Lung cancer patients are usually prescribed either Tarceva (erlotinib) or Iressa (glefitinib). Doctors will probably tell the unfortunate patient that the drugs stop the growth of the cancers by blocking the signaling from a molecule that's vital to the survival of the cancer cells.
What he may not mention is that the drugs are effective in only 10 per cent of patients, especially those with non-small cell lung cancer (NSCLC), which is often contracted by non-smokers. And after a while, they are not effective at all - and, in fact, encourage the growth of the cancer.
Oncologists know that the drugs seem to trigger fresh tumour growth, which is known as acquired or secondary resistance, but researchers are trying to figure out why this phenomenon occurs.
They tracked six NSCLC patients who were given the drugs, and three developed fresh tumours.
They weren't able to establish why the tumours develop such a virulent resistance to the drugs, but were able to confirm that the new mutations contained gene variants that "they had come across before". So that's a relief.