Drug treatment to be revolutionised by new research

A powerful tool for finding the right drug to treat a particular disease has been invented by scientists who believe it could revolutionise the way new medicines are developed.

The researchers have likened the approach to an internet search engine which is able to sift through masses of data to find the best match between the attributes of a drug and the symptoms of a disease.

The approach has been called a "connectivity map" because it directs scientists towards the connections that can link different drugs to various diseases, said Todd Golub, director of the cancer programme at the Broad Institute of the Massachusetts Institute of Technology and Harvard University.

"The connectivity map works much like a Google search to discover connections among drugs and diseases," Dr Golub said.

"These connections are notoriously difficult to find in part because drugs and diseases are characterised in completely different scientific languages," he said.

The idea is based on analysing all the genes in the human genome that could be affected by the actions of a given drug to see how that chemical may act against a certain disease.

Scientists would take a small sample of living cells from a patient with a disease and compare the activity levels of all the genes against those of a healthy person.

Some genes in a diseased cell may become more active while others become less active compared to healthy cells.

This gives scientists a "genomic signature" for each disease.

Such signatures can then be used to search a database of similar genomic signatures generated by each of the 1400 or so drugs approved by the regulatory authorities, said Justin Lamb, the lead author of the study, which is published in the journal Science.

"This is a powerful discovery tool for the scientific community.

By analysing just a small fraction of available drugs, we have already confirmed several biological connections between drugs and human disease, and made entirely new ones too," Dr Lamb said.

Eventually, when the genomic signatures of all approved drugs are entered on the computer database, it will be possible for doctors to search for medicines that could help to treat patients with difficult disorders.

"Its primarily a tool for biomedical researchers. It is not intended to be used in a doctor's surgery," Dr Lamb said.

A pilot project using a preliminary connectivity map has already found a possible drug for treating patients with a drug-resistant form of the blood cancer acute lymphoblastic leukaemia.

Dr Lamb said that these patients do not respond to anti-cancer drugs known as glucocorticoids.

But test on human cells in a test tube shows that they may respond with the help of a known drug called rapamycin.

In a separate study, the connectivity map enabled the scientists to work out how a drug called gedunin, derived from plant extracts, can be used to screen for potential treatments against prostate cancer.

"Although this first version of the connectivity map is limited mainly to drugs, the same concepts could be applied universally across all facets of human biology," said Eric Lander, a member of the research team and director of the Broad Institute.

"Expanding this initial map to encompass all aspects of human biology would provide a valuable public resource for the scientific community," Dr Lander said.

"Such an effort would parallel the sequencing of the human genome, both in its scope and in its potential to accelerate the pace of biomedical research," he said.

- INDEPENDENT