A major trial of one of a new generation of "smart" drugs for cancer is to be launched.
Advanced lung cancer is difficult to treat
Researchers at more than 70 UK centres will test the drug, Tarceva, as a treatment for advanced lung cancer.
The drug, taken as a simple white pill, targets a molecule which plays a key role in the growth and extended lifespan of cancer cells.
The trial is being coordinated by the Cancer Research UK and University College London.
Not only is the trial designed to evaluate the effectiveness of the drug, experts also hope it will provide information on which patients will benefit the most.
The drug cannot cure people with advanced lung cancer - but it is hoped it will boost their life expectancy.
Doctors will aim to recruit 664 patients with advanced non-small cell lung cancer, which accounts for three quarters of cases of the disease.
Lead researcher Dr Siow Ming Lee said: "Conventional chemotherapy is of limited use against advanced lung cancer.
"Tumour cells quickly become resistant to treatment, while chemotherapy doesn't properly distinguish between cancerous cells and healthy ones and has too many side effects for many very ill lung cancer patients to cope with."
Dr Lee said the new approach was rather more subtle. It involves targeting a molecule which is more important for cancer cells than for their healthy counterparts.
The molecule - epidermal growth factor receptor (EGFR) - relays instructions to cells to grow and divide, and to ignore signals telling them to die.
It seems to be particularly important for the growth and survival of some cancer cells and large amounts of the molecule are often present in the cells of non-small cell lung cancers, sometimes in a mutated, over-active form.
After treatment, researchers will analyse patients' tumour and blood samples, to determine whether the type or amount of EGFR affects the way a patient responds to treatment.
This could pave the way for a test to predict which patients are most likely to benefit from the drug.
Tarceva has already produced promising results in a trial on patients with non-small cell lung cancer who had already been heavily treated with chemotherapy.
The new trial will assess the benefits of the drug as a first line treatment on patients considered unsuitable for standard chemotherapy.
Dr Lee said: "Tarceva has minimal side effects and patients should be able to cope with it much better than they would with conventional chemotherapy."
Professor Robert Souhami, of Cancer Research UK, said: "We are seeing important changes in our approach to the treatment of some cancers, with researchers beginning to test out more specific anti-cancer therapies in place of broad-action chemotherapy. "
"The new trial will test out one such selective anti-cancer agent, which we hope will make some headway against a disease which is notoriously difficult to treat.
"By providing a treatment which patients can take at home in simple pill form, it may also make a significant contribution to improving the quality of life of very ill cancer patients."