Revolution heralded in treating the 'incurable': Gene therapy signals way forward

INCURABLE cancers, heart disease and arthritis have become the focus for a revolutionary treatment that involves 'stitching' genetic material into patients.

Next month, Britain's ethics committee on gene therapy will consider the first proposal in the United Kingdom to treat cancer with a genetic vaccine - the first of many to tackle fatal and not necessarily inherited diseases using the new genetic technology.

'We are about to witness a revolution in our ability to tackle certain life-threatening illnesses,' Professor Karol Sikora, a cancer expert with the Royal Postgraduate Medical School at Hammersmith Hospital, London, said. 'By the end of the decade, some form of gene therapy will be routinely available in hospitals throughout the world.'

Medical researchers at the Institute of Cancer Research at the Royal Marsden Hospital in London are preparing for the first clinical trial of gene therapy on UK cancer patients, which is scheduled for this summer, if approved by the government's Gene Therapy Advisory Committee.

They will take tumour cells from about a dozen volunteers suffering from malignant melanoma - the most lethal kind of skin cancer - and infect them with a genetically engineered virus to create a vaccine that should stimulate the patient's own immune system to attack the tumour.

The vaccine will consist of inactivated tumour cells containing a gene for interleukin-2, a natural substance in the body that triggers killer cells in the blood to attack invading microbes. On this occasion, the scientists hope the killer cells will destroy the tumour.

Professor Sikora said that there were so many proposals in gene therapy poised for clinical trials it had been necessary to launch a new scientific journal, Gene Therapy, specifically designed to keep researchers in touch with new developments.

It was only four years since doctors inserted the first functional gene into a patient suffering from a rare inherited disorder, he said. Now, more than 50 proposals were being considered by ethics committees or undergoing trials.

Among the incurable diseases being considered for gene therapy are:

Arthritis. Work has begun to insert genes into the tissues forming the membrane around arthritic joints. The genes will cause the release of natural substances that block the action of cytokines - chemical messengers that are secreted in inappropriately large amounts in patients with arthritis.

Aids. Researchers hope to introduce 'decoy' genes into the body's white blood cells, which are the targets of infection by HIV. The decoys will signal the virus to replicate but will prevent it from completing the task, so hopefully rendering it harmless.

Heart disease. Genes that help to unclog furred-up arteries in heart patients could be inserted into blood vessels as they are being cleaned out following a heart attack. Scientists hope this will help prevent further attacks as the arteries slowly release natural 'clot-busting' drugs.

Professor Sikora said one of the greatest problems with gene therapy is being able to stitch enough genes into the right place for the treatment to work. The Human Genome Project, which aims to map the precise position and chemical structure of the estimated 100,000 genes in the human genetic blueprint, will help to achieve this, he said.

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